clojure.core — org.clojure/clojure 1.12.0-alpha5

Fundamental library of the Clojure language

* clj

(*)

(* x)

(* x y)

(* x y & more)

Returns the product of nums. (*) returns 1. Does not auto-promote longs, will throw on overflow. See also: *'

*' clj

(*')

(*' x)

(*' x y)

(*' x y & more)

Returns the product of nums. (*') returns 1. Supports arbitrary precision. See also: *

*1 clj

bound in a repl thread to the most recent value printed

*2 clj

bound in a repl thread to the second most recent value printed

*3 clj

bound in a repl thread to the third most recent value printed

*agent* clj

The agent currently running an action on this thread, else nil

*allow-unresolved-vars* clj

*assert* clj

*clojure-version* clj

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"

*command-line-args* clj

A sequence of the supplied command line arguments, or nil if none were supplied

*compile-files* clj

Set to true when compiling files, false otherwise.

*compile-path* clj

Specifies the directory where 'compile' will write out .class files. This directory must be in the classpath for 'compile' to work.

Defaults to "classes"

*compiler-options* clj

A map of keys to options. Note, when binding dynamically make sure to merge with previous value. Supported options: :elide-meta - a collection of metadata keys to elide during compilation. :disable-locals-clearing - set to true to disable clearing, useful for using a debugger :direct-linking - set to true to use direct static invocation of functions, rather than vars Note that call sites compiled with direct linking will not be affected by var redefinition. Use ^:redef (or ^:dynamic) on a var to prevent direct linking and allow redefinition. See https://clojure.org/reference/compilation for more information.

*data-readers* clj

Map from reader tag symbols to data reader Vars.

When Clojure starts, it searches for files named 'data_readers.clj' and 'data_readers.cljc' at the root of the classpath. Each such file must contain a literal map of symbols, like this:

{foo/bar my.project.foo/bar
 foo/baz my.project/baz}

The first symbol in each pair is a tag that will be recognized by the Clojure reader. The second symbol in the pair is the fully-qualified name of a Var which will be invoked by the reader to parse the form following the tag. For example, given the data_readers.clj file above, the Clojure reader would parse this form:

#foo/bar [1 2 3]

by invoking the Var #'my.project.foo/bar on the vector [1 2 3]. The data reader function is invoked on the form AFTER it has been read as a normal Clojure data structure by the reader.

Reader tags without namespace qualifiers are reserved for Clojure. Default reader tags are defined in clojure.core/default-data-readers but may be overridden in data_readers.clj, data_readers.cljc, or by rebinding this Var.

*default-data-reader-fn* clj

When no data reader is found for a tag and default-data-reader-fn is non-nil, it will be called with two arguments, the tag and the value. If default-data-reader-fn is nil (the default), an exception will be thrown for the unknown tag.

*e clj

bound in a repl thread to the most recent exception caught by the repl

*err* clj

A java.io.Writer object representing standard error for print operations.

Defaults to System/err, wrapped in a PrintWriter

*file* clj

The path of the file being evaluated, as a String.

When there is no file, e.g. in the REPL, the value is not defined.

*flush-on-newline* clj

When set to true, output will be flushed whenever a newline is printed.

Defaults to true.

*fn-loader* clj

*in* clj

A java.io.Reader object representing standard input for read operations.

Defaults to System/in, wrapped in a LineNumberingPushbackReader

*math-context* clj

*ns* clj

A clojure.lang.Namespace object representing the current namespace.

*out* clj

A java.io.Writer object representing standard output for print operations.

Defaults to System/out, wrapped in an OutputStreamWriter

*print-dup* clj

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* clj

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.

*print-level* clj

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.

*print-meta* clj

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-namespace-maps* clj

print-namespace-maps controls whether the printer will print namespace map literal syntax. It defaults to false, but the REPL binds to true.

*print-readably* clj

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* clj

Defaults to true (or value specified by system property, see below) This setting implies that the full power of the reader is in play, including syntax that can cause code to execute. It should never be used with untrusted sources. See also: clojure.edn/read.

When set to logical false in the thread-local binding, the eval reader (#=) and record/type literal syntax are disabled in read/load. Example (will fail): (binding [read-eval false] (read-string "#=(* 2 21)"))

The default binding can be controlled by the system property 'clojure.read.eval' System properties can be set on the command line like this:

java -Dclojure.read.eval=false ...

The system property can also be set to 'unknown' via -Dclojure.read.eval=unknown, in which case the default binding is :unknown and all reads will fail in contexts where read-eval has not been explicitly bound to either true or false. This setting can be a useful diagnostic tool to ensure that all of your reads occur in considered contexts. You can also accomplish this in a particular scope by binding read-eval to :unknown

*reader-resolver* clj

*repl* clj

Bound to true in a repl thread

*source-path* clj

*suppress-read* clj

*unchecked-math* clj

While bound to true, compilations of +, -, *, inc, dec and the coercions will be done without overflow checks. While bound to :warn-on-boxed, same behavior as true, and a warning is emitted when compilation uses boxed math. Default: false.

*use-context-classloader* clj

*verbose-defrecords* clj

*warn-on-reflection* clj

When set to true, the compiler will emit warnings when reflection is needed to resolve Java method calls or field accesses.

Defaults to false.

+ clj

(+)

(+ x)

(+ x y)

(+ x y & more)

Returns the sum of nums. (+) returns 0. Does not auto-promote longs, will throw on overflow. See also: +'

+' clj

(+')

(+' x)

(+' x y)

(+' x y & more)

Returns the sum of nums. (+') returns 0. Supports arbitrary precision. See also: +

- clj

(- x)

(- x y)

(- x y & more)

If no ys are supplied, returns the negation of x, else subtracts the ys from x and returns the result. Does not auto-promote longs, will throw on overflow. See also: -'

-' clj

(-' x)

(-' x y)

(-' x y & more)

If no ys are supplied, returns the negation of x, else subtracts the ys from x and returns the result. Supports arbitrary precision. See also: -

-> clj macro

(-> x & forms)

Threads the expr through the forms. Inserts x as the second item in the first form, making a list of it if it is not a list already. If there are more forms, inserts the first form as the second item in second form, etc.

->> clj macro

(->> x & forms)

Threads the expr through the forms. Inserts x as the last item in the first form, making a list of it if it is not a list already. If there are more forms, inserts the first form as the last item in second form, etc.

-cache-protocol-fn clj

(-cache-protocol-fn pf x c interf)

-reset-methods clj

(-reset-methods protocol)

.. clj macro

(.. 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.

/ clj

(/ x)

(/ x y)

(/ x y & more)

If no denominators are supplied, returns 1/numerator, else returns numerator divided by all of the denominators.

< clj

(< x)

(< x y)

(< x y & more)

Returns non-nil if nums are in monotonically increasing order, otherwise false.

<= clj

(<= x)

(<= x y)

(<= x y & more)

Returns non-nil if nums are in monotonically non-decreasing order, otherwise false.

= clj

(= 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.

== clj

(== x)

(== x y)

(== x y & more)

Returns non-nil if nums all have the equivalent value (type-independent), otherwise false

> clj

(> x)

(> x y)

(> x y & more)

Returns non-nil if nums are in monotonically decreasing order, otherwise false.

>= clj

(>= x)

(>= x y)

(>= x y & more)

Returns non-nil if nums are in monotonically non-increasing order, otherwise false.

abs clj

(abs a)

Returns the absolute value of a. If a is Long/MIN_VALUE => Long/MIN_VALUE If a is a double and zero => +0.0 If a is a double and ##Inf or ##-Inf => ##Inf If a is a double and ##NaN => ##NaN

accessor clj

(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.

aclone clj

(aclone array)

Returns a clone of the Java array. Works on arrays of known types.

add-classpath clj deprecated

(add-classpath url)

DEPRECATED

Adds the url (String or URL object) to the classpath per URLClassLoader.addURL

add-tap clj

(add-tap f)

adds f, a fn of one argument, to the tap set. This function will be called with anything sent via tap>. This function may (briefly) block (e.g. for streams), and will never impede calls to tap>, but blocking indefinitely may cause tap values to be dropped. Remember f in order to remove-tap

add-watch clj

(add-watch reference key fn)

Adds a watch function to an agent/atom/var/ref reference. The watch fn must be a fn of 4 args: a key, the reference, its old-state, its new-state. Whenever the reference's state might have been changed, any registered watches will have their functions called. The watch fn will be called synchronously, on the agent's thread if an agent, before any pending sends if agent or ref. Note that an atom's or ref's state may have changed again prior to the fn call, so use old/new-state rather than derefing the reference. Note also that watch fns may be called from multiple threads simultaneously. Var watchers are triggered only by root binding changes, not thread-local set!s. Keys must be unique per reference, and can be used to remove the watch with remove-watch, but are otherwise considered opaque by the watch mechanism.

agent clj

(agent state & options)

Creates and returns an agent with an initial value of state and zero or more options (in any order):

:meta metadata-map

:validator validate-fn

:error-handler handler-fn

:error-mode mode-keyword

If metadata-map is supplied, it will become the metadata on the agent. validate-fn must be nil or a side-effect-free fn of one argument, which will be passed the intended new state on any state change. If the new state is unacceptable, the validate-fn should return false or throw an exception. handler-fn is called if an action throws an exception or if validate-fn rejects a new state -- see set-error-handler! for details. The mode-keyword may be either :continue (the default if an error-handler is given) or :fail (the default if no error-handler is given) -- see set-error-mode! for details.

agent-error clj

(agent-error a)

Returns the exception thrown during an asynchronous action of the agent if the agent is failed. Returns nil if the agent is not failed.

agent-errors clj deprecated

(agent-errors a)

DEPRECATED: Use 'agent-error' instead. Returns a sequence of the exceptions thrown during asynchronous actions of the agent.

aget clj

(aget array idx)

(aget array idx & idxs)

Returns the value at the index/indices. Works on Java arrays of all types.

alength clj

(alength array)

Returns the length of the Java array. Works on arrays of all types.

alias clj

(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.

all-ns clj

(all-ns)

Returns a sequence of all namespaces.

alter clj

(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.

alter-meta! clj

(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

alter-var-root clj

(alter-var-root v f & args)

Atomically alters the root binding of var v by applying f to its current value plus any args

amap clj macro

(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.

ancestors clj

(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

and clj macro

(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.

any? clj

(any? x)

Returns true given any argument.

apply clj

(apply f args)

(apply f x args)

(apply f x y args)

(apply f x y z args)

(apply f a b c d & args)

Applies fn f to the argument list formed by prepending intervening arguments to args.

areduce clj macro

(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.

array-map clj

(array-map)

(array-map & keyvals)

Constructs an array-map. If any keys are equal, they are handled as if by repeated uses of assoc.

as-> clj macro

(as-> expr name & forms)

Binds name to expr, evaluates the first form in the lexical context of that binding, then binds name to that result, repeating for each successive form, returning the result of the last form.

aset clj

(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.

aset-boolean clj

(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.

aset-byte clj

(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.

aset-char clj

(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.

aset-double clj

(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.

aset-float clj

(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.

aset-int clj

(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.

aset-long clj

(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.

aset-short clj

(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.

assert clj macro

(assert x)

(assert x message)

Evaluates expr and throws an exception if it does not evaluate to logical true.

assoc clj

(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).

assoc! clj

(assoc! coll key val)

(assoc! coll key val & kvs)

When applied to a transient map, adds mapping of key(s) to val(s). When applied to a transient vector, sets the val at index. Note - index must be <= (count vector). Returns coll.

assoc-in clj

(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.

associative? clj

(associative? coll)

Returns true if coll implements Associative

atom clj

(atom x)

(atom x & options)

Creates and returns an Atom with an initial value of x and zero or more options (in any order):

:meta metadata-map

:validator validate-fn

If metadata-map is supplied, it will become the metadata on the atom. validate-fn must be nil or a side-effect-free fn of one argument, which will be passed the intended new state on any state change. If the new state is unacceptable, the validate-fn should return false or throw an exception.

