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.
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*1
var
bound in a repl thread to the most recent value printed
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*2
var
bound in a repl thread to the second most recent value printed
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*3
var
bound in a repl thread to the third most recent value printed
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*agent*
var
The agent currently running an action on this thread, else nil
*clojure-version*
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"
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*command-line-args*
var
A sequence of the supplied command line arguments, or nil if
none were supplied
*compile-files*
var
Set to true when compiling files, false otherwise.
*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"
*e
var
bound in a repl thread to the most recent exception caught by the repl
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*err*
var
A java.io.Writer object representing standard error for print operations.
Defaults to System/err, wrapped in a PrintWriter
*file*
var
The path of the file being evaluated, as a String.
Evaluates to nil when there is no file, eg. in the REPL.
*flush-on-newline*
var
When set to true, output will be flushed whenever a newline is printed.
Defaults to true.
*in*
var
A java.io.Reader object representing standard input for read operations.
Defaults to System/in, wrapped in a LineNumberingPushbackReader
*ns*
var
A clojure.lang.Namespace object representing the current namespace.
*out*
var
A java.io.Writer object representing standard output for print operations.
Defaults to System/out
*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.
*print-length*
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.
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*print-level*
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.
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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.
*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
*read-eval*
var
When set to logical false, the EvalReader (#=(...)) is disabled in the
read/load in the thread-local binding.
Example: (binding [*read-eval* false] (read-string "#=(eval (def x 3))"))
Defaults to true
*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.
+
function
Usage: (+)
(+ x)
(+ x y)
(+ x y & more)
Returns the sum of nums. (+) returns 0.
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-
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.
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->
macro
Usage: (-> x)
(-> x form)
(-> x form & more)
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.
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->>
macro
Usage: (->> x form)
(->> x form & more)
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.
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.
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.
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/
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.
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<
function
Usage: (< x)
(< x y)
(< x y & more)
Returns non-nil if nums are in monotonically increasing order,
otherwise false.
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<=
function
Usage: (<= x)
(<= x y)
(<= x y & more)
Returns non-nil if nums are in monotonically non-decreasing order,
otherwise false.
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=
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.
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==
function
Usage: (== x)
(== x y)
(== x y & more)
Returns non-nil if nums all have the same value, otherwise false
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>
function
Usage: (> x)
(> x y)
(> x y & more)
Returns non-nil if nums are in monotonically decreasing order,
otherwise false.
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>=
function
Usage: (>= x)
(>= x y)
(>= x y & more)
Returns non-nil if nums are in monotonically non-increasing order,
otherwise false.
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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.
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aclone
function
Usage: (aclone array)
Returns a clone of the Java array. Works on arrays of known
types.
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add-classpath
function
Usage: (add-classpath url)
DEPRECATED
Adds the url (String or URL object) to the classpath per
URLClassLoader.addURL
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add-watch
function
Usage: (add-watch reference key fn)
Alpha - subject to change.
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.
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agent
function
Usage: (agent state)
(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
If metadata-map is supplied, it will be come 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.
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agent-errors
function
Usage: (agent-errors a)
Returns a sequence of the exceptions thrown during asynchronous
actions of the agent.
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aget
function
Usage: (aget array idx)
(aget array idx & idxs)
Returns the value at the index/indices. Works on Java arrays of all
types.
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alength
function
Usage: (alength array)
Returns the length of the Java array. Works on arrays of all
types.
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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.
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all-ns
function
Usage: (all-ns)
Returns a sequence of all namespaces.
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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.
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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
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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
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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.
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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
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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.
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apply
function
Usage: (apply f args* argseq)
Applies fn f to the argument list formed by prepending args to argseq.
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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.
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array-map
function
Usage: (array-map)
(array-map & keyvals)
Constructs an array-map.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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assert
macro
Usage: (assert x)
Evaluates expr and throws an exception if it does not evaluate to
logical true.
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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).
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assoc!
function
Usage: (assoc! coll key val)
(assoc! coll key val & kvs)
Alpha - subject to change.
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.
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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.
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associative?
function
Usage: (associative? coll)
Returns true if coll implements Associative
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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 be come 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.
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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.
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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 nil if returning due
to timeout, non-nil otherwise.
