On Wed, Dec 3, 2008 at 9:36 PM, Eric Suen <[EMAIL PROTECTED]> wrote:
>
>
> No,
>
> ^(x) is not a legal expression, so you don't have to make
> block in same line, no semicolon insertion will happens here.
You're looking at the wrong part of the example. Sorry -- the
"wrapper" lambda is superfluous, and I should have left it out for
clarity.
Using the GNU bracing style:
x = x * x
^(a,b,c,d,e,f,g)
{
x
}
The above parses as an xor expression followed by a block, like so:
x = x * x ^ (a,b,c,d,e,f,g)
{
x
}
... which is odd, to be sure, but perfectly legal.
The second example:
x = x * x
^(a,b,c,d,e,f,g) {x}
is not ambiguous, but it's unsuitable for top-down parsing. (I tried
to underscore the point by using a long list of formals.) The parser
has to get to the opening brace before it can determine that it isn't
dealing with an xor expression.
-Jon
>
> see this post:
>
> https://mail.mozilla.org/pipermail/es-discuss/2008-December/008296.html
>
> ----- Original Message -----
> From: "Jon Zeppieri" <[EMAIL PROTECTED]>
> Newsgroups: gmane.comp.lang.javascript.ecmascript4.general
> To: "P T Withington" <[EMAIL PROTECTED]>
> Cc: "es-discuss" <[EMAIL PROTECTED]>
> Sent: Thursday, December 04, 2008 3:09 AM
> Subject: Re: Allen's lambda syntax proposal
>
>
>> 2008/12/3 P T Withington <[EMAIL PROTECTED]>:
>>>
>>> - prefix ^ might be confused with the infix operator of the same name
>>
>> With semicolon insertion, isn't this a bigger problem?
>>
>> The opening brace will need to be on the same line as the formals,
>> otherwise the syntax is ambiguous:
>>
>> ^(x) {
>> x = x * x
>> ^(a,b,c,d,e,f,g)
>> {
>> x
>> }
>> }
>>
>> And, if it is on the same line, it's still bad for a top-down parser:
>>
>> ^(x) {
>> x = x * x
>> ^(a,b,c,d,e,f,g) {x}
>> }
>>
>> Will semicolon insertion be illegal inside a lambda body?
>>
>> -Jon
>
>
>
>
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