Public Variables and Functions
&
special syntax
Syntax for use with fn.
Please see https://clojure.org/reference/special_forms#fn
Added in Clojure version 1.0
*
function
Usage: (*)
(* x)
(* x y)
(* x y & more)
Returns the product of nums. (*) returns 1. Does not auto-promote
longs, will throw on overflow. See also: *'
Added in Clojure version 1.2
Source
*'
function
Usage: (*')
(*' x)
(*' x y)
(*' x y & more)
Returns the product of nums. (*') returns 1. Supports arbitrary precision.
See also: *
Added in Clojure version 1.0
Source
*1
dynamic var
bound in a repl thread to the most recent value printed
Added in Clojure version 1.0
Source
*2
dynamic var
bound in a repl thread to the second most recent value printed
Added in Clojure version 1.0
Source
*3
dynamic var
bound in a repl thread to the third most recent value printed
Added in Clojure version 1.0
Source
*agent*
var
The agent currently running an action on this thread, else nil
Added in Clojure version 1.0
*assert*
var
When set to logical false, 'assert' will omit assertion checks in
compiled code. Defaults to true.
Added in Clojure version 1.0
*clojure-version*
dynamic var
The version info for Clojure core, as a map containing :major :minor
:incremental and :qualifier keys. Feature releases may increment
:minor and/or :major, bugfix releases will increment :incremental.
Possible values of :qualifier include "GA", "SNAPSHOT", "RC-x" "BETA-x"
Added in Clojure version 1.0
Source
*command-line-args*
var
A sequence of the supplied command line arguments, or nil if
none were supplied
Added in Clojure version 1.0
*compile-files*
var
Set to true when compiling files, false otherwise.
Added in Clojure version 1.0
*compile-path*
var
Specifies the directory where 'compile' will write out .class
files. This directory must be in the classpath for 'compile' to
work.
Defaults to "classes"
Added in Clojure version 1.0
*compiler-options*
var
A map of keys to options.
Note, when binding dynamically make sure to merge with previous value.
Supported options:
:elide-meta - a collection of metadata keys to elide during compilation.
:disable-locals-clearing - set to true to disable clearing, useful for using a debugger
:direct-linking - set to true to use direct static invocation of functions, rather than vars
Note that call sites compiled with direct linking will not be affected by var redefinition.
Use ^:redef (or ^:dynamic) on a var to prevent direct linking and allow redefinition.
See https://clojure.org/reference/compilation for more information.
Added in Clojure version 1.4
*data-readers*
dynamic var
Map from reader tag symbols to data reader Vars.
When Clojure starts, it searches for files named 'data_readers.clj'
and 'data_readers.cljc' at the root of the classpath. Each such file
must contain a literal map of symbols, like this:
{foo/bar my.project.foo/bar
foo/baz my.project/baz}
The first symbol in each pair is a tag that will be recognized by
the Clojure reader. The second symbol in the pair is the
fully-qualified name of a Var which will be invoked by the reader to
parse the form following the tag. For example, given the
data_readers.clj file above, the Clojure reader would parse this
form:
#foo/bar [1 2 3]
by invoking the Var #'my.project.foo/bar on the vector [1 2 3]. The
data reader function is invoked on the form AFTER it has been read
as a normal Clojure data structure by the reader.
Reader tags without namespace qualifiers are reserved for
Clojure. Default reader tags are defined in
clojure.core/default-data-readers but may be overridden in
data_readers.clj, data_readers.cljc, or by rebinding this Var.
Added in Clojure version 1.4
Source
*default-data-reader-fn*
dynamic var
When no data reader is found for a tag and *default-data-reader-fn*
is non-nil, it will be called with two arguments,
the tag and the value. If *default-data-reader-fn* is nil (the
default), an exception will be thrown for the unknown tag.
Added in Clojure version 1.5
Source
*e
dynamic var
bound in a repl thread to the most recent exception caught by the repl
Added in Clojure version 1.0
Source
*err*
var
A java.io.Writer object representing standard error for print operations.
Defaults to System/err, wrapped in a PrintWriter
Added in Clojure version 1.0
*file*
var
The path of the file being evaluated, as a String.
When there is no file, e.g. in the REPL, the value is not defined.
Added in Clojure version 1.0
*flush-on-newline*
var
When set to true, output will be flushed whenever a newline is printed.
Defaults to true.
Added in Clojure version 1.0
*in*
var
A java.io.Reader object representing standard input for read operations.
Defaults to System/in, wrapped in a LineNumberingPushbackReader
Added in Clojure version 1.0
*ns*
var
A clojure.lang.Namespace object representing the current namespace.
Added in Clojure version 1.0
*out*
var
A java.io.Writer object representing standard output for print operations.
Defaults to System/out, wrapped in an OutputStreamWriter
Added in Clojure version 1.0
*print-dup*
var
When set to logical true, objects will be printed in a way that preserves
their type when read in later.
Defaults to false.
Added in Clojure version 1.0
*print-length*
dynamic var
*print-length* controls how many items of each collection the
printer will print. If it is bound to logical false, there is no
limit. Otherwise, it must be bound to an integer indicating the maximum
number of items of each collection to print. If a collection contains
more items, the printer will print items up to the limit followed by
'...' to represent the remaining items. The root binding is nil
indicating no limit.
Added in Clojure version 1.0
Source
*print-level*
dynamic var
*print-level* controls how many levels deep the printer will
print nested objects. If it is bound to logical false, there is no
limit. Otherwise, it must be bound to an integer indicating the maximum
level to print. Each argument to print is at level 0; if an argument is a
collection, its items are at level 1; and so on. If an object is a
collection and is at a level greater than or equal to the value bound to
*print-level*, the printer prints '#' to represent it. The root binding
is nil indicating no limit.
Added in Clojure version 1.0
Source
var
If set to logical true, when printing an object, its metadata will also
be printed in a form that can be read back by the reader.
Defaults to false.
Added in Clojure version 1.0
*print-namespace-maps*
dynamic var
*print-namespace-maps* controls whether the printer will print
namespace map literal syntax. It defaults to false, but the REPL binds
to true.
Added in Clojure version 1.9
Source
*print-readably*
var
When set to logical false, strings and characters will be printed with
non-alphanumeric characters converted to the appropriate escape sequences.
Defaults to true
Added in Clojure version 1.0
*read-eval*
var
Defaults to true (or value specified by system property, see below)
***This setting implies that the full power of the reader is in play,
including syntax that can cause code to execute. It should never be
used with untrusted sources. See also: clojure.edn/read.***
When set to logical false in the thread-local binding,
the eval reader (#=) and record/type literal syntax are disabled in read/load.
Example (will fail): (binding [*read-eval* false] (read-string "#=(* 2 21)"))
The default binding can be controlled by the system property
'clojure.read.eval' System properties can be set on the command line
like this:
java -Dclojure.read.eval=false ...
The system property can also be set to 'unknown' via
-Dclojure.read.eval=unknown, in which case the default binding
is :unknown and all reads will fail in contexts where *read-eval*
has not been explicitly bound to either true or false. This setting
can be a useful diagnostic tool to ensure that all of your reads
occur in considered contexts. You can also accomplish this in a
particular scope by binding *read-eval* to :unknown
Added in Clojure version 1.0
*repl*
dynamic var
Bound to true in a repl thread
Added in Clojure version 1.12
Source
*unchecked-math*
var
While bound to true, compilations of +, -, *, inc, dec and the
coercions will be done without overflow checks. While bound
to :warn-on-boxed, same behavior as true, and a warning is emitted
when compilation uses boxed math. Default: false.
Added in Clojure version 1.3
*warn-on-reflection*
var
When set to true, the compiler will emit warnings when reflection is
needed to resolve Java method calls or field accesses.
Defaults to false.
Added in Clojure version 1.0
+
function
Usage: (+)
(+ x)
(+ x y)
(+ x y & more)
Returns the sum of nums. (+) returns 0. Does not auto-promote
longs, will throw on overflow. See also: +'
Added in Clojure version 1.2
Source
+'
function
Usage: (+')
(+' x)
(+' x y)
(+' x y & more)
Returns the sum of nums. (+') returns 0. Supports arbitrary precision.
See also: +
Added in Clojure version 1.0
Source
-
function
Usage: (- x)
(- x y)
(- x y & more)
If no ys are supplied, returns the negation of x, else subtracts
the ys from x and returns the result. Does not auto-promote
longs, will throw on overflow. See also: -'
Added in Clojure version 1.2
Source
-'
function
Usage: (-' x)
(-' x y)
(-' x y & more)
If no ys are supplied, returns the negation of x, else subtracts
the ys from x and returns the result. Supports arbitrary precision.
See also: -
Added in Clojure version 1.0
Source
->
macro
Usage: (-> x & forms)
Threads the expr through the forms. Inserts x as the
second item in the first form, making a list of it if it is not a
list already. If there are more forms, inserts the first form as the
second item in second form, etc.
Added in Clojure version 1.0
Source
->>
macro
Usage: (->> x & forms)
Threads the expr through the forms. Inserts x as the
last item in the first form, making a list of it if it is not a
list already. If there are more forms, inserts the first form as the
last item in second form, etc.
Added in Clojure version 1.1
Source
->ArrayChunk
function
Usage: (->ArrayChunk am arr off end)
Positional factory function for class clojure.core.ArrayChunk.
Source
->Eduction
function
Usage: (->Eduction xform coll)
Positional factory function for class clojure.core.Eduction.
Source
->Vec
function
Usage: (->Vec am cnt shift root tail _meta)
Positional factory function for class clojure.core.Vec.
Source
->VecNode
function
Usage: (->VecNode edit arr)
Positional factory function for class clojure.core.VecNode.
Source
->VecSeq
function
Usage: (->VecSeq am vec anode i offset _meta)
Positional factory function for class clojure.core.VecSeq.
Source
.
special form
Usage: (.instanceMember instance args*)
(.instanceMember Classname args*)
(Classname/staticMethod args*)
Classname/staticField
The instance member form works for both fields and methods.
They all expand into calls to the dot operator at macroexpansion time.
Please see https://clojure.org/java_interop#dot
Added in Clojure version 1.0
..
macro
Usage: (.. x form)
(.. x form & more)
form => fieldName-symbol or (instanceMethodName-symbol args*)
Expands into a member access (.) of the first member on the first
argument, followed by the next member on the result, etc. For
instance:
(.. System (getProperties) (get "os.name"))
expands to:
(. (. System (getProperties)) (get "os.name"))
but is easier to write, read, and understand.
Added in Clojure version 1.0
Source
/
function
Usage: (/ x)
(/ x y)
(/ x y & more)
If no denominators are supplied, returns 1/numerator,
else returns numerator divided by all of the denominators.
Added in Clojure version 1.0
Source
<
function
Usage: (< x)
(< x y)
(< x y & more)
Returns non-nil if nums are in monotonically increasing order,
otherwise false.
Added in Clojure version 1.0
Source
<=
function
Usage: (<= x)
(<= x y)
(<= x y & more)
Returns non-nil if nums are in monotonically non-decreasing order,
otherwise false.
Added in Clojure version 1.0
Source
=
function
Usage: (= x)
(= x y)
(= x y & more)
Equality. Returns true if x equals y, false if not. Same as
Java x.equals(y) except it also works for nil, and compares
numbers and collections in a type-independent manner. Clojure's immutable data
structures define equals() (and thus =) as a value, not an identity,
comparison.
Added in Clojure version 1.0
Source
==
function
Usage: (== x)
(== x y)
(== x y & more)
Returns non-nil if nums all have the equivalent
value (type-independent), otherwise false
Added in Clojure version 1.0
Source
>
function
Usage: (> x)
(> x y)
(> x y & more)
Returns non-nil if nums are in monotonically decreasing order,
otherwise false.
Added in Clojure version 1.0
Source
>=
function
Usage: (>= x)
(>= x y)
(>= x y & more)
Returns non-nil if nums are in monotonically non-increasing order,
otherwise false.
Added in Clojure version 1.0
Source
NaN?
function
Usage: (NaN? num)
Returns true if num is NaN, else false
Added in Clojure version 1.11
Source
PrintWriter-on
function
Usage: (PrintWriter-on flush-fn close-fn)
(PrintWriter-on flush-fn close-fn autoflush?)
implements java.io.PrintWriter given flush-fn, which will be called
when .flush() is called, with a string built up since the last call to .flush().
if not nil, close-fn will be called with no arguments when .close is called.
autoflush? determines if the PrintWriter will autoflush, false by default.
Added in Clojure version 1.10
Source
StackTraceElement->vec
function
Usage: (StackTraceElement->vec o)
Constructs a data representation for a StackTraceElement: [class method file line]
Added in Clojure version 1.9
Source
Throwable->map
function
Usage: (Throwable->map o)
Constructs a data representation for a Throwable with keys:
:cause - root cause message
:phase - error phase
:via - cause chain, with cause keys:
:type - exception class symbol
:message - exception message
:data - ex-data
:at - top stack element
:trace - root cause stack elements
Added in Clojure version 1.7
Source
abs
function
Usage: (abs a)
Returns the absolute value of a.
If a is Long/MIN_VALUE => Long/MIN_VALUE
If a is a double and zero => +0.0
If a is a double and ##Inf or ##-Inf => ##Inf
If a is a double and ##NaN => ##NaN
Added in Clojure version 1.11
Source
accessor
function
Usage: (accessor s key)
Returns a fn that, given an instance of a structmap with the basis,
returns the value at the key. The key must be in the basis. The
returned function should be (slightly) more efficient than using
get, but such use of accessors should be limited to known
performance-critical areas.
Added in Clojure version 1.0
Source
aclone
function
Usage: (aclone array)
Returns a clone of the Java array. Works on arrays of known
types.
Added in Clojure version 1.0
Source
add-classpath
function
Usage: (add-classpath url)
DEPRECATED
Adds the url (String or URL object) to the classpath per
URLClassLoader.addURL
Added in Clojure version 1.0
Deprecated since Clojure version 1.1
Source
add-tap
function
Usage: (add-tap f)
adds f, a fn of one argument, to the tap set. This function will be called with anything sent via tap>.
This function may (briefly) block (e.g. for streams), and will never impede calls to tap>,
but blocking indefinitely may cause tap values to be dropped.
Remember f in order to remove-tap
Added in Clojure version 1.10
Source
add-watch
function
Usage: (add-watch reference key fn)
Adds a watch function to an agent/atom/var/ref reference. The watch
fn must be a fn of 4 args: a key, the reference, its old-state, its
new-state. Whenever the reference's state might have been changed,
any registered watches will have their functions called. The watch fn
will be called synchronously, on the agent's thread if an agent,
before any pending sends if agent or ref. Note that an atom's or
ref's state may have changed again prior to the fn call, so use
old/new-state rather than derefing the reference. Note also that watch
fns may be called from multiple threads simultaneously. Var watchers
are triggered only by root binding changes, not thread-local
set!s. Keys must be unique per reference, and can be used to remove
the watch with remove-watch, but are otherwise considered opaque by
the watch mechanism.
Added in Clojure version 1.0
Source
agent
function
Usage: (agent state & options)
Creates and returns an agent with an initial value of state and
zero or more options (in any order):
:meta metadata-map
:validator validate-fn
:error-handler handler-fn
:error-mode mode-keyword
If metadata-map is supplied, it will become the metadata on the
agent. validate-fn must be nil or a side-effect-free fn of one
argument, which will be passed the intended new state on any state
change. If the new state is unacceptable, the validate-fn should
return false or throw an exception. handler-fn is called if an
action throws an exception or if validate-fn rejects a new state --
see set-error-handler! for details. The mode-keyword may be either
:continue (the default if an error-handler is given) or :fail (the
default if no error-handler is given) -- see set-error-mode! for
details.
Added in Clojure version 1.0
Source
agent-error
function
Usage: (agent-error a)
Returns the exception thrown during an asynchronous action of the
agent if the agent is failed. Returns nil if the agent is not
failed.
Added in Clojure version 1.2
Source
agent-errors
function
Usage: (agent-errors a)
DEPRECATED: Use 'agent-error' instead.
Returns a sequence of the exceptions thrown during asynchronous
actions of the agent.
Added in Clojure version 1.0
Deprecated since Clojure version 1.2
Source
aget
function
Usage: (aget array idx)
(aget array idx & idxs)
Returns the value at the index/indices. Works on Java arrays of all
types.
Added in Clojure version 1.0
Source
alength
function
Usage: (alength array)
Returns the length of the Java array. Works on arrays of all
types.
Added in Clojure version 1.0
Source
alias
function
Usage: (alias alias namespace-sym)
Add an alias in the current namespace to another
namespace. Arguments are two symbols: the alias to be used, and
the symbolic name of the target namespace. Use :as in the ns macro in preference
to calling this directly.
Added in Clojure version 1.0
Source
all-ns
function
Usage: (all-ns)
Returns a sequence of all namespaces.
Added in Clojure version 1.0
Source
alter
function
Usage: (alter ref fun & args)
Must be called in a transaction. Sets the in-transaction-value of
ref to:
(apply fun in-transaction-value-of-ref args)
and returns the in-transaction-value of ref.
Added in Clojure version 1.0
Source
function
Usage: (alter-meta! iref f & args)
Atomically sets the metadata for a namespace/var/ref/agent/atom to be:
(apply f its-current-meta args)
f must be free of side-effects
Added in Clojure version 1.0
Source
alter-var-root
function
Usage: (alter-var-root v f & args)
Atomically alters the root binding of var v by applying f to its
current value plus any args
Added in Clojure version 1.0
Source
amap
macro
Usage: (amap a idx ret expr)
Maps an expression across an array a, using an index named idx, and
return value named ret, initialized to a clone of a, then setting
each element of ret to the evaluation of expr, returning the new
array ret.
Added in Clojure version 1.0
Source
ancestors
function
Usage: (ancestors tag)
(ancestors h tag)
Returns the immediate and indirect parents of tag, either via a Java type
inheritance relationship or a relationship established via derive. h
must be a hierarchy obtained from make-hierarchy, if not supplied
defaults to the global hierarchy
Added in Clojure version 1.0
Source
and
macro
Usage: (and)
(and x)
(and x & next)
Evaluates exprs one at a time, from left to right. If a form
returns logical false (nil or false), and returns that value and
doesn't evaluate any of the other expressions, otherwise it returns
the value of the last expr. (and) returns true.
Added in Clojure version 1.0
Source
any?
function
Usage: (any? x)
Returns true given any argument.
Added in Clojure version 1.9
Source
apply
function
Usage: (apply f args)
(apply f x args)
(apply f x y args)
(apply f x y z args)
(apply f a b c d & args)
Applies fn f to the argument list formed by prepending intervening arguments to args.
Added in Clojure version 1.0
Source
areduce
macro
Usage: (areduce a idx ret init expr)
Reduces an expression across an array a, using an index named idx,
and return value named ret, initialized to init, setting ret to the
evaluation of expr at each step, returning ret.
Added in Clojure version 1.0
Source
array-map
function
Usage: (array-map)
(array-map & keyvals)
Constructs an array-map. If any keys are equal, they are handled as
if by repeated uses of assoc.
Added in Clojure version 1.0
Source
as->
macro
Usage: (as-> expr name & forms)
Binds name to expr, evaluates the first form in the lexical context
of that binding, then binds name to that result, repeating for each
successive form, returning the result of the last form.
Added in Clojure version 1.5
Source
aset
function
Usage: (aset array idx val)
(aset array idx idx2 & idxv)
Sets the value at the index/indices. Works on Java arrays of
reference types. Returns val.
Added in Clojure version 1.0
Source
aset-boolean
function
Usage: (aset-boolean array idx val)
(aset-boolean array idx idx2 & idxv)
Sets the value at the index/indices. Works on arrays of boolean. Returns val.
Added in Clojure version 1.0
Source
aset-byte
function
Usage: (aset-byte array idx val)
(aset-byte array idx idx2 & idxv)
Sets the value at the index/indices. Works on arrays of byte. Returns val.
Added in Clojure version 1.0
Source
aset-char
function
Usage: (aset-char array idx val)
(aset-char array idx idx2 & idxv)
Sets the value at the index/indices. Works on arrays of char. Returns val.
Added in Clojure version 1.0
Source
aset-double
function
Usage: (aset-double array idx val)
(aset-double array idx idx2 & idxv)
Sets the value at the index/indices. Works on arrays of double. Returns val.
