index.md

API

All functions are unitaries, exception when the second argument is optional. It has constants to help you to work with point-free style.

• all()
• allPass()
• always()
• any()
• anyPass()
• append()
• contains()
• compose()
• cond()
• divide()
• drop()
• equals()
• filter()
• find()
• flatten()
• gt()
• gte()
• has()
• head()
• id()
• ifElse()
• isEmpty()
• indexOf()
• init()
• join()
• last()
• lt()
• lte()
• map()
• memoize()
• merge()
• multiply()
• none()
• not()
• partial()
• pipe()
• prepend()
• prop()
• props()
• reduce()
• replace()
• slice()
• split()
• tail()
• take()
• toString()
• typeof()
• unless()
• when()

Constants from native functions

• keys
• values
• flip
• sum
• isNull
• isInt
• isFloat
• isNumeric
• isString
• isBool
• isScalar
• isArray
• isObject
• isCallable

---

all()

function all(callable $pred): \Closure;

function => closure([array]) => boolean

use const Prelude\isScalar;
use function Prelude\all;

$even = function ($n) {
    return $n % 2 === 0;
};

all($even)([2, 4, 6, 8, 10, 12]); // => true
all(isScalar)([1, 2, 3, 4]); // => true
all(isScalar)([1, 2, [], 4]); // => false

allPass()

function allPass(array $preds): \Closure;

function => closure => boolean

use function Prelude\partial;
use function Prelude\allPass;
use function Prelude\get;
use function Prelude\has;

$placeholders = [
   'to' => '[email protected]',
   'from' => '[email protected]'
];

$propEq = partial(function ($k, $v, array $xss) {
   return ($xss[$k] ?? false) === $v;
});

$y = allPass([has('from'), has('to')]);        
$y($placeholders); // => true

$x = allPass([$propEq('rank', 'Q'), $propEq('suit', '♠︎')]);

$x(['rank' => 'Q', 'suit' => '♠︎']); // => true
$x(['rank' => 'Q', 'suit' => '♣︎︎']); // => false

always()

function always($x): \Closure
{
    return function () use ($x) {
        return $x;
    };
}

any()

function any(callable $pred): \Closure;

function => closure([array]) => boolean

use function Prelude\any;

$isEven = function ($n) { return $n % 2 === 0; };
$isOdd = function ($n) { return $n % 2 === 1; };

any($isEven)([1, 3, 4, 5, 7]); // => true
any($isEven)([1, 3, 5, 7]); // => false

any($isOdd)([1, 3, 5, 7]); // => true
any($isOdd)([2, 4, 6]); // => false

any('is_array')([2, []]); // => true
any('is_array')(['s', 'x']); // => false

anyPass()

function anyPass(array $preds): \Closure;

[array] => closure(callable) => boolean

use function Prelude\anyPass;
use function Prelude\partial;
use function Prelude\equals;
use function Prelude\has;

$gt = partial(function ($a, $b) { return $a > $b; });
$gte = anyPass([$gt(3), equals(3)]);

$gte(2); // => true
$gte(3); // => true
$gte(4); // => false

$has = anyPass([has('user'), has('mobile')]);
$has(['user' => '']); // => true
$has(['mobile' => '']); // => true
$has([]); // => false

append()

function append($x): \Closure;

any => closure([array]) => [array]

use function Prelude\append;

append('tests')(['write', 'more']); // => ['write', 'more', 'tests']

$append = append(['tests']);
$append(['write', 'more']); // => ['write', 'more', ['tests']]

contains()

function contains($x): \Closure;

any => closure([array]) => bool

use function Prelude\Contains;

$ls = ['name' => 'James'];
contains('James')($ls); // => true
contains('Kirk')($ls); // => false

$nums = [10, 20, 30];
contains(10)($nums); // => true    

compose()

function compose(callable ...$callbacks): \Closure;

use function Prelude\compose;

$compose = compose(
    function ($x) {
        return "foo($x)";
    },
    function ($x) {
        return "bar($x)";
    },
    function ($x) {
        return "baz($x)";
    }
);

$compose('x'); // => foo(bar(baz(x)))

cond()

function cond(array $pairs): \Closure;

use const Prelude\id;
use function Prelude\cond;
use function Prelude\equals;
use function Prelude\always;

$fn = cond([
    [equals(0), always('water freezes at 0°C')],
    [equals(100), always('water boils at 100°C')],
    [always(true), function ($temp) {
        return 'nothing special happens at '.$temp.'°C';
    }]
]);

$fn(0); // => 'water freezes at 0°C'
$fn(50); // => 'nothing special happens at 50°C'
$fn(100); // => 'water boils at 100°C'

$fn = cond([
    [equals([]), always(true)]
]);

$fn(true); // => \Prelude\Exception\CondClauseException

divide()

function divide($x): \Closure;

use function Prelude\divide;

divide(10)(10); // => 1
divide(7)(2); // => 3.5

drop()

function drop(int $n): \Closure;

use function Prelude\drop;

drop(3)([1, 2, 3, 4, 5]); // => [4, 5]
drop(5)([1, 2, 3, 4, 5]); // => []

equals()

function equals($x): \Closure;

use function Prelude\equals;

equals(true)(true); // => true
equals(1)(1); // => true
equals("1")(1); // => false
equals("true")(true); // => false

$isTrue = equals(true);
$isTrue(true); // => true
$isTrue(false); // => false

filter()

function filter(callable $callback): \Closure;

use function Prelude\filter;
use function Prelude\equals;

$names = ['James' => true, 'Kirk' => false];

$istrue = filter(equals(true));

$istrue($names); // => ['James' => true]

find()

function find(callable $callback): \Closure;

use function Prelude\find;

$values = [100, 200, 300, 400];

$isGreaterThan200 = function (int $n) { return $n > 200; };

find($isGreaterThan200)($values); // => 300