Allen's lambda syntax proposal

Brendan Eich brendan at mozilla.com
Wed Dec 3 17:10:03 PST 2008


On Dec 3, 2008, at 4:06 PM, Sam Ruby wrote:

> 2008/11/30 Brendan Eich <brendan at mozilla.com>:
>> At the TC39 meeting two weeks ago in Kona, we had a brief  
>> bikeshedding
>> discussion about lambda syntax and why it matters.
>
> Has anybody given any thought to the C# (ECMA TC49) syntax?

Yes, it has come up on this list. Head of thread message is:

https://mail.mozilla.org/pipermail/es-discuss/2007-March/003893.html

In JS, the C# syntax creates an ambiguity with the comma expression in  
the n-ary n > 1 case. Bottom-up parsers can cope; top-down have a  
harder time changing their minds about what they are parsing when the  
see the => after the parameter list. It can be handled either way,  
though.

Having had several threads over a couple of years on this, my  
impression is almost no one has championed an "infix" syntax such as  
C#'s. The prefix crowd is split between those wanting lambda vs. a one- 
char punctuator. The "postfix" (not accurate but you know what I mean)  
position favors the Smalltalk homage.

/be



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