await clj

(await & agents)

Blocks the current thread (indefinitely!) until all actions dispatched thus far, from this thread or agent, to the agent(s) have occurred. Will block on failed agents. Will never return if a failed agent is restarted with :clear-actions true or shutdown-agents was called.

await-for clj

(await-for timeout-ms & agents)

Blocks the current thread until all actions dispatched thus far (from this thread or agent) to the agents have occurred, or the timeout (in milliseconds) has elapsed. Returns logical false if returning due to timeout, logical true otherwise.

await1 clj

(await1 a)

bases clj

(bases c)

Returns the immediate superclass and direct interfaces of c, if any

bean clj

(bean x)

Takes a Java object and returns a read-only implementation of the map abstraction based upon its JavaBean properties.

bigdec clj

(bigdec x)

Coerce to BigDecimal

bigint clj

(bigint x)

Coerce to BigInt

biginteger clj

(biginteger x)

Coerce to BigInteger

binding clj macro

(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.

bit-and clj

(bit-and x y)

(bit-and x y & more)

Bitwise and

bit-and-not clj

(bit-and-not x y)

(bit-and-not x y & more)

Bitwise and with complement

bit-clear clj

(bit-clear x n)

Clear bit at index n

bit-flip clj

(bit-flip x n)

Flip bit at index n

bit-not clj

(bit-not x)

Bitwise complement

bit-or clj

(bit-or x y)

(bit-or x y & more)

Bitwise or

bit-set clj

(bit-set x n)

Set bit at index n

bit-shift-left clj

(bit-shift-left x n)

Bitwise shift left

bit-shift-right clj

(bit-shift-right x n)

Bitwise shift right

bit-test clj

(bit-test x n)

Test bit at index n

bit-xor clj

(bit-xor x y)

(bit-xor x y & more)

Bitwise exclusive or

boolean clj

(boolean x)

Coerce to boolean

boolean-array clj

(boolean-array size-or-seq)

(boolean-array size init-val-or-seq)

Creates an array of booleans

boolean? clj

(boolean? x)

Return true if x is a Boolean

booleans clj

(booleans xs)

Casts to boolean[]

bound-fn clj macro

(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.

bound-fn* clj

(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.

bound? clj

(bound? & vars)

Returns true if all of the vars provided as arguments have any bound value, root or thread-local. Implies that deref'ing the provided vars will succeed. Returns true if no vars are provided.

bounded-count clj

(bounded-count n coll)

If coll is counted? returns its count, else will count at most the first n elements of coll using its seq

butlast clj

(butlast coll)

Return a seq of all but the last item in coll, in linear time

byte clj

(byte x)

Coerce to byte

byte-array clj

(byte-array size-or-seq)

(byte-array size init-val-or-seq)

Creates an array of bytes

bytes clj

(bytes xs)

Casts to bytes[]

bytes? clj

(bytes? x)

Return true if x is a byte array

case clj macro

(case e & clauses)

Takes an expression, and a set of clauses.

Each clause can take the form of either:

test-constant result-expr

(test-constant1 ... test-constantN) result-expr

The test-constants are not evaluated. They must be compile-time literals, and need not be quoted. If the expression is equal to a test-constant, the corresponding result-expr is returned. A single default expression can follow the clauses, and its value will be returned if no clause matches. If no default expression is provided and no clause matches, an IllegalArgumentException is thrown.

Unlike cond and condp, case does a constant-time dispatch, the clauses are not considered sequentially. All manner of constant expressions are acceptable in case, including numbers, strings, symbols, keywords, and (Clojure) composites thereof. Note that since lists are used to group multiple constants that map to the same expression, a vector can be used to match a list if needed. The test-constants need not be all of the same type.

cast clj

(cast c x)

Throws a ClassCastException if x is not a c, else returns x.

cat clj

(cat rf)

A transducer which concatenates the contents of each input, which must be a collection, into the reduction.

char clj

(char x)

Coerce to char

char-array clj

(char-array size-or-seq)

(char-array size init-val-or-seq)

Creates an array of chars

char-escape-string clj

Returns escape string for char or nil if none

char-name-string clj

Returns name string for char or nil if none

char? clj

(char? x)

Return true if x is a Character

chars clj

(chars xs)

Casts to chars[]

chunk clj

(chunk b)

chunk-append clj

(chunk-append b x)

chunk-buffer clj

(chunk-buffer capacity)

chunk-cons clj

(chunk-cons chunk rest)

chunk-first clj

(chunk-first s)

chunk-next clj

(chunk-next s)

chunk-rest clj

(chunk-rest s)

chunked-seq? clj

(chunked-seq? s)

class clj

(class x)

Returns the Class of x

class? clj

(class? x)

Returns true if x is an instance of Class

clear-agent-errors clj deprecated

(clear-agent-errors a)

DEPRECATED: Use 'restart-agent' instead. Clears any exceptions thrown during asynchronous actions of the agent, allowing subsequent actions to occur.

clojure-version clj

(clojure-version)

Returns clojure version as a printable string.

coll? clj

(coll? x)

Returns true if x implements IPersistentCollection

comment clj macro

(comment & body)

Ignores body, yields nil

commute clj

(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.

comp clj

(comp)

(comp f)

(comp f g)

(comp f g & fs)

Takes a set of functions and returns a fn that is the composition of those fns. The returned fn takes a variable number of args, applies the rightmost of fns to the args, the next fn (right-to-left) to the result, etc.

comparator clj

(comparator pred)

Returns an implementation of java.util.Comparator based upon pred.

compare clj

(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

compare-and-set! clj

(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

compile clj

(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.

complement clj

(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.

completing clj

(completing f)

(completing f cf)

Takes a reducing function f of 2 args and returns a fn suitable for transduce by adding an arity-1 signature that calls cf (default - identity) on the result argument.

concat clj

(concat)

(concat x)

(concat x y)

(concat x y & zs)

Returns a lazy seq representing the concatenation of the elements in the supplied colls.

cond clj macro

(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.

cond-> clj macro

(cond-> expr & clauses)

Takes an expression and a set of test/form pairs. Threads expr (via ->) through each form for which the corresponding test expression is true. Note that, unlike cond branching, cond-> threading does not short circuit after the first true test expression.

cond->> clj macro

(cond->> expr & clauses)

Takes an expression and a set of test/form pairs. Threads expr (via ->>) through each form for which the corresponding test expression is true. Note that, unlike cond branching, cond->> threading does not short circuit after the first true test expression.

condp clj macro

(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.

conj clj

(conj)

(conj coll)

(conj coll x)

(conj coll x & xs)

conj[oin]. Returns a new collection with the xs 'added'. (conj nil item) returns (item). (conj coll) returns coll. (conj) returns []. The 'addition' may happen at different 'places' depending on the concrete type.

conj! clj

(conj!)

(conj! coll)

(conj! coll x)

Adds x to the transient collection, and return coll. The 'addition' may happen at different 'places' depending on the concrete type.

cons clj

(cons x seq)

Returns a new seq where x is the first element and seq is the rest.

constantly clj

(constantly x)

Returns a function that takes any number of arguments and returns x.

construct-proxy clj

(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.

contains? clj

(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'.

count clj

(count coll)

Returns the number of items in the collection. (count nil) returns 0. Also works on strings, arrays, and Java Collections and Maps

counted? clj

(counted? coll)

Returns true if coll implements count in constant time

create-ns clj

(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.

create-struct clj

(create-struct & keys)

Returns a structure basis object.

cycle clj

(cycle coll)

Returns a lazy (infinite!) sequence of repetitions of the items in coll.

dec clj

(dec x)

Returns a number one less than num. Does not auto-promote longs, will throw on overflow. See also: dec'

dec' clj

(dec' x)

Returns a number one less than num. Supports arbitrary precision. See also: dec

decimal? clj

(decimal? n)

Returns true if n is a BigDecimal

declare clj macro

(declare & names)

defs the supplied var names with no bindings, useful for making forward declarations.

dedupe clj

(dedupe)

(dedupe coll)

Returns a lazy sequence removing consecutive duplicates in coll. Returns a transducer when no collection is provided.

default-data-readers clj

Default map of data reader functions provided by Clojure. May be overridden by binding data-readers.

definline clj macro

(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.

definterface clj macro

(definterface name & sigs)

Creates a new Java interface with the given name and method sigs. The method return types and parameter types may be specified with type hints, defaulting to Object if omitted.

(definterface MyInterface (^int method1 [x]) (^Bar method2 [^Baz b ^Quux q]))

defmacro clj macro

(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.

defmethod clj macro

(defmethod multifn dispatch-val & fn-tail)

Creates and installs a new method of multimethod associated with dispatch-value.

defmulti clj macro

(defmulti name docstring? attr-map? dispatch-fn & options)

Creates a new multimethod with the associated dispatch function. The docstring and attr-map are optional.

Options are key-value pairs and may be one of:

:default

The default dispatch value, defaults to :default

:hierarchy

The value used for hierarchical dispatch (e.g. ::square is-a ::shape)

Hierarchies are type-like relationships that do not depend upon type inheritance. By default Clojure's multimethods dispatch off of a global hierarchy map. However, a hierarchy relationship can be created with the derive function used to augment the root ancestor created with make-hierarchy.

Multimethods expect the value of the hierarchy option to be supplied as a reference type e.g. a var (i.e. via the Var-quote dispatch macro #' or the var special form).

defn clj macro

(defn name doc-string? attr-map? [params*] prepost-map? body)

(defn name doc-string? attr-map? ([params*] prepost-map? body) + attr-map?)

Same as (def name (fn [params* ] exprs*)) or (def name (fn ([params* ] exprs*)+)) with any doc-string or attrs added to the var metadata. prepost-map defines a map with optional keys :pre and :post that contain collections of pre or post conditions.

defn- clj macro

(defn- name & decls)

same as defn, yielding non-public def

defonce clj macro

(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

defprotocol clj macro

(defprotocol name & opts+sigs)

A protocol is a named set of named methods and their signatures: (defprotocol AProtocolName

;optional doc string "A doc string for AProtocol abstraction"

;options :extend-via-metadata true

;method signatures (bar [this a b] "bar docs") (baz [this a] [this a b] [this a b c] "baz docs"))

No implementations are provided. Docs can be specified for the protocol overall and for each method. The above yields a set of polymorphic functions and a protocol object. All are namespace-qualified by the ns enclosing the definition The resulting functions dispatch on the type of their first argument, which is required and corresponds to the implicit target object ('this' in Java parlance). defprotocol is dynamic, has no special compile-time effect, and defines no new types or classes. Implementations of the protocol methods can be provided using extend.

When :extend-via-metadata is true, values can extend protocols by adding metadata where keys are fully-qualified protocol function symbols and values are function implementations. Protocol implementations are checked first for direct definitions (defrecord, deftype, reify), then metadata definitions, then external extensions (extend, extend-type, extend-protocol)

defprotocol will automatically generate a corresponding interface, with the same name as the protocol, i.e. given a protocol: my.ns/Protocol, an interface: my.ns.Protocol. The interface will have methods corresponding to the protocol functions, and the protocol will automatically work with instances of the interface.

Note that you should not use this interface with deftype or reify, as they support the protocol directly:

(defprotocol P (foo [this]) (bar-me [this] [this y]))

(deftype Foo [a b c] P (foo [this] a) (bar-me [this] b) (bar-me [this y] (+ c y)))

(bar-me (Foo. 1 2 3) 42) => 45

(foo (let [x 42] (reify P (foo [this] 17) (bar-me [this] x) (bar-me [this y] x)))) => 17

defrecord clj macro

(defrecord name [& fields] & opts+specs)

(defrecord name [fields*] options* specs*)

Options are expressed as sequential keywords and arguments (in any order).

Supported options: :load-ns - if true, importing the record class will cause the namespace in which the record was defined to be loaded. Defaults to false.

Each spec consists of a protocol or interface name followed by zero or more method bodies:

protocol-or-interface-or-Object (methodName [args*] body)*

Dynamically generates compiled bytecode for class with the given name, in a package with the same name as the current namespace, the given fields, and, optionally, methods for protocols and/or interfaces.

