Anonymous function syntax

[Andrei Alexandrescu]

On 9/22/11 10:42 AM, pillsy wrote:
> == Quote from Andrei Alexandrescu (SeeWebsiteForEmail at erdani.org)'s article
>> On 9/22/11 1:47 AM, Max Klyga wrote:
>>> Actually Scala doesn't need type declarations in labmda literals. Most
>>> of the time argument types are infered.
>
>> Already does. We're looking for a briefer syntax.
>
> What is the problem with just inferring the `return`, allowing you to replace
>
>       (a,b) { return a + b; }
>
> with
>
>      (a, b) { a + b; }
>
> This seems competitive with the other syntaxes for brevity, but ISTR there was some objection to doing things that
> way.

The objection is that it introduces a number of questions:

1. How about using that syntax in regular functions?

2. What if the lambda wants to actually evaluate the expression but 
return void?

3. How is the semicolon relevant? (If its presence is used as a 
disambiguator for (2), it's poor design to predicate a large semantic 
difference on such a distinction.)

> Also would it make sense to have a template library along the lines of boost::proto/boost::lambda to allow even
> shorter, expression-based lambdas like
>
>      _1 + _2
>
> I'm not exactly a D template metaprogramming pro, but I think this would work for a lot of common cases.

Such an approach has caused more trouble than benefits in C++.


Andrei