A quick post-script. We could also give Function.prototype.name a different name, perhaps "identifier" if we don't want to trample over the existing FF and Chrome implementations. Too bad "name" is such a good name for this functionality.
>-----Original Message----- >From: [email protected] [mailto:es-discuss- >[email protected]] On Behalf Of Allen Wirfs-Brock >Sent: Tuesday, March 03, 2009 6:25 PM >To: Brendan Eich; Maciej Stachowiak >Cc: [email protected] >Subject: RE: name property for built-in functions?? > >Strictly speaking, this issue seems to be more about >Function.prototype.toString than it is about Function.prototype.name. > >Here is what each of the 5 browsers in our regular test set does for >each when called on a (new Function): > >(new Function).toString ==> "function anonymous() { }" assorted >whitespace/new line variations > FF(3.0.6), Safari(3.1.2), Chrome(1.0) , IE (7): > >(new Function).toString ==> "function (){}" (with various new lines >inserted) > Opera(9.63) > >(function() {}).toString() ==> "function (){}" (with various new lines >inserted) > FF, Safari, Chrome, Opera > >(function() {}).toString() ==> "(function (){})" (note the outer >parens) > IE > >(new Function).hasOwnProperty("name") ==> true >(new Function).name ==> "anonymous" >(function() {}).name ==> "" >FF, Chrome > >(new Function).hasOwnProperty("name") ==> false >Opera, Safari, IE > >Function.prototype.hasOwnProperty("name") ==> true >Function.prototype.name ==> "" > FF > >Function.prototype.hasOwnProperty("name") ==> true >Function.prototype.name ==> "Empty" > Chrome > >Function.prototype.hasOwnProperty("name") ==> false > Safari, Opera, IE > >ES3 says that Function.prototype.toString produces a string that has the >syntax of a FunctionDeclaration and FunctionDeclaration must have an >identifier in the function name position. All the implementation except >for Opera comply and agree upon the name "anonymous" for anonymous >functions created with (new Function). This is a case where Opera is >out of conformance with ES3 by generating what looks like a function >expression rather than a function declaration. However, all of the >browsers are out of conformance with ES3 for toString for anonymous >functions created using a FunctionExpression. IE throws in an extra set >of parens in that case. > >The Es3 extension of a name property for functions only appear to be >implemented by FF and Chrome, and they disagree about the name of >Function.prototype. > >The ES specification of Function.prototype.toString clearly does not >reflect reality. The goal is to achieve uniformity among implementations >while minimizing impact upon existing code. Given this, I propose that >we modify the first paragraph of 15.2.4.2 (Function.prototype.toString) >with the > >An implementation-dependent >>>string<<< representation of the function >is returned. This representation has the syntax of a >>>>FunctionExpression<<<. Note in particular that the use and placement >of white space, line terminators, and semicolons within the >representation string is implementation-dependent. >>>If the function >was created by evaluating a FunctionDeclaration then the returned >representation must include the identifier from the FunctionDeclaration >in the optional identifier position in the FunctionExpression. If the >function was created by a call to the standard built-in Function >constructor then the name "anonymous" must occur in the optional >identifier position of the returned string. If the function was created >by evaluating a FunctionExpression that did not include an identifier, >by a get or set property assignment in an ObjectLiteral, or by a call to >the Function.prototype.bind built-in method then no identifier is >included in the returned representation. > If the function is a built-in function then the property name assigned >to the function in this specification (or by the implementation if it is >a non-standard function) is included in as the identifier in the >returned representation. If the function is a host object then whether >or not an identifier is present is implementation defined.<<< > >(maybe I can work on the wording ;-) > >The above codifies what currently is most commonly implemented with some >elaboration for new features in ES3.1 and should take care of the actual >use case that Maciej identifier in the bug report. > >Regarding, Function.prototype.name, it doesn't appear to be nearly so >universally implemented. Given that, I suggest we use the opportunity >of defining it in ES3.1 to maximize its utility by providing more >descriptive names than what is current generated by >Function.prototype.toString. I'd prefer that we stick with what is in >current ES3.1 draft which is: > Defined by name >FunctionDeclaration the identifier from the declaration >FunctionExpression with name the identifier from the function >expression >FunctionExpresion w/o name the empty string >Object literal get/set "get <property name>" or "set ><property name>" >Bound function "bind <target function name>" or " >bind anonymous function" >(new Function) "new Function"* >Built-in specified name > >*the current draft says "" but I consider this to be a bug. I >apparently lost this change when Word crashed on me Sunday :-( > >>-----Original Message----- >>From: Brendan Eich [mailto:[email protected]] >>Sent: Tuesday, March 03, 2009 3:25 PM >>To: Maciej Stachowiak >>Cc: Allen Wirfs-Brock; [email protected] >>Subject: Re: name property for built-in functions?? >> >>On Mar 3, 2009, at 2:39 PM, Maciej Stachowiak wrote: >> >>> Surprising though it may be, it seems that (new Function).name === >>> "anonymous" may be relevant to Web compatibility. We changed >>> JavaScriptCore to match SpiderMonkey on this as a result of this bug: >>> >>> http://bugzilla.opendarwin.org/show_bug.cgi?id=7726 >> >>I can't reach that hostname, but >>https://bugs.webkit.org/show_bug.cgi?id=7726 >> works. >> >>BTW, the ability to write a program whose entire source is "function >>() {}" is an old, pre-ES3 feature of SpiderMonkey that people *still* >>depend on, especially when using eval (not new Function) to generate a >>lambda from source. >> >>Per ES3 this should be a syntax error as Darin Adler pointed out in >>the bugs.webkit.org bug, but we have had to keep compatibility with >>what came before ES3 on this point. There's an API option >>(JSOPTION_ANONFUNFIX) to make this case an error per spec. >> >> >>> I strongly suspect code also depends on (function(){}).name==="" but >>> I don't have a clear-cut example handy. >> >>I voiced the same suspicion. I didn't know any web site depending on >>Function().name == "anonymous", though. What a world! >> >>/be > >_______________________________________________ >Es-discuss mailing list >[email protected] >https://mail.mozilla.org/listinfo/es-discuss _______________________________________________ Es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