Added in Clojure version 1.0
Source
aset-float
function
Usage: (aset-float array idx val)
(aset-float array idx idx2 & idxv)
Sets the value at the index/indices. Works on arrays of float. Returns val.
Added in Clojure version 1.0
Source
aset-int
function
Usage: (aset-int array idx val)
(aset-int array idx idx2 & idxv)
Sets the value at the index/indices. Works on arrays of int. Returns val.
Added in Clojure version 1.0
Source
aset-long
function
Usage: (aset-long array idx val)
(aset-long array idx idx2 & idxv)
Sets the value at the index/indices. Works on arrays of long. Returns val.
Added in Clojure version 1.0
Source
aset-short
function
Usage: (aset-short array idx val)
(aset-short array idx idx2 & idxv)
Sets the value at the index/indices. Works on arrays of short. Returns val.
Added in Clojure version 1.0
Source
assert
macro
Usage: (assert x)
(assert x message)
Evaluates expression x and throws an AssertionError with optional
message if x does not evaluate to logical true.
Assertion checks are omitted from compiled code if '*assert*' is
false.
Added in Clojure version 1.0
Source
assoc
function
Usage: (assoc map key val)
(assoc map key val & kvs)
assoc[iate]. When applied to a map, returns a new map of the
same (hashed/sorted) type, that contains the mapping of key(s) to
val(s). When applied to a vector, returns a new vector that
contains val at index. Note - index must be <= (count vector).
Added in Clojure version 1.0
Source
assoc!
function
Usage: (assoc! coll key val)
(assoc! coll key val & kvs)
When applied to a transient map, adds mapping of key(s) to
val(s). When applied to a transient vector, sets the val at index.
Note - index must be <= (count vector). Returns coll.
Added in Clojure version 1.1
Source
assoc-in
function
Usage: (assoc-in m [k & ks] v)
Associates a value in a nested associative structure, where ks is a
sequence of keys and v is the new value and returns a new nested structure.
If any levels do not exist, hash-maps will be created.
Added in Clojure version 1.0
Source
associative?
function
Usage: (associative? coll)
Returns true if coll implements Associative
Added in Clojure version 1.0
Source
atom
function
Usage: (atom x)
(atom x & options)
Creates and returns an Atom with an initial value of x and zero or
more options (in any order):
:meta metadata-map
:validator validate-fn
If metadata-map is supplied, it will become the metadata on the
atom. validate-fn must be nil or a side-effect-free fn of one
argument, which will be passed the intended new state on any state
change. If the new state is unacceptable, the validate-fn should
return false or throw an exception.
Added in Clojure version 1.0
Source
await
function
Usage: (await & agents)
Blocks the current thread (indefinitely!) until all actions
dispatched thus far, from this thread or agent, to the agent(s) have
occurred. Will block on failed agents. Will never return if
a failed agent is restarted with :clear-actions true or shutdown-agents was called.
Added in Clojure version 1.0
Source
await-for
function
Usage: (await-for timeout-ms & agents)
Blocks the current thread until all actions dispatched thus
far (from this thread or agent) to the agents have occurred, or the
timeout (in milliseconds) has elapsed. Returns logical false if
returning due to timeout, logical true otherwise.
Added in Clojure version 1.0
Source
bases
function
Usage: (bases c)
Returns the immediate superclass and direct interfaces of c, if any
Added in Clojure version 1.0
Source
bean
function
Usage: (bean x)
Takes a Java object and returns a read-only implementation of the
map abstraction based upon its JavaBean properties.
Added in Clojure version 1.0
Source
bigdec
function
Usage: (bigdec x)
Coerce to BigDecimal
Added in Clojure version 1.0
Source
bigint
function
Usage: (bigint x)
Coerce to BigInt
Added in Clojure version 1.3
Source
biginteger
function
Usage: (biginteger x)
Coerce to BigInteger
Added in Clojure version 1.0
Source
binding
macro
Usage: (binding bindings & body)
binding => var-symbol init-expr
Creates new bindings for the (already-existing) vars, with the
supplied initial values, executes the exprs in an implicit do, then
re-establishes the bindings that existed before. The new bindings
are made in parallel (unlike let); all init-exprs are evaluated
before the vars are bound to their new values.
Added in Clojure version 1.0
Source
bit-and
function
Usage: (bit-and x y)
(bit-and x y & more)
Bitwise and
Added in Clojure version 1.0
Source
bit-and-not
function
Usage: (bit-and-not x y)
(bit-and-not x y & more)
Bitwise and with complement
Added in Clojure version 1.0
Source
bit-clear
function
Usage: (bit-clear x n)
Clear bit at index n
Added in Clojure version 1.0
Source
bit-flip
function
Usage: (bit-flip x n)
Flip bit at index n
Added in Clojure version 1.0
Source
bit-not
function
Usage: (bit-not x)
Bitwise complement
Added in Clojure version 1.0
Source
bit-or
function
Usage: (bit-or x y)
(bit-or x y & more)
Bitwise or
Added in Clojure version 1.0
Source
bit-set
function
Usage: (bit-set x n)
Set bit at index n
Added in Clojure version 1.0
Source
bit-shift-left
function
Usage: (bit-shift-left x n)
Bitwise shift left
Added in Clojure version 1.0
Source
bit-shift-right
function
Usage: (bit-shift-right x n)
Bitwise shift right
Added in Clojure version 1.0
Source
bit-test
function
Usage: (bit-test x n)
Test bit at index n
Added in Clojure version 1.0
Source
bit-xor
function
Usage: (bit-xor x y)
(bit-xor x y & more)
Bitwise exclusive or
Added in Clojure version 1.0
Source
boolean
function
Usage: (boolean x)
Coerce to boolean
Added in Clojure version 1.0
Source
boolean-array
function
Usage: (boolean-array size-or-seq)
(boolean-array size init-val-or-seq)
Creates an array of booleans
Added in Clojure version 1.1
Source
boolean?
function
Usage: (boolean? x)
Return true if x is a Boolean
Added in Clojure version 1.9
Source
booleans
function
Usage: (booleans xs)
Casts to boolean[]
Added in Clojure version 1.1
Source
bound-fn
macro
Usage: (bound-fn & fntail)
Returns a function defined by the given fntail, which will install the
same bindings in effect as in the thread at the time bound-fn was called.
This may be used to define a helper function which runs on a different
thread, but needs the same bindings in place.
Added in Clojure version 1.1
Source
bound-fn*
function
Usage: (bound-fn* f)
Returns a function, which will install the same bindings in effect as in
the thread at the time bound-fn* was called and then call f with any given
arguments. This may be used to define a helper function which runs on a
different thread, but needs the same bindings in place.
Added in Clojure version 1.1
Source
bound?
function
Usage: (bound? & vars)
Returns true if all of the vars provided as arguments have any bound value, root or thread-local.
Implies that deref'ing the provided vars will succeed. Returns true if no vars are provided.
Added in Clojure version 1.2
Source
bounded-count
function
Usage: (bounded-count n coll)
If coll is counted? returns its count, else will count at most the first n
elements of coll using its seq
Added in Clojure version 1.9
Source
butlast
function
Usage: (butlast coll)
Return a seq of all but the last item in coll, in linear time
Added in Clojure version 1.0
Source
byte
function
Usage: (byte x)
Coerce to byte
Added in Clojure version 1.0
Source
byte-array
function
Usage: (byte-array size-or-seq)
(byte-array size init-val-or-seq)
Creates an array of bytes
Added in Clojure version 1.1
Source
bytes
function
Usage: (bytes xs)
Casts to bytes[]
Added in Clojure version 1.1
Source
bytes?
function
Usage: (bytes? x)
Return true if x is a byte array
Added in Clojure version 1.9
Source
case
macro
Usage: (case e & clauses)
Takes an expression, and a set of clauses.
Each clause can take the form of either:
test-constant result-expr
(test-constant1 ... test-constantN) result-expr
The test-constants are not evaluated. They must be compile-time
literals, and need not be quoted. If the expression is equal to a
test-constant, the corresponding result-expr is returned. A single
default expression can follow the clauses, and its value will be
returned if no clause matches. If no default expression is provided
and no clause matches, an IllegalArgumentException is thrown.
Unlike cond and condp, case does a constant-time dispatch, the
clauses are not considered sequentially. All manner of constant
expressions are acceptable in case, including numbers, strings,
symbols, keywords, and (Clojure) composites thereof. Note that since
lists are used to group multiple constants that map to the same
expression, a vector can be used to match a list if needed. The
test-constants need not be all of the same type.
Added in Clojure version 1.2
Source
cast
function
Usage: (cast c x)
Throws a ClassCastException if x is not a c, else returns x.
Added in Clojure version 1.0
Source
cat
function
Usage: (cat rf)
A transducer which concatenates the contents of each input, which must be a
collection, into the reduction.
Added in Clojure version 1.7
Source
catch
special syntax
Syntax for use with try.
Please see https://clojure.org/reference/special_forms#try
Added in Clojure version 1.0
char
function
Usage: (char x)
Coerce to char
Added in Clojure version 1.1
Source
char-array
function
Usage: (char-array size-or-seq)
(char-array size init-val-or-seq)
Creates an array of chars
Added in Clojure version 1.1
Source
char-escape-string
var
Returns escape string for char or nil if none
Added in Clojure version 1.0
Source
char-name-string
var
Returns name string for char or nil if none
Added in Clojure version 1.0
Source
char?
function
Usage: (char? x)
Return true if x is a Character
Added in Clojure version 1.0
Source
chars
function
Usage: (chars xs)
Casts to chars[]
Added in Clojure version 1.1
Source
class
function
Usage: (class x)
Returns the Class of x
Added in Clojure version 1.0
Source
class?
function
Usage: (class? x)
Returns true if x is an instance of Class
Added in Clojure version 1.0
Source
clear-agent-errors
function
Usage: (clear-agent-errors a)
DEPRECATED: Use 'restart-agent' instead.
Clears any exceptions thrown during asynchronous actions of the
agent, allowing subsequent actions to occur.
Added in Clojure version 1.0
Deprecated since Clojure version 1.2
Source
clojure-version
function
Usage: (clojure-version)
Returns clojure version as a printable string.
Added in Clojure version 1.0
Source
coll?
function
Usage: (coll? x)
Returns true if x implements IPersistentCollection
Added in Clojure version 1.0
Source
macro
Usage: (comment & body)
Ignores body, yields nil
Added in Clojure version 1.0
Source
commute
function
Usage: (commute ref fun & args)
Must be called in a transaction. Sets the in-transaction-value of
ref to:
(apply fun in-transaction-value-of-ref args)
and returns the in-transaction-value of ref.
At the commit point of the transaction, sets the value of ref to be:
(apply fun most-recently-committed-value-of-ref args)
Thus fun should be commutative, or, failing that, you must accept
last-one-in-wins behavior. commute allows for more concurrency than
ref-set.
Added in Clojure version 1.0
Source
comp
function
Usage: (comp)
(comp f)
(comp f g)
(comp f g & fs)
Takes a set of functions and returns a fn that is the composition
of those fns. The returned fn takes a variable number of args,
applies the rightmost of fns to the args, the next
fn (right-to-left) to the result, etc.
Added in Clojure version 1.0
Source
comparator
function
Usage: (comparator pred)
Returns an implementation of java.util.Comparator based upon pred.
Added in Clojure version 1.0
Source
compare
function
Usage: (compare x y)
Comparator. Returns a negative number, zero, or a positive number
when x is logically 'less than', 'equal to', or 'greater than'
y. Same as Java x.compareTo(y) except it also works for nil, and
compares numbers and collections in a type-independent manner. x
must implement Comparable
Added in Clojure version 1.0
Source
compare-and-set!
function
Usage: (compare-and-set! atom oldval newval)
Atomically sets the value of atom to newval if and only if the
current value of the atom is identical to oldval. Returns true if
set happened, else false
Added in Clojure version 1.0
Source
compile
function
Usage: (compile lib)
Compiles the namespace named by the symbol lib into a set of
classfiles. The source for the lib must be in a proper
classpath-relative directory. The output files will go into the
directory specified by *compile-path*, and that directory too must
be in the classpath.
Added in Clojure version 1.0
Source
complement
function
Usage: (complement f)
Takes a fn f and returns a fn that takes the same arguments as f,
has the same effects, if any, and returns the opposite truth value.
Added in Clojure version 1.0
Source
completing
function
Usage: (completing f)
(completing f cf)
Takes a reducing function f of 2 args and returns a fn suitable for
transduce by adding an arity-1 signature that calls cf (default -
identity) on the result argument.
Added in Clojure version 1.7
Source
concat
function
Usage: (concat)
(concat x)
(concat x y)
(concat x y & zs)
Returns a lazy seq representing the concatenation of the elements in the supplied colls.
Added in Clojure version 1.0
Source
cond
macro
Usage: (cond & clauses)
Takes a set of test/expr pairs. It evaluates each test one at a
time. If a test returns logical true, cond evaluates and returns
the value of the corresponding expr and doesn't evaluate any of the
other tests or exprs. (cond) returns nil.
Added in Clojure version 1.0
Source
cond->
macro
Usage: (cond-> expr & clauses)
Takes an expression and a set of test/form pairs. Threads expr (via ->)
through each form for which the corresponding test
expression is true. Note that, unlike cond branching, cond-> threading does
not short circuit after the first true test expression.
Added in Clojure version 1.5
Source
cond->>
macro
Usage: (cond->> expr & clauses)
Takes an expression and a set of test/form pairs. Threads expr (via ->>)
through each form for which the corresponding test expression
is true. Note that, unlike cond branching, cond->> threading does not short circuit
after the first true test expression.
Added in Clojure version 1.5
Source
condp
macro
Usage: (condp pred expr & clauses)
Takes a binary predicate, an expression, and a set of clauses.
Each clause can take the form of either:
test-expr result-expr
test-expr :>> result-fn
Note :>> is an ordinary keyword.
For each clause, (pred test-expr expr) is evaluated. If it returns
logical true, the clause is a match. If a binary clause matches, the
result-expr is returned, if a ternary clause matches, its result-fn,
which must be a unary function, is called with the result of the
predicate as its argument, the result of that call being the return
value of condp. A single default expression can follow the clauses,
and its value will be returned if no clause matches. If no default
expression is provided and no clause matches, an
IllegalArgumentException is thrown.
Added in Clojure version 1.0
Source
conj
function
Usage: (conj)
(conj coll)
(conj coll x)
(conj coll x & xs)
conj[oin]. Returns a new collection with the xs
'added'. (conj nil item) returns (item).
(conj coll) returns coll. (conj) returns [].
The 'addition' may happen at different 'places' depending
on the concrete type.
Added in Clojure version 1.0
Source
conj!
function
Usage: (conj!)
(conj! coll)
(conj! coll x)
Adds x to the transient collection, and return coll. The 'addition'
may happen at different 'places' depending on the concrete type.
Added in Clojure version 1.1
Source
cons
function
Usage: (cons x seq)
Returns a new seq where x is the first element and seq is
the rest.
Added in Clojure version 1.0
Source
constantly
function
Usage: (constantly x)
Returns a function that takes any number of arguments and returns x.
Added in Clojure version 1.0
Source
construct-proxy
function
Usage: (construct-proxy c & ctor-args)
Takes a proxy class and any arguments for its superclass ctor and
creates and returns an instance of the proxy.
Added in Clojure version 1.0
Source
contains?
function
Usage: (contains? coll key)
Returns true if key is present in the given collection, otherwise
returns false. Note that for numerically indexed collections like
vectors and Java arrays, this tests if the numeric key is within the
range of indexes. 'contains?' operates constant or logarithmic time;
it will not perform a linear search for a value. See also 'some'.
Added in Clojure version 1.0
Source
count
function
Usage: (count coll)
Returns the number of items in the collection. (count nil) returns
0. Also works on strings, arrays, and Java Collections and Maps
Added in Clojure version 1.0
Source
counted?
function
Usage: (counted? coll)
Returns true if coll implements count in constant time
Added in Clojure version 1.0
Source
create-ns
function
Usage: (create-ns sym)
Create a new namespace named by the symbol if one doesn't already
exist, returns it or the already-existing namespace of the same
name.
Added in Clojure version 1.0
Source
create-struct
function
Usage: (create-struct & keys)
Returns a structure basis object.
Added in Clojure version 1.0
Source
cycle
function
Usage: (cycle coll)
Returns a lazy (infinite!) sequence of repetitions of the items in coll.
Added in Clojure version 1.0
Source
dec
function
Usage: (dec x)
Returns a number one less than num. Does not auto-promote
longs, will throw on overflow. See also: dec'
Added in Clojure version 1.2
Source
dec'
function
Usage: (dec' x)
Returns a number one less than num. Supports arbitrary precision.
See also: dec
Added in Clojure version 1.0
Source
decimal?
function
Usage: (decimal? n)
Returns true if n is a BigDecimal
Added in Clojure version 1.0
Source
declare
macro
Usage: (declare & names)
defs the supplied var names with no bindings, useful for making forward declarations.
Added in Clojure version 1.0
Source
dedupe
function
Usage: (dedupe)
(dedupe coll)
Returns a lazy sequence removing consecutive duplicates in coll.
Returns a transducer when no collection is provided.
Added in Clojure version 1.7
Source
def
special form
Usage: (def symbol doc-string? init?)
Creates and interns a global var with the name
of symbol in the current namespace (*ns*) or locates such a var if
it already exists. If init is supplied, it is evaluated, and the
root binding of the var is set to the resulting value. If init is
not supplied, the root binding of the var is unaffected.
Please see https://clojure.org/reference/special_forms#def
Added in Clojure version 1.0
default-data-readers
var
Default map of data reader functions provided by Clojure. May be
overridden by binding *data-readers*.
Added in Clojure version 1.4
Source
definline
macro
Usage: (definline name & decl)
Experimental - like defmacro, except defines a named function whose
body is the expansion, calls to which may be expanded inline as if
it were a macro. Cannot be used with variadic (&) args.
Added in Clojure version 1.0
Source
definterface
macro
Usage: (definterface name & sigs)
Creates a new Java interface with the given name and method sigs.
The method return types and parameter types may be specified with type hints,
defaulting to Object if omitted.
(definterface MyInterface
(^int method1 [x])
(^Bar method2 [^Baz b ^Quux q]))
Added in Clojure version 1.2
Source
defmacro
macro
Usage: (defmacro name doc-string? attr-map? [params*] body)
(defmacro name doc-string? attr-map? ([params*] body) + attr-map?)
Like defn, but the resulting function name is declared as a
macro and will be used as a macro by the compiler when it is
called.
Added in Clojure version 1.0
Source
defmethod
macro
Usage: (defmethod multifn dispatch-val & fn-tail)
Creates and installs a new method of multimethod associated with dispatch-value.
Added in Clojure version 1.0
Source
defmulti
macro
Usage: (defmulti name docstring? attr-map? dispatch-fn & options)
Creates a new multimethod with the associated dispatch function.
The docstring and attr-map are optional.
Options are key-value pairs and may be one of:
:default
The default dispatch value, defaults to :default
:hierarchy
The value used for hierarchical dispatch (e.g. ::square is-a ::shape)
Hierarchies are type-like relationships that do not depend upon type
inheritance. By default Clojure's multimethods dispatch off of a
global hierarchy map. However, a hierarchy relationship can be
created with the derive function used to augment the root ancestor
created with make-hierarchy.
Multimethods expect the value of the hierarchy option to be supplied as
a reference type e.g. a var (i.e. via the Var-quote dispatch macro #'
or the var special form).
Added in Clojure version 1.0
Source
defn
macro
Usage: (defn name doc-string? attr-map? [params*] prepost-map? body)
(defn name doc-string? attr-map? ([params*] prepost-map? body) + attr-map?)
Same as (def name (fn [params* ] exprs*)) or (def
name (fn ([params* ] exprs*)+)) with any doc-string or attrs added
to the var metadata. prepost-map defines a map with optional keys
:pre and :post that contain collections of pre or post conditions.
Specs:
Args: (fspec
:args
:clojure.core.specs.alpha/defn-args
:ret
any?
:fn
nil)
Ret: (fspec
:args
:clojure.core.specs.alpha/defn-args
:ret
any?