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bases
function
Usage: (bases c)
Returns the immediate superclass and direct interfaces of c, if any
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bean
function
Usage: (bean x)
Takes a Java object and returns a read-only implementation of the
map abstraction based upon its JavaBean properties.
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bigdec
function
Usage: (bigdec x)
Coerce to BigDecimal
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bigint
function
Usage: (bigint x)
Coerce to BigInteger
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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.
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bit-and
function
Usage: (bit-and x y)
Bitwise and
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bit-and-not
function
Usage: (bit-and-not x y)
Bitwise and with complement
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bit-clear
function
Usage: (bit-clear x n)
Clear bit at index n
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bit-flip
function
Usage: (bit-flip x n)
Flip bit at index n
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bit-not
function
Usage: (bit-not x)
Bitwise complement
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bit-or
function
Usage: (bit-or x y)
Bitwise or
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bit-set
function
Usage: (bit-set x n)
Set bit at index n
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bit-shift-left
function
Usage: (bit-shift-left x n)
Bitwise shift left
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bit-shift-right
function
Usage: (bit-shift-right x n)
Bitwise shift right
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bit-test
function
Usage: (bit-test x n)
Test bit at index n
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bit-xor
function
Usage: (bit-xor x y)
Bitwise exclusive or
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boolean
function
Usage: (boolean x)
Coerce to boolean
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boolean-array
function
Usage: (boolean-array size-or-seq)
(boolean-array size init-val-or-seq)
Creates an array of booleans
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booleans
function
Usage: (booleans xs)
Casts to boolean[]
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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.
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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.
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butlast
function
Usage: (butlast coll)
Return a seq of all but the last item in coll, in linear time
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byte
function
Usage: (byte x)
Coerce to byte
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byte-array
function
Usage: (byte-array size-or-seq)
(byte-array size init-val-or-seq)
Creates an array of bytes
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bytes
function
Usage: (bytes xs)
Casts to bytes[]
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cast
function
Usage: (cast c x)
Throws a ClassCastException if x is not a c, else returns x.
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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
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char-array
function
Usage: (char-array size-or-seq)
(char-array size init-val-or-seq)
Creates an array of chars
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char-escape-string
var
Returns escape string for char or nil if none
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char-name-string
var
Returns name string for char or nil if none
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char?
function
Usage: (char? x)
Return true if x is a Character
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chars
function
Usage: (chars xs)
Casts to chars[]
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class
function
Usage: (class x)
Returns the Class of x
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class?
function
Usage: (class? x)
Returns true if x is an instance of Class
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clear-agent-errors
function
Usage: (clear-agent-errors a)
Clears any exceptions thrown during asynchronous actions of the
agent, allowing subsequent actions to occur.
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clojure-version
function
Usage: (clojure-version)
Returns clojure version as a printable string.
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coll?
function
Usage: (coll? x)
Returns true if x implements IPersistentCollection
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macro
Usage: (comment & body)
Ignores body, yields nil
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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.
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comp
function
Usage: (comp f)
(comp f g)
(comp f g h)
(comp f1 f2 f3 & 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.
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comparator
function
Usage: (comparator pred)
Returns an implementation of java.util.Comparator based upon pred.
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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
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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
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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.
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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.
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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.
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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.
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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.
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conj
function
Usage: (conj coll x)
(conj coll x & xs)
conj[oin]. Returns a new collection with the xs
'added'. (conj nil item) returns (item). The 'addition' may
happen at different 'places' depending on the concrete type.
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conj!
function
Usage: (conj! coll x)
Alpha - subject to change.
Adds x to the transient collection, and return coll. The 'addition'
may happen at different 'places' depending on the concrete type.
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cons
function
Usage: (cons x seq)
Returns a new seq where x is the first element and seq is
the rest.
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constantly
function
Usage: (constantly x)
Returns a function that takes any number of arguments and returns x.
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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.
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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'.
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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
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counted?
function
Usage: (counted? coll)
Returns true if coll implements count in constant time
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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.
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create-struct
function
Usage: (create-struct & keys)
Returns a structure basis object.
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cycle
function
Usage: (cycle coll)
Returns a lazy (infinite!) sequence of repetitions of the items in coll.
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dec
function
Usage: (dec x)
Returns a number one less than num.
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decimal?
function
Usage: (decimal? n)
Returns true if n is a BigDecimal
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declare
macro
Usage: (declare & names)
defs the supplied var names with no bindings, useful for making forward declarations.
