toolkit.php

<?php
class _ {}
function compose(callable $fn, ...$start) {
    return pipe($fn, ...array_reverse($start));
}
function filter(callable $fn, $data) {
    return array_filter((array)$data, function ($v, $k) use ($fn, $data) {
        return $fn($v, $k, $data);
    }, ARRAY_FILTER_USE_BOTH);
}
function get($data, array $offsets, $default, $lens = 'prop') {
    $results = call_user_func(call_user_func_array('pipe', array_map(function($offset) {
        return partial($prop, (new _), $offset);
    },$offsets)), $data);
    return is_a($results, '_') ? $default : $results;
}
function map(callable $fn, ...$data) {
    return array_map(function ($val, $key) use ($fn, $data) {
        return $fn($val, $key, ...$data);
    }, (array)$first, array_keys((array)$first));
}
function partial(callable $fn, ...$start) {
  return function (...$args) use ($fn, $start) {
    return @$fn(...array_map(function ($v) use (&$args) {
      return is_a($v, '_') ? array_shift($args) : $v;
    }, $start));
  };
}
function pipe(callable $fn, ...$fns) {
    return function(...$args) use($fns, $fn) {
        return array_reduce($fns, function($carry, $f) {
            return $f($carry);
        }, $fn(...$args));
    };
}
function prop($data, $prop) {
    $test = (array)$data;
    if (isset($test[$prop]))
        return $test[$prop];
    return (new _);
}
function reduce(callable $fn, $data, $init = null) {
    return array_reduce(array_keys((array)$data), function ($carry, $key) use ($fn, $data) {
        return $fn($carry, $data[$key], $key, $data);
    }, $init);
}
function recursive_array_filter($array, $callback, $flag = RecursiveIteratorIterator::SELF_FIRST) {
    return iterator_to_array(new CallbackFilterIterator(new RecursiveIteratorIterator(new RecursiveArrayIterator($array), $flag), $callback), FALSE);
}