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Die folgenden Listen enthält in PHP vordefinierten Bezeichner. Sie sollten die reservierten Worte aus diesen Listen keinesfalls in eigenen Skripten als Bezeichner benutzen. Die Listen enthalten Schlüsselworte, vordefinierte Variablen, Konstanten und Klassennamen. Beachten Sie bitte auch, dass diese Listen nicht unbedingt vollständig sind.
[Editorial note: parent and self are reserved class names. Functions and constants with their names can be declared, but not userspace classes]
true, false and null are not listed because they are globally-defined constants, not reserved words.
No idea about parent or self, though.
Naming a PHP5 class "variant" (with a constructor called the same) and then making an instance of it using __autoload triggers an error which disappears as soon as the name is changed. This should mean that "variant" is also a reserved word.
Two things:
1. It would be nice for this list to differentiate those reserved words, which are language constructs used *with* parentheses (isset, unset, empty, eval, exit, die, ...) and those rather to be used *without* parentheses (all includes, echo, print, return, ...?)
This would really help define some common coding styles...
2. Do you write NULL, TRUE, FALSE or null, true, false? (I find CAPITAL letters better, however typing them can be annoying so I stick with using all lowercase letters, but what's the standard?)
I don't see the boolean constants 'true' and 'false' listed among the reserved words/keywords/constants.
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