From ece7f872860d286536cb1a5d4f9d5b7da6dc88be Mon Sep 17 00:00:00 2001 From: Andrey Listopadov Date: Mon, 28 Aug 2023 23:56:23 +0300 Subject: update docs, fix doctests, include macros in the docs --- doc/cljlib.md | 2616 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ doc/core.md | 2099 --------------------------------------------- doc/macros.md | 559 ------------ 3 files changed, 2616 insertions(+), 2658 deletions(-) create mode 100644 doc/cljlib.md delete mode 100644 doc/core.md delete mode 100644 doc/macros.md (limited to 'doc') diff --git a/doc/cljlib.md b/doc/cljlib.md new file mode 100644 index 0000000..b1678f5 --- /dev/null +++ b/doc/cljlib.md @@ -0,0 +1,2616 @@ +# Cljlib (v1.1.1) +Fennel-cljlib - functions from Clojure's core.clj implemented on top of Fennel. + +This library contains a set of functions providing functions that behave similarly to Clojure's equivalents. +The library itself apart from macros has nothing Fennel-specific, so it should work on Lua, e.g.: + +``` lua +Lua 5.3.5 Copyright (C) 1994-2018 Lua.org, PUC-Rio +> clj = require"cljlib" +> table.concat(clj.mapv(function (x) return x * x end, {1, 2, 3}), " ") +-- 1 4 9 +``` + +This example is mapping an anonymous `function` over a table, producing a new table, and concatenating it with `" "`. + +However, this library also provides a Fennel-specific set of [macros](./macros.md), which provides additional facilities like [`defn`](#defn) or [`defmulti`](#defmulti) which extends the language allowing writing code that looks and works mostly like Clojure. + +Each function in this library is created with [`defn`](#defn), which is a special macro for creating multi-arity functions. +So when you see a function signature like `(foo [x])`, this means that this is function `foo`, which accepts exactly one argument `x`. +On the contrary, functions created with `fn` will produce a `(foo x)` signature (`x` is not inside brackets). + +Functions, which signatures look like `(foo ([x]) ([x y]) ([x y & zs]))`, it is a multi-arity function, which accepts either one, two, or three or more arguments. +Each `([...])` represents a different body of a function which is chosen by checking the amount of arguments passed to the function. +See [Clojure's doc section on multi-arity functions](https://clojure.org/guides/learn/functions#_multi_arity_functions). + +## Compatibility + +This library is mainly developed with Lua 5.4 and tested against Lua 5.2, 5.3, 5.4, and LuaJIT 2.1.0-beta3. +Note, that in Lua 5.2 and LuaJIT equality semantics are a bit different from Lua 5.3 and Lua 5.4. +The main difference is that when comparing two tables, they must have exactly the same `__eq` metamethods, so comparing hash sets with hash sets will work, but comparing sets with other tables works only in Lua5.3+. +Another difference is that Lua 5.2 and LuaJIT don't have an inbuilt UTF-8 library, therefore [`seq`](#seq) function will not work for non-ASCII strings. + +**Table of contents** + +- [`ns`](#ns) +- [`in-ns`](#in-ns) +- [`def`](#def) +- [`fn*`](#fn) +- [`defn`](#defn) +- [`defn-`](#defn-) +- [`time`](#time) +- [`if-let`](#if-let) +- [`when-let`](#when-let) +- [`if-some`](#if-some) +- [`when-some`](#when-some) +- [`defmulti`](#defmulti) +- [`defmethod`](#defmethod) +- [`cond`](#cond) +- [`loop`](#loop) +- [`try`](#try) +- [`lazy-seq`](#lazy-seq) +- [`lazy-cat`](#lazy-cat) +- [`apply`](#apply) +- [`add`](#add) +- [`sub`](#sub) +- [`mul`](#mul) +- [`div`](#div) +- [`le`](#le) +- [`lt`](#lt) +- [`ge`](#ge) +- [`gt`](#gt) +- [`inc`](#inc) +- [`dec`](#dec) +- [`eq`](#eq) +- [`map?`](#map) +- [`vector?`](#vector) +- [`multifn?`](#multifn) +- [`set?`](#set) +- [`nil?`](#nil) +- [`zero?`](#zero) +- [`pos?`](#pos) +- [`neg?`](#neg) +- [`even?`](#even) +- [`odd?`](#odd) +- [`string?`](#string) +- [`boolean?`](#boolean) +- [`true?`](#true) +- [`false?`](#false) +- [`int?`](#int) +- [`pos-int?`](#pos-int) +- [`neg-int?`](#neg-int) +- [`double?`](#double) +- [`empty?`](#empty) +- [`not-empty`](#not-empty) +- [`vector`](#vector-1) +- [`seq`](#seq) +- [`first`](#first) +- [`rest`](#rest) +- [`last`](#last) +- [`butlast`](#butlast) +- [`conj`](#conj) +- [`disj`](#disj) +- [`cons`](#cons) +- [`concat`](#concat) +- [`reduce`](#reduce) +- [`reduced`](#reduced) +- [`reduce-kv`](#reduce-kv) +- [`mapv`](#mapv) +- [`filter`](#filter) +- [`every?`](#every) +- [`some`](#some) +- [`not-any?`](#not-any) +- [`range`](#range) +- [`reverse`](#reverse) +- [`take`](#take) +- [`nthrest`](#nthrest) +- [`partition`](#partition) +- [`identity`](#identity) +- [`comp`](#comp) +- [`complement`](#complement) +- [`constantly`](#constantly) +- [`memoize`](#memoize) +- [`assoc`](#assoc) +- [`hash-map`](#hash-map) +- [`get`](#get) +- [`get-in`](#get-in) +- [`keys`](#keys) +- [`vals`](#vals) +- [`find`](#find) +- [`dissoc`](#dissoc) +- [`remove-method`](#remove-method) +- [`remove-all-methods`](#remove-all-methods) +- [`methods`](#methods) +- [`get-method`](#get-method) +- [`hash-set`](#hash-set) +- [`assoc!`](#assoc-1) +- [`assoc-in`](#assoc-in) +- [`cat`](#cat) +- [`class`](#class) +- [`completing`](#completing) +- [`conj!`](#conj-1) +- [`contains?`](#contains) +- [`count`](#count) +- [`cycle`](#cycle) +- [`dedupe`](#dedupe) +- [`deref`](#deref) +- [`disj!`](#disj-1) +- [`dissoc!`](#dissoc-1) +- [`distinct`](#distinct) +- [`doall`](#doall) +- [`dorun`](#dorun) +- [`drop`](#drop) +- [`drop-last`](#drop-last) +- [`drop-while`](#drop-while) +- [`empty`](#empty-1) +- [`ensure-reduced`](#ensure-reduced) +- [`filterv`](#filterv) +- [`frequencies`](#frequencies) +- [`group-by`](#group-by) +- [`halt-when`](#halt-when) +- [`interleave`](#interleave) +- [`interpose`](#interpose) +- [`into`](#into) +- [`iterate`](#iterate) +- [`keep`](#keep) +- [`keep-indexed`](#keep-indexed) +- [`line-seq`](#line-seq) +- [`list`](#list) +- [`list*`](#list-1) +- [`map`](#map-1) +- [`map-indexed`](#map-indexed) +- [`mapcat`](#mapcat) +- [`merge`](#merge) +- [`next`](#next) +- [`nth`](#nth) +- [`nthnext`](#nthnext) +- [`partition-all`](#partition-all) +- [`partition-by`](#partition-by) +- [`persistent!`](#persistent) +- [`pop`](#pop) +- [`pop!`](#pop-1) +- [`random-sample`](#random-sample) +- [`realized?`](#realized) +- [`reduced?`](#reduced-1) +- [`reductions`](#reductions) +- [`remove`](#remove) +- [`repeat`](#repeat) +- [`repeatedly`](#repeatedly) +- [`replace`](#replace) +- [`rseq`](#rseq) +- [`seq?`](#seq-1) +- [`sequence`](#sequence) +- [`some?`](#some-1) +- [`sort`](#sort) +- [`split-at`](#split-at) +- [`split-with`](#split-with) +- [`take-last`](#take-last) +- [`take-nth`](#take-nth) +- [`take-while`](#take-while) +- [`transduce`](#transduce) +- [`transient`](#transient) +- [`tree-seq`](#tree-seq) +- [`unreduced`](#unreduced) +- [`update`](#update) +- [`update-in`](#update-in) +- [`vec`](#vec) +- [`zipmap`](#zipmap) + +## `ns` +Function signature: + +``` +(ns name commentary requirements) +``` + +Namespace declaration macro. +Accepts the `name` of the generated namespace, and creates a local +variable with this name holding a table. Optionally accepts +`commentary` describing what namespace is about and a `requirements` +spec, specifying what libraries should be required. + +The `requirements` spec is a list that consists of vectors, specifying +library name and a possible alias or a vector of names to refer to +without a prefix: + +``` fennel +(ns some-namespace + "Description of the some-namespace." + (:require [some.lib] + [some.other.lib :as lib2] + [another.lib :refer [foo bar baz]])) + +(defn inc [x] (+ x 1)) +``` + +Which is equivalent to: + +``` fennel +(local some-namespace {}) +(local lib (require :some.lib)) +(local lib2 (require :some.other.lib)) +(local {:bar bar :baz baz :foo foo} (require :another.lib)) +(comment "Description of the some-namespace.") +``` + +Note that when no `:as` alias is given, the library will be named +after the innermost part of the require path, i.e. `some.lib` is +transformed to `lib`. + +See `in-ns` on how to switch namespaces. + +## `in-ns` +Function signature: + +``` +(in-ns name) +``` + +Sets the compile-time variable `cljlib-namespaces` to the given `name`. +Affects such macros as `def`, `defn`, which will bind names to the +specified namespace. + +### Examples +Creating several namespaces in the file, and defining functions in each: + +``` fennel +(ns a) +(defn f [] "f from a") +(ns b) +(defn f [] "f from b") +(in-ns a) +(defn g [] "g from a") +(in-ns b) +(defn g [] "g from b") + +(assert-eq (a.f) "f from a") +(assert-eq (b.f) "f from b") +(assert-eq (a.g) "g from a") +(assert-eq (b.g) "g from b") +``` + +Note, switching namespaces in the REPL doesn't affect non-namespaced +local bindings. In other words, when defining a local with `def`, a +bot a local binding and a namespaced binding are created, and +switching current namespace won't change the local binding: + +``` fennel +>> (ns foo) +nil +>> (def x 42) +nil +>> (ns bar) +nil +>> (def x 1337) +nil +>> (in-ns foo) +# +>> x ; user might have expected to see 42 here +1337 +>> foo.x +42 +>> bar.x +1337 +``` + +Sadly, Fennel itself has no support for namespace switching in REPL, +so this feature can be only partially emulated by the cljlib library. + + +## `def` +Function signature: + +``` +(def ([name initializer]) ([meta name initializer])) +``` + +Name binding macro similar to `local` but acts in terms of current +namespace set with the `ns` macro, unless `:private` was passed before +the binding name. Accepts the `name` to be bound and the `initializer` +expression. `meta` can be either an associative table where keys are +strings, or a string representing a key from the table. If a sole +string is given, its value is set to `true` in the meta table. + +## `fn*` +Function signature: + +``` +(fn* ([name doc-string? [params*] pre-post? body]) ([name doc-string? ([params*] pre-post? body) +])) +``` + +Clojure-inspired `fn` macro for defining functions. +Accepts an optional `name` and `docstring?`, followed by the binding +list containing function's `params*`. The `body` is wrapped in an +implicit `do`. The `doc-string?` argument specifies an optional +documentation for the function. Supports multi-arity dispatching via +the following syntax: + +(fn* optional-name + optional-docstring + ([arity1] body1) + ([other arity2] body2)) + +Accepts `pre-post?` conditions in a form of a table after argument +list: + +(fn* optional-name + optional-docstring + [arg1 arg2] + {:pre [(check1 arg1 arg2) (check2 arg1)] + :post [(check1 $) ... (checkN $)]} + body) + +The same syntax applies to multi-arity version. + +(pre- and post-checks are not yet implemented) + +## `defn` +Function signature: + +``` +(defn ([name doc-string? [params*] pre-post? body]) ([name doc-string? ([params*] pre-post? body) +])) +``` + +Same as `(def name (fn* name docstring? [params*] pre-post? exprs*))` +or `(def name (fn* name docstring? ([params*] pre-post? exprs*)+))` +with any doc-string or attrs added to the function metadata. Accepts +`name` which will be used to refer to a function in the current +namespace, and optional `doc-string?`, a vector of function's +`params*`, `pre-post?` conditions, and the `body` of the function. +The body is wrapped in an implicit do. See `fn*` for more info. + +## `defn-` +Function signature: + +``` +(defn- ([name doc-string? [params*] pre-post? body]) ([name doc-string? ([params*] pre-post? body) +])) +``` + +Same as `(def :private name (fn* name docstring? [params*] pre-post? +exprs*))` or `(def :private name (fn* name docstring? ([params*] +pre-post? exprs*)+))` with any doc-string or attrs added to the +function metadata. Accepts `name` which will be used to refer to a +function, and optional `doc-string?`, a vector of function's +`params*`, `pre-post?` conditions, and the `body` of the function. +The body is wrapped in an implicit do. See `fn*` for more info. + +## `time` +Function signature: + +``` +(time expr) +``` + +Measure the CPU time spent executing `expr`. + +## `if-let` +Function signature: + +``` +(if-let [name test] if-branch else-branch) +``` + +When `test` is logical `true`, evaluates the `if-branch` with `name` +bound to the value of `test`. Otherwise, evaluates the `else-branch` + +## `when-let` +Function signature: + +``` +(when-let [name test] & body) +``` + +When `test` is logical `true`, evaluates the `body` with `name` bound +to the value of `test`. + +## `if-some` +Function signature: + +``` +(if-some [name test] if-branch else-branch) +``` + +When `test` is not `nil`, evaluates the `if-branch` with `name` +bound to the value of `test`. Otherwise, evaluates the `else-branch` + +## `when-some` +Function signature: + +``` +(when-some [name test] & body) +``` + +When `test` is not `nil`, evaluates the `body` with `name` bound to +the value of `test`. + +## `defmulti` +Function signature: + +``` +(defmulti name docstring? dispatch-fn options*) +``` + +Create multifunction `name` with runtime dispatching based on results +from `dispatch-fn`. Returns a proxy table with `__call` metamethod, +that calls `dispatch-fn` on its arguments. Amount of arguments +passed, should be the same as accepted by `dispatch-fn`. Looks for +multimethod based on result from `dispatch-fn`. + +Accepts optional `docstring?