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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
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.
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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.
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defmethod
macro
Usage: (defmethod multifn dispatch-val & fn-tail)
Creates and installs a new method of multimethod associated with dispatch-value.
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defmulti
macro
Usage: (defmulti name docstring? attr-map? dispatch-fn & options)
Creates a new multimethod with the associated dispatch function.
The docstring and attribute-map are optional.
Options are key-value pairs and may be one of:
:default the default dispatch value, defaults to :default
:hierarchy the isa? hierarchy to use for dispatching
defaults to the global hierarchy
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defn
macro
Usage: (defn name doc-string? attr-map? [params*] body)
(defn name doc-string? attr-map? ([params*] 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
Source
defn-
macro
Usage: (defn- name & decls)
same as defn, yielding non-public def
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
Source
defstruct
macro
Usage: (defstruct name & keys)
Same as (def name (create-struct keys...))
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), and
will cache the result and return it on all subsequent force
calls.
Source
delay?
function
Usage: (delay? x)
returns true if x is a Delay created with delay
Source
deliver
function
Usage: (deliver promise val)
Alpha - subject to change.
Delivers the supplied value to the promise, releasing any pending
derefs. A subsequent call to deliver on a promise will throw an exception.
Source
deref
function
Usage: (deref ref)
Also reader macro: @ref/@agent/@var/@atom/@delay/@future. 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
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.
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.
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).
Source
disj!
function
Usage: (disj! set)
(disj! set key)
(disj! set key & ks)
Alpha - subject to change.
disj[oin]. Returns a transient set of the same (hashed/sorted) type, that
does not contain key(s).
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).
Source
dissoc!
function
Usage: (dissoc! map key)
(dissoc! map key & ks)
Alpha - subject to change.
Returns a transient map that doesn't contain a mapping for key(s).
Source
distinct
function
Usage: (distinct coll)
Returns a lazy sequence of the elements of coll with duplicates removed
Source
distinct?
function
Usage: (distinct? x)
(distinct? x y)
(distinct? x y & more)
Returns true if no two of the arguments are =
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.
Source
doc
macro
Usage: (doc name)
Prints documentation for a var or special form given its name
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.
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.
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.
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.
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 from of the given arguments. The forms
are evaluated in order. Returns x.
(doto (new java.util.HashMap) (.put "a" 1) (.put "b" 2))
Source
double
function
Usage: (double x)
Coerce to double
Source
double-array
function
Usage: (double-array size-or-seq)
(double-array size init-val-or-seq)
Creates an array of doubles
Source
doubles
function
Usage: (doubles xs)
Casts to double[]
Source
drop
function
Usage: (drop n coll)
Returns a lazy sequence of all but the first n items in coll.
Source
drop-last
function
Usage: (drop-last s)
(drop-last n s)
Return a lazy sequence of all but the last n (default 1) items in coll
Source
drop-while
function
Usage: (drop-while pred coll)
Returns a lazy sequence of the items in coll starting from the first
item for which (pred item) returns nil.
Source
empty
function
Usage: (empty coll)
Returns an empty collection of the same category as coll, or nil
Source
empty?
function
Usage: (empty? coll)
Returns true if coll has no items - same as (not (seq coll)).
Please use the idiom (seq x) rather than (not (empty? x))
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)
Source
enumeration-seq
function
Usage: (enumeration-seq e)
Returns a seq on a java.util.Enumeration
Source
eval
function
Usage: (eval form)
Evaluates the form data structure (not text!) and returns the result.
Source
even?
function
Usage: (even? n)
Returns true if n is even, throws an exception if n is not an integer
Source
every?
function
Usage: (every? pred coll)
Returns true if (pred x) is logical true for every x in coll, else
false.
Source
false?
function
Usage: (false? x)
Returns true if x is the value false, false otherwise.
Source
ffirst
function
Usage: (ffirst x)
Same as (first (first x))
Source
file-seq
function
Usage: (file-seq dir)
A tree seq on java.io.Files
Source
filter
function
Usage: (filter pred coll)
Returns a lazy sequence of the items in coll for which
(pred item) returns true. pred must be free of side-effects.
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.
