ES6 and Error Object properties

[Brendan Eich]

On Nov 4, 2009, at 12:11 PM, Patrick Mueller wrote:

> Coincidently (!!!), I recently opened a feature request in WebKit on  
> this topic, kind of:
>
> 	https://bugs.webkit.org/show_bug.cgi?id=30933
>
> Not sure I'll have time to do anything about it, and surely won't  
> without some kind of real framework helping out to add support on  
> their end ...

SpiderMonkey, when you set the JSOPTION_ATLINE runtime option flag,  
understands a comment of this form:

//@line: n

as setting the next line's line number to n. You can coerce the  
filename too:

//@line: n, "f"


> BTW, I thought JavaScript was the new assembler, not the new C.

What's the difference? :-/.

/be

>
> On Nov 4, 2009, at 3:04 PM, P T Withington wrote:
>
>> Sure would be nifty to have #file and #line directives, now that  
>> Javascript is the new C.
>>
>> FWIW, OpenLaszlo generates annotations like so:
>>
>> Filename, line, column:
>>
>> /* -*- file: lpp-8534.lzx#10.7 -*- */
>>
>> Same file, but line numbering needs to be reset (because output has  
>> more or less lines corresponding to source):
>>
>> /* -*- file: #15 -*- */
>>
>> No corresponding source file (i.e., generated code follows):
>>
>> /* -*- file: -*- */
>>
>> I can see merits to one gigantic comment up front with a mapping  
>> table ala Caja, but we found interspersing them worked better for  
>> humans staring at Javascript "assembly" in a Javascript debugger.
>>
>> IWBNI @sourceurl could be expanded in some form to work with loaded  
>> files...
>>
>> On 2009-11-04, at 14:39, Patrick Mueller wrote:
>>
>>> Coincidently, I posted a blog entry on SyntaxError and eval()  
>>> yesterday:
>>>
>>> 	http://pmuellr.blogspot.com/2009/11/evil-eval.html
>>>
>>> On Nov 4, 2009, at 11:10 AM, Kevin Curtis wrote:
>>>
>>>> This has probably been chewed over but -
>>>>
>>>> The ES5 spec defines 'name' and 'message' as properties of the  
>>>> Error -
>>>> and ReferenceError, SyntaxError etc - objects.
>>>>
>>>> Currently engines have useful additional non-standard properties:
>>>> Mozilla - fileName, lineNumber and stack.
>>>> V8 - stack (and type, arguments). (The string returned by 'stack'  
>>>> is
>>>> not in the same format as Mozilla).
>>>> JSC - line, sourceId, sourceURL, expressionBeginOffset,
>>>> expressionCaretOffset ,expressionEndOffset - and a few others for
>>>> Statement errors.
>>>>
>>>>
>>>> Any chance for ES6 on standardizing Error object property/ies which
>>>> report back the error location.
>>>>
>>>> Maybe a property 'location' on the Error object which returns an  
>>>> object. e.g
>>>> e.location ->
>>>> {fileName:<filename>, pos: <character posNumber>,  
>>>> line:<lineNumber> ,
>>>> lineEnd:<lineNumber>, col:<colNumber> , colEnd:<colNumber>, stack:
>>>> <stackString>}
>>>>
>>>> With maybe pos and line being mandatory properties and the other
>>>> properties set if they can be set.
>>>>
>>>
>>
>
> Patrick Mueller - http://muellerware.org/
>
>
>
>
> _______________________________________________
> es-discuss mailing list
> es-discuss at mozilla.org
> https://mail.mozilla.org/listinfo/es-discuss