`, and `options*` arguments, where +`options*` is a sequence of key value pairs representing additional +attributes. Supported options: + +`:default` - the default dispatch value, defaults to `:default`. + +By default, multifunction has no multimethods, see +[`defmethod`](#defmethod) on how to add one. + +## `defmethod` +Function signature: + +``` +(defmethod multi-fn dispatch-value fnspec) +``` + +Attach new method to multi-function dispatch value. Accepts the +`multi-fn` as its first argument, the `dispatch-value` as second, and +`fnspec` - a function tail starting from argument list, followed by +function body as in [`fn*`](#fn). + +### Examples +Here are some examples how multimethods can be used. + +#### Factorial example +Key idea here is that multimethods can call itself with different +values, and will dispatch correctly. Here, `fac` recursively calls +itself with less and less number until it reaches `0` and dispatches +to another multimethod: + +``` fennel +(ns test) + +(defmulti fac (fn [x] x)) + +(defmethod fac 0 [_] 1) +(defmethod fac :default [x] (* x (fac (- x 1)))) + +(assert-eq (fac 4) 24) +``` + +`:default` is a special method which gets called when no other methods +were found for given dispatch value. + +#### Multi-arity dispatching +Multi-arity function tails are also supported: + +``` fennel +(ns test) + +(defmulti foo (fn* ([x] [x]) ([x y] [x y]))) + +(defmethod foo [10] [_] (print "I knew I'll get 10")) +(defmethod foo [10 20] [_ _] (print "I knew I'll get both 10 and 20")) +(defmethod foo :default ([x] (print (.. "Umm, got" x))) + ([x y] (print (.. "Umm, got both " x " and " y)))) +``` + +Calling `(foo 10)` will print `"I knew I'll get 10"`, and calling +`(foo 10 20)` will print `"I knew I'll get both 10 and 20"`. +However, calling `foo` with any other numbers will default either to +`"Umm, got x"` message, when called with single value, and `"Umm, got +both x and y"` when calling with two values. + +#### Dispatching on object's type +We can dispatch based on types the same way we dispatch on values. +For example, here's a naive conversion from Fennel's notation for +tables to Lua's one: + +``` fennel +(ns test) + +(defmulti to-lua-str (fn [x] (type x))) + +(defmethod to-lua-str :number [x] (tostring x)) +(defmethod to-lua-str :table [x] + (let [res []] + (each [k v (pairs x)] + (table.insert res (.. "[" (to-lua-str k) "] = " (to-lua-str v)))) + (.. "{" (table.concat res ", ") "}"))) +(defmethod to-lua-str :string [x] (.. "\"" x "\"")) +(defmethod to-lua-str :default [x] (tostring x)) + +(assert-eq (to-lua-str {:a {:b 10}}) "{[\"a\"] = {[\"b\"] = 10}}") + +(assert-eq (to-lua-str [:a :b :c [:d {:e :f}]]) + "{[1] = \"a\", [2] = \"b\", [3] = \"c\", [4] = {[1] = \"d\", [2] = {[\"e\"] = \"f\"}}}") +``` + +And if we call it on some table, we'll get a valid Lua table, which we +can then reformat as we want and use in Lua. + +All of this can be done with functions, and single entry point +function, that uses if statement and branches on the type, however one +of the additional features of multimethods, is that separate libraries +can extend such multimethod by adding additional claues to it without +needing to patch the source of the function. For example later on +support for userdata or coroutines can be added to `to-lua-str` +function as a separate multimethods for respective types. + +## `cond` +Function signature: + +``` +(cond ...) +``` + +Takes a set of test expression pairs. It evaluates each test one at a +time. If a test returns logical true, `cond` evaluates and returns +the value of the corresponding expression and doesn't evaluate any of +the other tests or exprs. `(cond)` returns nil. + +## `loop` +Function signature: + +``` +(loop binding-vec body*) +``` + +Recursive loop macro. + +Similar to `let`, but binds a special `recur` call that will reassign +the values of the `binding-vec` and restart the loop `body*`. Unlike +`let`, doesn't support multiple-value destructuring. + +The first argument is a binding table with alternating symbols (or destructure +forms), and the values to bind to them. + +For example: + +``` fennel +(loop [[first & rest] [1 2 3 4 5] + i 0] + (if (= nil first) + i + (recur rest (+ 1 i)))) +``` + +This would destructure the first table argument, with the first value inside it +being assigned to `first` and the remainder of the table being assigned to +`rest`. `i` simply gets bound to 0. + +The body of the form executes for every item in the table, calling `recur` each +time with the table lacking its head element (thus consuming one element per +iteration), and with `i` being called with one value greater than the previous. + +When the loop terminates (When the user doesn't call `recur`) it will return the +number of elements in the passed in table. (In this case, 5) + +### Limitations + +In order to only evaluate expressions once and support sequential +bindings, the binding table has to be transformed like this: + +``` fennel +(loop [[x & xs] (foo) + y (+ x 1)] + ...) + +(let [_1_ (foo) + [x & xs] _1_ + _2_ (+ x 1) + y _2_] + ((fn recur [[x & xs] y] ...) _1_ _2_) +``` + +This ensures that `foo` is called only once, its result is cached in a +`sym1#` binding, and that `y` can use the destructured value, obtained +from that binding. The value of this binding is later passed to the +function to begin the first iteration. + +This has two unfortunate consequences. One is that the initial +destructuring happens twice - first, to make sure that later bindings +can be properly initialized, and second, when the first looping +function call happens. Another one is that as a result, `loop` macro +can't work with multiple-value destructuring, because these can't be +cached as described above. E.g. this will not work: + +``` fennel +(loop [(x y) (foo)] ...) +``` + +Because it would be transformed to: + +``` fennel +(let [_1_ (foo) + (x y) _1_] + ((fn recur [(x y)] ...) _1_) +``` + +`x` is correctly set, but `y` is completely lost. Therefore, this +macro checks for lists in bindings. + +## `try` +Function signature: + +``` +(try body* catch-clause* finally-clause?) +``` + +General purpose try/catch/finally macro. +Wraps its body in `pcall` and checks the return value with `match` +macro. + +Catch clause is written either as `(catch symbol body*)`, thus acting +as catch-all, or `(catch value body*)` for catching specific errors. +It is possible to have several `catch` clauses. If no `catch` clauses +specified, an implicit catch-all clause is created. `body*`, and +inner expressions of `catch-clause*`, and `finally-clause?` are +wrapped in implicit `do`. + +The `finally` clause is optional, and written as (finally body*). If +present, it must be the last clause in the [`try`](#try) form, and the only +`finally` clause. Note that `finally` clause is for side effects +only, and runs either after succesful run of [`try`](#try) body, or after any +`catch` clause body, before returning the result. If no `catch` +clause is provided `finally` runs in implicit catch-all clause, and +trows error to upper scope using `error` function. + +To throw error from [`try`](#try) to catch it with `catch` clause use `error` +or `assert` functions. + +### Examples +Catch all errors, ignore those and return fallback value: + +``` fennel +(fn add [x y] + (try + (+ x y) + (catch _ 0))) + +(assert-eq (add nil 1) 0) +``` + +Catch error and do cleanup: + +``` fennel +(local tbl []) + +(try + (table.insert tbl "a") + (table.insert tbl "b" "c") + (catch _ + (each [k _ (pairs tbl)] + (tset tbl k nil)))) + +(assert-eq (length tbl) 0) + +``` + +Always run some side effect action: + +``` fennel +(local t []) +(local res (try 10 (finally (table.insert t :finally)))) +(assert-eq (. t 1) :finally) +(assert-eq res 10) + +(local res (try (error 10) (catch 10 nil) (finally (table.insert t :again)))) +(assert-eq (. t 2) :again) +(assert-eq res nil) +``` + +## `lazy-seq` +Function signature: + +``` +(lazy-seq & body) +``` + +Takes a `body` of expressions that returns a sequence, table or nil, +and yields a lazy sequence 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?` + +## `lazy-cat` +Function signature: + +``` +(lazy-cat & colls) +``` + +Expands to code which yields a lazy sequence of the concatenation of +`colls` - expressions returning collections. Each expression is not +evaluated until it is needed. + +## `apply` +Function signature: + +``` +(apply ([f args]) ([f a args]) ([f a b args]) ([f a b c args]) ([f a b c d & args])) +``` + +Apply `f` to the argument list formed by prepending intervening +arguments to `args`, and `f` must support variadic amount of +arguments. + +### Examples +Applying `add` to different amount of arguments: + +``` fennel +(assert-eq (apply add [1 2 3 4]) 10) +(assert-eq (apply add 1 [2 3 4]) 10) +(assert-eq (apply add 1 2 3 4 5 6 [7 8 9]) 45) +``` + +## `add` +Function signature: + +``` +(add ([]) ([a]) ([a b]) ([a b c]) ([a b c d]) ([a b c d & rest])) +``` + +Sum arbitrary amount of numbers. + +## `sub` +Function signature: + +``` +(sub ([]) ([a]) ([a b]) ([a b c]) ([a b c d]) ([a b c d & rest])) +``` + +Subtract arbitrary amount of numbers. + +## `mul` +Function signature: + +``` +(mul ([]) ([a]) ([a b]) ([a b c]) ([a b c d]) ([a b c d & rest])) +``` + +Multiply arbitrary amount of numbers. + +## `div` +Function signature: + +``` +(div ([a]) ([a b]) ([a b c]) ([a b c d]) ([a b c d & rest])) +``` + +Divide arbitrary amount of numbers. + +## `le` +Function signature: + +``` +(le ([a]) ([a b]) ([a b & [c d & more]])) +``` + +Returns true if nums are in monotonically non-decreasing order + +## `lt` +Function signature: + +``` +(lt ([a]) ([a b]) ([a b & [c d & more]])) +``` + +Returns true if nums are in monotonically decreasing order + +## `ge` +Function signature: + +``` +(ge ([a]) ([a b]) ([a b & [c d & more]])) +``` + +Returns true if nums are in monotonically non-increasing order + +## `gt` +Function signature: + +``` +(gt ([a]) ([a b]) ([a b & [c d & more]])) +``` + +Returns true if nums are in monotonically increasing order + +## `inc` +Function signature: + +``` +(inc [x]) +``` + +Increase number `x` by one + +## `dec` +Function signature: + +``` +(dec [x]) +``` + +Decrease number `x` by one + +## `eq` +Function signature: + +``` +(eq ([]) ([_]) ([a b]) ([a b & cs])) +``` + +Comparison function. + +Accepts arbitrary amount of values, and does the deep comparison. If +values implement `__eq` metamethod, tries to use it, by checking if +first value is equal to second value, and the second value is equal to +the first value. If values are not equal and are tables does the deep +comparison. Tables as keys are supported. + +## `map?` +Function signature: + +``` +(map? [x]) +``` + +Check whether `x` is an associative table. + +Non-empty tables are tested by calling `next`. If the length of the +table is greater than zero, the last integer key is passed to the +`next`, and if `next` returns a key, the table is considered +associative. If the length is zero, `next` is called with what `paris` +returns for the table, and if the key is returned, table is considered +associative. + +Empty tables can't be analyzed with this method, and `map?` will +always return `false`. If you need this test pass for empty table, +see `hash-map` for creating tables that have additional metadata +attached for this test to work. + +### Examples +Non-empty map: + +``` fennel +(assert-is (map? {:a 1 :b 2})) +``` + +Empty tables don't pass the test: + +``` fennel +(assert-not (map? {})) +``` + +Empty tables created with `hash-map` will pass the test: + +``` fennel +(assert-is (map? (hash-map))) +``` + +## `vector?` +Function signature: + +``` +(vector? [x]) +``` + +Check whether `tbl` is a sequential table. + +Non-empty sequential tables are tested for two things: +- `next` returns the key-value pair, +- key, that is returned by the `next` is equal to `1`. + +Empty tables can't be analyzed with this method, and `vector?` will +always return `false`. If you need this test pass for empty table, +see `vector` for creating tables that have additional +metadata attached for this test to work. + +### Examples +Non-empty vector: + +``` fennel +(assert-is (vector? [1 2 3 4])) +``` + +Empty tables don't pass the test: + +``` fennel +(assert-not (vector? [])) +``` + +Empty tables created with `vector` will pass the test: + +``` fennel +(assert-is (vector? (vector))) +``` + +## `multifn?` +Function signature: + +``` +(multifn? [mf]) +``` + +Test if `mf` is an instance of `multifn`. + +`multifn` is a special kind of table, created with [`defmulti`](#defmulti) macros +from `macros.fnl`. + +## `set?` +Function signature: + +``` +(set? [x]) +``` + +Check if object is a set. + +## `nil?` +Function signature: + +``` +(nil? ([]) ([x])) +``` + +Test if `x` is nil. + +## `zero?` +Function signature: + +``` +(zero? [x]) +``` + +Test if `x` is equal to zero. + +## `pos?` +Function signature: + +``` +(pos? [x]) +``` + +Test if `x` is greater than zero. + +## `neg?` +Function signature: + +``` +(neg? [x]) +``` + +Test if `x` is less than zero. + +## `even?` +Function signature: + +``` +(even? [x]) +``` + +Test if `x` is even. + +## `odd?` +Function signature: + +``` +(odd? [x]) +``` + +Test if `x` is odd. + +## `string?` +Function signature: + +``` +(string? [x]) +``` + +Test if `x` is a string. + +## `boolean?` +Function signature: + +``` +(boolean? [x]) +``` + +Test if `x` is a Boolean + +## `true?` +Function signature: + +``` +(true? [x]) +``` + +Test if `x` is `true` + +## `false?` +Function signature: + +``` +(false? [x]) +``` + +Test if `x` is `false` + +## `int?` +Function signature: + +``` +(int? [x]) +``` + +Test if `x` is a number without floating point data. + +Number is rounded with `math.floor` and compared with original number. + +## `pos-int?` +Function signature: + +``` +(pos-int? [x]) +``` + +Test if `x` is a positive integer. + +## `neg-int?` +Function signature: + +``` +(neg-int? [x]) +``` + +Test if `x` is a negative integer. + +## `double?` +Function signature: + +``` +(double? [x]) +``` + +Test if `x` is a number with floating point data. + +## `empty?` +Function signature: + +``` +(empty? [x]) +``` + +Check if collection is empty. + +## `not-empty` +Function signature: + +``` +(not-empty [x]) +``` + +If `x` is empty, returns `nil`, otherwise `x`. + +## `vector` +Function signature: + +``` +(vector [& args]) +``` + +Constructs sequential table out of its arguments. + +Sets additional metadata for function `vector?