This library implements iteration primitives like map() and filter()
using generators. To a large part this serves as a repository for small
examples of generator usage, but of course the functions are also practically
quite useful.
All functions in this library accept arbitrary iterables, i.e. arrays,
traversables, iterators and aggregates, which makes it quite different from
functions like array_map() (which only accept arrays) and the SPL iterators
(which usually only accept iterators, not even aggregates). The operations are
of course lazy.
A small usage example for the map() and range() functions:
<?php
use iter, iter\fn;
// require 'path/to/src/bootstrap.php'; has to happen somewhere
$nums = iter\range(1, 10);
$numsTimesTen = iter\map(fn\operator('*', 10), $nums);
// => iter(10, 20, 30, 40, 50, 60, 70, 80, 90, 100)You can find documentation and usage examples for the individual functions in iter.php, here I only list the function signatures as an overview:
Iterator range(number $start, number $end, number $step = null)
Iterator map(callable $function, iterable $iterable)
void apply(callable $function, iterable $iterable)
Iterator filter(callable $predicate, iterable $iterable)
mixed reduce(callable $function, iterable $iterable, mixed $startValue = null)
Iterator zip(iterable... $iterables)
Iterator zipKeyValue(iterable $keys, iterable $values)
Iterator chain(iterable... $iterables)
Iterator slice(iterable $iterable, int $start, int $length = INF)
Iterator take(int $num, iterable $iterable)
Iterator drop(int $num, iterable $iterable)
Iterator repeat(mixed $value, int $num = INF)
Iterator keys(iterable $iterable)
Iterator values(iterable $iterable)
bool any(callable $predicate, iterable $iterable)
bool all(callable $predicate, iterable $iterable)
Iterator takeWhile(callable $predicate, iterable $iterable)
Iterator dropWhile(callable $predicate, iterable $iterable)
int count(iterable $iterable)
Iterator toIter(iterable $iterable)
array toArray(iterable $iterable)
array toArrayWithKeys(iterable $iterable)
As the functionality is implemented using generators the resulting iterators are by default not rewindable. This library implements additional functionality to allow creating rewindable generators.
You can find documentation for this in iter.rewindable.php, here is just a small usage example of the two main functions:
<?php
use iter, iter\fn;
// require 'path/to/src/bootstrap.php';
/* Create a rewindable map function which can be used multiple times */
$rewindableMap = iter\makeRewindable('iter\\map');
$res = $rewindableMap(fn\operator('*', 3), [1, 2, 3]);
/* Do a rewindable call to map, just once */
$res = iter\callRewindable('iter\\map', fn\operator('*', 3), [1, 2, 3]);The above functions are only useful for your own generators though, for the
iter generators rewindable variants are directly provided with an
iter\rewindable prefix:
$res = iter\rewindable\map(fn\operator('*', 3), [1, 2, 3]);
// etc