The class will have the (immutable) fields named by fields, which can have type hints. Protocols/interfaces and methods are optional. The only methods that can be supplied are those declared in the protocols/interfaces. Note that method bodies are not closures, the local environment includes only the named fields, and those fields can be accessed directly.

Method definitions take the form:

(methodname [args*] body)

The argument and return types can be hinted on the arg and methodname symbols. If not supplied, they will be inferred, so type hints should be reserved for disambiguation.

Methods should be supplied for all methods of the desired protocol(s) and interface(s). You can also define overrides for methods of Object. Note that a parameter must be supplied to correspond to the target object ('this' in Java parlance). Thus methods for interfaces will take one more argument than do the interface declarations. Note also that recur calls to the method head should not pass the target object, it will be supplied automatically and can not be substituted.

In the method bodies, the (unqualified) name can be used to name the class (for calls to new, instance? etc).

The class will have implementations of several (clojure.lang) interfaces generated automatically: IObj (metadata support) and IPersistentMap, and all of their superinterfaces.

In addition, defrecord will define type-and-value-based =, and will defined Java .hashCode and .equals consistent with the contract for java.util.Map.

When AOT compiling, generates compiled bytecode for a class with the given name (a symbol), prepends the current ns as the package, and writes the .class file to the compile-path directory.

Two constructors will be defined, one taking the designated fields followed by a metadata map (nil for none) and an extension field map (nil for none), and one taking only the fields (using nil for meta and extension fields). Note that the field names __meta, __extmap, __hash and __hasheq are currently reserved and should not be used when defining your own records.

Given (defrecord TypeName ...), two factory functions will be defined: ->TypeName, taking positional parameters for the fields, and map->TypeName, taking a map of keywords to field values.

defstruct clj macro

(defstruct name & keys)

Same as (def name (create-struct keys...))

deftype clj macro

(deftype name [& fields] & opts+specs)

(deftype name [fields*] options* specs*)

Options are expressed as sequential keywords and arguments (in any order).

Supported options: :load-ns - if true, importing the type class will cause the namespace in which the type was defined to be loaded. Defaults to false.

Each spec consists of a protocol or interface name followed by zero or more method bodies:

protocol-or-interface-or-Object (methodName [args*] body)*

Dynamically generates compiled bytecode for class with the given name, in a package with the same name as the current namespace, the given fields, and, optionally, methods for protocols and/or interfaces.

The class will have the (by default, immutable) fields named by fields, which can have type hints. Protocols/interfaces and methods are optional. The only methods that can be supplied are those declared in the protocols/interfaces. Note that method bodies are not closures, the local environment includes only the named fields, and those fields can be accessed directly. Fields can be qualified with the metadata :volatile-mutable true or :unsynchronized-mutable true, at which point (set! afield aval) will be supported in method bodies. Note well that mutable fields are extremely difficult to use correctly, and are present only to facilitate the building of higher level constructs, such as Clojure's reference types, in Clojure itself. They are for experts only - if the semantics and implications of :volatile-mutable or :unsynchronized-mutable are not immediately apparent to you, you should not be using them.

Method definitions take the form:

(methodname [args*] body)

The argument and return types can be hinted on the arg and methodname symbols. If not supplied, they will be inferred, so type hints should be reserved for disambiguation.

Methods should be supplied for all methods of the desired protocol(s) and interface(s). You can also define overrides for methods of Object. Note that a parameter must be supplied to correspond to the target object ('this' in Java parlance). Thus methods for interfaces will take one more argument than do the interface declarations. Note also that recur calls to the method head should not pass the target object, it will be supplied automatically and can not be substituted.

In the method bodies, the (unqualified) name can be used to name the class (for calls to new, instance? etc).

When AOT compiling, generates compiled bytecode for a class with the given name (a symbol), prepends the current ns as the package, and writes the .class file to the compile-path directory.

One constructor will be defined, taking the designated fields. Note that the field names __meta, __extmap, __hash and __hasheq are currently reserved and should not be used when defining your own types.

Given (deftype TypeName ...), a factory function called ->TypeName will be defined, taking positional parameters for the fields

delay clj macro

(delay & body)

Takes a body of expressions and yields a Delay object that will invoke the body only the first time it is forced (with force or deref/@), and will cache the result and return it on all subsequent force calls. See also - realized?

delay? clj

(delay? x)

returns true if x is a Delay created with delay

deliver clj

(deliver promise val)

Delivers the supplied value to the promise, releasing any pending derefs. A subsequent call to deliver on a promise will have no effect.

denominator clj

(denominator r)

Returns the denominator part of a Ratio.

deref clj

(deref ref)

(deref ref timeout-ms timeout-val)

Also reader macro: @ref/@agent/@var/@atom/@delay/@future/@promise. Within a transaction, returns the in-transaction-value of ref, else returns the most-recently-committed value of ref. When applied to a var, agent or atom, returns its current state. When applied to a delay, forces it if not already forced. When applied to a future, will block if computation not complete. When applied to a promise, will block until a value is delivered. The variant taking a timeout can be used for blocking references (futures and promises), and will return timeout-val if the timeout (in milliseconds) is reached before a value is available. See also - realized?.

derive clj

(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.

descendants clj

(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.

destructure clj

(destructure bindings)

disj clj

(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).

disj! clj

(disj! set)

(disj! set key)

(disj! set key & ks)

disj[oin]. Returns a transient set of the same (hashed/sorted) type, that does not contain key(s).

dissoc clj

(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).

dissoc! clj

(dissoc! map key)

(dissoc! map key & ks)

Returns a transient map that doesn't contain a mapping for key(s).

distinct clj

(distinct)

(distinct coll)

Returns a lazy sequence of the elements of coll with duplicates removed. Returns a stateful transducer when no collection is provided.

distinct? clj

(distinct? x)

(distinct? x y)

(distinct? x y & more)

Returns true if no two of the arguments are =

doall clj

(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.

dorun clj

(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.

doseq clj macro

(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.

dosync clj macro

(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.

dotimes clj macro

(dotimes bindings & body)

bindings => name n

Repeatedly executes body (presumably for side-effects) with name bound to integers from 0 through n-1.

doto clj macro

(doto x & forms)

Evaluates x then calls all of the methods and functions with the value of x supplied at the front of the given arguments. The forms are evaluated in order. Returns x.

(doto (new java.util.HashMap) (.put "a" 1) (.put "b" 2))

double clj

(double x)

Coerce to double

double-array clj

(double-array size-or-seq)

(double-array size init-val-or-seq)

Creates an array of doubles

double? clj

(double? x)

Return true if x is a Double

doubles clj

(doubles xs)

Casts to double[]

drop clj

(drop n)

(drop n coll)

Returns a laziness-preserving sequence of all but the first n items in coll. Returns a stateful transducer when no collection is provided.

drop-last clj

(drop-last coll)

(drop-last n coll)

Return a lazy sequence of all but the last n (default 1) items in coll

drop-while clj

(drop-while pred)

(drop-while pred coll)

Returns a lazy sequence of the items in coll starting from the first item for which (pred item) returns logical false. Returns a stateful transducer when no collection is provided.

eduction clj

(eduction xform* coll)

Returns a reducible/iterable application of the transducers to the items in coll. Transducers are applied in order as if combined with comp. Note that these applications will be performed every time reduce/iterator is called.

empty clj

(empty coll)

Returns an empty collection of the same category as coll, or nil

EMPTY-NODE clj

empty? clj

(empty? coll)

Returns true if coll has no items. To check the emptiness of a seq, please use the idiom (seq x) rather than (not (empty? x))

ensure clj

(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)

ensure-reduced clj

(ensure-reduced x)

If x is already reduced?, returns it, else returns (reduced x)

enumeration-seq clj

(enumeration-seq e)

Returns a seq on a java.util.Enumeration

error-handler clj

(error-handler a)

Returns the error-handler of agent a, or nil if there is none. See set-error-handler!

error-mode clj

(error-mode a)

Returns the error-mode of agent a. See set-error-mode!

eval clj

(eval form)

Evaluates the form data structure (not text!) and returns the result.

even? clj

(even? n)

Returns true if n is even, throws an exception if n is not an integer

every-pred clj

(every-pred p)

(every-pred p1 p2)

(every-pred p1 p2 p3)

(every-pred p1 p2 p3 & ps)

Takes a set of predicates and returns a function f that returns true if all of its composing predicates return a logical true value against all of its arguments, else it returns false. Note that f is short-circuiting in that it will stop execution on the first argument that triggers a logical false result against the original predicates.

every? clj

(every? pred coll)

Returns true if (pred x) is logical true for every x in coll, else false.

ex-cause clj

(ex-cause ex)

Returns the cause of ex if ex is a Throwable. Otherwise returns nil.

ex-data clj

(ex-data ex)

Returns exception data (a map) if ex is an IExceptionInfo. Otherwise returns nil.

ex-info clj

(ex-info msg map)

(ex-info msg map cause)

Create an instance of ExceptionInfo, a RuntimeException subclass that carries a map of additional data.

ex-message clj

(ex-message ex)

Returns the message attached to ex if ex is a Throwable. Otherwise returns nil.

extend clj

(extend atype & proto+mmaps)

Implementations of protocol methods can be provided using the extend construct:

(extend AType AProtocol {:foo an-existing-fn :bar (fn [a b] ...) :baz (fn ([a]...) ([a b] ...)...)} BProtocol {...} ...)

extend takes a type/class (or interface, see below), and one or more protocol + method map pairs. It will extend the polymorphism of the protocol's methods to call the supplied methods when an AType is provided as the first argument.

Method maps are maps of the keyword-ized method names to ordinary fns. This facilitates easy reuse of existing fns and fn maps, for code reuse/mixins without derivation or composition. You can extend an interface to a protocol. This is primarily to facilitate interop with the host (e.g. Java) but opens the door to incidental multiple inheritance of implementation since a class can inherit from more than one interface, both of which extend the protocol. It is TBD how to specify which impl to use. You can extend a protocol on nil.

If you are supplying the definitions explicitly (i.e. not reusing exsting functions or mixin maps), you may find it more convenient to use the extend-type or extend-protocol macros.

Note that multiple independent extend clauses can exist for the same type, not all protocols need be defined in a single extend call.

See also: extends?, satisfies?, extenders

extend-protocol clj macro

(extend-protocol p & specs)

Useful when you want to provide several implementations of the same protocol all at once. Takes a single protocol and the implementation of that protocol for one or more types. Expands into calls to extend-type:

(extend-protocol Protocol AType (foo [x] ...) (bar [x y] ...) BType (foo [x] ...) (bar [x y] ...) AClass (foo [x] ...) (bar [x y] ...) nil (foo [x] ...) (bar [x y] ...))

expands into:

(do (clojure.core/extend-type AType Protocol (foo [x] ...) (bar [x y] ...)) (clojure.core/extend-type BType Protocol (foo [x] ...) (bar [x y] ...)) (clojure.core/extend-type AClass Protocol (foo [x] ...) (bar [x y] ...)) (clojure.core/extend-type nil Protocol (foo [x] ...) (bar [x y] ...)))

extend-type clj macro

(extend-type t & specs)

A macro that expands into an extend call. Useful when you are supplying the definitions explicitly inline, extend-type automatically creates the maps required by extend. Propagates the class as a type hint on the first argument of all fns.