` to work. + +### Examples + +``` fennel +(def :private v (vector 1 2 3 4)) +(assert-eq v [1 2 3 4]) +``` + +## `seq` +Function signature: + +``` +(seq [coll]) +``` + +Construct a sequence from the given collection `coll`. If `coll` is +an associative table, returns sequence of vectors with key and value. +If `col` is sequential table, returns its shallow copy. If `col` is +string, return sequential table of its codepoints. + +### Examples +Sequential tables are transformed to sequences: + +``` fennel +(seq [1 2 3 4]) ;; @seq(1 2 3 4) +``` + +Associative tables are transformed to format like this `[[key1 value1] +... [keyN valueN]]` and order is non-deterministic: + +``` fennel +(seq {:a 1 :b 2 :c 3}) ;; @seq([:b 2] [:a 1] [:c 3]) +``` + +## `first` +Function signature: + +``` +(first [coll]) +``` + +Return first element of a `coll`. Calls `seq` on its argument. + +## `rest` +Function signature: + +``` +(rest [coll]) +``` + +Returns a sequence of all elements of a `coll` but the first one. +Calls `seq` on its argument. + +## `last` +Function signature: + +``` +(last [coll]) +``` + +Returns the last element of a `coll`. Calls `seq` on its argument. + +## `butlast` +Function signature: + +``` +(butlast [coll]) +``` + +Returns everything but the last element of the `coll` as a new + sequence. Calls `seq` on its argument. + +## `conj` +Function signature: + +``` +(conj ([]) ([s]) ([s x]) ([s x & xs])) +``` + +Insert `x` as a last element of a table `tbl`. + +If `tbl` is a sequential table or empty table, inserts `x` and +optional `xs` as final element in the table. + +If `tbl` is an associative table, that satisfies `map?` test, +insert `[key value]` pair into the table. + +Mutates `tbl`. + +### Examples +Adding to sequential tables: + +``` fennel +(conj [] 1 2 3 4) +;; => [1 2 3 4] +(conj [1 2 3] 4 5) +;; => [1 2 3 4 5] +``` + +Adding to associative tables: + +``` fennel +(conj {:a 1} [:b 2] [:c 3]) +;; => {:a 1 :b 2 :c 3} +``` + +Note, that passing literal empty associative table `{}` will not work: + +``` fennel +(conj {} [:a 1] [:b 2]) +;; => [[:a 1] [:b 2]] +(conj (hash-map) [:a 1] [:b 2]) +;; => {:a 1 :b 2} +``` + +See `hash-map` for creating empty associative tables. + +## `disj` +Function signature: + +``` +(disj ([Set]) ([Set key]) ([Set key & keys])) +``` + +Returns a new set type, that does not contain the +specified `key` or `keys`. + +## `cons` +Function signature: + +``` +(cons [head tail]) +``` + +Construct a cons cell. +Prepends new `head` to a `tail`, which must be either a table, +sequence, or nil. + +### Examples + +``` fennel +(assert-eq [0 1] (cons 0 [1])) +(assert-eq (list 0 1 2 3) (cons 0 (cons 1 (list 2 3)))) +``` + +## `concat` +Function signature: + +``` +(concat [& colls]) +``` + +Return a lazy sequence of concatenated `colls`. + +## `reduce` +Function signature: + +``` +(reduce ([f coll]) ([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. Early termination is supported via `reduced`. + +### Examples + +``` fennel +(defn- add + ([] 0) + ([a] a) + ([a b] (+ a b)) + ([a b & cs] (apply add (+ a b) cs))) +;; no initial value +(assert-eq 10 (reduce add [1 2 3 4])) +;; initial value +(assert-eq 10 (reduce add 1 [2 3 4])) +;; empty collection - function is called with 0 args +(assert-eq 0 (reduce add [])) +(assert-eq 10.3 (reduce math.floor 10.3 [])) +;; collection with a single element doesn't call a function unless the +;; initial value is supplied +(assert-eq 10.3 (reduce math.floor [10.3])) +(assert-eq 7 (reduce add 3 [4])) +``` + +## `reduced` +Function signature: + +``` +(reduced [value]) +``` + +Terminates the `reduce` early with a given `value`. + +### Examples + +``` fennel +(assert-eq :NaN + (reduce (fn [acc x] + (if (not= :number (type x)) + (reduced :NaN) + (+ acc x))) + [1 2 :3 4 5])) +``` + +## `reduce-kv` +Function signature: + +``` +(reduce-kv [f val s]) +``` + +Reduces an associative table using function `f` and initial value `val`. + +`f` should be a function of 3 arguments. Returns the result of +applying `f` to `val`, the first key and the first value in `tbl`, +then applying `f` to that result and the 2nd key and value, etc. If +`tbl` contains no entries, returns `val` and `f` is not called. Note +that `reduce-kv` is supported on sequential tables and strings, where +the keys will be the ordinals. + +Early termination is possible with the use of `reduced` +function. + +### Examples +Reduce associative table by adding values from all keys: + +``` fennel +(local t {:a1 1 + :b1 2 + :a2 2 + :b2 3}) + +(reduce-kv #(+ $1 $3) 0 t) +;; => 8 +``` + +Reduce table by adding values from keys that start with letter `a`: + +``` fennel +(local t {:a1 1 + :b1 2 + :a2 2 + :b2 3}) + +(reduce-kv (fn [res k v] (if (= (string.sub k 1 1) :a) (+ res v) res)) + 0 t) +;; => 3 +``` + +## `mapv` +Function signature: + +``` +(mapv ([f coll]) ([f coll & 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 collections are ignored. +Function `f` should accept number-of-colls arguments. + +## `filter` +Function signature: + +``` +(filter ([pred]) ([pred coll])) +``` + +Returns a lazy sequence of the items in `coll` for which +`pred` returns logical true. Returns a transducer when no collection +is provided. + +## `every?` +Function signature: + +``` +(every? [pred coll]) +``` + +Test if every item in `coll` satisfies the `pred`. + +## `some` +Function signature: + +``` +(some [pred coll]) +``` + +Test if any item in `coll` satisfies the `pred`. + +## `not-any?` +Function signature: + +``` +(not-any? [pred coll]) +``` + +Test if no item in `coll` satisfy the `pred`. + +## `range` +Function signature: + +``` +(range ([]) ([upper]) ([lower upper]) ([lower upper step])) +``` + +Returns lazy sequence of numbers from `lower` to `upper` with optional +`step`. + +## `reverse` +Function signature: + +``` +(reverse [coll]) +``` + +Returns a lazy sequence with same items as in `coll` but in reverse order. + +## `take` +Function signature: + +``` +(take ([n]) ([n coll])) +``` + +Returns a lazy sequence of the first `n` items in `coll`, or all items if +there are fewer than `n`. + +## `nthrest` +Function signature: + +``` +(nthrest [coll n]) +``` + +Returns the nth rest of `coll`, `coll` when `n` is 0. + +### Examples + +``` fennel +(assert-eq (nthrest [1 2 3 4] 3) [4]) +(assert-eq (nthrest [1 2 3 4] 2) [3 4]) +(assert-eq (nthrest [1 2 3 4] 1) [2 3 4]) +(assert-eq (nthrest [1 2 3 4] 0) [1 2 3 4]) +``` + + +## `partition` +Function signature: + +``` +(partition ([n coll]) ([n step coll]) ([n step pad coll])) +``` + +Given a collection `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 up to `n` items. In case there are not enough padding +elements, return a partition with less than `n` items. + +## `identity` +Function signature: + +``` +(identity [x]) +``` + +Returns its argument. + +## `comp` +Function signature: + +``` +(comp ([]) ([f]) ([f g]) ([f g & fs])) +``` + +Compose functions. + +## `complement` +Function signature: + +``` +(complement [f]) +``` + +Takes a function `f` and returns the function that takes the same +amount of arguments as `f`, has the same effect, and returns the +opposite truth value. + +## `constantly` +Function signature: + +``` +(constantly [x]) +``` + +Returns a function that takes any number of arguments and returns `x`. + +## `memoize` +Function signature: + +``` +(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. + +## `assoc` +Function signature: + +``` +(assoc ([tbl]) ([tbl k v]) ([tbl k v & kvs])) +``` + +Associate `val` under a `key`. +Accepts extra keys and values. + +### Examples + +``` fennel +(assert-eq {:a 1 :b 2} (assoc {:a 1} :b 2)) +(assert-eq {:a 1 :b 2} (assoc {:a 1 :b 1} :b 2)) +(assert-eq {:a 1 :b 2 :c 3} (assoc {:a 1 :b 1} :b 2 :c 3)) +``` + +## `hash-map` +Function signature: + +``` +(hash-map [& kvs]) +``` + +Create associative table from `kvs` represented as sequence of keys +and values + +## `get` +Function signature: + +``` +(get ([tbl key]) ([tbl key not-found])) +``` + +Get value from the table by accessing it with a `key`. +Accepts additional `not-found` as a marker to return if value wasn't +found in the table. + +## `get-in` +Function signature: + +``` +(get-in ([tbl keys]) ([tbl keys not-found])) +``` + +Get value from nested set of tables by providing key sequence. +Accepts additional `not-found` as a marker to return if value wasn't +found in the table. + +## `keys` +Function signature: + +``` +(keys [coll]) +``` + +Returns a sequence of the map's keys, in the same order as `seq`. + +## `vals` +Function signature: + +``` +(vals [coll]) +``` + +Returns a sequence of the table's values, in the same order as `seq`. + +## `find` +Function signature: + +``` +(find [coll key]) +``` + +Returns the map entry for `key`, or `nil` if key is not present in +`coll`. + +## `dissoc` +Function signature: + +``` +(dissoc ([tbl]) ([tbl key]) ([tbl key & keys])) +``` + +Remove `key` from table `tbl`. Optionally takes more `keys`. + +## `remove-method` +Function signature: + +``` +(remove-method [multimethod dispatch-value]) +``` + +Remove method from `multimethod` for given `dispatch-value`. + +## `remove-all-methods` +Function signature: + +``` +(remove-all-methods [multimethod]) +``` + +Removes all methods of `multimethod` + +## `methods` +Function signature: + +``` +(methods [multimethod]) +``` + +Given a `multimethod`, returns a map of dispatch values -> dispatch fns + +## `get-method` +Function signature: + +``` +(get-method [multimethod dispatch-value]) +``` + +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. + +## `hash-set` +Function signature: + +``` +(hash-set [& xs]) +``` + +Create hash set. + +Set is a collection of unique elements, which sore purpose is only to +tell you if something is in the set or not. + +## `assoc!` +Function signature: + +``` +(assoc! [map k & ks]) +``` + +Remove `k`from transient map, and return `map`. + +## `assoc-in` +Function signature: + +``` +(assoc-in [tbl key-seq val]) +``` + +Associate `val` into set of immutable nested tables `t`, via given `key-seq`. +Returns a new immutable table. Returns a new immutable table. + +### Examples + +Replace value under nested keys: + +``` fennel +(assert-eq + {:a {:b {:c 1}}} + (assoc-in {:a {:b {:c 0}}} [:a :b :c] 1)) +``` + +Create new entries as you go: + +``` fennel +(assert-eq + {:a {:b {:c 1}} :e 2} + (assoc-in {:e 2} [:a :b :c] 1)) +``` + +## `cat` +Function signature: + +``` +(cat [rf]) +``` + +A transducer which concatenates the contents of each input, which must be a + collection, into the reduction. Accepts the reducing function `rf`. + +## `class` +Function signature: + +``` +(class [x]) +``` + +Return cljlib type of the `x`, or lua type. + +## `completing` +Function signature: + +``` +(completing ([f]) ([f cf])) +``` + +Takes a reducing function `f` of 2 args and returns a function +suitable for transduce by adding an arity-1 signature that calls +`cf` (default - `identity`) on the result argument. + +## `conj!` +Function signature: + +``` +(conj! ([]) ([coll]) ([coll x])) +``` + +Adds `x` to the transient collection, and return `coll`. + +## `contains?` +Function signature: + +``` +(contains? [coll elt]) +``` + +Test if `elt` is in the `coll`. It may be a linear search depending +on the type of the collection. + +## `count` +Function signature: + +``` +(count [s]) +``` + +Count amount of elements in the sequence. + +## `cycle` +Function signature: + +``` +(cycle [coll]) +``` + +Create a lazy infinite sequence of repetitions of the items in the +`coll`. + +## `dedupe` +Function signature: + +``` +(dedupe ([]) ([coll])) +``` + +Returns a lazy sequence removing consecutive duplicates in coll. +Returns a transducer when no collection is provided. + +## `deref` +Function signature: + +``` +(deref [x]) +``` + +Dereference an object. + +## `disj!` +Function signature: + +``` +(disj! ([Set]) ([Set key & ks])) +``` + +disj[oin]. Returns a transient set of the same type, that does not +contain `key`. + +## `dissoc!