Source
find-doc
function
Usage: (find-doc re-string-or-pattern)
Prints documentation for any var whose documentation or name
contains a match for re-string-or-pattern
Source
find-ns
function
Usage: (find-ns sym)
Returns the namespace named by the symbol or nil if it doesn't exist.
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.
Source
first
function
Usage: (first coll)
Returns the first item in the collection. Calls seq on its
argument. If coll is nil, returns nil.
Source
float
function
Usage: (float x)
Coerce to float
Source
float-array
function
Usage: (float-array size-or-seq)
(float-array size init-val-or-seq)
Creates an array of floats
Source
float?
function
Usage: (float? n)
Returns true if n is a floating point number
Source
floats
function
Usage: (floats xs)
Casts to float[]
Source
flush
function
Usage: (flush)
Flushes the output stream that is the current value of
*out*
Source
fn
macro
Usage: (fn & sigs)
(fn name? [params* ] exprs*)
(fn name? ([params* ] exprs*)+)
params => positional-params* , or positional-params* & next-param
positional-param => binding-form
next-param => binding-form
name => symbol
Defines a function
Source
fn?
function
Usage: (fn? x)
Returns true if x implements Fn, i.e. is an object created via fn.
Source
fnext
function
Usage: (fnext x)
Same as (first (next x))
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]))
Source
force
function
Usage: (force x)
If x is a Delay, returns the (possibly cached) value of its expression, else returns x
Source
function
Usage: (format fmt & args)
Formats a string using java.lang.String.format, see java.util.Formatter for format
string syntax
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.
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.
Source
future-cancel
function
Usage: (future-cancel f)
Cancels the future, if possible.
Source
future-cancelled?
function
Usage: (future-cancelled? f)
Returns true if future f is cancelled
Source
future-done?
function
Usage: (future-done? f)
Returns true if future f is done
Source
future?
function
Usage: (future? x)
Returns true if x is a future
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.
It's 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.
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.
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__'.
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.
Source
get-in
function
Usage: (get-in m ks)
returns the value in a nested associative structure, where ks is a sequence of keys
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
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.
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.
Source
get-validator
function
Usage: (get-validator iref)
Gets the validator-fn for a var/ref/agent/atom.
Source
hash
function
Usage: (hash x)
Returns the hash code of its argument
Source
hash-map
function
Usage: (hash-map)
(hash-map & keyvals)
keyval => key val
Returns a new hash map with supplied mappings.
Source
hash-set
function
Usage: (hash-set)
(hash-set & keys)
Returns a new hash set with supplied keys.
Source
identical?
function
Usage: (identical? x y)
Tests if 2 arguments are the same object
identity
function
Usage: (identity x)
Returns its argument.
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
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.
Source
ifn?
function
Usage: (ifn? x)
Returns true if x implements IFn. Note that many data structures
(e.g. sets and maps) implement IFn
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.
Source
in-ns
function
Usage: (in-ns name)
Sets *ns* to the namespace named by the symbol, creating it if needed.
inc
function
Usage: (inc x)
Returns a number one greater than num.
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.
Source
instance?
function
Usage: (instance? c x)
Evaluates x and tests if it is an instance of the class
c. Returns true or false
Source
int
function
Usage: (int x)
Coerce to int
Source
int-array
function
Usage: (int-array size-or-seq)
(int-array size init-val-or-seq)
Creates an array of ints
Source
integer?
function
Usage: (integer? n)
Returns true if n is an integer
Source
interleave
function
Usage: (interleave c1 c2)
(interleave c1 c2 & colls)
Returns a lazy seq of the first item in each coll, then the second etc.
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.
Source
interpose
function
Usage: (interpose sep coll)
Returns a lazy seq of the elements of coll separated by sep
Source
into
function
Usage: (into to from)
Returns a new coll consisting of to-coll with all of the items of
from-coll conjoined.
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.
Source
ints
function
Usage: (ints xs)
Casts to int[]
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.
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
Source
iterate
function
Usage: (iterate f x)
Returns a lazy sequence of x, (f x), (f (f x)) etc. f must be free of side-effects
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.
Source
juxt
function
Usage: (juxt f)
(juxt f g)
(juxt f g h)
(juxt f g h & fs)
Alpha - name subject to change.
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)]
Source
key
function
Usage: (key e)
Returns the key of the map entry.