(extend-type MyType Countable (cnt [c] ...) Foo (bar [x y] ...) (baz ([x] ...) ([x y & zs] ...)))

expands into:

(extend MyType Countable {:cnt (fn [c] ...)} Foo {:baz (fn ([x] ...) ([x y & zs] ...)) :bar (fn [x y] ...)})

extenders clj

(extenders protocol)

Returns a collection of the types explicitly extending protocol

extends? clj

(extends? protocol atype)

Returns true if atype extends protocol

false? clj

(false? x)

Returns true if x is the value false, false otherwise.

ffirst clj

(ffirst x)

Same as (first (first x))

file-seq clj

(file-seq dir)

A tree seq on java.io.Files

filter clj

(filter pred)

(filter pred coll)

Returns a lazy sequence of the items in coll for which (pred item) returns logical true. pred must be free of side-effects. Returns a transducer when no collection is provided.

filterv clj

(filterv pred coll)

Returns a vector of the items in coll for which (pred item) returns logical true. pred must be free of side-effects.

find clj

(find map key)

Returns the map entry for key, or nil if key not present.

find-keyword clj

(find-keyword name)

(find-keyword ns name)

Returns a Keyword with the given namespace and name if one already exists. This function will not intern a new keyword. If the keyword has not already been interned, it will return nil. Do not use : in the keyword strings, it will be added automatically.

find-ns clj

(find-ns sym)

Returns the namespace named by the symbol or nil if it doesn't exist.

find-protocol-impl clj

(find-protocol-impl protocol x)

find-protocol-method clj

(find-protocol-method protocol methodk x)

find-var clj

(find-var sym)

Returns the global var named by the namespace-qualified symbol, or nil if no var with that name.

first clj

(first coll)

Returns the first item in the collection. Calls seq on its argument. If coll is nil, returns nil.

flatten clj

(flatten x)

Takes any nested combination of sequential things (lists, vectors, etc.) and returns their contents as a single, flat lazy sequence. (flatten nil) returns an empty sequence.

float clj

(float x)

Coerce to float

float-array clj

(float-array size-or-seq)

(float-array size init-val-or-seq)

Creates an array of floats

float? clj

(float? n)

Returns true if n is a floating point number

floats clj

(floats xs)

Casts to float[]

flush clj

(flush)

Flushes the output stream that is the current value of out

fn clj macro

(fn & sigs)

params => positional-params*, or positional-params* & rest-param positional-param => binding-form rest-param => binding-form binding-form => name, or destructuring-form

Defines a function.

See https://clojure.org/reference/special_forms#fn for more information

fn? clj

(fn? x)

Returns true if x implements Fn, i.e. is an object created via fn.

fnext clj

(fnext x)

Same as (first (next x))

fnil clj

(fnil f x)

(fnil f x y)

(fnil f x y z)

Takes a function f, and returns a function that calls f, replacing a nil first argument to f with the supplied value x. Higher arity versions can replace arguments in the second and third positions (y, z). Note that the function f can take any number of arguments, not just the one(s) being nil-patched.

for clj macro

(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]))

force clj

(force x)

If x is a Delay, returns the (possibly cached) value of its expression, else returns x

format clj

(format fmt & args)

Formats a string using java.lang.String.format, see java.util.Formatter for format string syntax

frequencies clj

(frequencies coll)

Returns a map from distinct items in coll to the number of times they appear.

future clj macro

(future & body)

Takes a body of expressions and yields a future object that will invoke the body in another thread, and will cache the result and return it on all subsequent calls to deref/@. If the computation has not yet finished, calls to deref/@ will block, unless the variant of deref with timeout is used. See also - realized?.

future-call clj

(future-call f)

Takes a function of no args and yields a future object that will invoke the function in another thread, and will cache the result and return it on all subsequent calls to deref/@. If the computation has not yet finished, calls to deref/@ will block, unless the variant of deref with timeout is used. See also - realized?.

future-cancel clj

(future-cancel f)

Cancels the future, if possible.

future-cancelled? clj

(future-cancelled? f)

Returns true if future f is cancelled

future-done? clj

(future-done? f)

Returns true if future f is done

future? clj

(future? x)

Returns true if x is a future

gen-class clj macro

(gen-class & options)

When compiling, generates compiled bytecode for a class with the given package-qualified :name (which, as all names in these parameters, can be a string or symbol), and writes the .class file to the compile-path directory. When not compiling, does nothing. The gen-class construct contains no implementation, as the implementation will be dynamically sought by the generated class in functions in an implementing Clojure namespace. Given a generated class org.mydomain.MyClass with a method named mymethod, gen-class will generate an implementation that looks for a function named by (str prefix mymethod) (default prefix: "-") in a Clojure namespace specified by :impl-ns (defaults to the current namespace). All inherited methods, generated methods, and init and main functions (see :methods, :init, and :main below) will be found similarly prefixed. By default, the static initializer for the generated class will attempt to load the Clojure support code for the class as a resource from the classpath, e.g. in the example case, org/mydomain/MyClass__init.class. This behavior can be controlled by :load-impl-ns

Note that methods with a maximum of 18 parameters are supported.

In all subsequent sections taking types, the primitive types can be referred to by their Java names (int, float etc), and classes in the java.lang package can be used without a package qualifier. All other classes must be fully qualified.

Options should be a set of key/value pairs, all except for :name are optional:

:name aname

The package-qualified name of the class to be generated

:extends aclass

Specifies the superclass, the non-private methods of which will be overridden by the class. If not provided, defaults to Object.

:implements [interface ...]

One or more interfaces, the methods of which will be implemented by the class.

:init name

If supplied, names a function that will be called with the arguments to the constructor. Must return [ [superclass-constructor-args] state] If not supplied, the constructor args are passed directly to the superclass constructor and the state will be nil

:constructors {[param-types] [super-param-types], ...}

By default, constructors are created for the generated class which match the signature(s) of the constructors for the superclass. This parameter may be used to explicitly specify constructors, each entry providing a mapping from a constructor signature to a superclass constructor signature. When you supply this, you must supply an :init specifier.

:post-init name

If supplied, names a function that will be called with the object as the first argument, followed by the arguments to the constructor. It will be called every time an object of this class is created, immediately after all the inherited constructors have completed. Its return value is ignored.

:methods [ [name [param-types] return-type], ...]

The generated class automatically defines all of the non-private methods of its superclasses/interfaces. This parameter can be used to specify the signatures of additional methods of the generated class. Static methods can be specified with ^{:static true} in the signature's metadata. Do not repeat superclass/interface signatures here.

:main boolean

If supplied and true, a static public main function will be generated. It will pass each string of the String[] argument as a separate argument to a function called (str prefix main).

:factory name

If supplied, a (set of) public static factory function(s) will be created with the given name, and the same signature(s) as the constructor(s).

:state name

If supplied, a public final instance field with the given name will be created. You must supply an :init function in order to provide a value for the state. Note that, though final, the state can be a ref or agent, supporting the creation of Java objects with transactional or asynchronous mutation semantics.

:exposes {protected-field-name {:get name :set name}, ...}

Since the implementations of the methods of the generated class occur in Clojure functions, they have no access to the inherited protected fields of the superclass. This parameter can be used to generate public getter/setter methods exposing the protected field(s) for use in the implementation.

:exposes-methods {super-method-name exposed-name, ...}

It is sometimes necessary to call the superclass' implementation of an overridden method. Those methods may be exposed and referred in the new method implementation by a local name.

:prefix string

Default: "-" Methods called e.g. Foo will be looked up in vars called prefixFoo in the implementing ns.

:impl-ns name

Default: the name of the current ns. Implementations of methods will be looked up in this namespace.

:load-impl-ns boolean

Default: true. Causes the static initializer for the generated class to reference the load code for the implementing namespace. Should be true when implementing-ns is the default, false if you intend to load the code via some other method.

gen-interface clj macro

(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.

gensym clj

(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__'.

get clj

(get map key)

(get map key not-found)

Returns the value mapped to key, not-found or nil if key not present in associative collection, set, string, array, or ILookup instance.

get-in clj

(get-in m ks)

(get-in m ks not-found)

Returns the value in a nested associative structure, where ks is a sequence of keys. Returns nil if the key is not present, or the not-found value if supplied.

get-method clj

(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

get-proxy-class clj

(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.

get-thread-bindings clj

(get-thread-bindings)

Get a map with the Var/value pairs which is currently in effect for the current thread.

get-validator clj

(get-validator iref)

Gets the validator-fn for a var/ref/agent/atom.

group-by clj

(group-by f coll)

Returns a map of the elements of coll keyed by the result of f on each element. The value at each key will be a vector of the corresponding elements, in the order they appeared in coll.

halt-when clj

(halt-when pred)

(halt-when pred retf)

Returns a transducer that ends transduction when pred returns true for an input. When retf is supplied it must be a fn of 2 arguments - it will be passed the (completed) result so far and the input that triggered the predicate, and its return value (if it does not throw an exception) will be the return value of the transducer. If retf is not supplied, the input that triggered the predicate will be returned. If the predicate never returns true the transduction is unaffected.

hash clj

(hash x)

Returns the hash code of its argument. Note this is the hash code consistent with =, and thus is different than .hashCode for Integer, Short, Byte and Clojure collections.

hash-combine clj

(hash-combine x y)

hash-map clj

(hash-map)

(hash-map & keyvals)

keyval => key val Returns a new hash map with supplied mappings. If any keys are equal, they are handled as if by repeated uses of assoc.

hash-ordered-coll clj

(hash-ordered-coll coll)

Returns the hash code, consistent with =, for an external ordered collection implementing Iterable. See http://clojure.org/data_structures#hash for full algorithms.

hash-set clj

(hash-set)

(hash-set & keys)

Returns a new hash set with supplied keys. Any equal keys are handled as if by repeated uses of conj.

hash-unordered-coll clj

(hash-unordered-coll coll)

Returns the hash code, consistent with =, for an external unordered collection implementing Iterable. For maps, the iterator should return map entries whose hash is computed as (hash-ordered-coll [k v]). See http://clojure.org/data_structures#hash for full algorithms.

ident? clj

(ident? x)

Return true if x is a symbol or keyword

identical? clj

(identical? x y)

Tests if 2 arguments are the same object

identity clj

(identity x)

Returns its argument.

if-let clj macro

(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

if-not clj macro

(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.

if-some clj macro

(if-some bindings then)

(if-some bindings then else & oldform)

bindings => binding-form test

If test is not nil, evaluates then with binding-form bound to the value of test, if not, yields else

ifn? clj

(ifn? x)

Returns true if x implements IFn. Note that many data structures (e.g. sets and maps) implement IFn

import clj macro

(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.

in-ns clj

(in-ns name)

Sets ns to the namespace named by the symbol, creating it if needed.

inc clj

(inc x)

Returns a number one greater than num. Does not auto-promote longs, will throw on overflow. See also: inc'

inc' clj

(inc' x)

Returns a number one greater than num. Supports arbitrary precision. See also: inc

indexed? clj

(indexed? coll)

Return true if coll implements Indexed, indicating efficient lookup by index

infinite? clj

(infinite? num)

Returns true if num is negative or positive infinity, else false

init-proxy clj

(init-proxy proxy mappings)

Takes a proxy instance and a map of strings (which must correspond to methods of the proxy superclass/superinterfaces) to fns (which must take arguments matching the corresponding method, plus an additional (explicit) first arg corresponding to this, and sets the proxy's fn map. Returns the proxy.

Inst clj protocol

inst-ms* clj

(inst-ms* inst)

inst-ms clj

(inst-ms inst)

Return the number of milliseconds since January 1, 1970, 00:00:00 GMT

inst? clj

(inst? x)

Return true if x satisfies Inst

instance? clj

(instance? c x)

Evaluates x and tests if it is an instance of the class c. Returns true or false

int clj

(int x)

Coerce to int

int-array clj

(int-array size-or-seq)

(int-array size init-val-or-seq)

Creates an array of ints

int? clj

(int? x)

Return true if x is a fixed precision integer

integer? clj

(integer? n)

Returns true if n is an integer

interleave clj

(interleave)

(interleave c1)

(interleave c1 c2)

(interleave c1 c2 & colls)

Returns a lazy seq of the first item in each coll, then the second etc.

intern clj

(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.

interpose clj

(interpose sep)

(interpose sep coll)

Returns a lazy seq of the elements of coll separated by sep. Returns a stateful transducer when no collection is provided.

into clj

(into)

(into to)

(into to from)

(into to xform from)

Returns a new coll consisting of to-coll with all of the items of from-coll conjoined. A transducer may be supplied.

into-array clj

(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.

ints clj

(ints xs)

Casts to int[]

io! clj macro

(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.

isa? clj

(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

iterate clj

(iterate f x)

Returns a lazy sequence of x, (f x), (f (f x)) etc. f must be free of side-effects

iteration clj

(iteration step
           &
           {:keys [somef vf kf initk]
            :or {vf identity kf identity somef some? initk nil}})

Creates a seqable/reducible via repeated calls to step, a function of some (continuation token) 'k'. The first call to step will be passed initk, returning 'ret'. Iff (somef ret) is true, (vf ret) will be included in the iteration, else iteration will terminate and vf/kf will not be called. If (kf ret) is non-nil it will be passed to the next step call, else iteration will terminate.

