Brendan Eich brendan at
Thu Mar 29 07:19:24 PDT 2012

Herby Vojčík wrote:
> Question 1: Do people want it? Do TC39 plan to have it in

No, not in the block-lambda TCP sense. See my mail of 7:11am today. At 
most the desire is for an equivalence over expressions, not statements:

   e ~= do { e; }

So |this| must work, and we ban 'arguments' and 'yield' in arrow bodies.

I forgot to mention 'yield' in the 7:11am mail -- it was  good catch by 
Mark. Generators require a * in the head, after function or before the 
generator function's name. Arrows cannot be generators, there's no place 
for the * and YAGNI. Therefore 'yield' is not allowed, as it breaks the 
expression-TCP equivalence, and restoring that equivalence would mean 
deep continuations, which we have ruled out for years.


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