:fn
nil)
Added in Clojure version 1.0
Source
defn-
macro
Usage: (defn- name & decls)
same as defn, yielding non-public def
Specs:
Args: (fspec
:args
:clojure.core.specs.alpha/defn-args
:ret
any?
:fn
nil)
Ret: (fspec
:args
:clojure.core.specs.alpha/defn-args
:ret
any?
:fn
nil)
Added in Clojure version 1.0
Source
defonce
macro
Usage: (defonce name expr)
defs name to have the root value of the expr iff the named var has no root value,
else expr is unevaluated
Added in Clojure version 1.0
Source
defprotocol
macro
Usage: (defprotocol name & opts+sigs)
A protocol is a named set of named methods and their signatures:
(defprotocol AProtocolName
;optional doc string
"A doc string for AProtocol abstraction"
;options
:extend-via-metadata true
;method signatures
(bar [this a b] "bar docs")
(baz [this a] [this a b] [this a b c] "baz docs"))
No implementations are provided. Docs can be specified for the
protocol overall and for each method. The above yields a set of
polymorphic functions and a protocol object. All are
namespace-qualified by the ns enclosing the definition The resulting
functions dispatch on the type of their first argument, which is
required and corresponds to the implicit target object ('this' in
Java parlance). defprotocol is dynamic, has no special compile-time
effect, and defines no new types or classes. Implementations of
the protocol methods can be provided using extend.
When :extend-via-metadata is true, values can extend protocols by
adding metadata where keys are fully-qualified protocol function
symbols and values are function implementations. Protocol
implementations are checked first for direct definitions (defrecord,
deftype, reify), then metadata definitions, then external
extensions (extend, extend-type, extend-protocol)
defprotocol will automatically generate a corresponding interface,
with the same name as the protocol, i.e. given a protocol:
my.ns/Protocol, an interface: my.ns.Protocol. The interface will
have methods corresponding to the protocol functions, and the
protocol will automatically work with instances of the interface.
Note that you should not use this interface with deftype or
reify, as they support the protocol directly:
(defprotocol P
(foo [this])
(bar-me [this] [this y]))
(deftype Foo [a b c]
P
(foo [this] a)
(bar-me [this] b)
(bar-me [this y] (+ c y)))
(bar-me (Foo. 1 2 3) 42)
=> 45
(foo
(let [x 42]
(reify P
(foo [this] 17)
(bar-me [this] x)
(bar-me [this y] x))))
=> 17
Added in Clojure version 1.2
Source
defrecord
macro
Usage: (defrecord name [& fields] & opts+specs)
(defrecord name [fields*] options* specs*)
Options are expressed as sequential keywords and arguments (in any order).
Supported options:
:load-ns - if true, importing the record class will cause the
namespace in which the record was defined to be loaded.
Defaults to false.
Each spec consists of a protocol or interface name followed by zero
or more method bodies:
protocol-or-interface-or-Object
(methodName [args*] body)*
Dynamically generates compiled bytecode for class with the given
name, in a package with the same name as the current namespace, the
given fields, and, optionally, methods for protocols and/or
interfaces.
The class will have the (immutable) fields named by
fields, which can have type hints. Protocols/interfaces and methods
are optional. The only methods that can be supplied are those
declared in the protocols/interfaces. Note that method bodies are
not closures, the local environment includes only the named fields,
and those fields can be accessed directly.
Method definitions take the form:
(methodname [args*] body)
The argument and return types can be hinted on the arg and
methodname symbols. If not supplied, they will be inferred, so type
hints should be reserved for disambiguation.
Methods should be supplied for all methods of the desired
protocol(s) and interface(s). You can also define overrides for
methods of Object. Note that a parameter must be supplied to
correspond to the target object ('this' in Java parlance). Thus
methods for interfaces will take one more argument than do the
interface declarations. Note also that recur calls to the method
head should *not* pass the target object, it will be supplied
automatically and can not be substituted.
In the method bodies, the (unqualified) name can be used to name the
class (for calls to new, instance? etc).
The class will have implementations of several (clojure.lang)
interfaces generated automatically: IObj (metadata support) and
IPersistentMap, and all of their superinterfaces.
In addition, defrecord will define type-and-value-based =,
and will defined Java .hashCode and .equals consistent with the
contract for java.util.Map.
When AOT compiling, generates compiled bytecode for a class with the
given name (a symbol), prepends the current ns as the package, and
writes the .class file to the *compile-path* directory.
Two constructors will be defined, one taking the designated fields
followed by a metadata map (nil for none) and an extension field
map (nil for none), and one taking only the fields (using nil for
meta and extension fields). Note that the field names __meta,
__extmap, __hash and __hasheq are currently reserved and should not
be used when defining your own records.
Given (defrecord TypeName ...), two factory functions will be
defined: ->TypeName, taking positional parameters for the fields,
and map->TypeName, taking a map of keywords to field values.
Added in Clojure version 1.2
Source
defstruct
macro
Usage: (defstruct name & keys)
Same as (def name (create-struct keys...))
Added in Clojure version 1.0
Source
deftype
macro
Usage: (deftype name [& fields] & opts+specs)
(deftype name [fields*] options* specs*)
Options are expressed as sequential keywords and arguments (in any order).
Supported options:
:load-ns - if true, importing the type class will cause the
namespace in which the type was defined to be loaded.
Defaults to false.
Each spec consists of a protocol or interface name followed by zero
or more method bodies:
protocol-or-interface-or-Object
(methodName [args*] body)*
Dynamically generates compiled bytecode for class with the given
name, in a package with the same name as the current namespace, the
given fields, and, optionally, methods for protocols and/or
interfaces.
The class will have the (by default, immutable) fields named by
fields, which can have type hints. Protocols/interfaces and methods
are optional. The only methods that can be supplied are those
declared in the protocols/interfaces. Note that method bodies are
not closures, the local environment includes only the named fields,
and those fields can be accessed directly. Fields can be qualified
with the metadata :volatile-mutable true or :unsynchronized-mutable
true, at which point (set! afield aval) will be supported in method
bodies. Note well that mutable fields are extremely difficult to use
correctly, and are present only to facilitate the building of higher
level constructs, such as Clojure's reference types, in Clojure
itself. They are for experts only - if the semantics and
implications of :volatile-mutable or :unsynchronized-mutable are not
immediately apparent to you, you should not be using them.
Method definitions take the form:
(methodname [args*] body)
The argument and return types can be hinted on the arg and
methodname symbols. If not supplied, they will be inferred, so type
hints should be reserved for disambiguation.
Methods should be supplied for all methods of the desired
protocol(s) and interface(s). You can also define overrides for
methods of Object. Note that a parameter must be supplied to
correspond to the target object ('this' in Java parlance). Thus
methods for interfaces will take one more argument than do the
interface declarations. Note also that recur calls to the method
head should *not* pass the target object, it will be supplied
automatically and can not be substituted.
In the method bodies, the (unqualified) name can be used to name the
class (for calls to new, instance? etc).
When AOT compiling, generates compiled bytecode for a class with the
given name (a symbol), prepends the current ns as the package, and
writes the .class file to the *compile-path* directory.
One constructor will be defined, taking the designated fields. Note
that the field names __meta, __extmap, __hash and __hasheq are currently
reserved and should not be used when defining your own types.
Given (deftype TypeName ...), a factory function called ->TypeName
will be defined, taking positional parameters for the fields
Added in Clojure version 1.2
Source
delay
macro
Usage: (delay & body)
Takes a body of expressions and yields a Delay object that will
invoke the body only the first time it is forced (with force or deref/@), and
will cache the result and return it on all subsequent force
calls. See also - realized?
Added in Clojure version 1.0
Source
delay?
function
Usage: (delay? x)
returns true if x is a Delay created with delay
Added in Clojure version 1.0
Source
deliver
function
Usage: (deliver promise val)
Delivers the supplied value to the promise, releasing any pending
derefs. A subsequent call to deliver on a promise will have no effect.
Added in Clojure version 1.1
Source
denominator
function
Usage: (denominator r)
Returns the denominator part of a Ratio.
Added in Clojure version 1.2
Source
deref
function
Usage: (deref ref)
(deref ref timeout-ms timeout-val)
Also reader macro: @ref/@agent/@var/@atom/@delay/@future/@promise. Within a transaction,
returns the in-transaction-value of ref, else returns the
most-recently-committed value of ref. When applied to a var, agent
or atom, returns its current state. When applied to a delay, forces
it if not already forced. When applied to a future, will block if
computation not complete. When applied to a promise, will block
until a value is delivered. The variant taking a timeout can be
used for blocking references (futures and promises), and will return
timeout-val if the timeout (in milliseconds) is reached before a
value is available. See also - realized?.
Added in Clojure version 1.0
Source
derive
function
Usage: (derive tag parent)
(derive h tag parent)
Establishes a parent/child relationship between parent and
tag. Parent must be a namespace-qualified symbol or keyword and
child can be either a namespace-qualified symbol or keyword or a
class. h must be a hierarchy obtained from make-hierarchy, if not
supplied defaults to, and modifies, the global hierarchy.
Added in Clojure version 1.0
Source
descendants
function
Usage: (descendants tag)
(descendants h tag)
Returns the immediate and indirect children of tag, through a
relationship established via derive. h must be a hierarchy obtained
from make-hierarchy, if not supplied defaults to the global
hierarchy. Note: does not work on Java type inheritance
relationships.
Added in Clojure version 1.0
Source
disj
function
Usage: (disj set)
(disj set key)
(disj set key & ks)
disj[oin]. Returns a new set of the same (hashed/sorted) type, that
does not contain key(s).
Added in Clojure version 1.0
Source
disj!
function
Usage: (disj! set)
(disj! set key)
(disj! set key & ks)
disj[oin]. Returns a transient set of the same (hashed/sorted) type, that
does not contain key(s).
Added in Clojure version 1.1
Source
dissoc
function
Usage: (dissoc map)
(dissoc map key)
(dissoc map key & ks)
dissoc[iate]. Returns a new map of the same (hashed/sorted) type,
that does not contain a mapping for key(s).
Added in Clojure version 1.0
Source
dissoc!
function
Usage: (dissoc! map key)
(dissoc! map key & ks)
Returns a transient map that doesn't contain a mapping for key(s).
Added in Clojure version 1.1
Source
distinct
function
Usage: (distinct)
(distinct coll)
Returns a lazy sequence of the elements of coll with duplicates removed.
Returns a stateful transducer when no collection is provided.
Added in Clojure version 1.0
Source
distinct?
function
Usage: (distinct? x)
(distinct? x y)
(distinct? x y & more)
Returns true if no two of the arguments are =
Added in Clojure version 1.0
Source
do
special form
Usage: (do exprs*)
Evaluates the expressions in order and returns the value of
the last. If no expressions are supplied, returns nil.
Please see https://clojure.org/reference/special_forms#do
Added in Clojure version 1.0
doall
function
Usage: (doall coll)
(doall n coll)
When lazy sequences are produced via functions that have side
effects, any effects other than those needed to produce the first
element in the seq do not occur until the seq is consumed. doall can
be used to force any effects. Walks through the successive nexts of
the seq, retains the head and returns it, thus causing the entire
seq to reside in memory at one time.
Added in Clojure version 1.0
Source
dorun
function
Usage: (dorun coll)
(dorun n coll)
When lazy sequences are produced via functions that have side
effects, any effects other than those needed to produce the first
element in the seq do not occur until the seq is consumed. dorun can
be used to force any effects. Walks through the successive nexts of
the seq, does not retain the head and returns nil.
Added in Clojure version 1.0
Source
doseq
macro
Usage: (doseq seq-exprs & body)
Repeatedly executes body (presumably for side-effects) with
bindings and filtering as provided by "for". Does not retain
the head of the sequence. Returns nil.
Added in Clojure version 1.0
Source
dosync
macro
Usage: (dosync & exprs)
Runs the exprs (in an implicit do) in a transaction that encompasses
exprs and any nested calls. Starts a transaction if none is already
running on this thread. Any uncaught exception will abort the
transaction and flow out of dosync. The exprs may be run more than
once, but any effects on Refs will be atomic.
Added in Clojure version 1.0
Source
dotimes
macro
Usage: (dotimes bindings & body)
bindings => name n
Repeatedly executes body (presumably for side-effects) with name
bound to integers from 0 through n-1.
Added in Clojure version 1.0
Source
doto
macro
Usage: (doto x & forms)
Evaluates x then calls all of the methods and functions with the
value of x supplied at the front of the given arguments. The forms
are evaluated in order. Returns x.
(doto (new java.util.HashMap) (.put "a" 1) (.put "b" 2))
Added in Clojure version 1.0
Source
double
function
Usage: (double x)
Coerce to double
Added in Clojure version 1.0
Source
double-array
function
Usage: (double-array size-or-seq)
(double-array size init-val-or-seq)
Creates an array of doubles
Added in Clojure version 1.0
Source
double?
function
Usage: (double? x)
Return true if x is a Double
Added in Clojure version 1.9
Source
doubles
function
Usage: (doubles xs)
Casts to double[]
Added in Clojure version 1.0
Source
drop
function
Usage: (drop n)
(drop n coll)
Returns a laziness-preserving sequence of all but the first n items in coll.
Returns a stateful transducer when no collection is provided.
Added in Clojure version 1.0
Source
drop-last
function
Usage: (drop-last coll)
(drop-last n coll)
Return a lazy sequence of all but the last n (default 1) items in coll
Added in Clojure version 1.0
Source
drop-while
function
Usage: (drop-while pred)
(drop-while pred coll)
Returns a lazy sequence of the items in coll starting from the
first item for which (pred item) returns logical false. Returns a
stateful transducer when no collection is provided.
Added in Clojure version 1.0
Source
eduction
function
Usage: (eduction xform* coll)
Returns a reducible/iterable application of the transducers
to the items in coll. Transducers are applied in order as if
combined with comp. Note that these applications will be
performed every time reduce/iterator is called.
Added in Clojure version 1.7
Source
empty
function
Usage: (empty coll)
Returns an empty collection of the same category as coll, or nil
Added in Clojure version 1.0
Source
empty?
function
Usage: (empty? coll)
Returns true if coll has no items. To check the emptiness of a seq,
please use the idiom (seq x) rather than (not (empty? x))
Added in Clojure version 1.0
Source
ensure
function
Usage: (ensure ref)
Must be called in a transaction. Protects the ref from modification
by other transactions. Returns the in-transaction-value of
ref. Allows for more concurrency than (ref-set ref @ref)
Added in Clojure version 1.0
Source
ensure-reduced
function
Usage: (ensure-reduced x)
If x is already reduced?, returns it, else returns (reduced x)
Added in Clojure version 1.7
Source
enumeration-seq
function
Usage: (enumeration-seq e)
Returns a seq on a java.util.Enumeration
Added in Clojure version 1.0
Source
error-handler
function
Usage: (error-handler a)
Returns the error-handler of agent a, or nil if there is none.
See set-error-handler!
Added in Clojure version 1.2
Source
error-mode
function
Usage: (error-mode a)
Returns the error-mode of agent a. See set-error-mode!
Added in Clojure version 1.2
Source
eval
function
Usage: (eval form)
Evaluates the form data structure (not text!) and returns the result.
Added in Clojure version 1.0
Source
even?
function
Usage: (even? n)
Returns true if n is even, throws an exception if n is not an integer
Added in Clojure version 1.0
Source
every-pred
function
Usage: (every-pred p)
(every-pred p1 p2)
(every-pred p1 p2 p3)
(every-pred p1 p2 p3 & ps)
Takes a set of predicates and returns a function f that returns true if all of its
composing predicates return a logical true value against all of its arguments, else it returns
false. Note that f is short-circuiting in that it will stop execution on the first
argument that triggers a logical false result against the original predicates.
Added in Clojure version 1.3
Source
every?
function
Usage: (every? pred coll)
Returns true if (pred x) is logical true for every x in coll, else
false.
Added in Clojure version 1.0
Source
ex-cause
function
Usage: (ex-cause ex)
Returns the cause of ex if ex is a Throwable.
Otherwise returns nil.
Added in Clojure version 1.10
Source
ex-data
function
Usage: (ex-data ex)
Returns exception data (a map) if ex is an IExceptionInfo.
Otherwise returns nil.
Added in Clojure version 1.4
Source
ex-info
function
Usage: (ex-info msg map)
(ex-info msg map cause)
Create an instance of ExceptionInfo, a RuntimeException subclass
that carries a map of additional data.
Added in Clojure version 1.4
Source
ex-message
function
Usage: (ex-message ex)
Returns the message attached to ex if ex is a Throwable.
Otherwise returns nil.
Added in Clojure version 1.10
Source
extend
function
Usage: (extend atype & proto+mmaps)
Implementations of protocol methods can be provided using the extend construct:
(extend AType
AProtocol
{:foo an-existing-fn
:bar (fn [a b] ...)
:baz (fn ([a]...) ([a b] ...)...)}
BProtocol
{...}
...)
extend takes a type/class (or interface, see below), and one or more
protocol + method map pairs. It will extend the polymorphism of the
protocol's methods to call the supplied methods when an AType is
provided as the first argument.
Method maps are maps of the keyword-ized method names to ordinary
fns. This facilitates easy reuse of existing fns and fn maps, for
code reuse/mixins without derivation or composition. You can extend
an interface to a protocol. This is primarily to facilitate interop
with the host (e.g. Java) but opens the door to incidental multiple
inheritance of implementation since a class can inherit from more
than one interface, both of which extend the protocol. It is TBD how
to specify which impl to use. You can extend a protocol on nil.
If you are supplying the definitions explicitly (i.e. not reusing
exsting functions or mixin maps), you may find it more convenient to
use the extend-type or extend-protocol macros.
Note that multiple independent extend clauses can exist for the same
type, not all protocols need be defined in a single extend call.
See also:
extends?, satisfies?, extenders
Added in Clojure version 1.2
Source
extend-protocol
macro
Usage: (extend-protocol p & specs)
Useful when you want to provide several implementations of the same
protocol all at once. Takes a single protocol and the implementation
of that protocol for one or more types. Expands into calls to
extend-type:
(extend-protocol Protocol
AType
(foo [x] ...)
(bar [x y] ...)
BType
(foo [x] ...)
(bar [x y] ...)
AClass
(foo [x] ...)
(bar [x y] ...)
nil
(foo [x] ...)
(bar [x y] ...))
expands into:
(do
(clojure.core/extend-type AType Protocol
(foo [x] ...)
(bar [x y] ...))
(clojure.core/extend-type BType Protocol
(foo [x] ...)
(bar [x y] ...))
(clojure.core/extend-type AClass Protocol
(foo [x] ...)
(bar [x y] ...))
(clojure.core/extend-type nil Protocol
(foo [x] ...)
(bar [x y] ...)))
Added in Clojure version 1.2
Source
extend-type
macro
Usage: (extend-type t & specs)
A macro that expands into an extend call. Useful when you are
supplying the definitions explicitly inline, extend-type
automatically creates the maps required by extend. Propagates the
class as a type hint on the first argument of all fns.
(extend-type MyType
Countable
(cnt [c] ...)
Foo
(bar [x y] ...)
(baz ([x] ...) ([x y & zs] ...)))
expands into:
(extend MyType
Countable
{:cnt (fn [c] ...)}
Foo
{:baz (fn ([x] ...) ([x y & zs] ...))
:bar (fn [x y] ...)})
Added in Clojure version 1.2
Source
extenders
function
Usage: (extenders protocol)
Returns a collection of the types explicitly extending protocol
Added in Clojure version 1.2
Source
extends?
function
Usage: (extends? protocol atype)
Returns true if atype extends protocol
Added in Clojure version 1.2
Source
false?
function
Usage: (false? x)
Returns true if x is the value false, false otherwise.
Added in Clojure version 1.0
Source
ffirst
function
Usage: (ffirst x)
Same as (first (first x))
Added in Clojure version 1.0
Source
file-seq
function
Usage: (file-seq dir)
A tree seq on java.io.Files
Added in Clojure version 1.0
Source
filter
function
Usage: (filter pred)
(filter pred coll)
Returns a lazy sequence of the items in coll for which
(pred item) returns logical true. pred must be free of side-effects.
Returns a transducer when no collection is provided.
