PHP 5.6.18 is available



以下に PHP で定義済みの ID の一覧を示します。ここに示す ID はいずれも スクリプトの中で ID として使用することはできません。これらの一覧には キーワード、定義済みの変数、定数、クラス名が含まれています。これらの一覧は、 全てを網羅しているわけではありません。

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User Contributed Notes 4 notes

londonx at gmail dot com
8 years ago
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.
10 years ago
I don't see the boolean constants 'true' and 'false' listed among the reserved words/keywords/constants.
8 years ago
[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.
9 years ago
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?)
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