Source
keys
function
Usage: (keys map)
Returns a sequence of the map's keys.
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.
Source
keyword?
function
Usage: (keyword? x)
Return true if x is a Keyword
Source
last
function
Usage: (last coll)
Return the last item in coll, in linear time
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))
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.
Source
let
macro
Usage: (let bindings & body)
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.
Source
letfn
macro
Usage: (letfn fnspecs & body)
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.
fnspec ==> (fname [params*] exprs) or (fname ([params*] exprs)+)
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.
Source
list
function
Usage: (list & items)
Creates a new list containing the items.
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 list containing the items prepended to the rest, the
last of which will be treated as a sequence.
Source
list?
function
Usage: (list? x)
Returns true if x implements IPersistentList
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.
Source
load-file
function
Usage: (load-file name)
Sequentially read and evaluate the set of forms contained in the file.
load-reader
function
Usage: (load-reader rdr)
Sequentially read and evaluate the set of forms contained in the
stream/file
Source
load-string
function
Usage: (load-string s)
Sequentially read and evaluate the set of forms contained in the
string
Source
loaded-libs
function
Usage: (loaded-libs)
Returns a sorted set of symbols naming the currently loaded libs
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.
Source
long
function
Usage: (long x)
Coerce to long
Source
long-array
function
Usage: (long-array size-or-seq)
(long-array size init-val-or-seq)
Creates an array of longs
Source
longs
function
Usage: (longs xs)
Casts to long[]
Source
loop
macro
Usage: (loop bindings & body)
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.
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.
Source
macroexpand-1
function
Usage: (macroexpand-1 form)
If form represents a macro form, returns its expansion,
else returns form.
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.
Source
make-hierarchy
function
Usage: (make-hierarchy)
Creates a hierarchy object for use with derive, isa? etc.
Source
map
function
Usage: (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.
Source
map?
function
Usage: (map? x)
Return true if x implements IPersistentMap
Source
mapcat
function
Usage: (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.
Source
max
function
Usage: (max x)
(max x y)
(max x y & more)
Returns the greatest of the nums.
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.
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.
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.
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.
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).
Source
function
Usage: (meta obj)
Returns the metadata of obj, returns nil if there is no metadata.
Source
methods
function
Usage: (methods multifn)
Given a multimethod, returns a map of dispatch values -> dispatch fns
Source
min
function
Usage: (min x)
(min x y)
(min x y & more)
Returns the least of the nums.
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.
Source
mod
function
Usage: (mod num div)
Modulus of num and div. Truncates toward negative infinity.
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 symbol or keyword.
Source
namespace
function
Usage: (namespace x)
Returns the namespace String of a symbol or keyword, or nil if not present.
Source
neg?
function
Usage: (neg? x)
Returns true if num is less than zero, else false
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 newline to the output stream that is the current value of
*out*
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.
Source
nfirst
function
Usage: (nfirst x)
Same as (next (first x))
Source
nil?
function
Usage: (nil? x)
Returns true if x is nil, false otherwise.
Source
nnext
function
Usage: (nnext x)
Same as (next (next x))
Source
not
function
Usage: (not x)
Returns true if x is logical false, false otherwise.
Source
not-any?
function
Usage: (not-any? pred coll)
Returns false if (pred x) is logical true for any x in coll,
else true.
Source
not-empty
function
Usage: (not-empty coll)
If coll is empty, returns nil, else coll
Source
not-every?
function
Usage: (not-every? pred coll)
Returns false if (pred x) is logical true for every x in
coll, else true.
Source
not=
function
Usage: (not= x)
(not= x y)
(not= x y & more)
Same as (not (= obj1 obj2))
Source
ns
macro
Usage: (ns name & 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) 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 sql.tests))
(:use (my.lib this that))
(:import (java.util Date Timer Random)
(java.sql Connection Statement)))
Source
ns-aliases
function
Usage: (ns-aliases ns)
Returns a map of the aliases for the namespace.
Source
ns-imports
function
Usage: (ns-imports ns)
Returns a map of the import mappings for the namespace.
Source
ns-interns
function
Usage: (ns-interns ns)
Returns a map of the intern mappings for the namespace.
Source
ns-map
function
Usage: (ns-map ns)
Returns a map of all the mappings for the namespace.
Source
ns-name
function
Usage: (ns-name ns)
Returns the name of the namespace, a symbol.
