Re: incrementing boolean values

Hello Derick, Sunday, June 5, 2005, 10:27:51 PM, you wrote: > On Sun, 5 Jun 2005, Johannes Schlueter wrote: >> Hi, >> >> PHP is a weak-typed language which casts in the background as required - at >> least most of the time. I recently found an exception which bugged me: >> >> $a = false; >> $a++; >> >> Here $a isn't casted to int or "incremented" to true but the incrementing >> has >> no effect. By checking zend_operators.c I saw that booleans had no explicit >> incrementing rule but uses just the default in the relevant switch. >> >> Looking a bit deeper it got quite interesting: NULL++ gives as result the >> integer one. This is fine for incrementing undefined variables but imho >> inconsistent with the behavior of false. NULL-- evaluates to NULL similar to >> false but different from NULL++. >> >> All this makes using PHP harder than needed. At least I spent quite some time >> finding that my variable was set to false instead of 0 (or NULL). >> >> I wrote the attached patch which allows in-/decrementing of simple types by >> casting bools and NULL to long. Yes, it would be a BC break but I don't think >> someone relies on false++ being false and it would make life simpler. >> >> Comments? > I did this a year or so ago, and after discussing with Andi we decided > not to promote types in this case. Not promoting types would mean adding false++, and true-- doesn't it? And again not doing this complicaates php needlessly. For example the two snippets below are different, tell me why: 1) if (($p=strpos(...)+1) > 0) ... 2) $p = strpos(...); $p++; if ($p > 0) ... Sidenote: Why is the following a parser error: if (($p=strpos(...))++ > 0) ... -- Best regards, Marcus mailto:mail@marcus-boerger.de