Added in Clojure version 1.0
Source
filterv
function
Usage: (filterv pred coll)
Returns a vector of the items in coll for which
(pred item) returns logical true. pred must be free of side-effects.
Added in Clojure version 1.4
Source
finally
special syntax
Syntax for use with try.
Please see https://clojure.org/reference/special_forms#try
Added in Clojure version 1.0
find
function
Usage: (find map key)
Returns the map entry for key, or nil if key not present.
Added in Clojure version 1.0
Source
find-keyword
function
Usage: (find-keyword name)
(find-keyword ns name)
Returns a Keyword with the given namespace and name if one already
exists. This function will not intern a new keyword. If the keyword
has not already been interned, it will return nil. Do not use :
in the keyword strings, it will be added automatically.
Added in Clojure version 1.3
Source
find-ns
function
Usage: (find-ns sym)
Returns the namespace named by the symbol or nil if it doesn't exist.
Added in Clojure version 1.0
Source
find-var
function
Usage: (find-var sym)
Returns the global var named by the namespace-qualified symbol, or
nil if no var with that name.
Added in Clojure version 1.0
Source
first
function
Usage: (first coll)
Returns the first item in the collection. Calls seq on its
argument. If coll is nil, returns nil.
Added in Clojure version 1.0
Source
flatten
function
Usage: (flatten x)
Takes any nested combination of sequential things (lists, vectors,
etc.) and returns their contents as a single, flat lazy sequence.
(flatten nil) returns an empty sequence.
Added in Clojure version 1.2
Source
float
function
Usage: (float x)
Coerce to float
Added in Clojure version 1.0
Source
float-array
function
Usage: (float-array size-or-seq)
(float-array size init-val-or-seq)
Creates an array of floats
Added in Clojure version 1.0
Source
float?
function
Usage: (float? n)
Returns true if n is a floating point number
Added in Clojure version 1.0
Source
floats
function
Usage: (floats xs)
Casts to float[]
Added in Clojure version 1.0
Source
flush
function
Usage: (flush)
Flushes the output stream that is the current value of
*out*
Added in Clojure version 1.0
Source
fn
special form
Usage: (fn name? [params*] exprs*)
(fn name? ([params*] exprs*) +)
params => positional-params*, or positional-params* & rest-param
positional-param => binding-form
rest-param => binding-form
binding-form => name, or destructuring-form
Defines a function.
See https://clojure.org/reference/special_forms#fn for more information
Specs:
Args: (fspec
:args
(cat
:fn-name (? simple-symbol?)
:fn-tail (alt
:arity-1 :clojure.core.specs.alpha/params+body
:arity-n (+
(spec
:clojure.core.specs.alpha/params+body))))
:ret
any?
:fn
nil)
Ret: (fspec
:args
(cat
:fn-name (? simple-symbol?)
:fn-tail (alt
:arity-1 :clojure.core.specs.alpha/params+body
:arity-n (+
(spec
:clojure.core.specs.alpha/params+body))))
:ret
any?
:fn
nil)
Added in Clojure version 1.0
Source
fn?
function
Usage: (fn? x)
Returns true if x implements Fn, i.e. is an object created via fn.
Added in Clojure version 1.0
Source
fnext
function
Usage: (fnext x)
Same as (first (next x))
Added in Clojure version 1.0
Source
fnil
function
Usage: (fnil f x)
(fnil f x y)
(fnil f x y z)
Takes a function f, and returns a function that calls f, replacing
a nil first argument to f with the supplied value x. Higher arity
versions can replace arguments in the second and third
positions (y, z). Note that the function f can take any number of
arguments, not just the one(s) being nil-patched.
Added in Clojure version 1.2
Source
for
macro
Usage: (for seq-exprs body-expr)
List comprehension. Takes a vector of one or more
binding-form/collection-expr pairs, each followed by zero or more
modifiers, and yields a lazy sequence of evaluations of expr.
Collections are iterated in a nested fashion, rightmost fastest,
and nested coll-exprs can refer to bindings created in prior
binding-forms. Supported modifiers are: :let [binding-form expr ...],
:while test, :when test.
(take 100 (for [x (range 100000000) y (range 1000000) :while (< y x)] [x y]))
Added in Clojure version 1.0
Source
force
function
Usage: (force x)
If x is a Delay, returns the (possibly cached) value of its expression, else returns x
Added in Clojure version 1.0
Source
function
Usage: (format fmt & args)
Formats a string using java.lang.String.format, see java.util.Formatter for format
string syntax
Added in Clojure version 1.0
Source
frequencies
function
Usage: (frequencies coll)
Returns a map from distinct items in coll to the number of times
they appear.
Added in Clojure version 1.2
Source
future
macro
Usage: (future & body)
Takes a body of expressions and yields a future object that will
invoke the body in another thread, and will cache the result and
return it on all subsequent calls to deref/@. If the computation has
not yet finished, calls to deref/@ will block, unless the variant of
deref with timeout is used. See also - realized?.
Added in Clojure version 1.1
Source
future-call
function
Usage: (future-call f)
Takes a function of no args and yields a future object that will
invoke the function in another thread, and will cache the result and
return it on all subsequent calls to deref/@. If the computation has
not yet finished, calls to deref/@ will block, unless the variant
of deref with timeout is used. See also - realized?.
Added in Clojure version 1.1
Source
future-cancel
function
Usage: (future-cancel f)
Cancels the future, if possible.
Added in Clojure version 1.1
Source
future-cancelled?
function
Usage: (future-cancelled? f)
Returns true if future f is cancelled
Added in Clojure version 1.1
Source
future-done?
function
Usage: (future-done? f)
Returns true if future f is done
Added in Clojure version 1.1
Source
future?
function
Usage: (future? x)
Returns true if x is a future
Added in Clojure version 1.1
Source
gen-class
macro
Usage: (gen-class & options)
When compiling, generates compiled bytecode for a class with the
given package-qualified :name (which, as all names in these
parameters, can be a string or symbol), and writes the .class file
to the *compile-path* directory. When not compiling, does
nothing. The gen-class construct contains no implementation, as the
implementation will be dynamically sought by the generated class in
functions in an implementing Clojure namespace. Given a generated
class org.mydomain.MyClass with a method named mymethod, gen-class
will generate an implementation that looks for a function named by
(str prefix mymethod) (default prefix: "-") in a
Clojure namespace specified by :impl-ns
(defaults to the current namespace). All inherited methods,
generated methods, and init and main functions (see :methods, :init,
and :main below) will be found similarly prefixed. By default, the
static initializer for the generated class will attempt to load the
Clojure support code for the class as a resource from the classpath,
e.g. in the example case, ``org/mydomain/MyClass__init.class``. This
behavior can be controlled by :load-impl-ns
Note that methods with a maximum of 18 parameters are supported.
In all subsequent sections taking types, the primitive types can be
referred to by their Java names (int, float etc), and classes in the
java.lang package can be used without a package qualifier. All other
classes must be fully qualified.
Options should be a set of key/value pairs, all except for :name are optional:
:name aname
The package-qualified name of the class to be generated
:extends aclass
Specifies the superclass, the non-private methods of which will be
overridden by the class. If not provided, defaults to Object.
:implements [interface ...]
One or more interfaces, the methods of which will be implemented by the class.
:init name
If supplied, names a function that will be called with the arguments
to the constructor. Must return [ [superclass-constructor-args] state]
If not supplied, the constructor args are passed directly to
the superclass constructor and the state will be nil
:constructors {[param-types] [super-param-types], ...}
By default, constructors are created for the generated class which
match the signature(s) of the constructors for the superclass. This
parameter may be used to explicitly specify constructors, each entry
providing a mapping from a constructor signature to a superclass
constructor signature. When you supply this, you must supply an :init
specifier.
:post-init name
If supplied, names a function that will be called with the object as
the first argument, followed by the arguments to the constructor.
It will be called every time an object of this class is created,
immediately after all the inherited constructors have completed.
Its return value is ignored.
:methods [ [name [param-types] return-type], ...]
The generated class automatically defines all of the non-private
methods of its superclasses/interfaces. This parameter can be used
to specify the signatures of additional methods of the generated
class. Static methods can be specified with ^{:static true} in the
signature's metadata. Do not repeat superclass/interface signatures
here.
:main boolean
If supplied and true, a static public main function will be generated. It will
pass each string of the String[] argument as a separate argument to
a function called (str prefix main).
:factory name
If supplied, a (set of) public static factory function(s) will be
created with the given name, and the same signature(s) as the
constructor(s).
:state name
If supplied, a public final instance field with the given name will be
created. You must supply an :init function in order to provide a
value for the state. Note that, though final, the state can be a ref
or agent, supporting the creation of Java objects with transactional
or asynchronous mutation semantics.
:exposes {protected-field-name {:get name :set name}, ...}
Since the implementations of the methods of the generated class
occur in Clojure functions, they have no access to the inherited
protected fields of the superclass. This parameter can be used to
generate public getter/setter methods exposing the protected field(s)
for use in the implementation.
:exposes-methods {super-method-name exposed-name, ...}
It is sometimes necessary to call the superclass' implementation of an
overridden method. Those methods may be exposed and referred in
the new method implementation by a local name.
:prefix string
Default: "-" Methods called e.g. Foo will be looked up in vars called
prefixFoo in the implementing ns.
:impl-ns name
Default: the name of the current ns. Implementations of methods will be
looked up in this namespace.
:load-impl-ns boolean
Default: true. Causes the static initializer for the generated class
to reference the load code for the implementing namespace. Should be
true when implementing-ns is the default, false if you intend to
load the code via some other method.
Added in Clojure version 1.0
Source
gen-interface
macro
Usage: (gen-interface & options)
When compiling, generates compiled bytecode for an interface with
the given package-qualified :name (which, as all names in these
parameters, can be a string or symbol), and writes the .class file
to the *compile-path* directory. When not compiling, does nothing.
In all subsequent sections taking types, the primitive types can be
referred to by their Java names (int, float etc), and classes in the
java.lang package can be used without a package qualifier. All other
classes must be fully qualified.
Options should be a set of key/value pairs, all except for :name are
optional:
:name aname
The package-qualified name of the class to be generated
:extends [interface ...]
One or more interfaces, which will be extended by this interface.
:methods [ [name [param-types] return-type], ...]
This parameter is used to specify the signatures of the methods of
the generated interface. Do not repeat superinterface signatures
here.
Added in Clojure version 1.0
Source
gensym
function
Usage: (gensym)
(gensym prefix-string)
Returns a new symbol with a unique name. If a prefix string is
supplied, the name is prefix# where # is some unique number. If
prefix is not supplied, the prefix is 'G__'.
Added in Clojure version 1.0
Source
get
function
Usage: (get map key)
(get map key not-found)
Returns the value mapped to key, not-found or nil if key not present
in associative collection, set, string, array, or ILookup instance.
Added in Clojure version 1.0
Source
get-in
function
Usage: (get-in m ks)
(get-in m ks not-found)
Returns the value in a nested associative structure,
where ks is a sequence of keys. Returns nil if the key
is not present, or the not-found value if supplied.
Added in Clojure version 1.2
Source
get-method
function
Usage: (get-method multifn dispatch-val)
Given a multimethod and a dispatch value, returns the dispatch fn
that would apply to that value, or nil if none apply and no default
Added in Clojure version 1.0
Source
get-proxy-class
function
Usage: (get-proxy-class & bases)
Takes an optional single class followed by zero or more
interfaces. If not supplied class defaults to Object. Creates an
returns an instance of a proxy class derived from the supplied
classes. The resulting value is cached and used for any subsequent
requests for the same class set. Returns a Class object.
Added in Clojure version 1.0
Source
get-thread-bindings
function
Usage: (get-thread-bindings)
Get a map with the Var/value pairs which is currently in effect for the
current thread.
Added in Clojure version 1.1
Source
get-validator
function
Usage: (get-validator iref)
Gets the validator-fn for a var/ref/agent/atom.
Added in Clojure version 1.0
Source
group-by
function
Usage: (group-by f coll)
Returns a map of the elements of coll keyed by the result of
f on each element. The value at each key will be a vector of the
corresponding elements, in the order they appeared in coll.
Added in Clojure version 1.2
Source
halt-when
function
Usage: (halt-when pred)
(halt-when pred retf)
Returns a transducer that ends transduction when pred returns true
for an input. When retf is supplied it must be a fn of 2 arguments -
it will be passed the (completed) result so far and the input that
triggered the predicate, and its return value (if it does not throw
an exception) will be the return value of the transducer. If retf
is not supplied, the input that triggered the predicate will be
returned. If the predicate never returns true the transduction is
unaffected.
Added in Clojure version 1.9
Source
hash
function
Usage: (hash x)
Returns the hash code of its argument. Note this is the hash code
consistent with =, and thus is different than .hashCode for Integer,
Short, Byte and Clojure collections.
Added in Clojure version 1.0
Source
hash-map
function
Usage: (hash-map)
(hash-map & keyvals)
keyval => key val
Returns a new hash map with supplied mappings. If any keys are
equal, they are handled as if by repeated uses of assoc.
Added in Clojure version 1.0
Source
hash-ordered-coll
function
Usage: (hash-ordered-coll coll)
Returns the hash code, consistent with =, for an external ordered
collection implementing Iterable.
See http://clojure.org/data_structures#hash for full algorithms.
Added in Clojure version 1.6
Source
hash-set
function
Usage: (hash-set)
(hash-set & keys)
Returns a new hash set with supplied keys. Any equal keys are
handled as if by repeated uses of conj.
Added in Clojure version 1.0
Source
hash-unordered-coll
function
Usage: (hash-unordered-coll coll)
Returns the hash code, consistent with =, for an external unordered
collection implementing Iterable. For maps, the iterator should
return map entries whose hash is computed as
(hash-ordered-coll [k v]).
See http://clojure.org/data_structures#hash for full algorithms.
Added in Clojure version 1.6
Source
ident?
function
Usage: (ident? x)
Return true if x is a symbol or keyword
Added in Clojure version 1.9
Source
identical?
function
Usage: (identical? x y)
Tests if 2 arguments are the same object
Added in Clojure version 1.0
Source
identity
function
Usage: (identity x)
Returns its argument.
Added in Clojure version 1.0
Source
if
special form
Usage: (if test then else?)
Evaluates test. If not the singular values nil or false,
evaluates and yields then, otherwise, evaluates and yields else. If
else is not supplied it defaults to nil.
Please see https://clojure.org/reference/special_forms#if
Added in Clojure version 1.0
if-let
macro
Usage: (if-let bindings then)
(if-let bindings then else & oldform)
bindings => binding-form test
If test is true, evaluates then with binding-form bound to the value of
test, if not, yields else
Specs:
Args: (fspec
:args
(cat
:bindings (and vector? :clojure.core.specs.alpha/binding)
:then any?
:else (? any?))
:ret
any?
:fn
nil)
Ret: (fspec
:args
(cat
:bindings (and vector? :clojure.core.specs.alpha/binding)
:then any?
:else (? any?))
:ret
any?
:fn
nil)
Added in Clojure version 1.0
Source
if-not
macro
Usage: (if-not test then)
(if-not test then else)
Evaluates test. If logical false, evaluates and returns then expr,
otherwise else expr, if supplied, else nil.
Added in Clojure version 1.0
Source
if-some
macro
Usage: (if-some bindings then)
(if-some bindings then else & oldform)
bindings => binding-form test
If test is not nil, evaluates then with binding-form bound to the
value of test, if not, yields else
Added in Clojure version 1.6
Source
ifn?
function
Usage: (ifn? x)
Returns true if x implements IFn. Note that many data structures
(e.g. sets and maps) implement IFn
Added in Clojure version 1.0
Source
import
macro
Usage: (import & import-symbols-or-lists)
import-list => (package-symbol class-name-symbols*)
For each name in class-name-symbols, adds a mapping from name to the
class named by package.name to the current namespace. Use :import in the ns
macro in preference to calling this directly.
Specs:
Args: (fspec
:args
:clojure.core.specs.alpha/quotable-import-list
:ret
any?
:fn
nil)
Ret: (fspec
:args
:clojure.core.specs.alpha/quotable-import-list
:ret
any?
:fn
nil)
Added in Clojure version 1.0
Source
in-ns
function
Usage: (in-ns name)
Sets *ns* to the namespace named by the symbol, creating it if needed.
Added in Clojure version 1.0
inc
function
Usage: (inc x)
Returns a number one greater than num. Does not auto-promote
longs, will throw on overflow. See also: inc'
Added in Clojure version 1.2
Source
inc'
function
Usage: (inc' x)
Returns a number one greater than num. Supports arbitrary precision.
See also: inc
Added in Clojure version 1.0
Source
indexed?
function
Usage: (indexed? coll)
Return true if coll implements Indexed, indicating efficient lookup by index
Added in Clojure version 1.9
Source
infinite?
function
Usage: (infinite? num)
Returns true if num is negative or positive infinity, else false
Added in Clojure version 1.11
Source
init-proxy
function
Usage: (init-proxy proxy mappings)
Takes a proxy instance and a map of strings (which must
correspond to methods of the proxy superclass/superinterfaces) to
fns (which must take arguments matching the corresponding method,
plus an additional (explicit) first arg corresponding to this, and
sets the proxy's fn map. Returns the proxy.
Added in Clojure version 1.0
Source
inst-ms
function
Usage: (inst-ms inst)
Return the number of milliseconds since January 1, 1970, 00:00:00 GMT
Added in Clojure version 1.9
Source
inst?
function
Usage: (inst? x)
Return true if x satisfies Inst
Added in Clojure version 1.9
Source
instance?
function
Usage: (instance? c x)
Evaluates x and tests if it is an instance of the class
c. Returns true or false
Added in Clojure version 1.0
Source
int
function
Usage: (int x)
Coerce to int
Added in Clojure version 1.0
Source
int-array
function
Usage: (int-array size-or-seq)
(int-array size init-val-or-seq)
Creates an array of ints
Added in Clojure version 1.0
Source
int?
function
Usage: (int? x)
Return true if x is a fixed precision integer
Added in Clojure version 1.9
Source
integer?
function
Usage: (integer? n)
Returns true if n is an integer
Added in Clojure version 1.0
Source
interleave
function
Usage: (interleave)
(interleave c1)
(interleave c1 c2)
(interleave c1 c2 & colls)
Returns a lazy seq of the first item in each coll, then the second etc.
Added in Clojure version 1.0
Source
intern
function
Usage: (intern ns name)
(intern ns name val)
Finds or creates a var named by the symbol name in the namespace
ns (which can be a symbol or a namespace), setting its root binding
to val if supplied. The namespace must exist. The var will adopt any
metadata from the name symbol. Returns the var.
Added in Clojure version 1.0
Source
interpose
function
Usage: (interpose sep)
(interpose sep coll)
Returns a lazy seq of the elements of coll separated by sep.
Returns a stateful transducer when no collection is provided.
Added in Clojure version 1.0
Source
into
function
Usage: (into)
(into to)
(into to from)
(into to xform from)
Returns a new coll consisting of to with all of the items of
from conjoined. A transducer may be supplied.
(into x) returns x. (into) returns [].
Added in Clojure version 1.0
Source
into-array
function
Usage: (into-array aseq)
(into-array type aseq)
Returns an array with components set to the values in aseq. The array's
component type is type if provided, or the type of the first value in
aseq if present, or Object. All values in aseq must be compatible with
the component type. Class objects for the primitive types can be obtained
using, e.g., Integer/TYPE.
Added in Clojure version 1.0
Source
ints
function
Usage: (ints xs)
Casts to int[]
Added in Clojure version 1.0
Source
io!
macro
Usage: (io! & body)
If an io! block occurs in a transaction, throws an
IllegalStateException, else runs body in an implicit do. If the
first expression in body is a literal string, will use that as the
exception message.
Added in Clojure version 1.0
Source
isa?
function
Usage: (isa? child parent)
(isa? h child parent)
Returns true if (= child parent), or child is directly or indirectly derived from
parent, either via a Java type inheritance relationship or a
relationship established via derive. h must be a hierarchy obtained
from make-hierarchy, if not supplied defaults to the global
hierarchy
Added in Clojure version 1.0
Source
iterate
function
Usage: (iterate f x)
Returns a lazy (infinite!) sequence of x, (f x), (f (f x)) etc.
f must be free of side-effects
Added in Clojure version 1.0
Source
iteration
function
Usage: (iteration step & {:keys [somef vf kf initk], :or {vf identity, kf identity, somef some?, initk nil}})
Creates a seqable/reducible via repeated calls to step,
a function of some (continuation token) 'k'. The first call to step
will be passed initk, returning 'ret'. Iff (somef ret) is true,
(vf ret) will be included in the iteration, else iteration will
terminate and vf/kf will not be called. If (kf ret) is non-nil it
will be passed to the next step call, else iteration will terminate.