Source
ns-publics
function
Usage: (ns-publics ns)
Returns a map of the public intern mappings for the namespace.
Source
ns-refers
function
Usage: (ns-refers ns)
Returns a map of the refer mappings for the namespace.
Source
ns-resolve
function
Usage: (ns-resolve ns sym)
Returns the var or Class to which a symbol will be resolved in the
namespace, else nil. Note that if the symbol is fully qualified,
the var/Class to which it resolves need not be present in the
namespace.
Source
ns-unalias
function
Usage: (ns-unalias ns sym)
Removes the alias for the symbol from the namespace.
Source
ns-unmap
function
Usage: (ns-unmap ns sym)
Removes the mappings for the symbol from the namespace.
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.
Source
nthnext
function
Usage: (nthnext coll n)
Returns the nth next of coll, (seq coll) when n is 0.
Source
num
function
Usage: (num x)
Coerce to Number
Source
number?
function
Usage: (number? x)
Returns true if x is a Number
Source
odd?
function
Usage: (odd? n)
Returns true if n is odd, throws an exception if n is not an integer
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.
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
Source
partial
function
Usage: (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.
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.
Source
pcalls
function
Usage: (pcalls & fns)
Executes the no-arg fns in parallel, returning a lazy sequence of
their values
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.
Source
persistent!
function
Usage: (persistent! coll)
Alpha - subject to change.
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.
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.
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.
Source
pop!
function
Usage: (pop! coll)
Alpha - subject to change.
Removes the last item from a transient vector. If
the collection is empty, throws an exception. Returns coll
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.
Source
pos?
function
Usage: (pos? x)
Returns true if num is greater than zero, else false
Source
pr
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
Source
pr-str
function
Usage: (pr-str & xs)
pr to a string, returning it
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
Source
prefers
function
Usage: (prefers multifn)
Given a multimethod, returns a map of preferred value -> set of other values
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.
Source
print-namespace-doc
function
Usage: (print-namespace-doc nspace)
Print the documentation string of a Namespace.
Source
print-str
function
Usage: (print-str & xs)
print to a string, returning it
Source
printf
function
Usage: (printf fmt & args)
Prints formatted output, as per format
Source
println
function
Usage: (println & more)
Same as print followed by (newline)
Source
println-str
function
Usage: (println-str & xs)
println to a string, returning it
Source
prn
function
Usage: (prn & more)
Same as pr followed by (newline). Observes *flush-on-newline*
Source
prn-str
function
Usage: (prn-str & xs)
prn to a string, returning it
Source
promise
function
Usage: (promise)
Alpha - subject to change.
Returns a promise object that can be read with deref/@, and set,
once only, with deliver. Calls to deref/@ prior to delivery will
block. All subsequent derefs will return the same delivered value
without blocking.
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 methd 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.
Source
proxy-mappings
function
Usage: (proxy-mappings proxy)
Takes a proxy instance and returns the proxy's fn map.
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
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)))
Source
pvalues
macro
Usage: (pvalues & exprs)
Returns a lazy sequence of the values of the exprs, which are
evaluated in parallel
Source
quot
function
Usage: (quot num div)
quot[ient] of dividing numerator by denominator.
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).
Source
rand-int
function
Usage: (rand-int n)
Returns a random integer between 0 (inclusive) and n (exclusive).
Source
range
function
Usage: (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 and step to 1.
Source
ratio?
function
Usage: (ratio? n)
Returns true if n is a Ratio
Source
rationalize
function
Usage: (rationalize num)
returns the rational value of num
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.
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.
Source
re-matcher
function
Usage: (re-matcher re s)
Returns an instance of java.util.regex.Matcher, for use, e.g. in
re-find.
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.
Source
re-pattern
function
Usage: (re-pattern s)
Returns an instance of java.util.regex.Pattern, for use, e.g. in
re-matcher.
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.
Source
read
function
Usage: (read)
(read stream)
(read stream eof-error? eof-value)
(read stream eof-error? eof-value recursive?)
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* .
Source
read-line
function
Usage: (read-line)
Reads the next line from stream that is the current value of *in* .
Source
read-string
function
Usage: (read-string s)
Reads one object from the string s
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.
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 be come 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.