This can be used e.g. to consume APIs that return paginated or batched data.

step - (possibly impure) fn of 'k' -> 'ret'

:somef - fn of 'ret' -> logical true/false, default 'some?' :vf - fn of 'ret' -> 'v', a value produced by the iteration, default 'identity' :kf - fn of 'ret' -> 'next-k' or nil (signaling 'do not continue'), default 'identity' :initk - the first value passed to step, default 'nil'

It is presumed that step with non-initk is unreproducible/non-idempotent. If step with initk is unreproducible it is on the consumer to not consume twice.

iterator-seq clj

(iterator-seq iter)

Returns a seq on a java.util.Iterator. Note that most collections providing iterators implement Iterable and thus support seq directly. Seqs cache values, thus iterator-seq should not be used on any iterator that repeatedly returns the same mutable object.

juxt clj

(juxt f)

(juxt f g)

(juxt f g h)

(juxt f g h & fs)

Takes a set of functions and returns a fn that is the juxtaposition of those fns. The returned fn takes a variable number of args, and returns a vector containing the result of applying each fn to the args (left-to-right). ((juxt a b c) x) => [(a x) (b x) (c x)]

keep clj

(keep f)

(keep f coll)

Returns a lazy sequence of the non-nil results of (f item). Note, this means false return values will be included. f must be free of side-effects. Returns a transducer when no collection is provided.

keep-indexed clj

(keep-indexed f)

(keep-indexed f coll)

Returns a lazy sequence of the non-nil results of (f index item). Note, this means false return values will be included. f must be free of side-effects. Returns a stateful transducer when no collection is provided.

key clj

(key e)

Returns the key of the map entry.

keys clj

(keys map)

Returns a sequence of the map's keys, in the same order as (seq map).

keyword clj

(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.

keyword? clj

(keyword? x)

Return true if x is a Keyword

last clj

(last coll)

Return the last item in coll, in linear time

lazy-cat clj macro

(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))

lazy-seq clj macro

(lazy-seq & body)

Takes a body of expressions that returns an ISeq or nil, and yields a Seqable object that will invoke the body only the first time seq is called, and will cache the result and return it on all subsequent seq calls. See also - realized?

let clj macro

(let bindings & body)

binding => binding-form init-expr binding-form => name, or destructuring-form destructuring-form => map-destructure-form, or seq-destructure-form

Evaluates the exprs in a lexical context in which the symbols in the binding-forms are bound to their respective init-exprs or parts therein.

See https://clojure.org/reference/special_forms#binding-forms for more information about destructuring.

letfn clj macro

(letfn fnspecs & body)

fnspec ==> (fname [params*] exprs) or (fname ([params*] exprs)+)

Takes a vector of function specs and a body, and generates a set of bindings of functions to their names. All of the names are available in all of the definitions of the functions, as well as the body.

line-seq clj

(line-seq rdr)

Returns the lines of text from rdr as a lazy sequence of strings. rdr must implement java.io.BufferedReader.

list clj

(list & items)

Creates a new list containing the items.

list* clj

(list* args)

(list* a args)

(list* a b args)

(list* a b c args)

(list* a b c d & more)

Creates a new seq containing the items prepended to the rest, the last of which will be treated as a sequence.

list? clj

(list? x)

Returns true if x implements IPersistentList

load clj

(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.

load-file clj

(load-file name)

Sequentially read and evaluate the set of forms contained in the file.

load-reader clj

(load-reader rdr)

Sequentially read and evaluate the set of forms contained in the stream/file

load-string clj

(load-string s)

Sequentially read and evaluate the set of forms contained in the string

loaded-libs clj

(loaded-libs)

Returns a sorted set of symbols naming the currently loaded libs

locking clj macro

(locking x & body)

Executes exprs in an implicit do, while holding the monitor of x. Will release the monitor of x in all circumstances.

long clj

(long x)

Coerce to long

long-array clj

(long-array size-or-seq)

(long-array size init-val-or-seq)

Creates an array of longs

longs clj

(longs xs)

Casts to long[]

loop clj macro

(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.

macroexpand clj

(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.

macroexpand-1 clj

(macroexpand-1 form)

If form represents a macro form, returns its expansion, else returns form.

make-array clj

(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.

make-hierarchy clj

(make-hierarchy)

Creates a hierarchy object for use with derive, isa? etc.

map clj

(map f)

(map f coll)

(map f c1 c2)

(map f c1 c2 c3)

(map f c1 c2 c3 & colls)

Returns a lazy sequence consisting of the result of applying f to the set of first items of each coll, followed by applying f to the set of second items in each coll, until any one of the colls is exhausted. Any remaining items in other colls are ignored. Function f should accept number-of-colls arguments. Returns a transducer when no collection is provided.

map-entry? clj

(map-entry? x)

Return true if x is a map entry

map-indexed clj

(map-indexed f)

(map-indexed f coll)

Returns a lazy sequence consisting of the result of applying f to 0 and the first item of coll, followed by applying f to 1 and the second item in coll, etc, until coll is exhausted. Thus function f should accept 2 arguments, index and item. Returns a stateful transducer when no collection is provided.

map? clj

(map? x)

Return true if x implements IPersistentMap

mapcat clj

(mapcat f)

(mapcat f & colls)

Returns the result of applying concat to the result of applying map to f and colls. Thus function f should return a collection. Returns a transducer when no collections are provided

mapv clj

(mapv f coll)

(mapv f c1 c2)

(mapv f c1 c2 c3)

(mapv f c1 c2 c3 & colls)

Returns a vector consisting of the result of applying f to the set of first items of each coll, followed by applying f to the set of second items in each coll, until any one of the colls is exhausted. Any remaining items in other colls are ignored. Function f should accept number-of-colls arguments.

max clj

(max x)

(max x y)

(max x y & more)

Returns the greatest of the nums.

max-key clj

(max-key k x)

(max-key k x y)

(max-key k x y & more)

Returns the x for which (k x), a number, is greatest.

If there are multiple such xs, the last one is returned.

memfn clj macro

(memfn name & args)

Expands into code that creates a fn that expects to be passed an object and any args and calls the named instance method on the object passing the args. Use when you want to treat a Java method as a first-class fn. name may be type-hinted with the method receiver's type in order to avoid reflective calls.

memoize clj

(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.

merge clj

(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.

merge-with clj

(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).

meta clj

(meta obj)

Returns the metadata of obj, returns nil if there is no metadata.

method-sig clj

(method-sig meth)

methods clj

(methods multifn)

Given a multimethod, returns a map of dispatch values -> dispatch fns

min clj

(min x)

(min x y)

(min x y & more)

Returns the least of the nums.

min-key clj

(min-key k x)

(min-key k x y)

(min-key k x y & more)

Returns the x for which (k x), a number, is least.

If there are multiple such xs, the last one is returned.

mix-collection-hash clj

(mix-collection-hash hash-basis count)

Mix final collection hash for ordered or unordered collections. hash-basis is the combined collection hash, count is the number of elements included in the basis. Note this is the hash code consistent with =, different from .hashCode. See http://clojure.org/data_structures#hash for full algorithms.

mod clj

(mod num div)

Modulus of num and div. Truncates toward negative infinity.

munge clj

(munge s)

name clj

(name x)

Returns the name String of a string, symbol or keyword.

namespace clj

(namespace x)

Returns the namespace String of a symbol or keyword, or nil if not present.

namespace-munge clj

(namespace-munge ns)

Convert a Clojure namespace name to a legal Java package name.

NaN? clj

(NaN? num)

Returns true if num is NaN, else false

nat-int? clj

(nat-int? x)

Return true if x is a non-negative fixed precision integer

neg-int? clj

(neg-int? x)

Return true if x is a negative fixed precision integer

neg? clj

(neg? num)

Returns true if num is less than zero, else false

newline clj

(newline)

Writes a platform-specific newline to out

next clj

(next coll)

Returns a seq of the items after the first. Calls seq on its argument. If there are no more items, returns nil.

nfirst clj

(nfirst x)

Same as (next (first x))

nil? clj

(nil? x)

Returns true if x is nil, false otherwise.

nnext clj

(nnext x)

Same as (next (next x))

not clj

(not x)

Returns true if x is logical false, false otherwise.

not-any? clj

(not-any? pred coll)

Returns false if (pred x) is logical true for any x in coll, else true.

not-empty clj

(not-empty coll)

If coll is empty, returns nil, else coll

not-every? clj

(not-every? pred coll)

Returns false if (pred x) is logical true for every x in coll, else true.

not= clj

(not= x)

(not= x y)

(not= x y & more)

Same as (not (= obj1 obj2))

ns clj macro

(ns name docstring? attr-map? references*)

Sets ns to the namespace named by name (unevaluated), creating it if needed. references can be zero or more of: (:refer-clojure ...) (:require ...) (:use ...) (:import ...) (:load ...) (:gen-class) with the syntax of refer-clojure/require/use/import/load/gen-class respectively, except the arguments are unevaluated and need not be quoted. (:gen-class ...), when supplied, defaults to :name corresponding to the ns name, :main true, :impl-ns same as ns, and :init-impl-ns true. All options of gen-class are supported. The :gen-class directive is ignored when not compiling. If :gen-class is not supplied, when compiled only an nsname__init.class will be generated. If :refer-clojure is not used, a default (refer 'clojure.core) is used. Use of ns is preferred to individual calls to in-ns/require/use/import:

(ns foo.bar (:refer-clojure :exclude [ancestors printf]) (:require (clojure.contrib sql combinatorics)) (:use (my.lib this that)) (:import (java.util Date Timer Random) (java.sql Connection Statement)))

ns-aliases clj

(ns-aliases ns)

Returns a map of the aliases for the namespace.

ns-imports clj

(ns-imports ns)

Returns a map of the import mappings for the namespace.

ns-interns clj

(ns-interns ns)

Returns a map of the intern mappings for the namespace.

ns-map clj

(ns-map ns)

Returns a map of all the mappings for the namespace.

ns-name clj

(ns-name ns)

Returns the name of the namespace, a symbol.

ns-publics clj

(ns-publics ns)

Returns a map of the public intern mappings for the namespace.

ns-refers clj

(ns-refers ns)

Returns a map of the refer mappings for the namespace.

ns-resolve clj

(ns-resolve ns sym)

(ns-resolve ns env sym)

Returns the var or Class to which a symbol will be resolved in the namespace (unless found in the environment), else nil. Note that if the symbol is fully qualified, the var/Class to which it resolves need not be present in the namespace.

ns-unalias clj

(ns-unalias ns sym)

Removes the alias for the symbol from the namespace.

ns-unmap clj

(ns-unmap ns sym)

Removes the mappings for the symbol from the namespace.

nth clj

(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.

nthnext clj

(nthnext coll n)

Returns the nth next of coll, (seq coll) when n is 0.

nthrest clj

(nthrest coll n)

Returns the nth rest of coll, coll when n is 0.

num clj

(num x)

Coerce to Number

number? clj

(number? x)

Returns true if x is a Number

numerator clj

(numerator r)

Returns the numerator part of a Ratio.

object-array clj

(object-array size-or-seq)

Creates an array of objects

odd? clj

(odd? n)

Returns true if n is odd, throws an exception if n is not an integer

or clj macro

(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.

parents clj

(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

parse-boolean clj

(parse-boolean s)

Parse strings "true" or "false" and return a boolean, or nil if invalid

parse-double clj

(parse-double s)

Parse string with floating point components and return a Double value, or nil if parse fails.