This can be used e.g. to consume APIs that return paginated or batched data.
step - (possibly impure) fn of 'k' -> 'ret'
:somef - fn of 'ret' -> logical true/false, default 'some?'
:vf - fn of 'ret' -> 'v', a value produced by the iteration, default 'identity'
:kf - fn of 'ret' -> 'next-k' or nil (signaling 'do not continue'), default 'identity'
:initk - the first value passed to step, default 'nil'
It is presumed that step with non-initk is unreproducible/non-idempotent.
If step with initk is unreproducible it is on the consumer to not consume twice.
Added in Clojure version 1.11
Source
iterator-seq
function
Usage: (iterator-seq iter)
Returns a seq on a java.util.Iterator. Note that most collections
providing iterators implement Iterable and thus support seq directly.
Seqs cache values, thus iterator-seq should not be used on any
iterator that repeatedly returns the same mutable object.
Added in Clojure version 1.0
Source
juxt
function
Usage: (juxt f)
(juxt f g)
(juxt f g h)
(juxt f g h & fs)
Takes a set of functions and returns a fn that is the juxtaposition
of those fns. The returned fn takes a variable number of args, and
returns a vector containing the result of applying each fn to the
args (left-to-right).
((juxt a b c) x) => [(a x) (b x) (c x)]
Added in Clojure version 1.1
Source
keep
function
Usage: (keep f)
(keep f coll)
Returns a lazy sequence of the non-nil results of (f item). Note,
this means false return values will be included. f must be free of
side-effects. Returns a transducer when no collection is provided.
Added in Clojure version 1.2
Source
keep-indexed
function
Usage: (keep-indexed f)
(keep-indexed f coll)
Returns a lazy sequence of the non-nil results of (f index item). Note,
this means false return values will be included. f must be free of
side-effects. Returns a stateful transducer when no collection is
provided.
Added in Clojure version 1.2
Source
key
function
Usage: (key e)
Returns the key of the map entry.
Added in Clojure version 1.0
Source
keys
function
Usage: (keys map)
Returns a sequence of the map's keys, in the same order as (seq map).
Added in Clojure version 1.0
Source
keyword
function
Usage: (keyword name)
(keyword ns name)
Returns a Keyword with the given namespace and name. Do not use :
in the keyword strings, it will be added automatically.
Added in Clojure version 1.0
Source
keyword?
function
Usage: (keyword? x)
Return true if x is a Keyword
Added in Clojure version 1.0
Source
last
function
Usage: (last coll)
Return the last item in coll, in linear time
Added in Clojure version 1.0
Source
lazy-cat
macro
Usage: (lazy-cat & colls)
Expands to code which yields a lazy sequence of the concatenation
of the supplied colls. Each coll expr is not evaluated until it is
needed.
(lazy-cat xs ys zs) === (concat (lazy-seq xs) (lazy-seq ys) (lazy-seq zs))
Added in Clojure version 1.0
Source
lazy-seq
macro
Usage: (lazy-seq & body)
Takes a body of expressions that returns an ISeq or nil, and yields
a Seqable object that will invoke the body only the first time seq
is called, and will cache the result and return it on all subsequent
seq calls. See also - realized?
Added in Clojure version 1.0
Source
let
special form
Usage: (let [bindings*] exprs*)
binding => binding-form init-expr
binding-form => name, or destructuring-form
destructuring-form => map-destructure-form, or seq-destructure-form
Evaluates the exprs in a lexical context in which the symbols in
the binding-forms are bound to their respective init-exprs or parts
therein.
See https://clojure.org/reference/special_forms#binding-forms for
more information about destructuring.
Specs:
Args: (fspec
:args
(cat
:bindings :clojure.core.specs.alpha/bindings
:body (* any?))
:ret
any?
:fn
nil)
Ret: (fspec
:args
(cat
:bindings :clojure.core.specs.alpha/bindings
:body (* any?))
:ret
any?
:fn
nil)
Added in Clojure version 1.0
Source
letfn
special form
Usage: (letfn [fnspecs*] exprs*)
fnspec ==> (fname [params*] exprs) or (fname ([params*] exprs)+)
Takes a vector of function specs and a body, and generates a set of
bindings of functions to their names. All of the names are available
in all of the definitions of the functions, as well as the body.
Added in Clojure version 1.0
Source
line-seq
function
Usage: (line-seq rdr)
Returns the lines of text from rdr as a lazy sequence of strings.
rdr must implement java.io.BufferedReader.
Added in Clojure version 1.0
Source
list
function
Usage: (list & items)
Creates a new list containing the items.
Added in Clojure version 1.0
Source
list*
function
Usage: (list* args)
(list* a args)
(list* a b args)
(list* a b c args)
(list* a b c d & more)
Creates a new seq containing the items prepended to the rest, the
last of which will be treated as a sequence.
Added in Clojure version 1.0
Source
list?
function
Usage: (list? x)
Returns true if x implements IPersistentList
Added in Clojure version 1.0
Source
load
function
Usage: (load & paths)
Loads Clojure code from resources in classpath. A path is interpreted as
classpath-relative if it begins with a slash or relative to the root
directory for the current namespace otherwise.
Added in Clojure version 1.0
Source
load-file
function
Usage: (load-file name)
Sequentially read and evaluate the set of forms contained in the file.
Added in Clojure version 1.0
load-reader
function
Usage: (load-reader rdr)
Sequentially read and evaluate the set of forms contained in the
stream/file
Added in Clojure version 1.0
Source
load-string
function
Usage: (load-string s)
Sequentially read and evaluate the set of forms contained in the
string
Added in Clojure version 1.0
Source
loaded-libs
function
Usage: (loaded-libs)
Returns a sorted set of symbols naming the currently loaded libs
Added in Clojure version 1.0
Source
locking
macro
Usage: (locking x & body)
Executes exprs in an implicit do, while holding the monitor of x.
Will release the monitor of x in all circumstances.
Added in Clojure version 1.0
Source
long
function
Usage: (long x)
Coerce to long
Added in Clojure version 1.0
Source
long-array
function
Usage: (long-array size-or-seq)
(long-array size init-val-or-seq)
Creates an array of longs
Added in Clojure version 1.0
Source
longs
function
Usage: (longs xs)
Casts to long[]
Added in Clojure version 1.0
Source
loop
special form
Usage: (loop [bindings*] exprs*)
Evaluates the exprs in a lexical context in which the symbols in
the binding-forms are bound to their respective init-exprs or parts
therein. Acts as a recur target.
Added in Clojure version 1.0
Source
macroexpand
function
Usage: (macroexpand form)
Repeatedly calls macroexpand-1 on form until it no longer
represents a macro form, then returns it. Note neither
macroexpand-1 nor macroexpand expand macros in subforms.
Added in Clojure version 1.0
Source
macroexpand-1
function
Usage: (macroexpand-1 form)
If form represents a macro form, returns its expansion,
else returns form.
Added in Clojure version 1.0
Source
make-array
function
Usage: (make-array type len)
(make-array type dim & more-dims)
Creates and returns an array of instances of the specified class of
the specified dimension(s). Note that a class object is required.
Class objects can be obtained by using their imported or
fully-qualified name. Class objects for the primitive types can be
obtained using, e.g., Integer/TYPE.
Added in Clojure version 1.0
Source
make-hierarchy
function
Usage: (make-hierarchy)
Creates a hierarchy object for use with derive, isa? etc.
Added in Clojure version 1.0
Source
map
function
Usage: (map f)
(map f coll)
(map f c1 c2)
(map f c1 c2 c3)
(map f c1 c2 c3 & colls)
Returns a lazy sequence consisting of the result of applying f to
the set of first items of each coll, followed by applying f to the
set of second items in each coll, until any one of the colls is
exhausted. Any remaining items in other colls are ignored. Function
f should accept number-of-colls arguments. Returns a transducer when
no collection is provided.
Added in Clojure version 1.0
Source
map-entry?
function
Usage: (map-entry? x)
Return true if x is a map entry
Added in Clojure version 1.8
Source
map-indexed
function
Usage: (map-indexed f)
(map-indexed f coll)
Returns a lazy sequence consisting of the result of applying f to 0
and the first item of coll, followed by applying f to 1 and the second
item in coll, etc, until coll is exhausted. Thus function f should
accept 2 arguments, index and item. Returns a stateful transducer when
no collection is provided.
Added in Clojure version 1.2
Source
map?
function
Usage: (map? x)
Return true if x implements IPersistentMap
Added in Clojure version 1.0
Source
mapcat
function
Usage: (mapcat f)
(mapcat f & colls)
Returns the result of applying concat to the result of applying map
to f and colls. Thus function f should return a collection. Returns
a transducer when no collections are provided
Added in Clojure version 1.0
Source
mapv
function
Usage: (mapv f coll)
(mapv f c1 c2)
(mapv f c1 c2 c3)
(mapv f c1 c2 c3 & colls)
Returns a vector consisting of the result of applying f to the
set of first items of each coll, followed by applying f to the set
of second items in each coll, until any one of the colls is
exhausted. Any remaining items in other colls are ignored. Function
f should accept number-of-colls arguments.
Added in Clojure version 1.4
Source
max
function
Usage: (max x)
(max x y)
(max x y & more)
Returns the greatest of the nums.
Added in Clojure version 1.0
Source
max-key
function
Usage: (max-key k x)
(max-key k x y)
(max-key k x y & more)
Returns the x for which (k x), a number, is greatest.
If there are multiple such xs, the last one is returned.
Added in Clojure version 1.0
Source
memfn
macro
Usage: (memfn name & args)
Expands into code that creates a fn that expects to be passed an
object and any args and calls the named instance method on the
object passing the args. Use when you want to treat a Java method as
a first-class fn. name may be type-hinted with the method receiver's
type in order to avoid reflective calls.
Added in Clojure version 1.0
Source
memoize
function
Usage: (memoize f)
Returns a memoized version of a referentially transparent function. The
memoized version of the function keeps a cache of the mapping from arguments
to results and, when calls with the same arguments are repeated often, has
higher performance at the expense of higher memory use.
Added in Clojure version 1.0
Source
merge
function
Usage: (merge & maps)
Returns a map that consists of the rest of the maps conj-ed onto
the first. If a key occurs in more than one map, the mapping from
the latter (left-to-right) will be the mapping in the result.
Added in Clojure version 1.0
Source
merge-with
function
Usage: (merge-with f & maps)
Returns a map that consists of the rest of the maps conj-ed onto
the first. If a key occurs in more than one map, the mapping(s)
from the latter (left-to-right) will be combined with the mapping in
the result by calling (f val-in-result val-in-latter).
Added in Clojure version 1.0
Source
function
Usage: (meta obj)
Returns the metadata of obj, returns nil if there is no metadata.
Added in Clojure version 1.0
Source
methods
function
Usage: (methods multifn)
Given a multimethod, returns a map of dispatch values -> dispatch fns
Added in Clojure version 1.0
Source
min
function
Usage: (min x)
(min x y)
(min x y & more)
Returns the least of the nums.
Added in Clojure version 1.0
Source
min-key
function
Usage: (min-key k x)
(min-key k x y)
(min-key k x y & more)
Returns the x for which (k x), a number, is least.
If there are multiple such xs, the last one is returned.
Added in Clojure version 1.0
Source
mix-collection-hash
function
Usage: (mix-collection-hash hash-basis count)
Mix final collection hash for ordered or unordered collections.
hash-basis is the combined collection hash, count is the number
of elements included in the basis. Note this is the hash code
consistent with =, different from .hashCode.
See http://clojure.org/data_structures#hash for full algorithms.
Added in Clojure version 1.6
Source
mod
function
Usage: (mod num div)
Modulus of num and div. Truncates toward negative infinity.
Added in Clojure version 1.0
Source
monitor-enter
special form
Usage: (monitor-enter x)
Synchronization primitive that should be avoided
in user code. Use the 'locking' macro.
Please see https://clojure.org/reference/special_forms#monitor-enter
Added in Clojure version 1.0
monitor-exit
special form
Usage: (monitor-exit x)
Synchronization primitive that should be avoided
in user code. Use the 'locking' macro.
Please see https://clojure.org/reference/special_forms#monitor-exit
Added in Clojure version 1.0
name
function
Usage: (name x)
Returns the name String of a string, symbol or keyword.
Added in Clojure version 1.0
Source
namespace
function
Usage: (namespace x)
Returns the namespace String of a symbol or keyword, or nil if not present.
Added in Clojure version 1.0
Source
namespace-munge
function
Usage: (namespace-munge ns)
Convert a Clojure namespace name to a legal Java package name.
Added in Clojure version 1.2
Source
nat-int?
function
Usage: (nat-int? x)
Return true if x is a non-negative fixed precision integer
Added in Clojure version 1.9
Source
neg-int?
function
Usage: (neg-int? x)
Return true if x is a negative fixed precision integer
Added in Clojure version 1.9
Source
neg?
function
Usage: (neg? num)
Returns true if num is less than zero, else false
Added in Clojure version 1.0
Source
new
special form
Usage: (Classname. args*)
(new Classname args*)
The args, if any, are evaluated from left to right, and
passed to the constructor of the class named by Classname. The
constructed object is returned.
Please see https://clojure.org/java_interop#new
Added in Clojure version 1.0
newline
function
Usage: (newline)
Writes a platform-specific newline to *out*
Added in Clojure version 1.0
Source
next
function
Usage: (next coll)
Returns a seq of the items after the first. Calls seq on its
argument. If there are no more items, returns nil.
Added in Clojure version 1.0
Source
nfirst
function
Usage: (nfirst x)
Same as (next (first x))
Added in Clojure version 1.0
Source
nil?
function
Usage: (nil? x)
Returns true if x is nil, false otherwise.
Added in Clojure version 1.0
Source
nnext
function
Usage: (nnext x)
Same as (next (next x))
Added in Clojure version 1.0
Source
not
function
Usage: (not x)
Returns true if x is logical false, false otherwise.
Added in Clojure version 1.0
Source
not-any?
function
Usage: (not-any? pred coll)
Returns false if (pred x) is logical true for any x in coll,
else true.
Added in Clojure version 1.0
Source
not-empty
function
Usage: (not-empty coll)
If coll is empty, returns nil, else coll
Added in Clojure version 1.0
Source
not-every?
function
Usage: (not-every? pred coll)
Returns false if (pred x) is logical true for every x in
coll, else true.
Added in Clojure version 1.0
Source
not=
function
Usage: (not= x)
(not= x y)
(not= x y & more)
Same as (not (= obj1 obj2))
Added in Clojure version 1.0
Source
ns
macro
Usage: (ns name docstring? attr-map? references*)
Sets *ns* to the namespace named by name (unevaluated), creating it
if needed. references can be zero or more of: (:refer-clojure ...)
(:require ...) (:use ...) (:import ...) (:load ...) (:gen-class)
with the syntax of refer-clojure/require/use/import/load/gen-class
respectively, except the arguments are unevaluated and need not be
quoted. (:gen-class ...), when supplied, defaults to :name
corresponding to the ns name, :main true, :impl-ns same as ns, and
:init-impl-ns true. All options of gen-class are
supported. The :gen-class directive is ignored when not
compiling. If :gen-class is not supplied, when compiled only an
nsname__init.class will be generated. If :refer-clojure is not used, a
default (refer 'clojure.core) is used. Use of ns is preferred to
individual calls to in-ns/require/use/import:
(ns foo.bar
(:refer-clojure :exclude [ancestors printf])
(:require (clojure.contrib sql combinatorics))
(:use (my.lib this that))
(:import (java.util Date Timer Random)
(java.sql Connection Statement)))
Specs:
Args: (fspec
:args
:clojure.core.specs.alpha/ns-form
:ret
any?
:fn
nil)
Ret: (fspec
:args
:clojure.core.specs.alpha/ns-form
:ret
any?
:fn
nil)
Added in Clojure version 1.0
Source
ns-aliases
function
Usage: (ns-aliases ns)
Returns a map of the aliases for the namespace.
Added in Clojure version 1.0
Source
ns-imports
function
Usage: (ns-imports ns)
Returns a map of the import mappings for the namespace.
Added in Clojure version 1.0
Source
ns-interns
function
Usage: (ns-interns ns)
Returns a map of the intern mappings for the namespace.
Added in Clojure version 1.0
Source
ns-map
function
Usage: (ns-map ns)
Returns a map of all the mappings for the namespace.
Added in Clojure version 1.0
Source
ns-name
function
Usage: (ns-name ns)
Returns the name of the namespace, a symbol.
Added in Clojure version 1.0
Source
ns-publics
function
Usage: (ns-publics ns)
Returns a map of the public intern mappings for the namespace.
Added in Clojure version 1.0
Source
ns-refers
function
Usage: (ns-refers ns)
Returns a map of the refer mappings for the namespace.
Added in Clojure version 1.0
Source
ns-resolve
function
Usage: (ns-resolve ns sym)
(ns-resolve ns env sym)
Returns the var or Class to which a symbol will be resolved in the
namespace (unless found in the environment), else nil. Note that
if the symbol is fully qualified, the var/Class to which it resolves
need not be present in the namespace.
Added in Clojure version 1.0
Source
ns-unalias
function
Usage: (ns-unalias ns sym)
Removes the alias for the symbol from the namespace.
Added in Clojure version 1.0
Source
ns-unmap
function
Usage: (ns-unmap ns sym)
Removes the mappings for the symbol from the namespace.
Added in Clojure version 1.0
Source
nth
function
Usage: (nth coll index)
(nth coll index not-found)
Returns the value at the index. get returns nil if index out of
bounds, nth throws an exception unless not-found is supplied. nth
also works for strings, Java arrays, regex Matchers and Lists, and,
in O(n) time, for sequences.
Added in Clojure version 1.0
Source
nthnext
function
Usage: (nthnext coll n)
Returns the nth next of coll, (seq coll) when n is 0.
Added in Clojure version 1.0
Source
nthrest
function
Usage: (nthrest coll n)
Returns the nth rest of coll, coll when n is 0.
Added in Clojure version 1.3
Source
num
function
Usage: (num x)
Coerce to Number
Added in Clojure version 1.0
Source
number?
function
Usage: (number? x)
Returns true if x is a Number
Added in Clojure version 1.0
Source
numerator
function
Usage: (numerator r)
Returns the numerator part of a Ratio.
Added in Clojure version 1.2
Source
object-array
function
Usage: (object-array size-or-seq)
Creates an array of objects
Added in Clojure version 1.2
Source
odd?
function
Usage: (odd? n)
Returns true if n is odd, throws an exception if n is not an integer
Added in Clojure version 1.0
Source
or
macro
Usage: (or)
(or x)
(or x & next)
Evaluates exprs one at a time, from left to right. If a form
returns a logical true value, or returns that value and doesn't
evaluate any of the other expressions, otherwise it returns the
value of the last expression. (or) returns nil.
Added in Clojure version 1.0
Source
parents
function
Usage: (parents tag)
(parents h tag)
Returns the immediate parents of tag, either via a Java type
inheritance relationship or a relationship established via derive. h
must be a hierarchy obtained from make-hierarchy, if not supplied
defaults to the global hierarchy
Added in Clojure version 1.0
Source
parse-boolean
function
Usage: (parse-boolean s)
Parse strings "true" or "false" and return a boolean, or nil if invalid
Added in Clojure version 1.11
Source
parse-double
function
Usage: (parse-double s)
Parse string with floating point components and return a Double value,
or nil if parse fails.
Grammar: https://docs.oracle.com/javase/8/docs/api/java/lang/Double.html#valueOf-java.lang.String-
Added in Clojure version 1.11
Source
parse-long
function
Usage: (parse-long s)
Parse string of decimal digits with optional leading -/+ and return a
Long value, or nil if parse fails
Added in Clojure version 1.11
Source
parse-uuid
function
Usage: (parse-uuid s)
Parse a string representing a UUID and return a java.util.UUID instance,
or nil if parse fails.