` +Function signature: + +``` +(dissoc! [map k & ks]) +``` + +Remove `k`from transient map, and return `map`. + +## `distinct` +Function signature: + +``` +(distinct ([]) ([coll])) +``` + +Returns a lazy sequence of the elements of the `coll` without +duplicates. Comparison is done by equality. Returns a transducer when +no collection is provided. + +## `doall` +Function signature: + +``` +(doall [seq]) +``` + +Realize whole lazy sequence `seq`. + +Walks whole sequence, realizing each cell. Use at your own risk on +infinite sequences. + +## `dorun` +Function signature: + +``` +(dorun [seq]) +``` + +Realize whole sequence `seq` for side effects. + +Walks whole sequence, realizing each cell. Use at your own risk on +infinite sequences. + +## `drop` +Function signature: + +``` +(drop ([n]) ([n coll])) +``` + +Drop `n` elements from collection `coll`, returning a lazy sequence +of remaining elements. Returns a transducer when no collection is +provided. + +## `drop-last` +Function signature: + +``` +(drop-last ([]) ([coll]) ([n coll])) +``` + +Return a lazy sequence from `coll` without last `n` elements. + +## `drop-while` +Function signature: + +``` +(drop-while ([pred]) ([pred coll])) +``` + +Drop the elements from the collection `coll` until `pred` returns logical +false for any of the elemnts. Returns a lazy sequence. Returns a +transducer when no collection is provided. + +## `empty` +Function signature: + +``` +(empty [x]) +``` + +Get an empty variant of a given collection. + +## `ensure-reduced` +Function signature: + +``` +(ensure-reduced [x]) +``` + +If x is already reduced?, returns it, else returns (reduced x) + +## `filterv` +Function signature: + +``` +(filterv [pred coll]) +``` + +Returns a vector of the items in `coll` for which +`pred` returns logical true. + +## `frequencies` +Function signature: + +``` +(frequencies [t]) +``` + +Return a table of unique entries from table `t` associated to amount +of their appearances. + +### Examples + +Count each entry of a random letter: + +``` fennel +(let [fruits [:banana :banana :apple :strawberry :apple :banana]] + (assert-eq (frequencies fruits) + {:banana 3 + :apple 2 + :strawberry 1})) +``` + +## `group-by` +Function signature: + +``` +(group-by [f t]) +``` + +Group table items in an associative table under the keys that are +results of calling `f` on each element of sequential table `t`. +Elements that the function call resulted in `nil` returned in a +separate table. + +### Examples + +Group rows by their date: + +``` fennel +(local rows + [{:date "2007-03-03" :product "pineapple"} + {:date "2007-03-04" :product "pizza"} + {:date "2007-03-04" :product "pineapple pizza"} + {:date "2007-03-05" :product "bananas"}]) + +(assert-eq (group-by #(. $ :date) rows) + {"2007-03-03" + [{:date "2007-03-03" :product "pineapple"}] + "2007-03-04" + [{:date "2007-03-04" :product "pizza"} + {:date "2007-03-04" :product "pineapple pizza"}] + "2007-03-05" + [{:date "2007-03-05" :product "bananas"}]}) +``` + +## `halt-when` +Function signature: + +``` +(halt-when ([pred]) ([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. + +## `interleave` +Function signature: + +``` +(interleave ([]) ([s]) ([s1 s2]) ([s1 s2 & ss])) +``` + +Returns a lazy sequence of the first item in each sequence, then the +second one, until any sequence exhausts. + +## `interpose` +Function signature: + +``` +(interpose ([sep]) ([separator coll])) +``` + +Returns a lazy sequence of the elements of `coll` separated by +`separator`. Returns a transducer when no collection is provided. + +## `into` +Function signature: + +``` +(into ([]) ([to]) ([to from]) ([to xform from])) +``` + +Returns a new coll consisting of `to` with all of the items of `from` +conjoined. A transducer `xform` may be supplied. + +### Examples + +Insert items of one collection into another collection: + +```fennel +(assert-eq [1 2 3 :a :b :c] (into [1 2 3] "abc")) +(assert-eq {:a 2 :b 3} (into {:a 1} {:a 2 :b 3})) +``` + +Transform a hash-map into a sequence of key-value pairs: + +``` fennel +(assert-eq [[:a 1]] (into (vector) {:a 1})) +``` + +You can also construct a hash-map from a sequence of key-value pairs: + +``` fennel +(assert-eq {:a 1 :b 2 :c 3} + (into (hash-map) [[:a 1] [:b 2] [:c 3]])) +``` + +## `iterate` +Function signature: + +``` +(iterate [f x]) +``` + +Returns an infinete lazy sequence of x, (f x), (f (f x)) etc. + +## `keep` +Function signature: + +``` +(keep ([f]) ([f coll])) +``` + +Returns a lazy sequence of the non-nil results of calling `f` on the +items of the `coll`. Returns a transducer when no collection is +provided. + +## `keep-indexed` +Function signature: + +``` +(keep-indexed ([f]) ([f coll])) +``` + +Returns a lazy sequence of the non-nil results of (f index item) in +the `coll`. Note, this means false return values will be included. +`f` must be free of side effects. Returns a transducer when no +collection is provided. + +## `line-seq` +Function signature: + +``` +(line-seq [file]) +``` + +Accepts a `file` handle, and creates a lazy sequence of lines using +`lines` metamethod. + +### Examples + +Lazy sequence of file lines may seem similar to an iterator over a +file, but the main difference is that sequence can be shared onve +realized, and iterator can't. Lazy sequence can be consumed in +iterator style with the `doseq` macro. + +Bear in mind, that since the sequence is lazy it should be realized or +truncated before the file is closed: + +``` fennel +(let [lines (with-open [f (io.open "cljlib.fnl" :r)] + (line-seq f))] + ;; this will error because only first line was realized, but the + ;; file was closed before the rest of lines were cached + (assert-not (pcall next lines))) +``` + +Sequence is realized with `doall` before file was closed and can be shared: + +``` fennel +(let [lines (with-open [f (io.open "cljlib.fnl" :r)] + (doall (line-seq f)))] + (assert-is (pcall next lines))) +``` + +Infinite files can't be fully realized, but can be partially realized +with `take`: + +``` fennel +(let [lines (with-open [f (io.open "/dev/urandom" :r)] + (doall (take 3 (line-seq f))))] + (assert-is (pcall next lines))) +``` + +## `list` +Function signature: + +``` +(list ...) +``` + +Create eager sequence of provided values. + +### Examples + +``` fennel +(local l (list 1 2 3 4 5)) +(assert-eq [1 2 3 4 5] l) +``` + +## `list*` +Function signature: + +``` +(list* [& args]) +``` + +Creates a new sequence containing the items prepended to the rest, +the last of which will be treated as a sequence. + +### Examples + +``` fennel +(local l (list* 1 2 3 [4 5])) +(assert-eq [1 2 3 4 5] l) +``` + +## `map` +Function signature: + +``` +(map ([f]) ([f coll]) ([f coll & 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. + +### Examples + +``` fennel +(map #(+ $ 1) [1 2 3]) ;; => @seq(2 3 4) +(map #(+ $1 $2) [1 2 3] [4 5 6]) ;; => @seq(5 7 9) +(def :private res (map #(+ $ 1) [:a :b :c])) ;; will raise an error only when realized +``` + +## `map-indexed` +Function signature: + +``` +(map-indexed ([f]) ([f coll])) +``` + +Returns a lazy sequence consisting of the result of applying `f` to 1 +and the first item of `coll`, followed by applying `f` to 2 and the +second item in `coll`, etc., until `coll` is exhausted. Returns a +transducer when no collection is provided. + +## `mapcat` +Function signature: + +``` +(mapcat ([f]) ([f & colls])) +``` + +Apply `concat` to the result of calling `map` with `f` and +collections `colls`. Returns a transducer when no collection is +provided. + +## `merge` +Function signature: + +``` +(merge [& maps]) +``` + +Merge `maps` rght to left into a single hash-map. + +## `next` +Function signature: + +``` +(next [s]) +``` + +Return the tail of a sequence. + +If the sequence is empty, returns nil. + +## `nth` +Function signature: + +``` +(nth ([coll i]) ([coll i not-found])) +``` + +Returns the value at the `index`. `get` returns `nil` if `index` out +of bounds, `nth` raises an error unless `not-found` is supplied. +`nth` also works for strings and sequences. + +## `nthnext` +Function signature: + +``` +(nthnext [coll n]) +``` + +Returns the nth next of `coll`, (seq coll) when `n` is 0. + +## `partition-all` +Function signature: + +``` +(partition-all ([n]) ([n coll]) ([n step coll])) +``` + +Given a collection `coll`, returns a lazy sequence of lists like +`partition`, but may include partitions with fewer than n items at the +end. Accepts addiitonal `step` argument, similarly to `partition`. +Returns a transducer, if collection is not supplied. + +## `partition-by` +Function signature: + +``` +(partition-by ([f]) ([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 +transducer, if collection is not supplied. + +## `persistent!` +Function signature: + +``` +(persistent! [coll]) +``` + +Returns a new, persistent version of the transient collection. The +transient collection cannot be used after this call, any such use will +raise an error. + +## `pop` +Function signature: + +``` +(pop [coll]) +``` + +If `coll` is a list returns a new list without the first +item. If `coll` is a vector, returns a new vector without the last +item. If the collection is empty, raises an error. Not the same as +`next` or `butlast`. + +## `pop!` +Function signature: + +``` +(pop! [coll]) +``` + +Removes the last item from a transient vector. If the collection is +empty, raises an error Returns coll + +## `random-sample` +Function signature: + +``` +(random-sample ([prob]) ([prob coll])) +``` + +Returns items from `coll` with random probability of `prob` (0.0 - +1.0). Returns a transducer when no collection is provided. + +## `realized?` +Function signature: + +``` +(realized? [s]) +``` + +Check if sequence's first element is realized. + +## `reduced?` +Function signature: + +``` +(reduced? [x]) +``` + +Returns true if `x` is the result of a call to reduced + +## `reductions` +Function signature: + +``` +(reductions ([f coll]) ([f init coll])) +``` + +Returns a lazy seq of the intermediate values of the reduction (as +per reduce) of `coll` by `f`, starting with `init`. + +## `remove` +Function signature: + +``` +(remove ([pred]) ([pred coll])) +``` + +Returns a lazy sequence of the items in the `coll` without elements +for wich `pred` returns logical true. Returns a transducer when no +collection is provided. + +## `repeat` +Function signature: + +``` +(repeat [x]) +``` + +Takes a value `x` and returns an infinite lazy sequence of this value. + +### Examples + +``` fennel +(assert-eq 20 (reduce add (take 10 (repeat 2)))) +``` + +## `repeatedly` +Function signature: + +``` +(repeatedly [f & args]) +``` + +Takes a function `f` and returns an infinite lazy sequence of +function applications. Rest arguments are passed to the function. + +## `replace` +Function signature: + +``` +(replace ([smap]) ([smap coll])) +``` + +Given a map of replacement pairs and a vector/collection `coll`, +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. + +## `rseq` +Function signature: + +``` +(rseq [rev]) +``` + +Returns, in possibly-constant time, a seq of the items in `rev` in reverse order. +Input must be traversable with `ipairs`. Doesn't work in constant +time if `rev` implements a linear-time `__len` metamethod, or invoking +Lua `#` operator on `rev` takes linar time. If `t` is empty returns +`nil`. + +### Examples + +``` fennel +(def :private v [1 2 3]) +(def :private r (rseq v)) + +(assert-eq (reverse v) r) +``` + +## `seq?` +Function signature: + +``` +(seq? [x]) +``` + +Check if object is a sequence. + +## `sequence` +Function signature: + +``` +(sequence ([coll]) ([xform coll]) ([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 an empty list, +When a transducer `xform` is supplied, returns a lazy sequence of +applications of the transform to the items in `coll`, 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 + +## `some?` +Function signature: + +``` +(some? [x]) +``` + +Returns true if x is not nil, false otherwise. + +## `sort` +Function signature: + +``` +(sort ([coll]) ([comparator coll])) +``` + +Returns a sorted sequence of the items in `coll`. If no `comparator` +is supplied, uses `<`. + +## `split-at` +Function signature: + +``` +(split-at [n coll]) +``` + +Return a table with sequence `coll` being split at `n` + +## `split-with` +Function signature: + +``` +(split-with [pred coll]) +``` + +Return a table with sequence `coll` being split with `pred` + +## `take-last` +Function signature: + +``` +(take-last [n coll]) +``` + +Return a sequence of last `n` elements of the `coll`. + +## `take-nth` +Function signature: + +``` +(take-nth ([n]) ([n coll])) +``` + +Return a lazy sequence of every `n` item in `coll`. Returns a +transducer when no collection is provided. + +## `take-while` +Function signature: + +``` +(take-while ([pred]) ([pred coll])) +``` + +Take the elements from the collection `coll` until `pred` returns logical +false for any of the elemnts. Returns a lazy sequence. Returns a +transducer when no collection is provided. + +## `transduce` +Function signature: + +``` +(transduce ([xform f coll]) ([xform f init coll])) +``` + +`reduce` with a transformation of `f` (`xform`). 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) `xform` to `init` and the first item in +`coll`, then applying `xform` 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` +Function signature: + +``` +(transient [coll]) +``` + +Returns a new, transient version of the collection. + +## `tree-seq` +Function signature: + +``` +(tree-seq [branch? children root]) +``` + +Returns a lazy sequence of the nodes in a tree, via a depth-first walk. + +`branch?` must be a function of one arg that returns true if passed a +node that can have children (but may not). `children` must be a +function 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. + +### Examples + +For the given tree `["A" ["B" ["D"] ["E"]] ["C" ["F"]]]`: + + A + / \ + B C + / \ \ + D E F + +Calling `tree-seq` with `next` as the `branch?` and `rest` as the +`children` returns a flat representation of a tree: + +``` fennel +(assert-eq (map first (tree-seq next rest ["A" ["B" ["D"] ["E"]] ["C" ["F"]]])) + ["A" "B" "D" "E" "C" "F"]) +``` + +## `unreduced` +Function signature: + +``` +(unreduced [x]) +``` + +If `x` is `reduced?`, returns `(deref x)`, else returns `x`. + +## `update` +Function signature: + +``` +(update [tbl key f]) +``` + +Update table value stored under `key` by calling a function `f` on +that value. `f` must take one argument, which will be a value stored +under the key in the table. + +### Examples + +Same as `assoc` but accepts function to produce new value based on key value. + +``` fennel +(assert-eq + {:data "THIS SHOULD BE UPPERCASE"} + (update {:data "this should be uppercase"} :data string.upper)) +``` + +## `update-in` +Function signature: + +``` +(update-in [tbl key-seq f]) +``` + +Update table value stored under set of immutable nested tables, via +given `key-seq` by calling a function `f` on the value stored under the +last key. `f` must take one argument, which will be a value stored +under the key in the table. Returns a new immutable table. + +### Examples + +Same as `assoc-in` but accepts function to produce new value based on key value. + +``` fennel +(fn capitalize-words [s] + (pick-values 1 + (s:gsub "(%a)([%w_`]*)" #(.. ($1:upper) ($2:lower))))) + +(assert-eq + {:user {:name "John Doe"}} + (update-in {:user {:name "john doe"}} [:user :name] capitalize-words)) +``` + +## `vec` +Function signature: + +``` +(vec [coll]) +``` + +Coerce collection `coll` to a vector. + +## `zipmap` +Function signature: + +``` +(zipmap [keys vals]) +``` + +Return an associative table with the `keys` mapped to the +corresponding `vals`. + + +--- + +Copyright (C) 2020-2021 Andrey Listopadov + +License: [MIT](https://gitlab.com/andreyorst/fennel-cljlib/-/raw/master/LICENSE) + + + diff --git a/doc/core.md b/doc/core.md deleted file mode 100644 index 578efef..0000000 --- a/doc/core.md +++ /dev/null @@ -1,2099 +0,0 @@ -# Core (v1.1.1) -Fennel-cljlib - functions from Clojure's core.clj implemented on top -of Fennel. - -This library contains a set of functions providing functions that -behave similarly to Clojure's equivalents. Library itself has nothing -Fennel specific, so it should work on Lua, e.g: - -``` lua -Lua 5.3.5 Copyright (C) 1994-2018 Lua.org, PUC-Rio -> clj = require"cljlib" -> table.concat(clj.mapv(function (x) return x * x end, {1, 2, 3}), " ") --- 1 4 9 -``` - -This example is mapping an anonymous `function` over a table, -producing new table and concatenating it with `" "`. - -However, this library also provides Fennel-specific set of -[macros](./macros.md), that provides additional facilities like `defn` -or `defmulti` which extend the language allowing writing code that -looks and works mostly like Clojure. - -Each function in this library is created with `defn`, which is a -special macro for creating multi-arity functions. So when you see -function signature like `(foo [x])`, this means that this is function -`foo`, that accepts exactly one argument `x`. In contrary, functions -created with `fn` will produce `(foo x)` signature (`x` is not inside -brackets). - -Functions, which signatures look like `(foo ([x]) ([x y]) ([x y & -zs]))`, it is a multi-arity function, which accepts either one, two, -or three-or-more arguments. Each `([...])