Subj : Re: new operator and call operator
To   : netscape.public.mozilla.jseng
From : =?ISO-8859-1?Q?Georg_Maa=DF?= <georg@bioshop.de>
Date : Sat Mar 29 2003 07:28 am

Thank you for that many useful information about misunderstood details.

Waldemar Horwat wrote:
> That is also a new operator.  The parentheses and any contained 
> arguments are part of the new operator.  This follows from the grammar 
> in ECMA 262 Edition 3, section 11.2.
> 
>> Are there two new operators?
> 
> 
> You can think of it as either two operators or one with an optional 
> argument list.
> 
>> new FUNCTION
>> and
>> new FUNCTION (OPERANDLIST)
>> where OPERANDLIST is used as arguments for the constructor function?
>>
>> I ask this for correctly documenting the language. Should I speak 
>> about two new operator variation or should I speak about a pure new 
>> operator and a combination of new operator and call operator?
> 
> 
> It is definitely not a combination of a new operator and a call 
> operator.  It took us a bit of trouble to make sure that the grammar in 
> section 11.2 disambiguates that.
> 
>> Experiments with Selection in the Mozilla browser let me think it 
>> might be better to speak about two new operator variations, because
>>
>> Selection();
>>
>> results in an error message, where
>>
>> new Selection();
>> and also
>> new Selection;
>>
>> results in an exception. This gives me the idea, that there is no 
>> "call operator" in the second sample but the () must be a part of the 
>> new operator, which causes me to say, that there are two new 
>> operators, one with () and an other without, both doing the same.
> 
> 
> Furthermore, if you follow the grammar in 11.2, you'll find that the 
> arguments are associated with the closest unmatched 'new' just like an 
> 'else' is associated with the closest unmatched 'if'.  If there are no 
> more unmatched 'new' tokens, then the arguments form a function call.  
> Here is a little food for thought:
> 
> new a(b)(c)  means  (new a(b))(c)  and not  new (a(b))(c)  or  (new 
> a)(b)(c)
> 
> new new a(b)  means  new (new a(b))
> 
> new new a(b)(c)  means  new (new a(b))(c)
> 
> new new a(b)(c)(d)  means  (new (new a(b))(c))(d)
> 
> new a.b  means  new (a.b)  and not  (new a).b
> 
> new a[b]  means  new (a[b])  and not  (new a)[b]
> 
> new a++  means (new a)++  and not  new (a++)
> 
>     Waldemar
> 


-- 
Georg Maaß   -   bioshop.de       D-93466 Chamerau, Roßbergweg 42
JavaScript, C++ Engineering
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                       http://sourceforge.net/projects/gml-modul

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