Grammar: https://docs.oracle.com/javase/8/docs/api/java/util/UUID.html#toString--
Added in Clojure version 1.11
Source
partial
function
Usage: (partial f)
(partial f arg1)
(partial f arg1 arg2)
(partial f arg1 arg2 arg3)
(partial f arg1 arg2 arg3 & more)
Takes a function f and fewer than the normal arguments to f, and
returns a fn that takes a variable number of additional args. When
called, the returned function calls f with args + additional args.
Added in Clojure version 1.0
Source
partition
function
Usage: (partition n coll)
(partition n step coll)
(partition n step pad coll)
Returns a lazy sequence of lists of n items each, at offsets step
apart. If step is not supplied, defaults to n, i.e. the partitions
do not overlap. If a pad collection is supplied, use its elements as
necessary to complete last partition upto n items. In case there are
not enough padding elements, return a partition with less than n items.
Added in Clojure version 1.0
Source
partition-all
function
Usage: (partition-all n)
(partition-all n coll)
(partition-all n step coll)
Returns a lazy sequence of lists like partition, but may include
partitions with fewer than n items at the end. Returns a stateful
transducer when no collection is provided.
Added in Clojure version 1.2
Source
partition-by
function
Usage: (partition-by f)
(partition-by f coll)
Applies f to each value in coll, splitting it each time f returns a
new value. Returns a lazy seq of partitions. Returns a stateful
transducer when no collection is provided.
Added in Clojure version 1.2
Source
partitionv
function
Usage: (partitionv n coll)
(partitionv n step coll)
(partitionv n step pad coll)
Returns a lazy sequence of vectors of n items each, at offsets step
apart. If step is not supplied, defaults to n, i.e. the partitions
do not overlap. If a pad collection is supplied, use its elements as
necessary to complete last partition upto n items. In case there are
not enough padding elements, return a partition with less than n items.
Added in Clojure version 1.12
Source
partitionv-all
function
Usage: (partitionv-all n)
(partitionv-all n coll)
(partitionv-all n step coll)
Returns a lazy sequence of vector partitions, but may include
partitions with fewer than n items at the end.
Returns a stateful transducer when no collection is provided.
Added in Clojure version 1.12
Source
pcalls
function
Usage: (pcalls & fns)
Executes the no-arg fns in parallel, returning a lazy sequence of
their values
Added in Clojure version 1.0
Source
peek
function
Usage: (peek coll)
For a list or queue, same as first, for a vector, same as, but much
more efficient than, last. If the collection is empty, returns nil.
Added in Clojure version 1.0
Source
persistent!
function
Usage: (persistent! coll)
Returns a new, persistent version of the transient collection, in
constant time. The transient collection cannot be used after this
call, any such use will throw an exception.
Added in Clojure version 1.1
Source
pmap
function
Usage: (pmap f coll)
(pmap f coll & colls)
Like map, except f is applied in parallel. Semi-lazy in that the
parallel computation stays ahead of the consumption, but doesn't
realize the entire result unless required. Only useful for
computationally intensive functions where the time of f dominates
the coordination overhead.
Added in Clojure version 1.0
Source
pop
function
Usage: (pop coll)
For a list or queue, returns a new list/queue without the first
item, for a vector, returns a new vector without the last item. If
the collection is empty, throws an exception. Note - not the same
as next/butlast.
Added in Clojure version 1.0
Source
pop!
function
Usage: (pop! coll)
Removes the last item from a transient vector. If
the collection is empty, throws an exception. Returns coll
Added in Clojure version 1.1
Source
pop-thread-bindings
function
Usage: (pop-thread-bindings)
Pop one set of bindings pushed with push-binding before. It is an error to
pop bindings without pushing before.
Added in Clojure version 1.1
Source
pos-int?
function
Usage: (pos-int? x)
Return true if x is a positive fixed precision integer
Added in Clojure version 1.9
Source
pos?
function
Usage: (pos? num)
Returns true if num is greater than zero, else false
Added in Clojure version 1.0
Source
pr
dynamic function
Usage: (pr)
(pr x)
(pr x & more)
Prints the object(s) to the output stream that is the current value
of *out*. Prints the object(s), separated by spaces if there is
more than one. By default, pr and prn print in a way that objects
can be read by the reader
Added in Clojure version 1.0
Source
pr-str
function
Usage: (pr-str & xs)
pr to a string, returning it
Added in Clojure version 1.0
Source
prefer-method
function
Usage: (prefer-method multifn dispatch-val-x dispatch-val-y)
Causes the multimethod to prefer matches of dispatch-val-x over dispatch-val-y
when there is a conflict
Added in Clojure version 1.0
Source
prefers
function
Usage: (prefers multifn)
Given a multimethod, returns a map of preferred value -> set of other values
Added in Clojure version 1.0
Source
print
function
Usage: (print & more)
Prints the object(s) to the output stream that is the current value
of *out*. print and println produce output for human consumption.
Added in Clojure version 1.0
Source
print-str
function
Usage: (print-str & xs)
print to a string, returning it
Added in Clojure version 1.0
Source
printf
function
Usage: (printf fmt & args)
Prints formatted output, as per format
Added in Clojure version 1.0
Source
println
function
Usage: (println & more)
Same as print followed by (newline)
Added in Clojure version 1.0
Source
println-str
function
Usage: (println-str & xs)
println to a string, returning it
Added in Clojure version 1.0
Source
prn
function
Usage: (prn & more)
Same as pr followed by (newline). Observes *flush-on-newline*
Added in Clojure version 1.0
Source
prn-str
function
Usage: (prn-str & xs)
prn to a string, returning it
Added in Clojure version 1.0
Source
promise
function
Usage: (promise)
Returns a promise object that can be read with deref/@, and set,
once only, with deliver. Calls to deref/@ prior to delivery will
block, unless the variant of deref with timeout is used. All
subsequent derefs will return the same delivered value without
blocking. See also - realized?.
Added in Clojure version 1.1
Source
proxy
macro
Usage: (proxy class-and-interfaces args & fs)
class-and-interfaces - a vector of class names
args - a (possibly empty) vector of arguments to the superclass
constructor.
f => (name [params*] body) or
(name ([params*] body) ([params+] body) ...)
Expands to code which creates a instance of a proxy class that
implements the named class/interface(s) by calling the supplied
fns. A single class, if provided, must be first. If not provided it
defaults to Object.
The interfaces names must be valid interface types. If a method fn
is not provided for a class method, the superclass method will be
called. If a method fn is not provided for an interface method, an
UnsupportedOperationException will be thrown should it be
called. Method fns are closures and can capture the environment in
which proxy is called. Each method fn takes an additional implicit
first arg, which is bound to 'this. Note that while method fns can
be provided to override protected methods, they have no other access
to protected members, nor to super, as these capabilities cannot be
proxied.
Added in Clojure version 1.0
Source
proxy-mappings
function
Usage: (proxy-mappings proxy)
Takes a proxy instance and returns the proxy's fn map.
Added in Clojure version 1.0
Source
proxy-super
macro
Usage: (proxy-super meth & args)
Use to call a superclass method in the body of a proxy method.
Note, expansion captures 'this
Added in Clojure version 1.0
Source
push-thread-bindings
function
Usage: (push-thread-bindings bindings)
WARNING: This is a low-level function. Prefer high-level macros like
binding where ever possible.
Takes a map of Var/value pairs. Binds each Var to the associated value for
the current thread. Each call *MUST* be accompanied by a matching call to
pop-thread-bindings wrapped in a try-finally!
(push-thread-bindings bindings)
(try
...
(finally
(pop-thread-bindings)))
Added in Clojure version 1.1
Source
pvalues
macro
Usage: (pvalues & exprs)
Returns a lazy sequence of the values of the exprs, which are
evaluated in parallel
Added in Clojure version 1.0
Source
qualified-ident?
function
Usage: (qualified-ident? x)
Return true if x is a symbol or keyword with a namespace
Added in Clojure version 1.9
Source
qualified-keyword?
function
Usage: (qualified-keyword? x)
Return true if x is a keyword with a namespace
Added in Clojure version 1.9
Source
qualified-symbol?
function
Usage: (qualified-symbol? x)
Return true if x is a symbol with a namespace
Added in Clojure version 1.9
Source
quot
function
Usage: (quot num div)
quot[ient] of dividing numerator by denominator.
Added in Clojure version 1.0
Source
quote
special form
Usage: (quote form)
Yields the unevaluated form.
Please see https://clojure.org/reference/special_forms#quote
Added in Clojure version 1.0
rand
function
Usage: (rand)
(rand n)
Returns a random floating point number between 0 (inclusive) and
n (default 1) (exclusive).
Added in Clojure version 1.0
Source
rand-int
function
Usage: (rand-int n)
Returns a random integer between 0 (inclusive) and n (exclusive).
Added in Clojure version 1.0
Source
rand-nth
function
Usage: (rand-nth coll)
Return a random element of the (sequential) collection. Will have
the same performance characteristics as nth for the given
collection.
Added in Clojure version 1.2
Source
random-sample
function
Usage: (random-sample prob)
(random-sample prob coll)
Returns items from coll with random probability of prob (0.0 -
1.0). Returns a transducer when no collection is provided.
Added in Clojure version 1.7
Source
random-uuid
function
Usage: (random-uuid)
Returns a pseudo-randomly generated java.util.UUID instance (i.e. type 4).
See: https://docs.oracle.com/javase/8/docs/api/java/util/UUID.html#randomUUID--
Added in Clojure version 1.11
Source
range
function
Usage: (range)
(range end)
(range start end)
(range start end step)
Returns a lazy seq of nums from start (inclusive) to end
(exclusive), by step, where start defaults to 0, step to 1, and end to
infinity. When step is equal to 0, returns an infinite sequence of
start. When start is equal to end, returns empty list.
Added in Clojure version 1.0
Source
ratio?
function
Usage: (ratio? n)
Returns true if n is a Ratio
Added in Clojure version 1.0
Source
rational?
function
Usage: (rational? n)
Returns true if n is a rational number
Added in Clojure version 1.0
Source
rationalize
function
Usage: (rationalize num)
returns the rational value of num
Added in Clojure version 1.0
Source
re-find
function
Usage: (re-find m)
(re-find re s)
Returns the next regex match, if any, of string to pattern, using
java.util.regex.Matcher.find(). Uses re-groups to return the
groups.
Added in Clojure version 1.0
Source
re-groups
function
Usage: (re-groups m)
Returns the groups from the most recent match/find. If there are no
nested groups, returns a string of the entire match. If there are
nested groups, returns a vector of the groups, the first element
being the entire match.
Added in Clojure version 1.0
Source
re-matcher
function
Usage: (re-matcher re s)
Returns an instance of java.util.regex.Matcher, for use, e.g. in
re-find.
Added in Clojure version 1.0
Source
re-matches
function
Usage: (re-matches re s)
Returns the match, if any, of string to pattern, using
java.util.regex.Matcher.matches(). Uses re-groups to return the
groups.
Added in Clojure version 1.0
Source
re-pattern
function
Usage: (re-pattern s)
Returns an instance of java.util.regex.Pattern, for use, e.g. in
re-matcher.
Added in Clojure version 1.0
Source
re-seq
function
Usage: (re-seq re s)
Returns a lazy sequence of successive matches of pattern in string,
using java.util.regex.Matcher.find(), each such match processed with
re-groups.
Added in Clojure version 1.0
Source
read
function
Usage: (read)
(read stream)
(read stream eof-error? eof-value)
(read stream eof-error? eof-value recursive?)
(read opts stream)
Reads the next object from stream, which must be an instance of
java.io.PushbackReader or some derivee. stream defaults to the
current value of *in*.
Opts is a persistent map with valid keys:
:read-cond - :allow to process reader conditionals, or
:preserve to keep all branches
:features - persistent set of feature keywords for reader conditionals
:eof - on eof, return value unless :eofthrow, then throw.
if not specified, will throw
Note that read can execute code (controlled by *read-eval*),
and as such should be used only with trusted sources.
For data structure interop use clojure.edn/read
Added in Clojure version 1.0
Source
read+string
function
Usage: (read+string)
(read+string stream)
(read+string stream eof-error? eof-value)
(read+string stream eof-error? eof-value recursive?)
(read+string opts stream)
Like read, and taking the same args. stream must be a LineNumberingPushbackReader.
Returns a vector containing the object read and the (whitespace-trimmed) string read.
Added in Clojure version 1.10
Source
read-line
function
Usage: (read-line)
Reads the next line from stream that is the current value of *in* .
Added in Clojure version 1.0
Source
read-string
function
Usage: (read-string s)
(read-string opts s)
Reads one object from the string s. Optionally include reader
options, as specified in read.
Note that read-string can execute code (controlled by *read-eval*),
and as such should be used only with trusted sources.
For data structure interop use clojure.edn/read-string
Added in Clojure version 1.0
Source
reader-conditional
function
Usage: (reader-conditional form splicing?)
Construct a data representation of a reader conditional.
If true, splicing? indicates read-cond-splicing.
Added in Clojure version 1.7
Source
reader-conditional?
function
Usage: (reader-conditional? value)
Return true if the value is the data representation of a reader conditional
Added in Clojure version 1.7
Source
realized?
function
Usage: (realized? x)
Returns true if a value has been produced for a promise, delay, future or lazy sequence.
Added in Clojure version 1.3
Source
record?
function
Usage: (record? x)
Returns true if x is a record
Added in Clojure version 1.6
Source
recur
special form
Usage: (recur exprs*)
Evaluates the exprs in order, then, in parallel, rebinds
the bindings of the recursion point to the values of the exprs.
Execution then jumps back to the recursion point, a loop or fn method.
Please see https://clojure.org/reference/special_forms#recur
Added in Clojure version 1.0
reduce
function
Usage: (reduce f coll)
(reduce f val coll)
f should be a function of 2 arguments. If val is not supplied,
returns the result of applying f to the first 2 items in coll, then
applying f to that result and the 3rd item, etc. If coll contains no
items, f must accept no arguments as well, and reduce returns the
result of calling f with no arguments. If coll has only 1 item, it
is returned and f is not called. If val is supplied, returns the
result of applying f to val and the first item in coll, then
applying f to that result and the 2nd item, etc. If coll contains no
items, returns val and f is not called.
Added in Clojure version 1.0
Source
reduce-kv
function
Usage: (reduce-kv f init coll)
Reduces an associative collection. f should be a function of 3
arguments. Returns the result of applying f to init, the first key
and the first value in coll, then applying f to that result and the
2nd key and value, etc. If coll contains no entries, returns init
and f is not called. Note that reduce-kv is supported on vectors,
where the keys will be the ordinals.
Added in Clojure version 1.4
Source
reduced
function
Usage: (reduced x)
Wraps x in a way such that a reduce will terminate with the value x
Added in Clojure version 1.5
Source
reduced?
function
Usage: (reduced? x)
Returns true if x is the result of a call to reduced
Added in Clojure version 1.5
Source
reductions
function
Usage: (reductions f coll)
(reductions f init coll)
Returns a lazy seq of the intermediate values of the reduction (as
per reduce) of coll by f, starting with init.
Added in Clojure version 1.2
Source
ref
function
Usage: (ref x)
(ref x & options)
Creates and returns a Ref with an initial value of x and zero or
more options (in any order):
:meta metadata-map
:validator validate-fn
:min-history (default 0)
:max-history (default 10)
If metadata-map is supplied, it will become the metadata on the
ref. validate-fn must be nil or a side-effect-free fn of one
argument, which will be passed the intended new state on any state
change. If the new state is unacceptable, the validate-fn should
return false or throw an exception. validate-fn will be called on
transaction commit, when all refs have their final values.
Normally refs accumulate history dynamically as needed to deal with
read demands. If you know in advance you will need history you can
set :min-history to ensure it will be available when first needed (instead
of after a read fault). History is limited, and the limit can be set
with :max-history.
Added in Clojure version 1.0
Source
ref-history-count
function
Usage: (ref-history-count ref)
Returns the history count of a ref
Added in Clojure version 1.1
Source
ref-max-history
function
Usage: (ref-max-history ref)
(ref-max-history ref n)
Gets the max-history of a ref, or sets it and returns the ref
Added in Clojure version 1.1
Source
ref-min-history
function
Usage: (ref-min-history ref)
(ref-min-history ref n)
Gets the min-history of a ref, or sets it and returns the ref
Added in Clojure version 1.1
Source
ref-set
function
Usage: (ref-set ref val)
Must be called in a transaction. Sets the value of ref.
Returns val.
Added in Clojure version 1.0
Source
refer
function
Usage: (refer ns-sym & filters)
refers to all public vars of ns, subject to filters.
filters can include at most one each of:
:exclude list-of-symbols
:only list-of-symbols
:rename map-of-fromsymbol-tosymbol
For each public interned var in the namespace named by the symbol,
adds a mapping from the name of the var to the var to the current
namespace. Throws an exception if name is already mapped to
something else in the current namespace. Filters can be used to
select a subset, via inclusion or exclusion, or to provide a mapping
to a symbol different from the var's name, in order to prevent
clashes. Use :use in the ns macro in preference to calling this directly.
Added in Clojure version 1.0
Source
refer-clojure
macro
Usage: (refer-clojure & filters)
Same as (refer 'clojure.core <filters>)
Specs:
Args: (fspec
:args
(*
(alt
:exclude (cat
:op (quotable #{:exclude})
:arg (quotable
:clojure.core.specs.alpha/exclude))
:only (cat
:op (quotable #{:only})
:arg (quotable :clojure.core.specs.alpha/only))
:rename (cat
:op (quotable #{:rename})
:arg (quotable
:clojure.core.specs.alpha/rename))))
:ret
any?
:fn
nil)
Ret: (fspec
:args
(*
(alt
:exclude (cat
:op (quotable #{:exclude})
:arg (quotable
:clojure.core.specs.alpha/exclude))
:only (cat
:op (quotable #{:only})
:arg (quotable :clojure.core.specs.alpha/only))
:rename (cat
:op (quotable #{:rename})
:arg (quotable
:clojure.core.specs.alpha/rename))))
:ret
any?
:fn
nil)
Added in Clojure version 1.0
Source
reify
macro
Usage: (reify & opts+specs)
reify creates an object implementing a protocol or interface.
reify is a macro with the following structure:
(reify options* specs*)
Currently there are no options.
Each spec consists of the protocol or interface name followed by zero
or more method bodies:
protocol-or-interface-or-Object
(methodName [args+] body)*
Methods should be supplied for all methods of the desired
protocol(s) and interface(s). You can also define overrides for
methods of Object. Note that the first parameter must be supplied to
correspond to the target object ('this' in Java parlance). Thus
methods for interfaces will take one more argument than do the
interface declarations. Note also that recur calls to the method
head should *not* pass the target object, it will be supplied
automatically and can not be substituted.
The return type can be indicated by a type hint on the method name,
and arg types can be indicated by a type hint on arg names. If you
leave out all hints, reify will try to match on same name/arity
method in the protocol(s)/interface(s) - this is preferred. If you
supply any hints at all, no inference is done, so all hints (or
default of Object) must be correct, for both arguments and return
type. If a method is overloaded in a protocol/interface, multiple
independent method definitions must be supplied. If overloaded with
same arity in an interface you must specify complete hints to
disambiguate - a missing hint implies Object.
Method heads are recursion points for recur, as in a fn. The method
bodies of reify are lexical closures, and can refer to the surrounding
local scope:
(str (let [f "foo"]
(reify Object
(toString [this] f))))
== "foo"
(seq (let [f "foo"]
(reify clojure.lang.Seqable
(seq [this] (seq f)))))
== (\f \o \o)
reify always implements clojure.lang.IObj and transfers meta
data of the form to the created object.
(meta ^{:k :v} (reify Object (toString [this] "foo")))
== {:k :v}
Added in Clojure version 1.2
Source
release-pending-sends
function
Usage: (release-pending-sends)
Normally, actions sent directly or indirectly during another action
are held until the action completes (changes the agent's
state). This function can be used to dispatch any pending sent
actions immediately. This has no impact on actions sent during a
transaction, which are still held until commit. If no action is
occurring, does nothing. Returns the number of actions dispatched.