` represents different body -of a function which is chosen by checking amount of arguments passed -to the function. See [Clojure's doc section on multi-arity -functions](https://clojure.org/guides/learn/functions#_multi_arity_functions). - -## Compatibility -This library is mainly developed with Lua 5.4, and tested against -Lua 5.2, 5.3, 5.4, and LuaJIT 2.1.0-beta3. Note, that in lua 5.2 and -LuaJIT equality semantics are a bit different from Lua 5.3 and Lua 5.4. -Main difference is that when comparing two tables, they must have -exactly the same `__eq` metamethods, so comparing hash sets with hash -sets will work, but comparing sets with other tables works only in -Lua5.3+. Another difference is that Lua 5.2 and LuaJIT don't have -inbuilt UTF-8 library, therefore [`seq`](#seq) function will not work for -non-ASCII strings. - -**Table of contents** - -- [`apply`](#apply) -- [`add`](#add) -- [`sub`](#sub) -- [`mul`](#mul) -- [`div`](#div) -- [`le`](#le) -- [`lt`](#lt) -- [`ge`](#ge) -- [`gt`](#gt) -- [`inc`](#inc) -- [`dec`](#dec) -- [`eq`](#eq) -- [`map?`](#map) -- [`vector?`](#vector) -- [`multifn?`](#multifn) -- [`set?`](#set) -- [`nil?`](#nil) -- [`zero?`](#zero) -- [`pos?`](#pos) -- [`neg?`](#neg) -- [`even?`](#even) -- [`odd?`](#odd) -- [`string?`](#string) -- [`boolean?`](#boolean) -- [`true?`](#true) -- [`false?`](#false) -- [`int?`](#int) -- [`pos-int?`](#pos-int) -- [`neg-int?`](#neg-int) -- [`double?`](#double) -- [`empty?`](#empty) -- [`not-empty`](#not-empty) -- [`vector`](#vector-1) -- [`seq`](#seq) -- [`first`](#first) -- [`rest`](#rest) -- [`last`](#last) -- [`butlast`](#butlast) -- [`conj`](#conj) -- [`disj`](#disj) -- [`cons`](#cons) -- [`concat`](#concat) -- [`reduce`](#reduce) -- [`reduced`](#reduced) -- [`reduce-kv`](#reduce-kv) -- [`mapv`](#mapv) -- [`filter`](#filter) -- [`every?`](#every) -- [`some`](#some) -- [`not-any?`](#not-any) -- [`range`](#range) -- [`reverse`](#reverse) -- [`take`](#take) -- [`nthrest`](#nthrest) -- [`partition`](#partition) -- [`identity`](#identity) -- [`comp`](#comp) -- [`complement`](#complement) -- [`constantly`](#constantly) -- [`memoize`](#memoize) -- [`assoc`](#assoc) -- [`hash-map`](#hash-map) -- [`get`](#get) -- [`get-in`](#get-in) -- [`keys`](#keys) -- [`vals`](#vals) -- [`find`](#find) -- [`dissoc`](#dissoc) -- [`remove-method`](#remove-method) -- [`remove-all-methods`](#remove-all-methods) -- [`methods`](#methods) -- [`get-method`](#get-method) -- [`hash-set`](#hash-set) -- [`assoc!`](#assoc-1) -- [`assoc-in`](#assoc-in) -- [`cat`](#cat) -- [`class`](#class) -- [`completing`](#completing) -- [`conj!`](#conj-1) -- [`contains?`](#contains) -- [`count`](#count) -- [`cycle`](#cycle) -- [`dedupe`](#dedupe) -- [`deref`](#deref) -- [`disj!`](#disj-1) -- [`dissoc!`](#dissoc-1) -- [`distinct`](#distinct) -- [`doall`](#doall) -- [`dorun`](#dorun) -- [`drop`](#drop) -- [`drop-last`](#drop-last) -- [`drop-while`](#drop-while) -- [`empty`](#empty-1) -- [`ensure-reduced`](#ensure-reduced) -- [`filterv`](#filterv) -- [`frequencies`](#frequencies) -- [`group-by`](#group-by) -- [`halt-when`](#halt-when) -- [`interleave`](#interleave) -- [`interpose`](#interpose) -- [`into`](#into) -- [`iterate`](#iterate) -- [`keep`](#keep) -- [`keep-indexed`](#keep-indexed) -- [`lazy-seq`](#lazy-seq) -- [`line-seq`](#line-seq) -- [`list`](#list) -- [`list*`](#list-1) -- [`map`](#map-1) -- [`map-indexed`](#map-indexed) -- [`mapcat`](#mapcat) -- [`merge`](#merge) -- [`next`](#next) -- [`nth`](#nth) -- [`nthnext`](#nthnext) -- [`partition-all`](#partition-all) -- [`partition-by`](#partition-by) -- [`persistent!`](#persistent) -- [`pop`](#pop) -- [`pop!`](#pop-1) -- [`random-sample`](#random-sample) -- [`realized?`](#realized) -- [`reduced?`](#reduced-1) -- [`reductions`](#reductions) -- [`remove`](#remove) -- [`repeat`](#repeat) -- [`repeatedly`](#repeatedly) -- [`replace`](#replace) -- [`rseq`](#rseq) -- [`seq?`](#seq-1) -- [`sequence`](#sequence) -- [`some?`](#some-1) -- [`sort`](#sort) -- [`split-at`](#split-at) -- [`split-with`](#split-with) -- [`take-last`](#take-last) -- [`take-nth`](#take-nth) -- [`take-while`](#take-while) -- [`transduce`](#transduce) -- [`transient`](#transient) -- [`tree-seq`](#tree-seq) -- [`unreduced`](#unreduced) -- [`update`](#update) -- [`update-in`](#update-in) -- [`vec`](#vec) -- [`zipmap`](#zipmap) - -## `apply` -Function signature: - -``` -(apply ([f args]) ([f a args]) ([f a b args]) ([f a b c args]) ([f a b c d & args])) -``` - -Apply `f` to the argument list formed by prepending intervening -arguments to `args`, and `f` must support variadic amount of -arguments. - -### Examples -Applying `add` to different amount of arguments: - -``` fennel -(assert-eq (apply add [1 2 3 4]) 10) -(assert-eq (apply add 1 [2 3 4]) 10) -(assert-eq (apply add 1 2 3 4 5 6 [7 8 9]) 45) -``` - -## `add` -Function signature: - -``` -(add ([]) ([a]) ([a b]) ([a b c]) ([a b c d]) ([a b c d & rest])) -``` - -Sum arbitrary amount of numbers. - -## `sub` -Function signature: - -``` -(sub ([]) ([a]) ([a b]) ([a b c]) ([a b c d]) ([a b c d & rest])) -``` - -Subtract arbitrary amount of numbers. - -## `mul` -Function signature: - -``` -(mul ([]) ([a]) ([a b]) ([a b c]) ([a b c d]) ([a b c d & rest])) -``` - -Multiply arbitrary amount of numbers. - -## `div` -Function signature: - -``` -(div ([a]) ([a b]) ([a b c]) ([a b c d]) ([a b c d & rest])) -``` - -Divide arbitrary amount of numbers. - -## `le` -Function signature: - -``` -(le ([a]) ([a b]) ([a b & [c d & more]])) -``` - -Returns true if nums are in monotonically non-decreasing order - -## `lt` -Function signature: - -``` -(lt ([a]) ([a b]) ([a b & [c d & more]])) -``` - -Returns true if nums are in monotonically decreasing order - -## `ge` -Function signature: - -``` -(ge ([a]) ([a b]) ([a b & [c d & more]])) -``` - -Returns true if nums are in monotonically non-increasing order - -## `gt` -Function signature: - -``` -(gt ([a]) ([a b]) ([a b & [c d & more]])) -``` - -Returns true if nums are in monotonically increasing order - -## `inc` -Function signature: - -``` -(inc [x]) -``` - -Increase number `x` by one - -## `dec` -Function signature: - -``` -(dec [x]) -``` - -Decrease number `x` by one - -## `eq` -Function signature: - -``` -(eq ([]) ([_]) ([a b]) ([a b & cs])) -``` - -Comparison function. - -Accepts arbitrary amount of values, and does the deep comparison. If -values implement `__eq` metamethod, tries to use it, by checking if -first value is equal to second value, and the second value is equal to -the first value. If values are not equal and are tables does the deep -comparison. Tables as keys are supported. - -## `map?` -Function signature: - -``` -(map? [x]) -``` - -Check whether `x` is an associative table. - -Non-empty tables are tested by calling `next`. If the length of the -table is greater than zero, the last integer key is passed to the -`next`, and if `next` returns a key, the table is considered -associative. If the length is zero, `next` is called with what `paris` -returns for the table, and if the key is returned, table is considered -associative. - -Empty tables can't be analyzed with this method, and `map?` will -always return `false`. If you need this test pass for empty table, -see `hash-map` for creating tables that have additional metadata -attached for this test to work. - -### Examples -Non-empty map: - -``` fennel -(assert-is (map? {:a 1 :b 2})) -``` - -Empty tables don't pass the test: - -``` fennel -(assert-not (map? {})) -``` - -Empty tables created with `hash-map` will pass the test: - -``` fennel -(assert-is (map? (hash-map))) -``` - -## `vector?` -Function signature: - -``` -(vector? [x]) -``` - -Check whether `tbl` is a sequential table. - -Non-empty sequential tables are tested for two things: -- `next` returns the key-value pair, -- key, that is returned by the `next` is equal to `1`. - -Empty tables can't be analyzed with this method, and `vector?` will -always return `false`. If you need this test pass for empty table, -see `vector` for creating tables that have additional -metadata attached for this test to work. - -### Examples -Non-empty vector: - -``` fennel -(assert-is (vector? [1 2 3 4])) -``` - -Empty tables don't pass the test: - -``` fennel -(assert-not (vector? [])) -``` - -Empty tables created with `vector` will pass the test: - -``` fennel -(assert-is (vector? (vector))) -``` - -## `multifn?` -Function signature: - -``` -(multifn? [mf]) -``` - -Test if `mf` is an instance of `multifn`. - -`multifn` is a special kind of table, created with `defmulti` macros -from `macros.fnl`. - -## `set?` -Function signature: - -``` -(set? [x]) -``` - -Check if object is a set. - -## `nil?` -Function signature: - -``` -(nil? ([]) ([x])) -``` - -Test if `x` is nil. - -## `zero?` -Function signature: - -``` -(zero? [x]) -``` - -Test if `x` is equal to zero. - -## `pos?` -Function signature: - -``` -(pos? [x]) -``` - -Test if `x` is greater than zero. - -## `neg?` -Function signature: - -``` -(neg? [x]) -``` - -Test if `x` is less than zero. - -## `even?` -Function signature: - -``` -(even? [x]) -``` - -Test if `x` is even. - -## `odd?` -Function signature: - -``` -(odd? [x]) -``` - -Test if `x` is odd. - -## `string?` -Function signature: - -``` -(string? [x]) -``` - -Test if `x` is a string. - -## `boolean?` -Function signature: - -``` -(boolean? [x]) -``` - -Test if `x` is a Boolean - -## `true?` -Function signature: - -``` -(true? [x]) -``` - -Test if `x` is `true` - -## `false?` -Function signature: - -``` -(false? [x]) -``` - -Test if `x` is `false` - -## `int?` -Function signature: - -``` -(int? [x]) -``` - -Test if `x` is a number without floating point data. - -Number is rounded with `math.floor` and compared with original number. - -## `pos-int?` -Function signature: - -``` -(pos-int? [x]) -``` - -Test if `x` is a positive integer. - -## `neg-int?` -Function signature: - -``` -(neg-int? [x]) -``` - -Test if `x` is a negative integer. - -## `double?` -Function signature: - -``` -(double? [x]) -``` - -Test if `x` is a number with floating point data. - -## `empty?` -Function signature: - -``` -(empty? [x]) -``` - -Check if collection is empty. - -## `not-empty` -Function signature: - -``` -(not-empty [x]) -``` - -If `x` is empty, returns `nil`, otherwise `x`. - -## `vector` -Function signature: - -``` -(vector [& args]) -``` - -Constructs sequential table out of its arguments. - -Sets additional metadata for function `vector?` to work. - -### Examples - -``` fennel -(def :private v (vector 1 2 3 4)) -(assert-eq v [1 2 3 4]) -``` - -## `seq` -Function signature: - -``` -(seq [coll]) -``` - -Construct a sequence from the given collection `coll`. If `coll` is -an associative table, returns sequence of vectors with key and value. -If `col` is sequential table, returns its shallow copy. If `col` is -string, return sequential table of its codepoints. - -### Examples -Sequential tables are transformed to sequences: - -``` fennel -(seq [1 2 3 4]) ;; @seq(1 2 3 4) -``` - -Associative tables are transformed to format like this `[[key1 value1] -... [keyN valueN]]` and order is non-deterministic: - -``` fennel -(seq {:a 1 :b 2 :c 3}) ;; @seq([:b 2] [:a 1] [:c 3]) -``` - -## `first` -Function signature: - -``` -(first [coll]) -``` - -Return first element of a `coll`. Calls `seq` on its argument. - -## `rest` -Function signature: - -``` -(rest [coll]) -``` - -Returns a sequence of all elements of a `coll` but the first one. -Calls `seq` on its argument. - -## `last` -Function signature: - -``` -(last [coll]) -``` - -Returns the last element of a `coll`. Calls `seq` on its argument. - -## `butlast` -Function signature: - -``` -(butlast [coll]) -``` - -Returns everything but the last element of the `coll` as a new - sequence. Calls `seq` on its argument. - -## `conj` -Function signature: - -``` -(conj ([]) ([s]) ([s x]) ([s x & xs])) -``` - -Insert `x` as a last element of a table `tbl`. - -If `tbl` is a sequential table or empty table, inserts `x` and -optional `xs` as final element in the table. - -If `tbl` is an associative table, that satisfies `map?