Grammar: https://docs.oracle.com/javase/8/docs/api/java/lang/Double.html#valueOf-java.lang.String-

parse-long clj

(parse-long s)

Parse string of decimal digits with optional leading -/+ and return a Long value, or nil if parse fails

parse-uuid clj

(parse-uuid s)

Parse a string representing a UUID and return a java.util.UUID instance, or nil if parse fails.

Grammar: https://docs.oracle.com/javase/8/docs/api/java/util/UUID.html#toString--

partial clj

(partial f)

(partial f arg1)

(partial f arg1 arg2)

(partial f arg1 arg2 arg3)

(partial f arg1 arg2 arg3 & more)

Takes a function f and fewer than the normal arguments to f, and returns a fn that takes a variable number of additional args. When called, the returned function calls f with args + additional args.

partition clj

(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.

partition-all clj

(partition-all n)

(partition-all n coll)

(partition-all n step coll)

Returns a lazy sequence of lists like partition, but may include partitions with fewer than n items at the end. Returns a stateful transducer when no collection is provided.

partition-by clj

(partition-by f)

(partition-by f coll)

Applies f to each value in coll, splitting it each time f returns a new value. Returns a lazy seq of partitions. Returns a stateful transducer when no collection is provided.

partitionv clj

(partitionv n coll)

(partitionv n step coll)

(partitionv n step pad coll)

Returns a lazy sequence of vectors of n items each, at offsets step apart. If step is not supplied, defaults to n, i.e. the partitions do not overlap. If a pad collection is supplied, use its elements as necessary to complete last partition upto n items. In case there are not enough padding elements, return a partition with less than n items.

partitionv-all clj

(partitionv-all n)

(partitionv-all n coll)

(partitionv-all n step coll)

Returns a lazy sequence of vector partitions, but may include partitions with fewer than n items at the end. Returns a stateful transducer when no collection is provided.

pcalls clj

(pcalls & fns)

Executes the no-arg fns in parallel, returning a lazy sequence of their values

peek clj

(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.

persistent! clj

(persistent! coll)

Returns a new, persistent version of the transient collection, in constant time. The transient collection cannot be used after this call, any such use will throw an exception.

pmap clj

(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.

pop clj

(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.

pop! clj

(pop! coll)

Removes the last item from a transient vector. If the collection is empty, throws an exception. Returns coll

pop-thread-bindings clj

(pop-thread-bindings)

Pop one set of bindings pushed with push-binding before. It is an error to pop bindings without pushing before.

pos-int? clj

(pos-int? x)

Return true if x is a positive fixed precision integer

pos? clj

(pos? num)

Returns true if num is greater than zero, else false

pr clj

(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

pr-str clj

(pr-str & xs)

pr to a string, returning it

prefer-method clj

(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

prefers clj

(prefers multifn)

Given a multimethod, returns a map of preferred value -> set of other values

primitives-classnames clj

print clj

(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.

print-ctor clj

(print-ctor o print-args w)

print-dup clj multimethod

print-method clj multimethod

print-simple clj

(print-simple o w)

print-str clj

(print-str & xs)

print to a string, returning it

printf clj

(printf fmt & args)

Prints formatted output, as per format

println clj

(println & more)

Same as print followed by (newline)

println-str clj

(println-str & xs)

println to a string, returning it

PrintWriter-on clj

(PrintWriter-on flush-fn close-fn)

implements java.io.PrintWriter given flush-fn, which will be called when .flush() is called, with a string built up since the last call to .flush(). if not nil, close-fn will be called with no arguments when .close is called

prn clj

(prn & more)

Same as pr followed by (newline). Observes flush-on-newline

prn-str clj

(prn-str & xs)

prn to a string, returning it

promise clj

(promise)

Returns a promise object that can be read with deref/@, and set, once only, with deliver. Calls to deref/@ prior to delivery will block, unless the variant of deref with timeout is used. All subsequent derefs will return the same delivered value without blocking. See also - realized?.

proxy clj macro

(proxy class-and-interfaces args & fs)

class-and-interfaces - a vector of class names

args - a (possibly empty) vector of arguments to the superclass constructor.

f => (name [params*] body) or (name ([params*] body) ([params+] body) ...)

Expands to code which creates a instance of a proxy class that implements the named class/interface(s) by calling the supplied fns. A single class, if provided, must be first. If not provided it defaults to Object.

The interfaces names must be valid interface types. If a method fn is not provided for a class method, the superclass method will be called. If a method fn is not provided for an interface method, an UnsupportedOperationException will be thrown should it be called. Method fns are closures and can capture the environment in which proxy is called. Each method fn takes an additional implicit first arg, which is bound to 'this. Note that while method fns can be provided to override protected methods, they have no other access to protected members, nor to super, as these capabilities cannot be proxied.

proxy-call-with-super clj

(proxy-call-with-super call this meth)

proxy-mappings clj

(proxy-mappings proxy)

Takes a proxy instance and returns the proxy's fn map.

proxy-name clj

(proxy-name super interfaces)

proxy-super clj macro

(proxy-super meth & args)

Use to call a superclass method in the body of a proxy method. Note, expansion captures 'this

push-thread-bindings clj

(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)))

pvalues clj macro

(pvalues & exprs)

Returns a lazy sequence of the values of the exprs, which are evaluated in parallel

qualified-ident? clj

(qualified-ident? x)

Return true if x is a symbol or keyword with a namespace

qualified-keyword? clj

(qualified-keyword? x)

Return true if x is a keyword with a namespace

qualified-symbol? clj

(qualified-symbol? x)

Return true if x is a symbol with a namespace

quot clj

(quot num div)

quot[ient] of dividing numerator by denominator.

rand clj

(rand)

(rand n)

Returns a random floating point number between 0 (inclusive) and n (default 1) (exclusive).

rand-int clj

(rand-int n)

Returns a random integer between 0 (inclusive) and n (exclusive).

rand-nth clj

(rand-nth coll)

Return a random element of the (sequential) collection. Will have the same performance characteristics as nth for the given collection.

random-sample clj

(random-sample prob)

(random-sample prob coll)

Returns items from coll with random probability of prob (0.0 - 1.0). Returns a transducer when no collection is provided.

random-uuid clj

(random-uuid)

Returns a pseudo-randomly generated java.util.UUID instance (i.e. type 4).

See: https://docs.oracle.com/javase/8/docs/api/java/util/UUID.html#randomUUID--

range clj

(range)

(range end)

(range start end)

(range start end step)

Returns a lazy seq of nums from start (inclusive) to end (exclusive), by step, where start defaults to 0, step to 1, and end to infinity. When step is equal to 0, returns an infinite sequence of start. When start is equal to end, returns empty list.

ratio? clj

(ratio? n)

Returns true if n is a Ratio

rational? clj

(rational? n)

Returns true if n is a rational number

rationalize clj

(rationalize num)

returns the rational value of num

re-find clj

(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.

re-groups clj

(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.

re-matcher clj

(re-matcher re s)

Returns an instance of java.util.regex.Matcher, for use, e.g. in re-find.

re-matches clj

(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.

re-pattern clj

(re-pattern s)

Returns an instance of java.util.regex.Pattern, for use, e.g. in re-matcher.

re-seq clj

(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.

read clj

(read)

(read stream)

(read opts 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.

Opts is a persistent map with valid keys: :read-cond - :allow to process reader conditionals, or :preserve to keep all branches :features - persistent set of feature keywords for reader conditionals :eof - on eof, return value unless :eofthrow, then throw. if not specified, will throw

Note that read can execute code (controlled by read-eval), and as such should be used only with trusted sources.

For data structure interop use clojure.edn/read

read+string clj

(read+string)

(read+string stream)

(read+string opts stream)

(read+string stream eof-error? eof-value)

(read+string stream eof-error? eof-value recursive?)

Like read, and taking the same args. stream must be a LineNumberingPushbackReader. Returns a vector containing the object read and the (whitespace-trimmed) string read.

read-line clj

(read-line)

Reads the next line from stream that is the current value of in .

read-string clj

(read-string s)

(read-string opts s)

Reads one object from the string s. Optionally include reader options, as specified in read.

Note that read-string can execute code (controlled by read-eval), and as such should be used only with trusted sources.

For data structure interop use clojure.edn/read-string

reader-conditional clj

(reader-conditional form splicing?)

Construct a data representation of a reader conditional. If true, splicing? indicates read-cond-splicing.

reader-conditional? clj

(reader-conditional? value)

Return true if the value is the data representation of a reader conditional

realized? clj

(realized? x)

Returns true if a value has been produced for a promise, delay, future or lazy sequence.

record? clj

(record? x)

Returns true if x is a record

reduce clj

(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.

reduce-kv clj

(reduce-kv f init coll)

Reduces an associative collection. f should be a function of 3 arguments. Returns the result of applying f to init, the first key and the first value in coll, then applying f to that result and the 2nd key and value, etc. If coll contains no entries, returns init and f is not called. Note that reduce-kv is supported on vectors, where the keys will be the ordinals.

reduced clj

(reduced x)

Wraps x in a way such that a reduce will terminate with the value x

reduced? clj

(reduced? x)

Returns true if x is the result of a call to reduced

reductions clj

(reductions f coll)

(reductions f init coll)

Returns a lazy seq of the intermediate values of the reduction (as per reduce) of coll by f, starting with init.

ref clj

(ref x)

(ref x & options)

Creates and returns a Ref with an initial value of x and zero or more options (in any order):

:meta metadata-map

:validator validate-fn

:min-history (default 0) :max-history (default 10)

If metadata-map is supplied, it will become the metadata on the ref. validate-fn must be nil or a side-effect-free fn of one argument, which will be passed the intended new state on any state change. If the new state is unacceptable, the validate-fn should return false or throw an exception. validate-fn will be called on transaction commit, when all refs have their final values.

Normally refs accumulate history dynamically as needed to deal with read demands. If you know in advance you will need history you can set :min-history to ensure it will be available when first needed (instead of after a read fault). History is limited, and the limit can be set with :max-history.

ref-history-count clj

(ref-history-count ref)

Returns the history count of a ref

ref-max-history clj

(ref-max-history ref)

(ref-max-history ref n)

Gets the max-history of a ref, or sets it and returns the ref

ref-min-history clj

(ref-min-history ref)

(ref-min-history ref n)

Gets the min-history of a ref, or sets it and returns the ref

ref-set clj

(ref-set ref val)

Must be called in a transaction. Sets the value of ref. Returns val.

refer clj

(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.

refer-clojure clj macro

(refer-clojure & filters)

Same as (refer 'clojure.core <filters>)

reify clj macro

(reify & opts+specs)

reify creates an object implementing a protocol or interface. reify is a macro with the following structure:

(reify options* specs*)

Currently there are no options.

Each spec consists of the protocol or interface name followed by zero or more method bodies:

protocol-or-interface-or-Object (methodName [args+] body)*

Methods should be supplied for all methods of the desired protocol(s) and interface(s). You can also define overrides for methods of Object. Note that the first parameter must be supplied to correspond to the target object ('this' in Java parlance). Thus methods for interfaces will take one more argument than do the interface declarations. Note also that recur calls to the method head should not pass the target object, it will be supplied automatically and can not be substituted.

The return type can be indicated by a type hint on the method name, and arg types can be indicated by a type hint on arg names. If you leave out all hints, reify will try to match on same name/arity method in the protocol(s)/interface(s) - this is preferred. If you supply any hints at all, no inference is done, so all hints (or default of Object) must be correct, for both arguments and return type. If a method is overloaded in a protocol/interface, multiple independent method definitions must be supplied. If overloaded with same arity in an interface you must specify complete hints to disambiguate - a missing hint implies Object.

recur works to method heads The method bodies of reify are lexical closures, and can refer to the surrounding local scope:

(str (let [f "foo"] (reify Object (toString [this] f)))) == "foo"

(seq (let [f "foo"] (reify clojure.lang.Seqable (seq [this] (seq f))))) == (\f \o \o))

reify always implements clojure.lang.IObj and transfers meta data of the form to the created object.

