Re: Re: variable_exists() patch

+1 for variable_exists Cristiano Duarte "Lars Torben Wilson" <torben@php.net> escreveu na mensagem news:1060889520.1036.45.camel@ali... > On Thu, 2003-08-14 at 08:42, Andi Gutmans wrote: > > I am not really convinced either that variable_exists() is > > function_exists() parallel. > > Under what circumstances is this needed? > > > > Andi > > The followup I sent to Ilia gives examples of how this patch can be > used to determine whether, for instance, array keys exist, without > having to use the array_key_exists() workaround; also, you can check > whether an object has defined an attribute, even if it hasn't yet > assigned it a value: > > <?php > class foo { > var $bar; > var $baz = null; > var $quux = 'quux'; > } > $foo = new foo; > > echo "variable_exists(\$foo-&gt;bar): " . (variable_exists($foo->bar) ? > 'yes' : 'no') . " (should be yes)\n"; > echo "variable_exists(\$foo-&gt;baz): " . (variable_exists($foo->baz) ? > 'yes' : 'no') . " (should be yes)\n"; > echo "variable_exists(\$foo-&gt;quux): " . (variable_exists($foo->quux) > ? 'yes' : 'no') . " (should be yes)\n"; > echo "variable_exists(\$foo-&gt;quuux): " . > (variable_exists($foo->quuux) ? 'yes' : 'no') . " (should be > no)\n"; > > echo "isset(\$foo-&gt;bar): " . (isset($foo->bar) ? 'yes' : > 'no') . " > (should be yes)\n"; > echo "isset(\$foo-&gt;baz): " . (isset($foo->baz) ? 'yes' : > 'no') . " > (should be yes)\n"; > echo "isset(\$foo-&gt;quux): " . (isset($foo->quux) ? 'yes' : > 'no') . " > (should be yes)\n"; > echo "isset(\$foo-&gt;quuux): " . (isset($foo->quuux) ? 'yes' : > 'no') . > " (should be no)\n"; > ?> > > ...the output from the above is: > > ----------------------------------------------------------------------- > variable_exists($foo->bar): yes (should be yes) > variable_exists($foo->baz): yes (should be yes) > variable_exists($foo->quux): yes (should be yes) > variable_exists($foo->quuux): no (should be no) > isset($foo->bar): no (should be yes) > isset($foo->baz): no (should be yes) > isset($foo->quux): yes (should be yes) > isset($foo->quuux): no (should be no) > ----------------------------------------------------------------------- > > etc. It's a little annoying at times that that isset() doesn't do what > its name suggests it should, which leads people to try to use it > for things which is seems that it should be able to do, but can't. When > I've tried to explain it, the only answer I can give is "Sorry, that's > just the way it is--and no, you can't do that in PHP". > > It seems basic enough functionality that is almost, but not quite, > satisfied by isset(). > > > -- > Torben Wilson <torben@php.net> +1.604.709.0506 > http://www.thebuttlesschaps.com > http://www.inflatableeye.com > http://www.hybrid17.com > http://www.themainonmain.com > -----==== Boycott Starbucks! http://www.haidabuckscafe.com > ====----- > > >