` test, -insert `[key value]` pair into the table. - -Mutates `tbl`. - -### Examples -Adding to sequential tables: - -``` fennel -(conj [] 1 2 3 4) -;; => [1 2 3 4] -(conj [1 2 3] 4 5) -;; => [1 2 3 4 5] -``` - -Adding to associative tables: - -``` fennel -(conj {:a 1} [:b 2] [:c 3]) -;; => {:a 1 :b 2 :c 3} -``` - -Note, that passing literal empty associative table `{}` will not work: - -``` fennel -(conj {} [:a 1] [:b 2]) -;; => [[:a 1] [:b 2]] -(conj (hash-map) [:a 1] [:b 2]) -;; => {:a 1 :b 2} -``` - -See `hash-map` for creating empty associative tables. - -## `disj` -Function signature: - -``` -(disj ([Set]) ([Set key]) ([Set key & keys])) -``` - -Returns a new set type, that does not contain the -specified `key` or `keys`. - -## `cons` -Function signature: - -``` -(cons [head tail]) -``` - -Construct a cons cell. -Prepends new `head` to a `tail`, which must be either a table, -sequence, or nil. - -### Examples - -``` fennel -(assert-eq [0 1] (cons 0 [1])) -(assert-eq (list 0 1 2 3) (cons 0 (cons 1 (list 2 3)))) -``` - -## `concat` -Function signature: - -``` -(concat [& colls]) -``` - -Return a lazy sequence of concatenated `colls`. - -## `reduce` -Function signature: - -``` -(reduce ([f coll]) ([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. Early termination is supported via `reduced`. - -### Examples - -``` fennel -(defn- add - ([] 0) - ([a] a) - ([a b] (+ a b)) - ([a b & cs] (apply add (+ a b) cs))) -;; no initial value -(assert-eq 10 (reduce add [1 2 3 4])) -;; initial value -(assert-eq 10 (reduce add 1 [2 3 4])) -;; empty collection - function is called with 0 args -(assert-eq 0 (reduce add [])) -(assert-eq 10.3 (reduce math.floor 10.3 [])) -;; collection with a single element doesn't call a function unless the -;; initial value is supplied -(assert-eq 10.3 (reduce math.floor [10.3])) -(assert-eq 7 (reduce add 3 [4])) -``` - -## `reduced` -Function signature: - -``` -(reduced [value]) -``` - -Terminates the `reduce` early with a given `value`. - -### Examples - -``` fennel -(assert-eq :NaN - (reduce (fn [acc x] - (if (not= :number (type x)) - (reduced :NaN) - (+ acc x))) - [1 2 :3 4 5])) -``` - -## `reduce-kv` -Function signature: - -``` -(reduce-kv [f val s]) -``` - -Reduces an associative table using function `f` and initial value `val`. - -`f` should be a function of 3 arguments. Returns the result of -applying `f` to `val`, the first key and the first value in `tbl`, -then applying `f` to that result and the 2nd key and value, etc. If -`tbl` contains no entries, returns `val` and `f` is not called. Note -that `reduce-kv` is supported on sequential tables and strings, where -the keys will be the ordinals. - -Early termination is possible with the use of `reduced` -function. - -### Examples -Reduce associative table by adding values from all keys: - -``` fennel -(local t {:a1 1 - :b1 2 - :a2 2 - :b2 3}) - -(reduce-kv #(+ $1 $3) 0 t) -;; => 8 -``` - -Reduce table by adding values from keys that start with letter `a`: - -``` fennel -(local t {:a1 1 - :b1 2 - :a2 2 - :b2 3}) - -(reduce-kv (fn [res k v] (if (= (string.sub k 1 1) :a) (+ res v) res)) - 0 t) -;; => 3 -``` - -## `mapv` -Function signature: - -``` -(mapv ([f coll]) ([f coll & 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 collections are ignored. -Function `f` should accept number-of-colls arguments. - -## `filter` -Function signature: - -``` -(filter ([pred]) ([pred coll])) -``` - -Returns a lazy sequence of the items in `coll` for which -`pred` returns logical true. Returns a transducer when no collection -is provided. - -## `every?` -Function signature: - -``` -(every? [pred coll]) -``` - -Test if every item in `coll` satisfies the `pred`. - -## `some` -Function signature: - -``` -(some [pred coll]) -``` - -Test if any item in `coll` satisfies the `pred`. - -## `not-any?` -Function signature: - -``` -(not-any? [pred coll]) -``` - -Test if no item in `coll` satisfy the `pred`. - -## `range` -Function signature: - -``` -(range ([]) ([upper]) ([lower upper]) ([lower upper step])) -``` - -Returns lazy sequence of numbers from `lower` to `upper` with optional -`step`. - -## `reverse` -Function signature: - -``` -(reverse [coll]) -``` - -Returns a lazy sequence with same items as in `coll` but in reverse order. - -## `take` -Function signature: - -``` -(take ([n]) ([n coll])) -``` - -Returns a lazy sequence of the first `n` items in `coll`, or all items if -there are fewer than `n`. - -## `nthrest` -Function signature: - -``` -(nthrest [coll n]) -``` - -Returns the nth rest of `coll`, `coll` when `n` is 0. - -### Examples - -``` fennel -(assert-eq (nthrest [1 2 3 4] 3) [4]) -(assert-eq (nthrest [1 2 3 4] 2) [3 4]) -(assert-eq (nthrest [1 2 3 4] 1) [2 3 4]) -(assert-eq (nthrest [1 2 3 4] 0) [1 2 3 4]) -``` - -## `partition` -Function signature: - -``` -(partition ([n coll]) ([n step coll]) ([n step pad coll])) -``` - -Given a collection `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 up to `n` items. In case there are not enough padding -elements, return a partition with less than `n` items. - -## `identity` -Function signature: - -``` -(identity [x]) -``` - -Returns its argument. - -## `comp` -Function signature: - -``` -(comp ([]) ([f]) ([f g]) ([f g & fs])) -``` - -Compose functions. - -## `complement` -Function signature: - -``` -(complement [f]) -``` - -Takes a function `f` and returns the function that takes the same -amount of arguments as `f`, has the same effect, and returns the -opposite truth value. - -## `constantly` -Function signature: - -``` -(constantly [x]) -``` - -Returns a function that takes any number of arguments and returns `x`. - -## `memoize` -Function signature: - -``` -(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. - -## `assoc` -Function signature: - -``` -(assoc ([tbl]) ([tbl k v]) ([tbl k v & kvs])) -``` - -Associate `val` under a `key`. -Accepts extra keys and values. - -### Examples - -``` fennel -(assert-eq {:a 1 :b 2} (assoc {:a 1} :b 2)) -(assert-eq {:a 1 :b 2} (assoc {:a 1 :b 1} :b 2)) -(assert-eq {:a 1 :b 2 :c 3} (assoc {:a 1 :b 1} :b 2 :c 3)) -``` - -## `hash-map` -Function signature: - -``` -(hash-map [& kvs]) -``` - -Create associative table from `kvs` represented as sequence of keys -and values - -## `get` -Function signature: - -``` -(get ([tbl key]) ([tbl key not-found])) -``` - -Get value from the table by accessing it with a `key`. -Accepts additional `not-found` as a marker to return if value wasn't -found in the table. - -## `get-in` -Function signature: - -``` -(get-in ([tbl keys]) ([tbl keys not-found])) -``` - -Get value from nested set of tables by providing key sequence. -Accepts additional `not-found` as a marker to return if value wasn't -found in the table. - -## `keys` -Function signature: - -``` -(keys [coll]) -``` - -Returns a sequence of the map's keys, in the same order as `seq`. - -## `vals` -Function signature: - -``` -(vals [coll]) -``` - -Returns a sequence of the table's values, in the same order as `seq`. - -## `find` -Function signature: - -``` -(find [coll key]) -``` - -Returns the map entry for `key`, or `nil` if key is not present in -`coll`. - -## `dissoc` -Function signature: - -``` -(dissoc ([tbl]) ([tbl key]) ([tbl key & keys])) -``` - -Remove `key` from table `tbl`. Optionally takes more `keys`. - -## `remove-method` -Function signature: - -``` -(remove-method [multimethod dispatch-value]) -``` - -Remove method from `multimethod` for given `dispatch-value`. - -## `remove-all-methods` -Function signature: - -``` -(remove-all-methods [multimethod]) -``` - -Removes all methods of `multimethod` - -## `methods` -Function signature: - -``` -(methods [multimethod]) -``` - -Given a `multimethod`, returns a map of dispatch values -> dispatch fns - -## `get-method` -Function signature: - -``` -(get-method [multimethod dispatch-value]) -``` - -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. - -## `hash-set` -Function signature: - -``` -(hash-set [& xs]) -``` - -Create hash set. - -Set is a collection of unique elements, which sore purpose is only to -tell you if something is in the set or not. - -## `assoc!` -Function signature: - -``` -(assoc! [map k & ks]) -``` - -Remove `k`from transient map, and return `map`. - -## `assoc-in` -Function signature: - -``` -(assoc-in [tbl key-seq val]) -``` - -Associate `val` into set of immutable nested tables `t`, via given `key-seq`. -Returns a new immutable table. Returns a new immutable table. - -### Examples - -Replace value under nested keys: - -``` fennel -(assert-eq - {:a {:b {:c 1}}} - (assoc-in {:a {:b {:c 0}}} [:a :b :c] 1)) -``` - -Create new entries as you go: - -``` fennel -(assert-eq - {:a {:b {:c 1}} :e 2} - (assoc-in {:e 2} [:a :b :c] 1)) -``` - -## `cat` -Function signature: - -``` -(cat [rf]) -``` - -A transducer which concatenates the contents of each input, which must be a - collection, into the reduction. Accepts the reducing function `rf`. - -## `class` -Function signature: - -``` -(class [x]) -``` - -Return cljlib type of the `x`, or lua type. - -## `completing` -Function signature: - -``` -(completing ([f]) ([f cf])) -``` - -Takes a reducing function `f` of 2 args and returns a function -suitable for transduce by adding an arity-1 signature that calls -`cf` (default - `identity`) on the result argument. - -## `conj!` -Function signature: - -``` -(conj! ([]) ([coll]) ([coll x])) -``` - -Adds `x` to the transient collection, and return `coll`. - -## `contains?` -Function signature: - -``` -(contains? [coll elt]) -``` - -Test if `elt` is in the `coll`. It may be a linear search depending -on the type of the collection. - -## `count` -Function signature: - -``` -(count [s]) -``` - -Count amount of elements in the sequence. - -## `cycle` -Function signature: - -``` -(cycle [coll]) -``` - -Create a lazy infinite sequence of repetitions of the items in the -`coll`. - -## `dedupe` -Function signature: - -``` -(dedupe ([]) ([coll])) -``` - -Returns a lazy sequence removing consecutive duplicates in coll. -Returns a transducer when no collection is provided. - -## `deref` -Function signature: - -``` -(deref [x]) -``` - -Dereference an object. - -## `disj!` -Function signature: - -``` -(disj! ([Set]) ([Set key & ks])) -``` - -disj[oin]. Returns a transient set of the same type, that does not -contain `key`. - -## `dissoc!` -Function signature: - -``` -(dissoc! [map k & ks]) -``` - -Remove `k`from transient map, and return `map`. - -## `distinct` -Function signature: - -``` -(distinct ([]) ([coll])) -``` - -Returns a lazy sequence of the elements of the `coll` without -duplicates. Comparison is done by equality. Returns a transducer when -no collection is provided. - -## `doall` -Function signature: - -``` -(doall [seq]) -``` - -Realize whole lazy sequence `seq`. - -Walks whole sequence, realizing each cell. Use at your own risk on -infinite sequences. - -## `dorun` -Function signature: - -``` -(dorun [seq]) -``` - -Realize whole sequence `seq` for side effects. - -Walks whole sequence, realizing each cell. Use at your own risk on -infinite sequences. - -## `drop` -Function signature: - -``` -(drop ([n]) ([n coll])) -``` - -Drop `n` elements from collection `coll`, returning a lazy sequence -of remaining elements. Returns a transducer when no collection is -provided. - -## `drop-last` -Function signature: - -``` -(drop-last ([]) ([coll]) ([n coll])) -``` - -Return a lazy sequence from `coll` without last `n` elements. - -## `drop-while` -Function signature: - -``` -(drop-while ([pred]) ([pred coll])) -``` - -Drop the elements from the collection `coll` until `pred` returns logical -false for any of the elemnts. Returns a lazy sequence. Returns a -transducer when no collection is provided. - -## `empty` -Function signature: - -``` -(empty [x]) -``` - -Get an empty variant of a given collection. - -## `ensure-reduced` -Function signature: - -``` -(ensure-reduced [x]) -``` - -If x is already reduced?, returns it, else returns (reduced x) - -## `filterv` -Function signature: - -``` -(filterv [pred coll]) -``` - -Returns a vector of the items in `coll` for which -`pred` returns logical true. - -## `frequencies` -Function signature: - -``` -(frequencies [t]) -``` - -Return a table of unique entries from table `t` associated to amount -of their appearances. - -### Examples - -Count each entry of a random letter: - -``` fennel -(let [fruits [:banana :banana :apple :strawberry :apple :banana]] - (assert-eq (frequencies fruits) - {:banana 3 - :apple 2 - :strawberry 1})) -``` - -## `group-by` -Function signature: - -``` -(group-by [f t]) -``` - -Group table items in an associative table under the keys that are -results of calling `f` on each element of sequential table `t`. -Elements that the function call resulted in `nil` returned in a -separate table. - -### Examples - -Group rows by their date: - -``` fennel -(local rows - [{:date "2007-03-03" :product "pineapple"} - {:date "2007-03-04" :product "pizza"} - {:date "2007-03-04" :product "pineapple pizza"} - {:date "2007-03-05" :product "bananas"}]) - -(assert-eq (group-by #(. $ :date) rows) - {"2007-03-03" - [{:date "2007-03-03" :product "pineapple"}] - "2007-03-04" - [{:date "2007-03-04" :product "pizza"} - {:date "2007-03-04" :product "pineapple pizza"}] - "2007-03-05" - [{:date "2007-03-05" :product "bananas"}]}) -``` - -## `halt-when` -Function signature: - -``` -(halt-when ([pred]) ([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. - -## `interleave` -Function signature: - -``` -(interleave ([]) ([s]) ([s1 s2]) ([s1 s2 & ss])) -``` - -Returns a lazy sequence of the first item in each sequence, then the -second one, until any sequence exhausts. - -## `interpose` -Function signature: - -``` -(interpose ([sep]) ([separator coll])) -``` - -Returns a lazy sequence of the elements of `coll` separated by -`separator`. Returns a transducer when no collection is provided. - -## `into` -Function signature: - -``` -(into ([]) ([to]) ([to from]) ([to xform from])) -``` - -Returns a new coll consisting of `to` with all of the items of `from` -conjoined. A transducer `xform` may be supplied. - -### Examples - -Insert items of one collection into another collection: - -```fennel -(assert-eq [1 2 3 :a :b :c] (into [1 2 3] "abc")) -(assert-eq {:a 2 :b 3} (into {:a 1} {:a 2 :b 3})) -``` - -Transform a hash-map into a sequence of key-value pairs: - -``` fennel -(assert-eq [[:a 1]] (into (vector) {:a 1})) -``` - -You can also construct a hash-map from a sequence of key-value pairs: - -``` fennel -(assert-eq {:a 1 :b 2 :c 3} - (into (hash-map) [[:a 1] [:b 2] [:c 3]])) -``` - -## `iterate` -Function signature: - -``` -(iterate [f x]) -``` - -Returns an infinete lazy sequence of x, (f x), (f (f x)) etc. - -## `keep` -Function signature: - -``` -(keep ([f]) ([f coll])) -``` - -Returns a lazy sequence of the non-nil results of calling `f` on the -items of the `coll`. Returns a transducer when no collection is -provided. - -## `keep-indexed` -Function signature: - -``` -(keep-indexed ([f]) ([f coll])) -``` - -Returns a lazy sequence of the non-nil results of (f index item) in -the `coll`. Note, this means false return values will be included. -`f` must be free of side effects. Returns a transducer when no -collection is provided. - -## `lazy-seq` -Function signature: - -``` -(lazy-seq [f]) -``` - -Create lazy sequence from the result of calling a function `f`. -Delays execution of `f` until sequence is consumed. `f` must return a -sequence or a vector. - -## `line-seq` -Function signature: - -``` -(line-seq [file]) -``` - -Accepts a `file` handle, and creates a lazy sequence of lines using -`lines` metamethod. - -### Examples - -Lazy sequence of file lines may seem similar to an iterator over a -file, but the main difference is that sequence can be shared onve -realized, and iterator can't. Lazy sequence can be consumed in -iterator style with the `doseq` macro. - -Bear in mind, that since the sequence is lazy it should be realized or -truncated before the file is closed: - -``` fennel -(let [lines (with-open [f (io.open "init.fnl" :r)] - (line-seq f))] - ;; this will error because only first line was realized, but the - ;; file was closed before the rest of lines were cached - (assert-not (pcall next lines))) -``` - -Sequence is realized with `doall` before file was closed and can be shared: - -``` fennel -(let [lines (with-open [f (io.open "init.fnl" :r)] - (doall (line-seq f)))] - (assert-is (pcall next lines))) -``` - -Infinite files can't be fully realized, but can be partially realized -with `take`: - -``` fennel -(let [lines (with-open [f (io.open "/dev/urandom" :r)] - (doall (take 3 (line-seq f))))] - (assert-is (pcall next lines))) -``` - -## `list` -Function signature: - -``` -(list ...) -``` - -Create eager sequence of provided values. - -### Examples - -``` fennel -(local l (list 1 2 3 4 5)) -(assert-eq [1 2 3 4 5] l) -``` - -## `list*` -Function signature: - -``` -(list* [& args]) -``` - -Creates a new sequence containing the items prepended to the rest, -the last of which will be treated as a sequence. - -### Examples - -``` fennel -(local l (list* 1 2 3 [4 5])) -(assert-eq [1 2 3 4 5] l) -``` - -## `map` -Function signature: - -``` -(map ([f]) ([f coll]) ([f coll & 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. - -### Examples - -``` fennel -(map #(+ $ 1) [1 2 3]) ;; => @seq(2 3 4) -(map #(+ $1 $2) [1 2 3] [4 5 6]) ;; => @seq(5 7 9) -(def :private res (map #(+ $ 1) [:a :b :c])) ;; will raise an error only when realized -``` - -## `map-indexed` -Function signature: - -``` -(map-indexed ([f]) ([f coll])) -``` - -Returns a lazy sequence consisting of the result of applying `f` to 1 -and the first item of `coll`, followed by applying `f` to 2 and the -second item in `coll`, etc., until `coll` is exhausted. Returns a -transducer when no collection is provided. - -## `mapcat` -Function signature: - -``` -(mapcat ([f]) ([f & colls])) -``` - -Apply `concat` to the result of calling `map` with `f` and -collections `colls`. Returns a transducer when no collection is -provided. - -## `merge` -Function signature: - -``` -(merge [& maps]) -``` - -Merge `maps` rght to left into a single hash-map. - -## `next` -Function signature: - -``` -(next [s]) -``` - -Return the tail of a sequence. - -If the sequence is empty, returns nil. - -## `nth` -Function signature: - -``` -(nth ([coll i]) ([coll i not-found])) -``` - -Returns the value at the `index`. `get` returns `nil` if `index` out -of bounds, `nth` raises an error unless `not-found` is supplied. -`nth` also works for strings and sequences. - -## `nthnext` -Function signature: - -``` -(nthnext [coll n]) -``` - -Returns the nth next of `coll`, (seq coll) when `n` is 0. - -## `partition-all` -Function signature: - -``` -(partition-all ([n]) ([n coll]) ([n step coll])) -``` - -Given a collection `coll`, returns a lazy sequence of lists like -`partition`, but may include partitions with fewer than n items at the -end. Accepts addiitonal `step` argument, similarly to `partition`. -Returns a transducer, if collection is not supplied. - -## `partition-by` -Function signature: - -``` -(partition-by ([f]) ([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 -transducer, if collection is not supplied. - -## `persistent!` -Function signature: - -``` -(persistent! [coll]) -``` - -Returns a new, persistent version of the transient collection. The -transient collection cannot be used after this call, any such use will -raise an error. - -## `pop` -Function signature: - -``` -(pop [coll]) -``` - -If `coll` is a list returns a new list without the first -item. If `coll` is a vector, returns a new vector without the last -item. If the collection is empty, raises an error. Not the same as -`next` or `butlast`. - -## `pop!` -Function signature: - -``` -(pop! [coll]) -``` - -Removes the last item from a transient vector. If the collection is -empty, raises an error Returns coll - -## `random-sample` -Function signature: - -``` -(random-sample ([prob]) ([prob coll])) -``` - -Returns items from `coll` with random probability of `prob` (0.0 - -1.0). Returns a transducer when no collection is provided. - -## `realized?` -Function signature: - -``` -(realized? [s]) -``` - -Check if sequence's first element is realized. - -## `reduced?` -Function signature: - -``` -(reduced? [x]) -``` - -Returns true if `x` is the result of a call to reduced - -## `reductions` -Function signature: - -``` -(reductions ([f coll]) ([f init coll])) -``` - -Returns a lazy seq of the intermediate values of the reduction (as -per reduce) of `coll` by `f`, starting with `init`. - -## `remove` -Function signature: - -``` -(remove ([pred]) ([pred coll])) -``` - -Returns a lazy sequence of the items in the `coll` without elements -for wich `pred` returns logical true. Returns a transducer when no -collection is provided. - -## `repeat` -Function signature: - -``` -(repeat [x]) -``` - -Takes a value `x` and returns an infinite lazy sequence of this value. - -### Examples - -``` fennel -(assert-eq 20 (reduce add (take 10 (repeat 2)))) -``` - -## `repeatedly` -Function signature: - -``` -(repeatedly [f & args]) -``` - -Takes a function `f` and returns an infinite lazy sequence of -function applications. Rest arguments are passed to the function. - -## `replace` -Function signature: - -``` -(replace ([smap]) ([smap coll])) -``` - -Given a map of replacement pairs and a vector/collection `coll`, -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. - -## `rseq` -Function signature: - -``` -(rseq [rev]) -``` - -Returns, in possibly-constant time, a seq of the items in `rev` in reverse order. -Input must be traversable with `ipairs`. Doesn't work in constant -time if `rev` implements a linear-time `__len` metamethod, or invoking -Lua `#` operator on `rev` takes linar time. If `t` is empty returns -`nil`. - -### Examples - -``` fennel -(def :private v [1 2 3]) -(def :private r (rseq v)) - -(assert-eq (reverse v) r) -``` - -## `seq?` -Function signature: - -``` -(seq? [x]) -``` - -Check if object is a sequence. - -## `sequence` -Function signature: - -``` -(sequence ([coll]) ([xform coll]) ([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 an empty list, -When a transducer `xform` is supplied, returns a lazy sequence of -applications of the transform to the items in `coll`, 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 - -## `some?` -Function signature: - -``` -(some? [x]) -``` - -Returns true if x is not nil, false otherwise. - -## `sort` -Function signature: - -``` -(sort ([coll]) ([comparator coll])) -``` - -Returns a sorted sequence of the items in `coll`. If no `comparator` -is supplied, uses `<`. - -## `split-at` -Function signature: - -``` -(split-at [n coll]) -``` - -Return a table with sequence `coll` being split at `n` - -## `split-with` -Function signature: - -``` -(split-with [pred coll]) -``` - -Return a table with sequence `coll` being split with `pred` - -## `take-last` -Function signature: - -``` -(take-last [n coll]) -``` - -Return a sequence of last `n` elements of the `coll`. - -## `take-nth` -Function signature: - -``` -(take-nth ([n]) ([n coll])) -``` - -Return a lazy sequence of every `n` item in `coll`. Returns a -transducer when no collection is provided. - -## `take-while` -Function signature: - -``` -(take-while ([pred]) ([pred coll])) -``` - -Take the elements from the collection `coll` until `pred` returns logical -false for any of the elemnts. Returns a lazy sequence. Returns a -transducer when no collection is provided. - -## `transduce` -Function signature: - -``` -(transduce ([xform f coll]) ([xform f init coll])) -``` - -`reduce` with a transformation of `f` (`xform`). 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) `xform` to `init` and the first item in -`coll`, then applying `xform` 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` -Function signature: - -``` -(transient [coll]) -``` - -Returns a new, transient version of the collection. - -## `tree-seq` -Function signature: - -``` -(tree-seq [branch? children root]) -``` - -Returns a lazy sequence of the nodes in a tree, via a depth-first walk. - -`branch?` must be a function of one arg that returns true if passed a -node that can have children (but may not). `children` must be a -function 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. - -### Examples - -For the given tree `["A" ["B" ["D"] ["E"]] ["C" ["F"]]]`: - - A - / \ - B C - / \ \ - D E F - -Calling `tree-seq` with `next` as the `branch?` and `rest` as the -`children` returns a flat representation of a tree: - -``` fennel -(assert-eq (map first (tree-seq next rest ["A" ["B" ["D"] ["E"]] ["C" ["F"]]])) - ["A" "B" "D" "E" "C" "F"]) -``` - -## `unreduced` -Function signature: - -``` -(unreduced [x]) -``` - -If `x` is `reduced?`, returns `(deref x)`, else returns `x`. - -## `update` -Function signature: - -``` -(update [tbl key f]) -``` - -Update table value stored under `key` by calling a function `f` on -that value. `f` must take one argument, which will be a value stored -under the key in the table. - -### Examples - -Same as `assoc` but accepts function to produce new value based on key value. - -``` fennel -(assert-eq - {:data "THIS SHOULD BE UPPERCASE"} - (update {:data "this should be uppercase"} :data string.upper)) -``` - -## `update-in` -Function signature: - -``` -(update-in [tbl key-seq f]) -``` - -Update table value stored under set of immutable nested tables, via -given `key-seq` by calling a function `f` on the value stored under the -last key. `f` must take one argument, which will be a value stored -under the key in the table. Returns a new immutable table. - -### Examples - -Same as `assoc-in` but accepts function to produce new value based on key value. - -``` fennel -(fn capitalize-words [s] - (pick-values 1 - (s:gsub "(%a)([%w_`]*)" #(.. ($1:upper) ($2:lower))))) - -(assert-eq - {:user {:name "John Doe"}} - (update-in {:user {:name "john doe"}} [:user :name] capitalize-words)) -``` - -## `vec` -Function signature: - -``` -(vec [coll]) -``` - -Coerce collection `coll` to a vector. - -## `zipmap` -Function signature: - -``` -(zipmap [keys vals]) -``` - -Return an associative table with the `keys` mapped to the -corresponding `vals`. - - ---- - -Copyright (C) 2020-2021 Andrey Listopadov - -License: [MIT](https://gitlab.com/andreyorst/fennel-cljlib/-/raw/master/LICENSE) - - - diff --git a/doc/macros.md b/doc/macros.md deleted file mode 100644 index 9c20e56..0000000 --- a/doc/macros.md +++ /dev/null @@ -1,559 +0,0 @@ -# Macros (v1.1.1) -Macros for fennel-cljlib. - -**Table of contents** - -- [`cond`](#cond) -- [`def`](#def) -- [`defmethod`](#defmethod) -- [`defmulti`](#defmulti) -- [`defn`](#defn) -- [`defn-`](#defn-) -- [`fn*`](#fn) -- [`if-let`](#if-let) -- [`if-some`](#if-some) -- [`in-ns`](#in-ns) -- [`lazy-cat`](#lazy-cat) -- [`lazy-seq`](#lazy-seq) -- [`loop`](#loop) -- [`ns`](#ns) -- [`time`](#time) -- [`try`](#try) -- [`when-let`](#when-let) -- [`when-some`](#when-some) - -## `cond` -Function signature: - -``` -(cond ...) -``` - -Takes a set of test expression pairs. It evaluates each test one at a -time. If a test returns logical true, `cond` evaluates and returns -the value of the corresponding expression and doesn't evaluate any of -the other tests or exprs. `(cond)` returns nil. - -## `def` -Function signature: - -``` -(def ([name initializer]) ([meta name initializer])) -``` - -Name binding macro similar to `local` but acts in terms of current -namespace set with the `ns` macro, unless `:private` was passed before -the binding name. Accepts the `name` to be bound and the `initializer` -expression. `meta` can be either an associative table where keys are -strings, or a string representing a key from the table. If a sole -string is given, its value is set to `true` in the meta table. - -## `defmethod` -Function signature: - -``` -(defmethod multi-fn dispatch-value fnspec) -``` - -Attach new method to multi-function dispatch value. Accepts the -`multi-fn` as its first argument, the `dispatch-value` as