(meta ^{:k :v} (reify Object (toString [this] "foo"))) == {:k :v}

release-pending-sends clj

(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.

rem clj

(rem num div)

remainder of dividing numerator by denominator.

remove clj

(remove pred)

(remove pred coll)

Returns a lazy sequence of the items in coll for which (pred item) returns logical false. pred must be free of side-effects. Returns a transducer when no collection is provided.

remove-all-methods clj

(remove-all-methods multifn)

Removes all of the methods of multimethod.

remove-method clj

(remove-method multifn dispatch-val)

Removes the method of multimethod associated with dispatch-value.

remove-ns clj

(remove-ns sym)

Removes the namespace named by the symbol. Use with caution. Cannot be used to remove the clojure namespace.

remove-tap clj

(remove-tap f)

Remove f from the tap set.

remove-watch clj

(remove-watch reference key)

Removes a watch (set by add-watch) from a reference

repeat clj

(repeat x)

(repeat n x)

Returns a lazy (infinite!, or length n if supplied) sequence of xs.

repeatedly clj

(repeatedly f)

(repeatedly n f)

Takes a function of no args, presumably with side effects, and returns an infinite (or length n if supplied) lazy sequence of calls to it

replace clj

(replace smap)

(replace smap coll)

Given a map of replacement pairs and a vector/collection, returns a vector/seq with any elements = a key in smap replaced with the corresponding val in smap. Returns a transducer when no collection is provided.

replicate clj deprecated

(replicate n x)

DEPRECATED: Use 'repeat' instead. Returns a lazy seq of n xs.

require clj

(require & args)

Loads libs, skipping any that are already loaded. Each argument is either a libspec that identifies a lib, a prefix list that identifies multiple libs whose names share a common prefix, or a flag that modifies how all the identified libs are loaded. Use :require in the ns macro in preference to calling this directly.

Libs

A 'lib' is a named set of resources in classpath whose contents define a library of Clojure code. Lib names are symbols and each lib is associated with a Clojure namespace and a Java package that share its name. A lib's name also locates its root directory within classpath using Java's package name to classpath-relative path mapping. All resources in a lib should be contained in the directory structure under its root directory. All definitions a lib makes should be in its associated namespace.

'require loads a lib by loading its root resource. The root resource path is derived from the lib name in the following manner: Consider a lib named by the symbol 'x.y.z; it has the root directory <classpath>/x/y/, and its root resource is <classpath>/x/y/z.clj, or <classpath>/x/y/z.cljc if <classpath>/x/y/z.clj does not exist. The root resource should contain code to create the lib's namespace (usually by using the ns macro) and load any additional lib resources.

Libspecs

A libspec is a lib name or a vector containing a lib name followed by options expressed as sequential keywords and arguments.

Recognized options: :as takes a symbol as its argument and makes that symbol an alias to the lib's namespace in the current namespace. :as-alias takes a symbol as its argument and aliases like :as, however the lib will not be loaded. If the lib has not been loaded, a new empty namespace will be created (as with create-ns). :refer takes a list of symbols to refer from the namespace or the :all keyword to bring in all public vars.

Prefix Lists

It's common for Clojure code to depend on several libs whose names have the same prefix. When specifying libs, prefix lists can be used to reduce repetition. A prefix list contains the shared prefix followed by libspecs with the shared prefix removed from the lib names. After removing the prefix, the names that remain must not contain any periods.

Flags

A flag is a keyword. Recognized flags: :reload, :reload-all, :verbose :reload forces loading of all the identified libs even if they are already loaded (has no effect on libspecs using :as-alias) :reload-all implies :reload and also forces loading of all libs that the identified libs directly or indirectly load via require or use (has no effect on libspecs using :as-alias) :verbose triggers printing information about each load, alias, and refer

Example:

The following would load the libraries clojure.zip and clojure.set abbreviated as 's'.

(require '(clojure zip [set :as s]))

requiring-resolve clj

(requiring-resolve sym)

Resolves namespace-qualified sym per 'resolve'. If initial resolve fails, attempts to require sym's namespace and retries.

reset! clj

(reset! atom newval)

Sets the value of atom to newval without regard for the current value. Returns newval.

reset-meta! clj

(reset-meta! iref metadata-map)

Atomically resets the metadata for a namespace/var/ref/agent/atom

reset-vals! clj

(reset-vals! atom newval)

Sets the value of atom to newval. Returns [old new], the value of the atom before and after the reset.

resolve clj

(resolve sym)

(resolve env sym)

same as (ns-resolve ns symbol) or (ns-resolve ns &env symbol)

rest clj

(rest coll)

Returns a possibly empty seq of the items after the first. Calls seq on its argument.

restart-agent clj

(restart-agent a new-state & options)

When an agent is failed, changes the agent state to new-state and then un-fails the agent so that sends are allowed again. If a :clear-actions true option is given, any actions queued on the agent that were being held while it was failed will be discarded, otherwise those held actions will proceed. The new-state must pass the validator if any, or restart will throw an exception and the agent will remain failed with its old state and error. Watchers, if any, will NOT be notified of the new state. Throws an exception if the agent is not failed.

resultset-seq clj

(resultset-seq rs)

Creates and returns a lazy sequence of structmaps corresponding to the rows in the java.sql.ResultSet rs

reverse clj

(reverse coll)

Returns a seq of the items in coll in reverse order. Not lazy.

reversible? clj

(reversible? coll)

Returns true if coll implements Reversible

rseq clj

(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

rsubseq clj

(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

run! clj

(run! proc coll)

Runs the supplied procedure (via reduce), for purposes of side effects, on successive items in the collection. Returns nil

satisfies? clj

(satisfies? protocol x)

Returns true if x satisfies the protocol

second clj

(second x)

Same as (first (next x))

select-keys clj

(select-keys map keyseq)

Returns a map containing only those entries in map whose key is in keys

send clj

(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)

send-off clj

(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)

send-via clj

(send-via executor a f & args)

Dispatch an action to an agent. Returns the agent immediately. Subsequently, in a thread supplied by executor, the state of the agent will be set to the value of:

(apply action-fn state-of-agent args)

seq clj

(seq coll)

Returns a seq on the collection. If the collection is empty, returns nil. (seq nil) returns nil. seq also works on Strings, native Java arrays (of reference types) and any objects that implement Iterable. Note that seqs cache values, thus seq should not be used on any Iterable whose iterator repeatedly returns the same mutable object.

seq-to-map-for-destructuring clj

(seq-to-map-for-destructuring s)

Builds a map from a seq as described in https://clojure.org/reference/special_forms#keyword-arguments

seq? clj

(seq? x)

Return true if x implements ISeq

seqable? clj

(seqable? x)

Return true if the seq function is supported for x

seque clj

(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.

sequence clj

(sequence coll)

(sequence xform coll)

(sequence xform coll & colls)

Coerces coll to a (possibly empty) sequence, if it is not already one. Will not force a lazy seq. (sequence nil) yields (), When a transducer is supplied, returns a lazy sequence of applications of the transform to the items in coll(s), i.e. to the set of first items of each coll, followed by the set of second items in each coll, until any one of the colls is exhausted. Any remaining items in other colls are ignored. The transform should accept number-of-colls arguments

sequential? clj

(sequential? coll)

Returns true if coll implements Sequential

set clj

(set coll)

Returns a set of the distinct elements of coll.

set-agent-send-executor! clj

(set-agent-send-executor! executor)

Sets the ExecutorService to be used by send

set-agent-send-off-executor! clj

(set-agent-send-off-executor! executor)

Sets the ExecutorService to be used by send-off

set-error-handler! clj

(set-error-handler! a handler-fn)

Sets the error-handler of agent a to handler-fn. If an action being run by the agent throws an exception or doesn't pass the validator fn, handler-fn will be called with two arguments: the agent and the exception.

set-error-mode! clj

(set-error-mode! a mode-keyword)

Sets the error-mode of agent a to mode-keyword, which must be either :fail or :continue. If an action being run by the agent throws an exception or doesn't pass the validator fn, an error-handler may be called (see set-error-handler!), after which, if the mode is :continue, the agent will continue as if neither the action that caused the error nor the error itself ever happened.

If the mode is :fail, the agent will become failed and will stop accepting new 'send' and 'send-off' actions, and any previously queued actions will be held until a 'restart-agent'. Deref will still work, returning the state of the agent before the error.

set-validator! clj

(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.

set? clj

(set? x)

Returns true if x implements IPersistentSet

short clj

(short x)

Coerce to short

short-array clj

(short-array size-or-seq)

(short-array size init-val-or-seq)

Creates an array of shorts

shorts clj

(shorts xs)

Casts to shorts[]

shuffle clj

(shuffle coll)

Return a random permutation of coll

shutdown-agents clj

(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

simple-ident? clj

(simple-ident? x)

Return true if x is a symbol or keyword without a namespace

simple-keyword? clj

(simple-keyword? x)

Return true if x is a keyword without a namespace

simple-symbol? clj

(simple-symbol? x)

Return true if x is a symbol without a namespace

slurp clj

(slurp f & opts)

Opens a reader on f and reads all its contents, returning a string. See clojure.java.io/reader for a complete list of supported arguments.

some clj

(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)

some-> clj macro

(some-> expr & forms)

When expr is not nil, threads it into the first form (via ->), and when that result is not nil, through the next etc

some->> clj macro

(some->> expr & forms)

When expr is not nil, threads it into the first form (via ->>), and when that result is not nil, through the next etc

some-fn clj

(some-fn p)

(some-fn p1 p2)

(some-fn p1 p2 p3)

(some-fn p1 p2 p3 & ps)

Takes a set of predicates and returns a function f that returns the first logical true value returned by one of its composing predicates against any of its arguments, else it returns logical false. Note that f is short-circuiting in that it will stop execution on the first argument that triggers a logical true result against the original predicates.

some? clj

(some? x)

Returns true if x is not nil, false otherwise.

sort clj

(sort coll)

(sort comp coll)

Returns a sorted sequence of the items in coll. If no comparator is supplied, uses compare. comparator must implement java.util.Comparator. Guaranteed to be stable: equal elements will not be reordered. If coll is a Java array, it will be modified. To avoid this, sort a copy of the array.

sort-by clj

(sort-by keyfn coll)

(sort-by keyfn comp coll)

Returns a sorted sequence of the items in coll, where the sort order is determined by comparing (keyfn item). If no comparator is supplied, uses compare. comparator must implement java.util.Comparator. Guaranteed to be stable: equal elements will not be reordered. If coll is a Java array, it will be modified. To avoid this, sort a copy of the array.

sorted-map clj

(sorted-map & keyvals)

keyval => key val Returns a new sorted map with supplied mappings. If any keys are equal, they are handled as if by repeated uses of assoc.

sorted-map-by clj

(sorted-map-by comparator & keyvals)

keyval => key val Returns a new sorted map with supplied mappings, using the supplied comparator. If any keys are equal, they are handled as if by repeated uses of assoc.

sorted-set clj

(sorted-set & keys)

Returns a new sorted set with supplied keys. Any equal keys are handled as if by repeated uses of conj.

sorted-set-by clj

(sorted-set-by comparator & keys)

Returns a new sorted set with supplied keys, using the supplied comparator. Any equal keys are handled as if by repeated uses of conj.

sorted? clj

(sorted? coll)

Returns true if coll implements Sorted

special-symbol? clj

(special-symbol? s)

Returns true if s names a special form

spit clj

(spit f content & options)

Opposite of slurp. Opens f with writer, writes content, then closes f. Options passed to clojure.java.io/writer.

split-at clj

(split-at n coll)

Returns a vector of [(take n coll) (drop n coll)]

split-with clj

(split-with pred coll)

