FAQ Topic - What is a function statement? (2010-05-24)
in [JavaScript]
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From: John G Harris on 27 May 2010 11:22 On Wed, 26 May 2010 at 13:14:54, in comp.lang.javascript, Ry Nohryb wrote: <snip> >Q: It looks like a function declaration, walks like a function >declaration, and quacks like a function declaration, and the specs >*permit* a function declaration there because syntax extensions are >permitted, so what ? >A: That this FAQ entry is pointless in the way it's worded right now. You need to be accurate : ECMAScript permits extensions, but it's only a Function Declaration if you say it is. As you do say it is, you have to require it to be processed the way that ECMA 262 requires Function Declarations to be processed. That is, the declaration is processed *before* the code surrounding it is executed. As a result, the function is declared unconditionally. Even if the declaration is inside an if, while, or for statement the declaration is always actioned even if code execution never passes through the declaration text. As Function Declarations are actioned unconditionally it is completely pointless to hide them inside any kind of Statement. It is worth while pointing this out to beginners. You have demonstrated that this is what IE and a few others do. You have also demonstrated that Mozilla is incompatible. It is worth while warning beginners of this : they can't predict how their code is going to behave if they use this extension. John -- John Harris |