Online PHP editor | refs for fqDZV

<?php function debugPrintFilter() { return function(\Traversable $input) { foreach ($input as $in) { var_dump($in); yield $in; } }; } function fooFilter() { return function(\Traversable $input) { foreach ($input as $in) { yield "foo"; } }; } function upperCaseStringFilter() { return function(\Traversable $input) { foreach ($input as $in) { yield strtoupper($in); } }; } class FilterPipeline implements \IteratorAggregate { protected $filters = []; protected $src; function __construct() { } function src(\Traversable $it) { $this->src = $it; return $this; } function pipe(callable $filter) { $this->filters[] = $filter; return $this; } function getIterator() { $it = $this->src; foreach ($this->filters as $filter) { $it = $filter($it); } return $it; } } $p = (new FilterPipeline) ->src(new \ArrayIterator(["foo", "bar", "baz"])) ->pipe(upperCaseStringFilter()) ->pipe(debugPrintFilter()) ->pipe(fooFilter()); foreach ($p as $val) { var_dump("Output", $val); }