Subj : Re: spidermonkey ecma extensions
To   : Martin.Honnen
From : Brendan Eich
Date : Mon Sep 12 2005 02:43 pm

Martin Honnen wrote:
> 
> 
> steveH wrote:
> 
>> The
>> other is the following code
>>
>> Tokenizer.prototype = {
>>     get input() {
>>         return this.source.substring(this.cursor);
>>     },
>>
>> is this use of get documented anywhere, I can see what it's doing -
>> defining a property getter, but I don't recall ever seeing it done like
>> this before ...


FYI, reading http://lxr.mozilla.org/mozilla/source/js/src/jsconfig.h and 
keeping score of which feature macros are on vs. which are off for 
JS_VERSION_ECMA_3 vs. JS_VERSION_1_6.


> The core JavaScript 1.5 guide has this section 
> <http://developer.mozilla.org/en/docs/Core_JavaScript_1.5_Guide:Creating_New_Objects:Defining_Getters_and_Setters> 
> on getters and setters which also uses the above syntax.
> 
> It is not entirely clear to me whether the above syntax is deprecated


It's not deprecated.  It was in fact a change from my original 
getter/setter syntax made at the behest of Waldemar Horwat, to be 
forward compatible with JS2/ES4.  But that was a while ago.

/be


> or 
> not in regardance to Mozilla JavaScript but on the web you can't use it 
> as other engines like the JScript engine in current IE versions or the 
> engine in Opera will give you a syntax error.
> 
> So on the web you need e.g.
>   if (typeof Tokenizer.prototype.__defineGetter__ != 'undefined') {
>     Tokenizer.prototype.__definerGetter__(
>       'input',
>       function () {
>         return this.source.substring(this.cursor);
>       }
>     );
>   }
>

.