Req #24949 [Com]: Requesting nicer way of setting undefined variables to default val. ifsetor / ?:

Edit report at http://bugs.php.net/bug.php?id=24949&edit=1 ID: 24949 Comment by: ken at smallboxcms dot com Reported by: nickj-php at nickj dot org Summary: Requesting nicer way of setting undefined variables to default val. ifsetor / ?: Status: Closed Type: Feature/Change Request Package: *General Issues Operating System: * PHP Version: 6 Assigned To: jani Block user comment: N Private report: N New Comment: I personally have never found a use for ?: and think at best it rarely would solve the problem that ifsetor has been requested for. because ?: throws a notice when the variable being tested for is undefined one is still forced to use the longer sintax $foo = isset($_REQUEST['name_of_really_long_variable']) ? $_REQUEST['name_of_really_long_variable'] : null; Hands down my biggest peeve with PHP Also sadly there is no way to implement something in userland because testing for a new element in an array has the unfortunate side effect of also setting that element. Only solution is an operator that works like isset or empty but has the potential to return the value of the variable being tested for instead of true or false. Previous Comments: ------------------------------------------------------------------------ [2010-11-18 23:08:00] jani@php.net ?: exists since 5.3. ------------------------------------------------------------------------ [2006-01-20 01:46:25] nickj-php at nickj dot org That workaround works for most situations, but maybe not all, such as for constants (which cannot be passed-by-reference): $val = _ifsetor(null, 'some value'); $php_ver = _ifsetor(PHP_VERSION, 'some value'); However, I'm not sure whether such a thing should ideally work (i.e. perhaps it's best that this doesn't work, but on the other hand I can't see why it shouldn't) - so I'm honestly not sure. The main point though is that it's a common requirement, especially for web forms, to have to test for a set value, and supply a default if none is set - so it could be good if the language core natively included this functionality. Happily, it looks like this is going to happen in PHP6. Please see: http://www.php.net/~derick/meeting-notes.html#ifsetor-as-replacement-for-foo-isset-foo-foo-something-else (long URL, so may have wraparound issues). The outcome was that PHP will get a new "?:" construct, like the one mentioned previously by Xuefer. Personally, I realise now that this is a far neater approach that having a function (such as ifsetor/noUnset/default), so kudos to the PHP developers. ------------------------------------------------------------------------ [2006-01-19 19:03:01] chris dot vigelius at gmx dot net Workaround: You can implement the functionality using references error_reporting (E_ALL); function _ifsetor(&$field, $defaultvalue) { return (isset($field))?$field:$defaultvalue; } $v1 = $v2 = 'x'; echo _ifsetor($v1, 'v1 is not set'); unset($v2); echo _ifsetor($v2, 'v2 is not set'); This works in 5.1.2 without warnings (haven't checked other versions, though) ------------------------------------------------------------------------ [2005-01-02 02:42:02] nickj-php at nickj dot org From Derick Rethans PHP Look Back 2004 [http://www.derickrethans.nl/month-2004-12.php?item=20041231#20041231], there were two discussions during the year on this topic on the PHP-DEV mailing list, which I am adding links to here (as they help to summarize various aspects of this) : 1) April 2004: http://groups.google.com.au/groups?threadm=c5m94m$31kh$1@FreeBSD.csie.NCTU.edu.tw 2) July 2004: http://groups.google.com.au/groups?threadm=cci54b$t6s$1@FreeBSD.csie.NCTU.edu.tw ------------------------------------------------------------------------ [2003-10-09 18:45:32] marcus at deck16 dot com I also came across that "problem" and voted for that "bug". It is possible to write a function though. Just pass the var Name as a string: <input type="text" name="Email" size="24" value="<?php echo Set_Form_Value('Email'); ?>"> ------------------------------------------------------------------------ The remainder of the comments for this report are too long. To view the rest of the comments, please view the bug report online at http://bugs.php.net/bug.php?id=24949 -- Edit this bug report at http://bugs.php.net/bug.php?id=24949&edit=1