Returns a vector of [(take-while pred coll) (drop-while pred coll)]

splitv-at clj

(splitv-at n coll)

Returns a vector of [(into [] (take n) coll) (drop n coll)]

StackTraceElement->vec clj

(StackTraceElement->vec o)

Constructs a data representation for a StackTraceElement: [class method file line]

str clj

(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.

string? clj

(string? x)

Return true if x is a String

struct clj

(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.

struct-map clj

(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.

subs clj

(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.

subseq clj

(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

subvec clj

(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.

supers clj

(supers class)

Returns the immediate and indirect superclasses and interfaces of c, if any

swap! clj

(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.

swap-vals! clj

(swap-vals! atom f)

(swap-vals! atom f x)

(swap-vals! atom f x y)

(swap-vals! atom f x y & args)

Atomically swaps the value of atom to be: (apply f current-value-of-atom args). Note that f may be called multiple times, and thus should be free of side effects. Returns [old new], the value of the atom before and after the swap.

symbol clj

(symbol name)

(symbol ns name)

Returns a Symbol with the given namespace and name. Arity-1 works on strings, keywords, and vars.

symbol? clj

(symbol? x)

Return true if x is a Symbol

sync clj macro

(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.

tagged-literal clj

(tagged-literal tag form)

Construct a data representation of a tagged literal from a tag symbol and a form.

tagged-literal? clj

(tagged-literal? value)

Return true if the value is the data representation of a tagged literal

take clj

(take n)

(take n coll)

Returns a lazy sequence of the first n items in coll, or all items if there are fewer than n. Returns a stateful transducer when no collection is provided.

take-last clj

(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.

take-nth clj

(take-nth n)

(take-nth n coll)

Returns a lazy seq of every nth item in coll. Returns a stateful transducer when no collection is provided.

take-while clj

(take-while pred)

(take-while pred coll)

Returns a lazy sequence of successive items from coll while (pred item) returns logical true. pred must be free of side-effects. Returns a transducer when no collection is provided.

tap> clj

(tap> x)

sends x to any taps. Will not block. Returns true if there was room in the queue, false if not (dropped).

test clj

(test v)

test [v] finds fn at key :test in var metadata and calls it, presuming failure will throw exception

the-ns clj

(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.

thread-bound? clj

(thread-bound? & vars)

Returns true if all of the vars provided as arguments have thread-local bindings. Implies that set!'ing the provided vars will succeed. Returns true if no vars are provided.

Throwable->map clj

(Throwable->map o)

Constructs a data representation for a Throwable with keys: :cause - root cause message :phase - error phase :via - cause chain, with cause keys: :type - exception class symbol :message - exception message :data - ex-data :at - top stack element :trace - root cause stack elements

time clj macro

(time expr)

Evaluates expr and prints the time it took. Returns the value of expr.

to-array clj

(to-array coll)

Returns an array of Objects containing the contents of coll, which can be any Collection. Maps to java.util.Collection.toArray().

to-array-2d clj

(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.

trampoline clj

(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.

transduce clj

(transduce xform f coll)

(transduce xform f init coll)

reduce with a transformation of f (xf). If init is not supplied, (f) will be called to produce it. f should be a reducing step function that accepts both 1 and 2 arguments, if it accepts only 2 you can add the arity-1 with 'completing'. Returns the result of applying (the transformed) xf to init and the first item in coll, then applying xf to that result and the 2nd item, etc. If coll contains no items, returns init and f is not called. Note that certain transforms may inject or skip items.

transient clj

(transient coll)

Returns a new, transient version of the collection, in constant time.

tree-seq clj

(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.

true? clj

(true? x)

Returns true if x is the value true, false otherwise.

type clj

(type x)

Returns the :type metadata of x, or its Class if none

unchecked-add clj

(unchecked-add x y)

Returns the sum of x and y, both long. Note - uses a primitive operator subject to overflow.

unchecked-add-int clj

(unchecked-add-int x y)

Returns the sum of x and y, both int. Note - uses a primitive operator subject to overflow.

unchecked-byte clj

(unchecked-byte x)

Coerce to byte. Subject to rounding or truncation.

unchecked-char clj

(unchecked-char x)

Coerce to char. Subject to rounding or truncation.

unchecked-dec clj

(unchecked-dec x)

Returns a number one less than x, a long. Note - uses a primitive operator subject to overflow.

unchecked-dec-int clj

(unchecked-dec-int x)

Returns a number one less than x, an int. Note - uses a primitive operator subject to overflow.

unchecked-divide-int clj

(unchecked-divide-int x y)

Returns the division of x by y, both int. Note - uses a primitive operator subject to truncation.

unchecked-double clj

(unchecked-double x)

Coerce to double. Subject to rounding.

unchecked-float clj

(unchecked-float x)

Coerce to float. Subject to rounding.

unchecked-inc clj

(unchecked-inc x)

Returns a number one greater than x, a long. Note - uses a primitive operator subject to overflow.

unchecked-inc-int clj

(unchecked-inc-int x)

Returns a number one greater than x, an int. Note - uses a primitive operator subject to overflow.

unchecked-int clj

(unchecked-int x)

Coerce to int. Subject to rounding or truncation.

unchecked-long clj

(unchecked-long x)

Coerce to long. Subject to rounding or truncation.

unchecked-multiply clj

(unchecked-multiply x y)

Returns the product of x and y, both long. Note - uses a primitive operator subject to overflow.

unchecked-multiply-int clj

(unchecked-multiply-int x y)

Returns the product of x and y, both int. Note - uses a primitive operator subject to overflow.

unchecked-negate clj

(unchecked-negate x)

Returns the negation of x, a long. Note - uses a primitive operator subject to overflow.

unchecked-negate-int clj

(unchecked-negate-int x)

Returns the negation of x, an int. Note - uses a primitive operator subject to overflow.

unchecked-remainder-int clj

(unchecked-remainder-int x y)

Returns the remainder of division of x by y, both int. Note - uses a primitive operator subject to truncation.

unchecked-short clj

(unchecked-short x)

Coerce to short. Subject to rounding or truncation.

unchecked-subtract clj

(unchecked-subtract x y)

Returns the difference of x and y, both long. Note - uses a primitive operator subject to overflow.

unchecked-subtract-int clj

(unchecked-subtract-int x y)

Returns the difference of x and y, both int. Note - uses a primitive operator subject to overflow.

underive clj

(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.

unquote clj

unquote-splicing clj

unreduced clj

(unreduced x)

If x is reduced?, returns (deref x), else returns x

unsigned-bit-shift-right clj

(unsigned-bit-shift-right x n)

Bitwise shift right, without sign-extension.

update clj

(update m k f)

(update m k f x)

(update m k f x y)

(update m k f x y z)

(update m k f x y z & more)

'Updates' a value in an associative structure, where k is a key and f is a function that will take the old value and any supplied args and return the new value, and returns a new structure. If the key does not exist, nil is passed as the old value.

update-in clj

(update-in m ks f & args)

'Updates' a value in a nested associative structure, where ks is a sequence of keys and f is a function that will take the old value and any supplied args and return the new value, and returns a new nested structure. If any levels do not exist, hash-maps will be created.

update-keys clj

(update-keys m f)

m f => {(f k) v ...}

Given a map m and a function f of 1-argument, returns a new map whose keys are the result of applying f to the keys of m, mapped to the corresponding values of m. f must return a unique key for each key of m, else the behavior is undefined.

update-proxy clj

(update-proxy proxy mappings)

Takes a proxy instance and a map of strings (which must correspond to methods of the proxy superclass/superinterfaces) to fns (which must take arguments matching the corresponding method, plus an additional (explicit) first arg corresponding to this, and updates (via assoc) the proxy's fn map. nil can be passed instead of a fn, in which case the corresponding method will revert to the default behavior. Note that this function can be used to update the behavior of an existing instance without changing its identity. Returns the proxy.

update-vals clj

(update-vals m f)

m f => {k (f v) ...}

Given a map m and a function f of 1-argument, returns a new map where the keys of m are mapped to result of applying f to the corresponding values of m.

uri? clj

(uri? x)

Return true if x is a java.net.URI

use clj

(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.

uuid? clj

(uuid? x)

Return true if x is a java.util.UUID

val clj

(val e)

Returns the value in the map entry.

vals clj

(vals map)

Returns a sequence of the map's values, in the same order as (seq map).

var-get clj

(var-get x)

Gets the value in the var object

var-set clj

(var-set x val)

Sets the value in the var object to val. The var must be thread-locally bound.

var? clj

(var? v)

Returns true if v is of type clojure.lang.Var

vary-meta clj

(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.

vec clj

(vec coll)

Creates a new vector containing the contents of coll. Java arrays will be aliased and should not be modified.

vector clj

(vector)

(vector a)

(vector a b)

(vector a b c)

(vector a b c d)

(vector a b c d e)

(vector a b c d e f)

(vector a b c d e f & args)

Creates a new vector containing the args.

vector-of clj

(vector-of t)

(vector-of t & elements)

Creates a new vector of a single primitive type t, where t is one of :int :long :float :double :byte :short :char or :boolean. The resulting vector complies with the interface of vectors in general, but stores the values unboxed internally.

Optionally takes one or more elements to populate the vector.

vector? clj

(vector? x)

Return true if x implements IPersistentVector

volatile! clj

(volatile! val)

Creates and returns a Volatile with an initial value of val.

volatile? clj

(volatile? x)

Returns true if x is a volatile.

vreset! clj

(vreset! vol newval)

Sets the value of volatile to newval without regard for the current value. Returns newval.

vswap! clj macro

(vswap! vol f & args)

Non-atomically swaps the value of the volatile as if: (apply f current-value-of-vol args). Returns the value that was swapped in.

when clj macro

(when test & body)

Evaluates test. If logical true, evaluates body in an implicit do.

when-first clj macro

(when-first bindings & body)

bindings => x xs

Roughly the same as (when (seq xs) (let [x (first xs)] body)) but xs is evaluated only once

when-let clj macro

(when-let bindings & body)

bindings => binding-form test

When test is true, evaluates body with binding-form bound to the value of test

when-not clj macro

(when-not test & body)

Evaluates test. If logical false, evaluates body in an implicit do.

when-some clj macro

(when-some bindings & body)

bindings => binding-form test

When test is not nil, evaluates body with binding-form bound to the value of test

while clj macro

(while test & body)

Repeatedly executes body while test expression is true. Presumes some side-effect will cause test to become false/nil. Returns nil

with-bindings clj macro

(with-bindings binding-map & body)

Takes a map of Var/value pairs. Installs for the given Vars the associated values as thread-local bindings. Then executes body. Pops the installed bindings after body was evaluated. Returns the value of body.

with-bindings* clj

(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.

with-in-str clj macro

(with-in-str s & body)

Evaluates body in a context in which in is bound to a fresh StringReader initialized with the string s.

with-loading-context clj macro

(with-loading-context & body)

with-local-vars clj macro

(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

with-meta clj

(with-meta obj m)

Returns an object of the same type and value as obj, with map m as its metadata.

with-open clj macro

(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.

with-out-str clj macro

(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.

with-precision clj macro

(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.

with-redefs clj macro

(with-redefs bindings & body)

binding => var-symbol temp-value-expr

Temporarily redefines Vars while executing the body. The temp-value-exprs will be evaluated and each resulting value will replace in parallel the root value of its Var. After the body is executed, the root values of all the Vars will be set back to their old values. These temporary changes will be visible in all threads. Useful for mocking out functions during testing.

with-redefs-fn clj

(with-redefs-fn binding-map func)

Temporarily redefines Vars during a call to func. Each val of binding-map will replace the root value of its key which must be a Var. After func is called with no args, the root values of all the Vars will be set back to their old values. These temporary changes will be visible in all threads. Useful for mocking out functions during testing.

xml-seq clj

(xml-seq root)

A tree seq on the xml elements as per xml/parse

zero? clj

(zero? num)

Returns true if num is zero, else false

zipmap clj

(zipmap keys vals)

Returns a map with the keys mapped to the corresponding vals.