Comments on: Undefined Constant Is a String?

By: kanenas

kanenas — Mon, 29 Jun 2009 01:04:21 +0000

Old post, but for those coming across this page who are also wondering “why?”, the feature was inspired by Perl. Barewords in Perl become strings, unless you use the “strict” module. The feature, both in Perl and PHP, is not officially deprecated but is considered harmful.

Reference:
Wall, Larry; “Programming Perl”, 3rd Ed; p860

By: terry chay

terry chay — Sat, 23 Dec 2006 23:54:26 +0000

Am I showing my age when I was really confused that you were confused with the contants parsed as strings when not defined?

By: Matt

Matt — Thu, 21 Dec 2006 23:01:39 +0000

This problem has bit me before too.

The worst is when people do conditional checks against undefined constants…

if(SUPER_CONSTANT){
do this
}

It will always pass if the constant isn’t defined. Now I always develop with notices turned on.

By: Joseph Crawford

Joseph Crawford — Thu, 21 Dec 2006 15:54:28 +0000

You will see this a lot in legacy code that many developers have worked on. The current codeset that i am working on has a ton of $foo[bar] and throws many errors about undefined constants. Time to cleanup and use proper methods.

By: PHPDeveloper.org

PHPDeveloper.org — Thu, 21 Dec 2006 13:19:53 +0000

Ben Ramsey’s Blog: Undefined Constant Is a String?

By: BEToptions

BEToptions — Wed, 20 Dec 2006 23:29:28 +0000

PHP Error reporting

Yet more reasons why error reporting should be set to E_ALL.

I have found the easiest way to do this in WAGERplayer is to add an error_reporting(E_ALL) to your scripts, just after including admin_config.php, as too much of the old stuff will emit a lot

By: hartmut

hartmut — Wed, 20 Dec 2006 22:19:00 +0000

Unquoted strings were a feature of PHP before PHP 3.0,
quoting strings was optional if there was no whitespace within the string.

With the introduction of constants in PHP 3 this has become a backward
compatibility burden, but even with the warning added in at least 4.0
(or was it already in 3.0?) there is still lots of code out there that
relies on this.

But on the other hand this one was the easiest to fix and the least likely to break of the NOTICE level warnings that i have encountered in making legacy code E_NOTICE free, there are way more serious things reported by it like use of uninitialized variables etc.

So always coding with E_NOTICE on is a must for any serious PHP developer IMHO, and just the fact that you inherited legacy code
to maintain is no excuse to have it set to off … but that might just be me …

By: Pierre

Pierre — Wed, 20 Dec 2006 22:08:08 +0000

Slap your coworker with a E_ALL|E_STRICT bat and don’t waste so much ink to explain something that exists since years

The fact that you ask if it is really a feature makes me wonder … bah

By: tony2001

tony2001 — Wed, 20 Dec 2006 21:58:37 +0000

>Note that this behavior of constants continues to exist even in the latest versions of PHP,
>including 5.2 and 6.0.0-dev. Why? I donâ€™t know.

There are 0 reasons to change it except for if you’re to break tons of poorly written apps (even if they deserve it).

By: Planeta Debian » Undefined Constant Is a String?

Planeta Debian » Undefined Constant Is a String? — Wed, 20 Dec 2006 21:53:02 +0000

[...] Original post by Ben Ramsey [...]