Chrome appears to follow the spec a little closer. Observe the following:
var someVar = 5;
//valid syntax, throws ReferenceError
function passPlease(){
alert(++++someVar);
}
//invalid syntax, throws SyntaxError
function failPlease(){
alert(someVar++++);
}
-Joe
Allen Wirfs-Brock <[email protected]> wrote:
>
>On Sep 6, 2012, at 12:17 PM, Joseph Spencer wrote:
>
>> My apologies on that one. I meant to type the following:
>>
>> PostfixExpression:
>> LeftHandSideExpression [no LineTerminator here] ++
>> LeftHandSideExpression [no LineTerminator here] --
>>
>> PrefixExpression:
>> ++ [no LineTerminator here] LeftHandSideExpression
>> -- [no LineTerminator here] LeftHandSideExpression
>>
>> It appears to me that as currently written the following is considered valid
>> sytax:
>>
>> ++++someVar;
>>
>> I hadn't thought about es3 compatability though, so I could see the
>> reasoning in keeping it as is.
>> As a noobie (and most likely someone in dire need of correction ;)
>> approaching this , it seems to
>> me that there are a few loose ends in the grammar. For instance, the
>> following statements seem
>> allowable by the grammar as currently written:
>>
>>
>> ++typeof someVar;
>> ++new Date();
>> ++null;
>>
>> My knowledge is lacking on this though, so I am probably missing something.
>> I was surprised
>> to find that the following is valid syntax and a perfectly legal
>> FunctionDeclaration, but throws a
>> ReferenceError when executed:
>>
>> function failPlease(){
>> alert(++++a);
>> }
>
>According to the specification, those all should produce runtime
>ReferenceError exceptions. However, at least Firefox, reports them as early
>syntax errors. Technically, that is out of conformance with the spec.
>
>Based upon that evidence, it would appear that FF implements a grammar that is
>closer to you are suggesting rather than what is in the spec. In either case
>there is an error, but the FF implementation prevents the entire Program unit
>from running.
>
>Allen
>
>
>
>
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