Source
ref-history-count
function
Usage: (ref-history-count ref)
Returns the history count of a ref
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
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
Source
ref-set
function
Usage: (ref-set ref val)
Must be called in a transaction. Sets the value of ref.
Returns val.
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.
Source
refer-clojure
macro
Usage: (refer-clojure & filters)
Same as (refer 'clojure.core <filters>)
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.
Source
rem
function
Usage: (rem num div)
remainder of dividing numerator by denominator.
Source
remove
function
Usage: (remove pred coll)
Returns a lazy sequence of the items in coll for which
(pred item) returns false. pred must be free of side-effects.
Source
remove-method
function
Usage: (remove-method multifn dispatch-val)
Removes the method of multimethod associated with dispatch-value.
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.
Source
remove-watch
function
Usage: (remove-watch reference key)
Alpha - subject to change.
Removes a watch (set by add-watch) from a reference
Source
repeat
function
Usage: (repeat x)
(repeat n x)
Returns a lazy (infinite!, or length n if supplied) sequence of xs.
Source
repeatedly
function
Usage: (repeatedly f)
Takes a function of no args, presumably with side effects, and returns an infinite
lazy sequence of calls to it
Source
replace
function
Usage: (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
Source
replicate
function
Usage: (replicate n x)
Returns a lazy seq of n xs.
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. 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
:as takes a symbol as its argument and makes that symbol an alias to the
lib's namespace in the current namespace.
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
:reload-all implies :reload and also forces loading of all libs that the
identified libs directly or indirectly load via require or use
: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]))
Source
reset!
function
Usage: (reset! atom newval)
Sets the value of atom to newval without regard for the
current value. Returns newval.
Source
function
Usage: (reset-meta! iref metadata-map)
Atomically resets the metadata for a namespace/var/ref/agent/atom
Source
resolve
function
Usage: (resolve sym)
same as (ns-resolve *ns* symbol)
Source
rest
function
Usage: (rest coll)
Returns a possibly empty seq of the items after the first. Calls seq on its
argument.
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
Source
reverse
function
Usage: (reverse coll)
Returns a seq of the items in coll in reverse order. Not lazy.
Source
reversible?
function
Usage: (reversible? coll)
Returns true if coll implements Reversible
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
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
Source
second
function
Usage: (second x)
Same as (first (next x))
Source
select-keys
function
Usage: (select-keys map keyseq)
Returns a map containing only those entries in map whose key is in keys
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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)
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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)
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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.
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seq?
function
Usage: (seq? x)
Return true if x implements ISeq
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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.
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sequence
function
Usage: (sequence coll)
Coerces coll to a (possibly empty) sequence, if it is not already
one. Will not force a lazy seq. (sequence nil) yields ()
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sequential?
function
Usage: (sequential? coll)
Returns true if coll implements Sequential
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set
function
Usage: (set coll)
Returns a set of the distinct elements of coll.
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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-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.
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set?
function
Usage: (set? x)
Returns true if x implements IPersistentSet
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short
function
Usage: (short x)
Coerce to short
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short-array
function
Usage: (short-array size-or-seq)
(short-array size init-val-or-seq)
Creates an array of shorts
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shorts
function
Usage: (shorts xs)
Casts to shorts[]
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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
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slurp
function
Usage: (slurp f)
(slurp f enc)
Reads the file named by f using the encoding enc into a string
and returns it.
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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)
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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.
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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.
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sorted-map
function
Usage: (sorted-map & keyvals)
keyval => key val
Returns a new sorted map with supplied mappings.
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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.
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sorted-set
function
Usage: (sorted-set & keys)
Returns a new sorted set with supplied keys.
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sorted-set-by
function
Usage: (sorted-set-by comparator & keys)
Returns a new sorted set with supplied keys, using the supplied comparator.
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sorted?
function
Usage: (sorted? coll)
Returns true if coll implements Sorted
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function
Usage: (special-form-anchor x)
Returns the anchor tag on http://clojure.org/special_forms for the
special form x, or nil
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special-symbol?
function
Usage: (special-symbol? s)
Returns true if s names a special form
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split-at
function
Usage: (split-at n coll)
Returns a vector of [(take n coll) (drop n coll)]
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split-with
function
Usage: (split-with pred coll)
Returns a vector of [(take-while pred coll) (drop-while pred coll)]
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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.
