note 119275 added to language.generators.overview

Bear in mind that execution of a generator function is postponed until iteration over its result (the Generator object) begins. This might confuse one if the result of a generator is assigned to a variable instead of immediate iteration. <?php $some_state = 'initial'; function gen() { global $some_state; echo "gen() execution start\n"; $some_state = "changed"; yield 1; yield 2; } function peek_state() { global $some_state; echo "\$some_state = $some_state\n"; } echo "calling gen()...\n"; $result = gen(); echo "gen() was called\n"; peek_state(); echo "iterating...\n"; foreach ($result as $val) { echo "iteration: $val\n"; peek_state(); } ?> If you need to perform some action when the function is called and before the result is used, you'll have to wrap your generator in another function. <?php /** * @return Generator */ function some_generator() { global $some_state; $some_state = "changed"; return gen(); } ?> ---- Server IP: 72.52.91.14 Probable Submitter: 77.114.92.28 ---- Manual Page -- http://php.net/manual/en/language.generators.overview.php Edit -- https://master.php.net/note/edit/119275 Del: integrated -- https://master.php.net/note/delete/119275/integrated Del: useless -- https://master.php.net/note/delete/119275/useless Del: bad code -- https://master.php.net/note/delete/119275/bad+code Del: spam -- https://master.php.net/note/delete/119275/spam Del: non-english -- https://master.php.net/note/delete/119275/non-english Del: in docs -- https://master.php.net/note/delete/119275/in+docs Del: other reasons-- https://master.php.net/note/delete/119275 Reject -- https://master.php.net/note/reject/119275 Search -- https://master.php.net/manage/user-notes.php