On May 23, 2011, at 7:06 AM, Jorge wrote:
> On 23/05/2011, at 07:15, Kam Kasravi wrote:
>
>> Is this valid?
>>
>> function Person(a) {
>> this.age = a;
>> }
>> Person.prototype.myage = {|| this.age};
>>
>> function info(myage) {
>> console.log('my age is '+myage());
>> }
>> info(new Person(10).myage);
>> info(new Person(12).myage);
>
>
> If it's valid (I don't know if there can be a block-lambda standing alone
> outside of a function), it would return the value of the global variable
> `age`, I think, because the enclosing scope's `this` in that code above seems
> to be the global Object.
Yes, see my reply. The code in between { and } (including {|...| and }, even
when used as an expression) can be factored out without names changing meaning.
> Brendan, do you really want these block-lambdas to be blocks?
Of course, that's part of the proposal and we've discussed this since at least
late 2008. See the link from the Prologue at
http://wiki.ecmascript.org/doku.php?id=strawman:block_lambda_revival
> I thought you were just going to borrow its syntax for shorter function(){}
> semantics, not blocks semantics ?
Please read the strawman.
> What if {||} were just the shorter function syntax we want, with the added
> features we want (completion value as return value, lexical/dynamic `this`,
> ... ?), but not true blocks ?
No, it does not look like a function. It looks like a Ruby block, based on
Smalltalk blocks which had different syntax. Different semantics for different
syntax.
/be
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