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stream?
function
Usage: (stream? x)
Returns true if x is an instance of Stream
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string?
function
Usage: (string? x)
Return true if x is a String
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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.
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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.
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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.
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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
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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.
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supers
function
Usage: (supers class)
Returns the immediate and indirect superclasses and interfaces of c, if any
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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.
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symbol
function
Usage: (symbol name)
(symbol ns name)
Returns a Symbol with the given namespace and name.
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symbol?
function
Usage: (symbol? x)
Return true if x is a Symbol
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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.
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syntax-symbol-anchor
function
Usage: (syntax-symbol-anchor x)
Returns the anchor tag on http://clojure.org/special_forms for the
special form that uses syntax symbol x, or nil
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take
function
Usage: (take n coll)
Returns a lazy sequence of the first n items in coll, or all items if
there are fewer than n.
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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.
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take-nth
function
Usage: (take-nth n coll)
Returns a lazy seq of every nth item in coll.
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take-while
function
Usage: (take-while pred coll)
Returns a lazy sequence of successive items from coll while
(pred item) returns true. pred must be free of side-effects.
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test
function
Usage: (test v)
test [v] finds fn at key :test in var metadata and calls it,
presuming failure will throw exception
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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.
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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.
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().
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.
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.
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transient
function
Usage: (transient coll)
Alpha - subject to change.
Returns a new, transient version of the collection, in constant time.
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.
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true?
function
Usage: (true? x)
Returns true if x is the value true, false otherwise.
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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
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unchecked-add
function
Usage: (unchecked-add x y)
Returns the sum of x and y, both int or long.
Note - uses a primitive operator subject to overflow.
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unchecked-dec
function
Usage: (unchecked-dec x)
Returns a number one less than x, an int or long.
Note - uses a primitive operator subject to overflow.
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unchecked-divide
function
Usage: (unchecked-divide x y)
Returns the division of x by y, both int or long.
Note - uses a primitive operator subject to truncation.
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unchecked-inc
function
Usage: (unchecked-inc x)
Returns a number one greater than x, an int or long.
Note - uses a primitive operator subject to overflow.
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unchecked-multiply
function
Usage: (unchecked-multiply x y)
Returns the product of x and y, both int or long.
Note - uses a primitive operator subject to overflow.
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unchecked-negate
function
Usage: (unchecked-negate x)
Returns the negation of x, an int or long.
Note - uses a primitive operator subject to overflow.
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unchecked-remainder
function
Usage: (unchecked-remainder x y)
Returns the remainder of division of x by y, both int or long.
Note - uses a primitive operator subject to truncation.
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unchecked-subtract
function
Usage: (unchecked-subtract x y)
Returns the difference of x and y, both int or long.
Note - uses a primitive operator subject to overflow.
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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.
Source
update-in
function
Usage: (update-in m [k & 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.
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.
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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.
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val
function
Usage: (val e)
Returns the value in the map entry.
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vals
function
Usage: (vals map)
Returns a sequence of the map's values.
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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
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.
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var?
function
Usage: (var? v)
Returns true if v is of type clojure.lang.Var
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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.
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vec
function
Usage: (vec coll)
Creates a new vector containing the contents of coll.
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vector
function
Usage: (vector)
(vector & args)
Creates a new vector containing the args.
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vector?
function
Usage: (vector? x)
Return true if x implements IPersistentVector
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when
macro
Usage: (when test & body)
Evaluates test. If logical true, evaluates body in an implicit do.
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when-first
macro
Usage: (when-first bindings & body)
bindings => x xs
Same as (when (seq xs) (let [x (first xs)] body))
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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
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when-not
macro
Usage: (when-not test & body)
Evaluates test. If logical false, evaluates body in an implicit do.
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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
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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. The executes body. Pops the installed
bindings after body was evaluated. Returns the value of body.
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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.
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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.
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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
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function
Usage: (with-meta obj m)
Returns an object of the same type and value as obj, with
map m as its metadata.
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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.
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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.
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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.
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xml-seq
function
Usage: (xml-seq root)
A tree seq on the xml elements as per xml/parse
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zero?
function
Usage: (zero? x)
Returns true if num is zero, else false
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zipmap
function
Usage: (zipmap keys vals)
Returns a map with the keys mapped to the corresponding vals.
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