Added in Clojure version 1.0
Source
rem
function
Usage: (rem num div)
remainder of dividing numerator by denominator.
Added in Clojure version 1.0
Source
remove
function
Usage: (remove pred)
(remove pred coll)
Returns a lazy sequence of the items in coll for which
(pred item) returns logical false. pred must be free of side-effects.
Returns a transducer when no collection is provided.
Added in Clojure version 1.0
Source
remove-all-methods
function
Usage: (remove-all-methods multifn)
Removes all of the methods of multimethod.
Added in Clojure version 1.2
Source
remove-method
function
Usage: (remove-method multifn dispatch-val)
Removes the method of multimethod associated with dispatch-value.
Added in Clojure version 1.0
Source
remove-ns
function
Usage: (remove-ns sym)
Removes the namespace named by the symbol. Use with caution.
Cannot be used to remove the clojure namespace.
Added in Clojure version 1.0
Source
remove-tap
function
Usage: (remove-tap f)
Remove f from the tap set.
Added in Clojure version 1.10
Source
remove-watch
function
Usage: (remove-watch reference key)
Removes a watch (set by add-watch) from a reference
Added in Clojure version 1.0
Source
repeat
function
Usage: (repeat x)
(repeat n x)
Returns a lazy (infinite!, or length n if supplied) sequence of xs.
Added in Clojure version 1.0
Source
repeatedly
function
Usage: (repeatedly f)
(repeatedly n f)
Takes a function of no args, presumably with side effects, and
returns an infinite (or length n if supplied) lazy sequence of calls
to it
Added in Clojure version 1.0
Source
replace
function
Usage: (replace smap)
(replace smap coll)
Given a map of replacement pairs and a vector/collection, returns a
vector/seq with any elements = a key in smap replaced with the
corresponding val in smap. Returns a transducer when no collection
is provided.
Added in Clojure version 1.0
Source
replicate
function
Usage: (replicate n x)
DEPRECATED: Use 'repeat' instead.
Returns a lazy seq of n xs.
Added in Clojure version 1.0
Deprecated since Clojure version 1.3
Source
require
function
Usage: (require & args)
Loads libs, skipping any that are already loaded. Each argument is
either a libspec that identifies a lib, a prefix list that identifies
multiple libs whose names share a common prefix, or a flag that modifies
how all the identified libs are loaded. Use :require in the ns macro
in preference to calling this directly.
Libs
A 'lib' is a named set of resources in classpath whose contents define a
library of Clojure code. Lib names are symbols and each lib is associated
with a Clojure namespace and a Java package that share its name. A lib's
name also locates its root directory within classpath using Java's
package name to classpath-relative path mapping. All resources in a lib
should be contained in the directory structure under its root directory.
All definitions a lib makes should be in its associated namespace.
'require loads a lib by loading its root resource. The root resource path
is derived from the lib name in the following manner:
Consider a lib named by the symbol 'x.y.z; it has the root directory
<classpath>/x/y/, and its root resource is <classpath>/x/y/z.clj, or
<classpath>/x/y/z.cljc if <classpath>/x/y/z.clj does not exist. The
root resource should contain code to create the lib's
namespace (usually by using the ns macro) and load any additional
lib resources.
Libspecs
A libspec is a lib name or a vector containing a lib name followed by
options expressed as sequential keywords and arguments.
Recognized options:
:as takes a symbol as its argument and makes that symbol an alias to the
lib's namespace in the current namespace.
:as-alias takes a symbol as its argument and aliases like :as, however
the lib will not be loaded. If the lib has not been loaded, a new
empty namespace will be created (as with create-ns).
:refer takes a list of symbols to refer from the namespace or the :all
keyword to bring in all public vars.
Prefix Lists
It's common for Clojure code to depend on several libs whose names have
the same prefix. When specifying libs, prefix lists can be used to reduce
repetition. A prefix list contains the shared prefix followed by libspecs
with the shared prefix removed from the lib names. After removing the
prefix, the names that remain must not contain any periods.
Flags
A flag is a keyword.
Recognized flags: :reload, :reload-all, :verbose
:reload forces loading of all the identified libs even if they are
already loaded (has no effect on libspecs using :as-alias)
:reload-all implies :reload and also forces loading of all libs that the
identified libs directly or indirectly load via require or use
(has no effect on libspecs using :as-alias)
:verbose triggers printing information about each load, alias, and refer
Example:
The following would load the libraries clojure.zip and clojure.set
abbreviated as 's'.
(require '(clojure zip [set :as s]))
Added in Clojure version 1.0
Source
requiring-resolve
function
Usage: (requiring-resolve sym)
Resolves namespace-qualified sym per 'resolve'. If initial resolve
fails, attempts to require sym's namespace and retries.
Added in Clojure version 1.10
Source
reset!
function
Usage: (reset! atom newval)
Sets the value of atom to newval without regard for the
current value. Returns newval.
Added in Clojure version 1.0
Source
function
Usage: (reset-meta! iref metadata-map)
Atomically resets the metadata for a namespace/var/ref/agent/atom
Added in Clojure version 1.0
Source
reset-vals!
function
Usage: (reset-vals! atom newval)
Sets the value of atom to newval. Returns [old new], the value of the
atom before and after the reset.
Added in Clojure version 1.9
Source
resolve
function
Usage: (resolve sym)
(resolve env sym)
same as (ns-resolve *ns* symbol) or (ns-resolve *ns* &env symbol)
Added in Clojure version 1.0
Source
rest
function
Usage: (rest coll)
Returns a possibly empty seq of the items after the first. Calls seq on its
argument.
Added in Clojure version 1.0
Source
restart-agent
function
Usage: (restart-agent a new-state & options)
When an agent is failed, changes the agent state to new-state and
then un-fails the agent so that sends are allowed again. If
a :clear-actions true option is given, any actions queued on the
agent that were being held while it was failed will be discarded,
otherwise those held actions will proceed. The new-state must pass
the validator if any, or restart will throw an exception and the
agent will remain failed with its old state and error. Watchers, if
any, will NOT be notified of the new state. Throws an exception if
the agent is not failed.
Added in Clojure version 1.2
Source
resultset-seq
function
Usage: (resultset-seq rs)
Creates and returns a lazy sequence of structmaps corresponding to
the rows in the java.sql.ResultSet rs
Added in Clojure version 1.0
Source
reverse
function
Usage: (reverse coll)
Returns a seq of the items in coll in reverse order. Not lazy.
Added in Clojure version 1.0
Source
reversible?
function
Usage: (reversible? coll)
Returns true if coll implements Reversible
Added in Clojure version 1.0
Source
rseq
function
Usage: (rseq rev)
Returns, in constant time, a seq of the items in rev (which
can be a vector or sorted-map), in reverse order. If rev is empty returns nil
Added in Clojure version 1.0
Source
rsubseq
function
Usage: (rsubseq sc test key)
(rsubseq sc start-test start-key end-test end-key)
sc must be a sorted collection, test(s) one of <, <=, > or
>=. Returns a reverse seq of those entries with keys ek for
which (test (.. sc comparator (compare ek key)) 0) is true
Added in Clojure version 1.0
Source
run!
function
Usage: (run! proc coll)
Runs the supplied procedure (via reduce), for purposes of side
effects, on successive items in the collection. Returns nil
Added in Clojure version 1.7
Source
satisfies?
function
Usage: (satisfies? protocol x)
Returns true if x satisfies the protocol
Added in Clojure version 1.2
Source
second
function
Usage: (second x)
Same as (first (next x))
Added in Clojure version 1.0
Source
select-keys
function
Usage: (select-keys map keyseq)
Returns a map containing only those entries in map whose key is in keys
Added in Clojure version 1.0
Source
send
function
Usage: (send a f & args)
Dispatch an action to an agent. Returns the agent immediately.
Subsequently, in a thread from a thread pool, the state of the agent
will be set to the value of:
(apply action-fn state-of-agent args)
Added in Clojure version 1.0
Source
send-off
function
Usage: (send-off a f & args)
Dispatch a potentially blocking action to an agent. Returns the
agent immediately. Subsequently, in a separate thread, the state of
the agent will be set to the value of:
(apply action-fn state-of-agent args)
Added in Clojure version 1.0
Source
send-via
function
Usage: (send-via executor a f & args)
Dispatch an action to an agent. Returns the agent immediately.
Subsequently, in a thread supplied by executor, the state of the agent
will be set to the value of:
(apply action-fn state-of-agent args)
Added in Clojure version 1.5
Source
seq
function
Usage: (seq coll)
Returns a seq on the collection. If the collection is
empty, returns nil. (seq nil) returns nil. seq also works on
Strings, native Java arrays (of reference types) and any objects
that implement Iterable. Note that seqs cache values, thus seq
should not be used on any Iterable whose iterator repeatedly
returns the same mutable object.
Added in Clojure version 1.0
Source
seq-to-map-for-destructuring
function
Usage: (seq-to-map-for-destructuring s)
Builds a map from a seq as described in
https://clojure.org/reference/special_forms#keyword-arguments
Added in Clojure version 1.11
Source
seq?
function
Usage: (seq? x)
Return true if x implements ISeq
Added in Clojure version 1.0
Source
seqable?
function
Usage: (seqable? x)
Return true if the seq function is supported for x
Added in Clojure version 1.9
Source
seque
function
Usage: (seque s)
(seque n-or-q s)
Creates a queued seq on another (presumably lazy) seq s. The queued
seq will produce a concrete seq in the background, and can get up to
n items ahead of the consumer. n-or-q can be an integer n buffer
size, or an instance of java.util.concurrent BlockingQueue. Note
that reading from a seque can block if the reader gets ahead of the
producer.
Added in Clojure version 1.0
Source
sequence
function
Usage: (sequence coll)
(sequence xform coll)
(sequence xform coll & colls)
Coerces coll to a (possibly empty) sequence, if it is not already
one. Will not force a lazy seq. (sequence nil) yields (), When a
transducer is supplied, returns a lazy sequence of applications of
the transform to the items in coll(s), i.e. to the set of first
items of each coll, followed by the set of second
items in each coll, until any one of the colls is exhausted. Any
remaining items in other colls are ignored. The transform should accept
number-of-colls arguments
Added in Clojure version 1.0
Source
sequential?
function
Usage: (sequential? coll)
Returns true if coll implements Sequential
Added in Clojure version 1.0
Source
set
function
Usage: (set coll)
Returns a set of the distinct elements of coll.
Added in Clojure version 1.0
Source
set!
special form
Usage: (set! var-symbol expr)
(set! (. instance-expr instanceFieldName-symbol) expr)
(set! (. Classname-symbol staticFieldName-symbol) expr)
Used to set thread-local-bound vars, Java object instance
fields, and Java class static fields.
Please see https://clojure.org/vars#set
Added in Clojure version 1.0
set-agent-send-executor!
function
Usage: (set-agent-send-executor! executor)
Sets the ExecutorService to be used by send
Added in Clojure version 1.5
Source
set-agent-send-off-executor!
function
Usage: (set-agent-send-off-executor! executor)
Sets the ExecutorService to be used by send-off
Added in Clojure version 1.5
Source
set-error-handler!
function
Usage: (set-error-handler! a handler-fn)
Sets the error-handler of agent a to handler-fn. If an action
being run by the agent throws an exception or doesn't pass the
validator fn, handler-fn will be called with two arguments: the
agent and the exception.
Added in Clojure version 1.2
Source
set-error-mode!
function
Usage: (set-error-mode! a mode-keyword)
Sets the error-mode of agent a to mode-keyword, which must be
either :fail or :continue. If an action being run by the agent
throws an exception or doesn't pass the validator fn, an
error-handler may be called (see set-error-handler!), after which,
if the mode is :continue, the agent will continue as if neither the
action that caused the error nor the error itself ever happened.
If the mode is :fail, the agent will become failed and will stop
accepting new 'send' and 'send-off' actions, and any previously
queued actions will be held until a 'restart-agent'. Deref will
still work, returning the state of the agent before the error.
Added in Clojure version 1.2
Source
set-validator!
function
Usage: (set-validator! iref validator-fn)
Sets the validator-fn for a var/ref/agent/atom. validator-fn must be nil or a
side-effect-free fn of one argument, which will be passed the intended
new state on any state change. If the new state is unacceptable, the
validator-fn should return false or throw an exception. If the current state (root
value if var) is not acceptable to the new validator, an exception
will be thrown and the validator will not be changed.
Added in Clojure version 1.0
Source
set?
function
Usage: (set? x)
Returns true if x implements IPersistentSet
Added in Clojure version 1.0
Source
short
function
Usage: (short x)
Coerce to short
Added in Clojure version 1.0
Source
short-array
function
Usage: (short-array size-or-seq)
(short-array size init-val-or-seq)
Creates an array of shorts
Added in Clojure version 1.1
Source
shorts
function
Usage: (shorts xs)
Casts to shorts[]
Added in Clojure version 1.1
Source
shuffle
function
Usage: (shuffle coll)
Return a random permutation of coll
Added in Clojure version 1.2
Source
shutdown-agents
function
Usage: (shutdown-agents)
Initiates a shutdown of the thread pools that back the agent
system. Running actions will complete, but no new actions will be
accepted
Added in Clojure version 1.0
Source
simple-ident?
function
Usage: (simple-ident? x)
Return true if x is a symbol or keyword without a namespace
Added in Clojure version 1.9
Source
simple-keyword?
function
Usage: (simple-keyword? x)
Return true if x is a keyword without a namespace
Added in Clojure version 1.9
Source
simple-symbol?
function
Usage: (simple-symbol? x)
Return true if x is a symbol without a namespace
Added in Clojure version 1.9
Source
slurp
function
Usage: (slurp f & opts)
Opens a reader on f and reads all its contents, returning a string.
See clojure.java.io/reader for a complete list of supported arguments.
Added in Clojure version 1.0
Source
some
function
Usage: (some pred coll)
Returns the first logical true value of (pred x) for any x in coll,
else nil. One common idiom is to use a set as pred, for example
this will return :fred if :fred is in the sequence, otherwise nil:
(some #{:fred} coll)
Added in Clojure version 1.0
Source
some->
macro
Usage: (some-> expr & forms)
When expr is not nil, threads it into the first form (via ->),
and when that result is not nil, through the next etc
Added in Clojure version 1.5
Source
some->>
macro
Usage: (some->> expr & forms)
When expr is not nil, threads it into the first form (via ->>),
and when that result is not nil, through the next etc
Added in Clojure version 1.5
Source
some-fn
function
Usage: (some-fn p)
(some-fn p1 p2)
(some-fn p1 p2 p3)
(some-fn p1 p2 p3 & ps)
Takes a set of predicates and returns a function f that returns the first logical true value
returned by one of its composing predicates against any of its arguments, else it returns
logical false. Note that f is short-circuiting in that it will stop execution on the first
argument that triggers a logical true result against the original predicates.
Added in Clojure version 1.3
Source
some?
function
Usage: (some? x)
Returns true if x is not nil, false otherwise.
Added in Clojure version 1.6
Source
sort
function
Usage: (sort coll)
(sort comp coll)
Returns a sorted sequence of the items in coll. If no comparator is
supplied, uses compare. comparator must implement
java.util.Comparator. Guaranteed to be stable: equal elements will
not be reordered. If coll is a Java array, it will be modified. To
avoid this, sort a copy of the array.
Added in Clojure version 1.0
Source
sort-by
function
Usage: (sort-by keyfn coll)
(sort-by keyfn comp coll)
Returns a sorted sequence of the items in coll, where the sort
order is determined by comparing (keyfn item). If no comparator is
supplied, uses compare. comparator must implement
java.util.Comparator. Guaranteed to be stable: equal elements will
not be reordered. If coll is a Java array, it will be modified. To
avoid this, sort a copy of the array.
Added in Clojure version 1.0
Source
sorted-map
function
Usage: (sorted-map & keyvals)
keyval => key val
Returns a new sorted map with supplied mappings. If any keys are
equal, they are handled as if by repeated uses of assoc.
Added in Clojure version 1.0
Source
sorted-map-by
function
Usage: (sorted-map-by comparator & keyvals)
keyval => key val
Returns a new sorted map with supplied mappings, using the supplied
comparator. If any keys are equal, they are handled as if by
repeated uses of assoc.
Added in Clojure version 1.0
Source
sorted-set
function
Usage: (sorted-set & keys)
Returns a new sorted set with supplied keys. Any equal keys are
handled as if by repeated uses of conj.
Added in Clojure version 1.0
Source
sorted-set-by
function
Usage: (sorted-set-by comparator & keys)
Returns a new sorted set with supplied keys, using the supplied
comparator. Any equal keys are handled as if by repeated uses of
conj.
Added in Clojure version 1.1
Source
sorted?
function
Usage: (sorted? coll)
Returns true if coll implements Sorted
Added in Clojure version 1.0
Source
special-symbol?
function
Usage: (special-symbol? s)
Returns true if s names a special form
Added in Clojure version 1.0
Source
spit
function
Usage: (spit f content & options)
Opposite of slurp. Opens f with writer, writes content, then
closes f. Options passed to clojure.java.io/writer.
Added in Clojure version 1.2
Source
split-at
function
Usage: (split-at n coll)
Returns a vector of [(take n coll) (drop n coll)]
Added in Clojure version 1.0
Source
split-with
function
Usage: (split-with pred coll)
Returns a vector of [(take-while pred coll) (drop-while pred coll)]
Added in Clojure version 1.0
Source
splitv-at
function
Usage: (splitv-at n coll)
Returns a vector of [(into [] (take n) coll) (drop n coll)]
Added in Clojure version 1.12
Source
str
function
Usage: (str)
(str x)
(str x & ys)
With no args, returns the empty string. With one arg x, returns
x.toString(). (str nil) returns the empty string. With more than
one arg, returns the concatenation of the str values of the args.
Added in Clojure version 1.0
Source
stream-into!
function
Usage: (stream-into! to stream)
(stream-into! to xform stream)
Returns a new coll consisting of coll with all of the items of the
stream conjoined. This is a terminal operation on the stream.
Added in Clojure version 1.12
Source
stream-reduce!
function
Usage: (stream-reduce! f s)
(stream-reduce! f init s)
Works like reduce but takes a java.util.stream.BaseStream as its source.
Honors 'reduced', is a terminal operation on the stream
Added in Clojure version 1.12
Source
stream-seq!
function
Usage: (stream-seq! stream)
Takes a java.util.stream.BaseStream instance s and returns a seq of its
contents. This is a terminal operation on the stream.
Added in Clojure version 1.12
Source
stream-transduce!
function
Usage: (stream-transduce! xform f stream)
(stream-transduce! xform f init stream)
Works like transduce but takes a java.util.stream.BaseStream as its source.
This is a terminal operation on the stream.
Added in Clojure version 1.12
Source
string?
function
Usage: (string? x)
Return true if x is a String
Added in Clojure version 1.0
Source
struct
function
Usage: (struct s & vals)
Returns a new structmap instance with the keys of the
structure-basis. vals must be supplied for basis keys in order -
where values are not supplied they will default to nil.
Added in Clojure version 1.0
Source
struct-map
function
Usage: (struct-map s & inits)
Returns a new structmap instance with the keys of the
structure-basis. keyvals may contain all, some or none of the basis
keys - where values are not supplied they will default to nil.
keyvals can also contain keys not in the basis.
Added in Clojure version 1.0
Source
subs
function
Usage: (subs s start)
(subs s start end)
Returns the substring of s beginning at start inclusive, and ending
at end (defaults to length of string), exclusive.
Added in Clojure version 1.0
Source
subseq
function
Usage: (subseq sc test key)
(subseq sc start-test start-key end-test end-key)
sc must be a sorted collection, test(s) one of <, <=, > or
>=. Returns a seq of those entries with keys ek for
which (test (.. sc comparator (compare ek key)) 0) is true
Added in Clojure version 1.0
Source
subvec
function
Usage: (subvec v start)
(subvec v start end)
Returns a persistent vector of the items in vector from
start (inclusive) to end (exclusive). If end is not supplied,
defaults to (count vector). This operation is O(1) and very fast, as
the resulting vector shares structure with the original and no
trimming is done.
