RE: [PHP-GENERAL] Evaluation of statements

huh? which languages do you mean for example? C and Perl for example keep to the order in the statement (AFAIK at least...) -p > -----Original Message----- > From: Matthew Kendall [mailto:mdkendall@hotmail.com] > Sent: Mittwoch, 7. Juni 2000 18:59 > To: php-general@lists.php.net > Subject: [PHP-GENERAL] Evaluation of statements > > > In several places, including some tutorials at www.zend.com, I > have seen > example code that checks that a variable is set, then checks for a > particular value, all in one statement, like this: > > if (isset($foo) && $foo=="bar" ) { > do something; > } > > Is this right? In other languages that I am familiar with the > compiler (or > interpreter) does not guarantee the order of execution of the two > conditions. It is free to evaluate them in whatever order it likes. > Furthermore, even if it does evaluate them in the order given, > it is free to > evaluate both of them before deciding whether the compound condition is > true. This means that the second condition may be evaluated > even if $foo is > not set, which is an error (or at least a warning in PHP). It certainly > defeats the intention of the isset() check. > > Does the PHP parser really guarantee order of execution, and > guarantee to > stop evaluating the expressions in a condition once the > condition is false, > or should the code really be written: > > if (isset($foo)) { > if ($foo=="bar) { > do something; > } > } > > > > > -- > PHP General Mailing List (http://www.php.net/) > To unsubscribe, e-mail: php-general-unsubscribe@lists.php.net > For additional commands, e-mail: php-general-help@lists.php.net > To contact the list administrators, e-mail: > php-list-admin@lists.php.net > >