second, and -`fnspec` - a function tail starting from argument list, followed by -function body as in [`fn*`](#fn). - -### Examples -Here are some examples how multimethods can be used. - -#### Factorial example -Key idea here is that multimethods can call itself with different -values, and will dispatch correctly. Here, `fac` recursively calls -itself with less and less number until it reaches `0` and dispatches -to another multimethod: - -``` fennel -(ns test) - -(defmulti fac (fn [x] x)) - -(defmethod fac 0 [_] 1) -(defmethod fac :default [x] (* x (fac (- x 1)))) - -(assert-eq (fac 4) 24) -``` - -`:default` is a special method which gets called when no other methods -were found for given dispatch value. - -#### Multi-arity dispatching -Multi-arity function tails are also supported: - -``` fennel -(ns test) - -(defmulti foo (fn* ([x] [x]) ([x y] [x y]))) - -(defmethod foo [10] [_] (print "I knew I'll get 10")) -(defmethod foo [10 20] [_ _] (print "I knew I'll get both 10 and 20")) -(defmethod foo :default ([x] (print (.. "Umm, got" x))) - ([x y] (print (.. "Umm, got both " x " and " y)))) -``` - -Calling `(foo 10)` will print `"I knew I'll get 10"`, and calling -`(foo 10 20)` will print `"I knew I'll get both 10 and 20"`. -However, calling `foo` with any other numbers will default either to -`"Umm, got x"` message, when called with single value, and `"Umm, got -both x and y"` when calling with two values. - -#### Dispatching on object's type -We can dispatch based on types the same way we dispatch on values. -For example, here's a naive conversion from Fennel's notation for -tables to Lua's one: - -``` fennel -(ns test) - -(defmulti to-lua-str (fn [x] (type x))) - -(defmethod to-lua-str :number [x] (tostring x)) -(defmethod to-lua-str :table [x] - (let [res []] - (each [k v (pairs x)] - (table.insert res (.. "[" (to-lua-str k) "] = " (to-lua-str v)))) - (.. "{" (table.concat res ", ") "}"))) -(defmethod to-lua-str :string [x] (.. "\"" x "\"")) -(defmethod to-lua-str :default [x] (tostring x)) - -(assert-eq (to-lua-str {:a {:b 10}}) "{[\"a\"] = {[\"b\"] = 10}}") - -(assert-eq (to-lua-str [:a :b :c [:d {:e :f}]]) - "{[1] = \"a\", [2] = \"b\", [3] = \"c\", [4] = {[1] = \"d\", [2] = {[\"e\"] = \"f\"}}}") -``` - -And if we call it on some table, we'll get a valid Lua table, which we -can then reformat as we want and use in Lua. - -All of this can be done with functions, and single entry point -function, that uses if statement and branches on the type, however one -of the additional features of multimethods, is that separate libraries -can extend such multimethod by adding additional claues to it without -needing to patch the source of the function. For example later on -support for userdata or coroutines can be added to `to-lua-str` -function as a separate multimethods for respective types. - -## `defmulti` -Function signature: - -``` -(defmulti name docstring? dispatch-fn options*) -``` - -Create multifunction `name` with runtime dispatching based on results -from `dispatch-fn`. Returns a proxy table with `__call` metamethod, -that calls `dispatch-fn` on its arguments. Amount of arguments -passed, should be the same as accepted by `dispatch-fn`. Looks for -multimethod based on result from `dispatch-fn`. - -Accepts optional `docstring?`, and `options*` arguments, where -`options*` is a sequence of key value pairs representing additional -attributes. Supported options: - -`:default` - the default dispatch value, defaults to `:default`. - -By default, multifunction has no multimethods, see -[`defmethod`](#defmethod) on how to add one. - -## `defn` -Function signature: - -``` -(defn ([name doc-string? [params*] pre-post? body]) ([name doc-string? ([params*] pre-post? body) +])) -``` - -Same as `(def name (fn* name docstring? [params*] pre-post? exprs*))` -or `(def name (fn* name docstring? ([params*] pre-post? exprs*)+))` -with any doc-string or attrs added to the function metadata. Accepts -`name` which will be used to refer to a function in the current -namespace, and optional `doc-string?`, a vector of function's -`params*`, `pre-post?` conditions, and the `body` of the function. -The body is wrapped in an implicit do. See `fn*` for more info. - -## `defn-` -Function signature: - -``` -(defn- ([name doc-string? [params*] pre-post? body]) ([name doc-string? ([params*] pre-post? body) +])) -``` - -Same as `(def :private name (fn* name docstring? [params*] pre-post? -exprs*))` or `(def :private name (fn* name docstring? ([params*] -pre-post? exprs*)+))` with any doc-string or attrs added to the -function metadata. Accepts `name` which will be used to refer to a -function, and optional `doc-string?`, a vector of function's -`params*`, `pre-post?` conditions, and the `body` of the function. -The body is wrapped in an implicit do. See `fn*` for more info. - -## `fn*` -Function signature: - -``` -(fn* ([name doc-string? [params*] pre-post? body]) ([name doc-string? ([params*] pre-post? body) +])) -``` - -Clojure-inspired `fn` macro for defining functions. -Accepts an optional `name` and `docstring?`, followed by the binding -list containing function's `params*`. The `body` is wrapped in an -implicit `do`. The `doc-string?` argument specifies an optional -documentation for the function. Supports multi-arity dispatching via -the following syntax: - -(fn* optional-name - optional-docstring - ([arity1] body1) - ([other arity2] body2)) - -Accepts `pre-post?` conditions in a form of a table after argument -list: - -(fn* optional-name - optional-docstring - [arg1 arg2] - {:pre [(check1 arg1 arg2) (check2 arg1)] - :post [(check1 $) ... (checkN $)]} - body) - -The same syntax applies to multi-arity version. - -(pre- and post-checks are not yet implemented) - -## `if-let` -Function signature: - -``` -(if-let [name test] if-branch else-branch) -``` - -When `test` is logical `true`, evaluates the `if-branch` with `name` -bound to the value of `test`. Otherwise, evaluates the `else-branch` - -## `if-some` -Function signature: - -``` -(if-some [name test] if-branch else-branch) -``` - -When `test` is not `nil`, evaluates the `if-branch` with `name` -bound to the value of `test`. Otherwise, evaluates the `else-branch` - -## `in-ns` -Function signature: - -``` -(in-ns name) -``` - -Sets the compile-time variable `cljlib-namespaces` to the given `name`. -Affects such macros as `def`, `defn`, which will bind names to the -specified namespace. - -### Examples -Creating several namespaces in the file, and defining functions in each: - -``` fennel -(ns a) -(defn f [] "f from a") -(ns b) -(defn f [] "f from b") -(in-ns a) -(defn g [] "g from a") -(in-ns b) -(defn g [] "g from b") - -(assert-eq (a.f) "f from a") -(assert-eq (b.f) "f from b") -(assert-eq (a.g) "g from a") -(assert-eq (b.g) "g from b") -``` - -Note, switching namespaces in the REPL doesn't affect non-namespaced -local bindings. In other words, when defining a local with `def`, a -bot a local binding and a namespaced binding are created, and -switching current namespace won't change the local binding: - -``` fennel ->> (ns foo) -nil ->> (def x 42) -nil ->> (ns bar) -nil ->> (def x 1337) -nil ->> (in-ns foo) -# ->> x ; user might have expected to see 42 here -1337 ->> foo.x -42 ->> bar.x -1337 -``` - -Sadly, Fennel itself has no support for namespace switching in REPL, -so this feature can be only partially emulated by the cljlib library. - -## `lazy-cat` -Function signature: - -``` -(lazy-cat & colls) -``` - -Expands to code which yields a lazy sequence of the concatenation of -`colls` - expressions returning collections. Each expression is not -evaluated until it is needed. - -## `lazy-seq` -Function signature: - -``` -(lazy-seq & body) -``` - -Takes a `body` of expressions that returns a sequence, table or nil, -and yields a lazy sequence 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?` - -## `loop` -Function signature: - -``` -(loop binding-vec body*) -``` - -Recursive loop macro. - -Similar to `let`, but binds a special `recur` call that will reassign -the values of the `binding-vec` and restart the loop `body*`. Unlike -`let`, doesn't support multiple-value destructuring. - -The first argument is a binding table with alternating symbols (or destructure -forms), and the values to bind to them. - -For example: - -``` fennel -(loop [[first & rest] [1 2 3 4 5] - i 0] - (if (= nil first) - i - (recur rest (+ 1 i)))) -``` - -This would destructure the first table argument, with the first value inside it -being assigned to `first` and the remainder of the table being assigned to -`rest`. `i` simply gets bound to 0. - -The body of the form executes for every item in the table, calling `recur` each -time with the table lacking its head element (thus consuming one element per -iteration), and with `i` being called with one value greater than the previous. - -When the loop terminates (When the user doesn't call `recur`) it will return the -number of elements in the passed in table. (In this case, 5) - -### Limitations - -In order to only evaluate expressions once and support sequential -bindings, the binding table has to be transformed like this: - -``` fennel -(loop [[x & xs] (foo) - y (+ x 1)] - ...) - -(let [_1_ (foo) - [x & xs] _1_ - _2_ (+ x 1) - y _2_] - ((fn recur [[x & xs] y] ...) _1_ _2_) -``` - -This ensures that `foo` is called only once, its result is cached in a -`sym1#` binding, and that `y` can use the destructured value, obtained -from that binding. The value of this binding is later passed to the -function to begin the first iteration. - -This has two unfortunate consequences. One is that the initial -destructuring happens twice - first, to make sure that later bindings -can be properly initialized, and second, when the first looping -function call happens. Another one is that as a result, `loop` macro -can't work with multiple-value destructuring, because these can't be -cached as described above. E.g. this will not work: - -``` fennel -(loop [(x y) (foo)] ...) -``` - -Because it would be transformed to: - -``` fennel -(let [_1_ (foo) - (x y) _1_] - ((fn recur [(x y)] ...) _1_) -``` - -`x` is correctly set, but `y` is completely lost. Therefore, this -macro checks for lists in bindings. - -## `ns` -Function signature: - -``` -(ns name commentary requirements) -``` - -Namespace declaration macro. -Accepts the `name` of the generated namespace, and creates a local -variable with this name holding a table. Optionally accepts -`commentary` describing what namespace is about and a `requirements` -spec, specifying what libraries should be required. - -The `requirements` spec is a list that consists of vectors, specifying -library name and a possible alias or a vector of names to refer to -without a prefix: - -``` fennel -(ns some-namespace - "Description of the some-namespace." - (:require [some.lib] - [some.other.lib :as lib2] - [another.lib :refer [foo bar baz]])) - -(defn inc [x] (+ x 1)) -``` - -Which is equivalent to: - -``` fennel -(local some-namespace {}) -(local lib (require :some.lib)) -(local lib2 (require :some.other.lib)) -(local {:bar bar :baz baz :foo foo} (require :another.lib)) -(comment "Description of the some-namespace.") -``` - -Note that when no `:as` alias is given, the library will be named -after the innermost part of the require path, i.e. `some.lib` is -transformed to `lib`. - -See `in-ns` on how to switch namespaces. - -## `time` -Function signature: - -``` -(time expr) -``` - -Measure the CPU time spent executing `expr`. - -## `try` -Function signature: - -``` -(try body* catch-clause* finally-clause?) -``` - -General purpose try/catch/finally macro. -Wraps its body in `pcall` and checks the return value with `match` -macro. - -Catch clause is written either as `(catch symbol body*)`, thus acting -as catch-all, or `(catch value body*)` for catching specific errors. -It is possible to have several `catch` clauses. If no `catch` clauses -specified, an implicit catch-all clause is created. `body*`, and -inner expressions of `catch-clause*`, and `finally-clause?` are -wrapped in implicit `do`. - -The `finally` clause is optional, and written as (finally body*). If -present, it must be the last clause in the [`try`](#try) form, and the only -`finally` clause. Note that `finally` clause is for side effects -only, and runs either after succesful run of [`try`](#try) body, or after any -`catch` clause body, before returning the result. If no `catch` -clause is provided `finally` runs in implicit catch-all clause, and -trows error to upper scope using `error` function. - -To throw error from [`try`](#try) to catch it with `catch` clause use `error` -or `assert` functions. - -### Examples -Catch all errors, ignore those and return fallback value: - -``` fennel -(fn add [x y] - (try - (+ x y) - (catch _ 0))) - -(assert-eq (add nil 1) 0) -``` - -Catch error and do cleanup: - -``` fennel -(local tbl []) - -(try - (table.insert tbl "a") - (table.insert tbl "b" "c") - (catch _ - (each [k _ (pairs tbl)] - (tset tbl k nil)))) - -(assert-eq (length tbl) 0) - -``` - -Always run some side effect action: - -``` fennel -(local t []) -(local res (try 10 (finally (table.insert t :finally)))) -(assert-eq (. t 1) :finally) -(assert-eq res 10) - -(local res (try (error 10) (catch 10 nil) (finally (table.insert t :again)))) -(assert-eq (. t 2) :again) -(assert-eq res nil) -``` - -## `when-let` -Function signature: - -``` -(when-let [name test] & body) -``` - -When `test` is logical `true`, evaluates the `body` with `name` bound -to the value of `test`. - -## `when-some` -Function signature: - -``` -(when-some [name test] & body) -``` - -When `test` is not `nil`, evaluates the `body` with `name` bound to -the value of `test`. - - ---- - -Copyright (C) 2020-2021 Andrey Listopadov - -License: [MIT](https://gitlab.com/andreyorst/fennel-cljlib/-/raw/master/LICENSE) - - - -- cgit v1.2.3