Added in Clojure version 1.0
Source
supers
function
Usage: (supers class)
Returns the immediate and indirect superclasses and interfaces of c, if any
Added in Clojure version 1.0
Source
swap!
function
Usage: (swap! atom f)
(swap! atom f x)
(swap! atom f x y)
(swap! atom f x y & args)
Atomically swaps the value of atom to be:
(apply f current-value-of-atom args). Note that f may be called
multiple times, and thus should be free of side effects. Returns
the value that was swapped in.
Added in Clojure version 1.0
Source
swap-vals!
function
Usage: (swap-vals! atom f)
(swap-vals! atom f x)
(swap-vals! atom f x y)
(swap-vals! atom f x y & args)
Atomically swaps the value of atom to be:
(apply f current-value-of-atom args). Note that f may be called
multiple times, and thus should be free of side effects.
Returns [old new], the value of the atom before and after the swap.
Added in Clojure version 1.9
Source
symbol
function
Usage: (symbol name)
(symbol ns name)
Returns a Symbol with the given namespace and name. Arity-1 works
on strings, keywords, and vars.
Added in Clojure version 1.0
Source
symbol?
function
Usage: (symbol? x)
Return true if x is a Symbol
Added in Clojure version 1.0
Source
sync
macro
Usage: (sync flags-ignored-for-now & body)
transaction-flags => TBD, pass nil for now
Runs the exprs (in an implicit do) in a transaction that encompasses
exprs and any nested calls. Starts a transaction if none is already
running on this thread. Any uncaught exception will abort the
transaction and flow out of sync. The exprs may be run more than
once, but any effects on Refs will be atomic.
Added in Clojure version 1.0
Source
tagged-literal
function
Usage: (tagged-literal tag form)
Construct a data representation of a tagged literal from a
tag symbol and a form.
Added in Clojure version 1.7
Source
tagged-literal?
function
Usage: (tagged-literal? value)
Return true if the value is the data representation of a tagged literal
Added in Clojure version 1.7
Source
take
function
Usage: (take n)
(take n coll)
Returns a lazy sequence of the first n items in coll, or all items if
there are fewer than n. Returns a stateful transducer when
no collection is provided.
Added in Clojure version 1.0
Source
take-last
function
Usage: (take-last n coll)
Returns a seq of the last n items in coll. Depending on the type
of coll may be no better than linear time. For vectors, see also subvec.
Added in Clojure version 1.1
Source
take-nth
function
Usage: (take-nth n)
(take-nth n coll)
Returns a lazy seq of every nth item in coll. Returns a stateful
transducer when no collection is provided.
Added in Clojure version 1.0
Source
take-while
function
Usage: (take-while pred)
(take-while pred coll)
Returns a lazy sequence of successive items from coll while
(pred item) returns logical true. pred must be free of side-effects.
Returns a transducer when no collection is provided.
Added in Clojure version 1.0
Source
tap>
function
Usage: (tap> x)
sends x to any taps. Will not block. Returns true if there was room in the queue,
false if not (dropped).
Added in Clojure version 1.10
Source
test
function
Usage: (test v)
test [v] finds fn at key :test in var metadata and calls it,
presuming failure will throw exception
Added in Clojure version 1.0
Source
the-ns
function
Usage: (the-ns x)
If passed a namespace, returns it. Else, when passed a symbol,
returns the namespace named by it, throwing an exception if not
found.
Added in Clojure version 1.0
Source
thread-bound?
function
Usage: (thread-bound? & vars)
Returns true if all of the vars provided as arguments have thread-local bindings.
Implies that set!'ing the provided vars will succeed. Returns true if no vars are provided.
Added in Clojure version 1.2
Source
throw
special form
Usage: (throw expr)
The expr is evaluated and thrown, therefore it should
yield an instance of some derivee of Throwable.
Please see https://clojure.org/reference/special_forms#throw
Added in Clojure version 1.0
time
macro
Usage: (time expr)
Evaluates expr and prints the time it took. Returns the value of
expr.
Added in Clojure version 1.0
Source
to-array
function
Usage: (to-array coll)
Returns an array of Objects containing the contents of coll, which
can be any Collection. Maps to java.util.Collection.toArray().
Added in Clojure version 1.0
Source
to-array-2d
function
Usage: (to-array-2d coll)
Returns a (potentially-ragged) 2-dimensional array of Objects
containing the contents of coll, which can be any Collection of any
Collection.
Added in Clojure version 1.0
Source
trampoline
function
Usage: (trampoline f)
(trampoline f & args)
trampoline can be used to convert algorithms requiring mutual
recursion without stack consumption. Calls f with supplied args, if
any. If f returns a fn, calls that fn with no arguments, and
continues to repeat, until the return value is not a fn, then
returns that non-fn value. Note that if you want to return a fn as a
final value, you must wrap it in some data structure and unpack it
after trampoline returns.
Added in Clojure version 1.0
Source
transduce
function
Usage: (transduce xform f coll)
(transduce xform f init coll)
reduce with a transformation of f (xf). If init is not
supplied, (f) will be called to produce it. f should be a reducing
step function that accepts both 1 and 2 arguments, if it accepts
only 2 you can add the arity-1 with 'completing'. Returns the result
of applying (the transformed) xf to init and the first item in coll,
then applying xf to that result and the 2nd item, etc. If coll
contains no items, returns init and f is not called. Note that
certain transforms may inject or skip items.
Added in Clojure version 1.7
Source
transient
function
Usage: (transient coll)
Returns a new, transient version of the collection, in constant time.
Transients support a parallel set of 'changing' operations, with similar names
followed by ! - assoc!, conj! etc. These do the same things as their persistent
counterparts except the return values are themselves transient.
Note in particular that transients are not designed to be bashed in-place. You
must capture and use the return value in the next call. In this way, they support
the same code structure as the functional persistent code they replace.
Added in Clojure version 1.1
Source
tree-seq
function
Usage: (tree-seq branch? children root)
Returns a lazy sequence of the nodes in a tree, via a depth-first walk.
branch? must be a fn of one arg that returns true if passed a node
that can have children (but may not). children must be a fn of one
arg that returns a sequence of the children. Will only be called on
nodes for which branch? returns true. Root is the root node of the
tree.
Added in Clojure version 1.0
Source
true?
function
Usage: (true? x)
Returns true if x is the value true, false otherwise.
Added in Clojure version 1.0
Source
try
special form
Usage: (try expr* catch-clause* finally-clause?)
catch-clause => (catch classname name expr*)
finally-clause => (finally expr*)
Catches and handles Java exceptions.
Please see https://clojure.org/reference/special_forms#try
Added in Clojure version 1.0
type
function
Usage: (type x)
Returns the :type metadata of x, or its Class if none
Added in Clojure version 1.0
Source
unchecked-add
function
Usage: (unchecked-add x y)
Returns the sum of x and y, both long.
Note - uses a primitive operator subject to overflow.
Added in Clojure version 1.0
Source
unchecked-add-int
function
Usage: (unchecked-add-int x y)
Returns the sum of x and y, both int.
Note - uses a primitive operator subject to overflow.
Added in Clojure version 1.0
Source
unchecked-byte
function
Usage: (unchecked-byte x)
Coerce to byte. Subject to rounding or truncation.
Added in Clojure version 1.3
Source
unchecked-char
function
Usage: (unchecked-char x)
Coerce to char. Subject to rounding or truncation.
Added in Clojure version 1.3
Source
unchecked-dec
function
Usage: (unchecked-dec x)
Returns a number one less than x, a long.
Note - uses a primitive operator subject to overflow.
Added in Clojure version 1.0
Source
unchecked-dec-int
function
Usage: (unchecked-dec-int x)
Returns a number one less than x, an int.
Note - uses a primitive operator subject to overflow.
Added in Clojure version 1.0
Source
unchecked-divide-int
function
Usage: (unchecked-divide-int x y)
Returns the division of x by y, both int.
Note - uses a primitive operator subject to truncation.
Added in Clojure version 1.0
Source
unchecked-double
function
Usage: (unchecked-double x)
Coerce to double. Subject to rounding.
Added in Clojure version 1.3
Source
unchecked-float
function
Usage: (unchecked-float x)
Coerce to float. Subject to rounding.
Added in Clojure version 1.3
Source
unchecked-inc
function
Usage: (unchecked-inc x)
Returns a number one greater than x, a long.
Note - uses a primitive operator subject to overflow.
Added in Clojure version 1.0
Source
unchecked-inc-int
function
Usage: (unchecked-inc-int x)
Returns a number one greater than x, an int.
Note - uses a primitive operator subject to overflow.
Added in Clojure version 1.0
Source
unchecked-int
function
Usage: (unchecked-int x)
Coerce to int. Subject to rounding or truncation.
Added in Clojure version 1.3
Source
unchecked-long
function
Usage: (unchecked-long x)
Coerce to long. Subject to rounding or truncation.
Added in Clojure version 1.3
Source
unchecked-multiply
function
Usage: (unchecked-multiply x y)
Returns the product of x and y, both long.
Note - uses a primitive operator subject to overflow.
Added in Clojure version 1.0
Source
unchecked-multiply-int
function
Usage: (unchecked-multiply-int x y)
Returns the product of x and y, both int.
Note - uses a primitive operator subject to overflow.
Added in Clojure version 1.0
Source
unchecked-negate
function
Usage: (unchecked-negate x)
Returns the negation of x, a long.
Note - uses a primitive operator subject to overflow.
Added in Clojure version 1.0
Source
unchecked-negate-int
function
Usage: (unchecked-negate-int x)
Returns the negation of x, an int.
Note - uses a primitive operator subject to overflow.
Added in Clojure version 1.0
Source
unchecked-remainder-int
function
Usage: (unchecked-remainder-int x y)
Returns the remainder of division of x by y, both int.
Note - uses a primitive operator subject to truncation.
Added in Clojure version 1.0
Source
unchecked-short
function
Usage: (unchecked-short x)
Coerce to short. Subject to rounding or truncation.
Added in Clojure version 1.3
Source
unchecked-subtract
function
Usage: (unchecked-subtract x y)
Returns the difference of x and y, both long.
Note - uses a primitive operator subject to overflow.
Added in Clojure version 1.0
Source
unchecked-subtract-int
function
Usage: (unchecked-subtract-int x y)
Returns the difference of x and y, both int.
Note - uses a primitive operator subject to overflow.
Added in Clojure version 1.0
Source
underive
function
Usage: (underive tag parent)
(underive h tag parent)
Removes a parent/child relationship between parent and
tag. h must be a hierarchy obtained from make-hierarchy, if not
supplied defaults to, and modifies, the global hierarchy.
Added in Clojure version 1.0
Source
unreduced
function
Usage: (unreduced x)
If x is reduced?, returns (deref x), else returns x
Added in Clojure version 1.7
Source
unsigned-bit-shift-right
function
Usage: (unsigned-bit-shift-right x n)
Bitwise shift right, without sign-extension.
Added in Clojure version 1.6
Source
update
function
Usage: (update m k f)
(update m k f x)
(update m k f x y)
(update m k f x y z)
(update m k f x y z & more)
'Updates' a value in an associative structure, where k is a
key and f is a function that will take the old value
and any supplied args and return the new value, and returns a new
structure. If the key does not exist, nil is passed as the old value.
Added in Clojure version 1.7
Source
update-in
function
Usage: (update-in m ks f & args)
'Updates' a value in a nested associative structure, where ks is a
sequence of keys and f is a function that will take the old value
and any supplied args and return the new value, and returns a new
nested structure. If any levels do not exist, hash-maps will be
created.
Added in Clojure version 1.0
Source
update-keys
function
Usage: (update-keys m f)
m f => {(f k) v ...}
Given a map m and a function f of 1-argument, returns a new map whose
keys are the result of applying f to the keys of m, mapped to the
corresponding values of m.
f must return a unique key for each key of m, else the behavior is undefined.
Added in Clojure version 1.11
Source
update-proxy
function
Usage: (update-proxy proxy mappings)
Takes a proxy instance and a map of strings (which must
correspond to methods of the proxy superclass/superinterfaces) to
fns (which must take arguments matching the corresponding method,
plus an additional (explicit) first arg corresponding to this, and
updates (via assoc) the proxy's fn map. nil can be passed instead of
a fn, in which case the corresponding method will revert to the
default behavior. Note that this function can be used to update the
behavior of an existing instance without changing its identity.
Returns the proxy.
Added in Clojure version 1.0
Source
update-vals
function
Usage: (update-vals m f)
m f => {k (f v) ...}
Given a map m and a function f of 1-argument, returns a new map where the keys of m
are mapped to result of applying f to the corresponding values of m.
Added in Clojure version 1.11
Source
uri?
function
Usage: (uri? x)
Return true if x is a java.net.URI
Added in Clojure version 1.9
Source
use
function
Usage: (use & args)
Like 'require, but also refers to each lib's namespace using
clojure.core/refer. Use :use in the ns macro in preference to calling
this directly.
'use accepts additional options in libspecs: :exclude, :only, :rename.
The arguments and semantics for :exclude, :only, and :rename are the same
as those documented for clojure.core/refer.
Added in Clojure version 1.0
Source
uuid?
function
Usage: (uuid? x)
Return true if x is a java.util.UUID
Added in Clojure version 1.9
Source
val
function
Usage: (val e)
Returns the value in the map entry.
Added in Clojure version 1.0
Source
vals
function
Usage: (vals map)
Returns a sequence of the map's values, in the same order as (seq map).
Added in Clojure version 1.0
Source
var
special form
Usage: (var symbol)
The symbol must resolve to a var, and the Var object
itself (not its value) is returned. The reader macro #'x
expands to (var x).
Please see https://clojure.org/reference/special_forms#var
Added in Clojure version 1.0
var-get
function
Usage: (var-get x)
Gets the value in the var object
Added in Clojure version 1.0
Source
var-set
function
Usage: (var-set x val)
Sets the value in the var object to val. The var must be
thread-locally bound.
Added in Clojure version 1.0
Source
var?
function
Usage: (var? v)
Returns true if v is of type clojure.lang.Var
Added in Clojure version 1.0
Source
function
Usage: (vary-meta obj f & args)
Returns an object of the same type and value as obj, with
(apply f (meta obj) args) as its metadata.
Added in Clojure version 1.0
Source
vec
function
Usage: (vec coll)
Creates a new vector containing the contents of coll. Java arrays
will be aliased and should not be modified.
Added in Clojure version 1.0
Source
vector
function
Usage: (vector)
(vector a)
(vector a b)
(vector a b c)
(vector a b c d)
(vector a b c d e)
(vector a b c d e f)
(vector a b c d e f & args)
Creates a new vector containing the args.
Added in Clojure version 1.0
Source
vector-of
function
Usage: (vector-of t)
(vector-of t & elements)
Creates a new vector of a single primitive type t, where t is one
of :int :long :float :double :byte :short :char or :boolean. The
resulting vector complies with the interface of vectors in general,
but stores the values unboxed internally.
Optionally takes one or more elements to populate the vector.
Added in Clojure version 1.2
Source
vector?
function
Usage: (vector? x)
Return true if x implements IPersistentVector
Added in Clojure version 1.0
Source
volatile!
function
Usage: (volatile! val)
Creates and returns a Volatile with an initial value of val.
Added in Clojure version 1.7
Source
volatile?
function
Usage: (volatile? x)
Returns true if x is a volatile.
Added in Clojure version 1.7
Source
vreset!
function
Usage: (vreset! vol newval)
Sets the value of volatile to newval without regard for the
current value. Returns newval.
Added in Clojure version 1.7
Source
vswap!
macro
Usage: (vswap! vol f & args)
Non-atomically swaps the value of the volatile as if:
(apply f current-value-of-vol args). Returns the value that
was swapped in.
Added in Clojure version 1.7
Source
when
macro
Usage: (when test & body)
Evaluates test. If logical true, evaluates body in an implicit do.
Added in Clojure version 1.0
Source
when-first
macro
Usage: (when-first bindings & body)
bindings => x xs
Roughly the same as (when (seq xs) (let [x (first xs)] body)) but xs is evaluated only once
Added in Clojure version 1.0
Source
when-let
macro
Usage: (when-let bindings & body)
bindings => binding-form test
When test is true, evaluates body with binding-form bound to the value of test
Specs:
Args: (fspec
:args
(cat
:bindings (and vector? :clojure.core.specs.alpha/binding)
:body (* any?))
:ret
any?
:fn
nil)
Ret: (fspec
:args
(cat
:bindings (and vector? :clojure.core.specs.alpha/binding)
:body (* any?))
:ret
any?
:fn
nil)
Added in Clojure version 1.0
Source
when-not
macro
Usage: (when-not test & body)
Evaluates test. If logical false, evaluates body in an implicit do.
Added in Clojure version 1.0
Source
when-some
macro
Usage: (when-some bindings & body)
bindings => binding-form test
When test is not nil, evaluates body with binding-form bound to the
value of test
Added in Clojure version 1.6
Source
while
macro
Usage: (while test & body)
Repeatedly executes body while test expression is true. Presumes
some side-effect will cause test to become false/nil. Returns nil
Added in Clojure version 1.0
Source
with-bindings
macro
Usage: (with-bindings binding-map & body)
Takes a map of Var/value pairs. Installs for the given Vars the associated
values as thread-local bindings. Then executes body. Pops the installed
bindings after body was evaluated. Returns the value of body.
Added in Clojure version 1.1
Source
with-bindings*
function
Usage: (with-bindings* binding-map f & args)
Takes a map of Var/value pairs. Installs for the given Vars the associated
values as thread-local bindings. Then calls f with the supplied arguments.
Pops the installed bindings after f returned. Returns whatever f returns.
Added in Clojure version 1.1
Source
with-in-str
macro
Usage: (with-in-str s & body)
Evaluates body in a context in which *in* is bound to a fresh
StringReader initialized with the string s.
Added in Clojure version 1.0
Source
with-local-vars
macro
Usage: (with-local-vars name-vals-vec & body)
varbinding=> symbol init-expr
Executes the exprs in a context in which the symbols are bound to
vars with per-thread bindings to the init-exprs. The symbols refer
to the var objects themselves, and must be accessed with var-get and
var-set
Added in Clojure version 1.0
Source
function
Usage: (with-meta obj m)
Returns an object of the same type and value as obj, with
map m as its metadata.
Added in Clojure version 1.0
Source
with-open
macro
Usage: (with-open bindings & body)
bindings => [name init ...]
Evaluates body in a try expression with names bound to the values
of the inits, and a finally clause that calls (.close name) on each
name in reverse order.
Added in Clojure version 1.0
Source
with-out-str
macro
Usage: (with-out-str & body)
Evaluates exprs in a context in which *out* is bound to a fresh
StringWriter. Returns the string created by any nested printing
calls.
Added in Clojure version 1.0
Source
with-precision
macro
Usage: (with-precision precision & exprs)
Sets the precision and rounding mode to be used for BigDecimal operations.
Usage: (with-precision 10 (/ 1M 3))
or: (with-precision 10 :rounding HALF_DOWN (/ 1M 3))
The rounding mode is one of CEILING, FLOOR, HALF_UP, HALF_DOWN,
HALF_EVEN, UP, DOWN and UNNECESSARY; it defaults to HALF_UP.
Added in Clojure version 1.0
Source
with-redefs
macro
Usage: (with-redefs bindings & body)
binding => var-symbol temp-value-expr
Temporarily redefines Vars while executing the body. The
temp-value-exprs will be evaluated and each resulting value will
replace in parallel the root value of its Var. After the body is
executed, the root values of all the Vars will be set back to their
old values. These temporary changes will be visible in all threads.
Useful for mocking out functions during testing.
Added in Clojure version 1.3
Source
with-redefs-fn
function
Usage: (with-redefs-fn binding-map func)
Temporarily redefines Vars during a call to func. Each val of
binding-map will replace the root value of its key which must be
a Var. After func is called with no args, the root values of all
the Vars will be set back to their old values. These temporary
changes will be visible in all threads. Useful for mocking out
functions during testing.
Added in Clojure version 1.3
Source
xml-seq
function
Usage: (xml-seq root)
A tree seq on the xml elements as per xml/parse
Added in Clojure version 1.0
Source
zero?
function
Usage: (zero? num)
Returns true if num is zero, else false
Added in Clojure version 1.0
Source
zipmap
function
Usage: (zipmap keys vals)
Returns a map with the keys mapped to the corresponding vals.
Added in Clojure version 1.0
Source