<?php
    //IteratorAggregate Generators

    //事例(一)
    class Language implements IteratorAggregate{
        private $names;
        public function __construct(){
            $this->names = explode(',','PHP,JS,JAVA,GO');
        }
        public function getIterator(){
            return new ArrayIterator($this->names);
        }

    }

    $langs = new Language();

    foreach($langs as $lang){
        echo $lang.PHP_EOL;
    }

    //事例(二) 返回一个外部迭代器，可以对数据本身及相关逻辑做更统一的封装
    class Test implements IteratorAggregate{
        private $data;
        public function __construct(array $data){
            $this->data = $data;
        }
        public function getIterator(){
            foreach($this->data as $key=>$value){
                yield $key=>$value;
            }
        }
    }

    $testArr = array(
        'xd'=>100,
        'action'=>123,
        'xingd'=>126
    );
    $test = new Test($testArr);

    foreach($test as $key=>$value){
        echo $key.'-'.$value.PHP_EOL;
    }