>From the ES5 spec section 12 statement semantics: NOTE Several widely used implementations of ECMAScript are known to support the use of FunctionDeclaration as a Statement. However there are significant and irreconcilable variations among the implementations in the semantics applied to such FunctionDeclarations. Because of these irreconcilable differences , the use of a FunctionDeclaration as a Statement results in code that is not reliably portable among implementations. It is recommended that ECMAScript implementations either disallow this usage of FunctionDeclaration or issue a warning when such a usage is encountered. Future editions of ECMAScript may define alternative portable means for declaring functions in a Statement context.
Also see section on functions in http://blogs.msdn.com/b/ie/archive/2010/08/25/chakra-interoperability-means-more-than-just-standards.aspx There seem to be more browsers that treat function declarations in blocks as straightforward extensions of the function hoisting semantics (unconditionally) but Firefox does something different. As I say in the above blog post, you have to have them in a browser but anything other than trivial usage is unlike to be interoperable. Allen > -----Original Message----- > From: es-discuss-boun...@mozilla.org [mailto:es-discuss- > boun...@mozilla.org] On Behalf Of Michael Day > Sent: Thursday, November 11, 2010 3:46 PM > To: ES-Discuss > Subject: Function declarations as statements > > Hi, > > In ECMAScript, function declarations are SourceElements, but not Statements. > This means that they can only occur at the top level, and may not be nested > inside a block. > > However, browsers support function declarations as statements, and many > scripts on the web seem to make use of this ability, especially after they > have > been minified. > > Is there a spec anywhere for how functions as statements should behave? > > Can they be rewritten to var + function expression, so that this: > > { > function f() { return 17 } > } > > becomes this: > > { > var f = function() { return 17 } > } > > When implementing non-standard features, it would be nice to do so in a > standard manner :) > > Best regards, > > Michael > > -- > Print XML with Prince! > http://www.princexml.com > _______________________________________________ > es-discuss mailing list > es-discuss@mozilla.org > https://mail.mozilla.org/listinfo/es-discuss _______________________________________________ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
