Lambda syntax, etc

[Denis Koroskin]

On Thu, 05 Feb 2009 12:32:15 +0300, Kagamin <spam at here.lot> wrote:

> bearophile Wrote:
>
>> C#2 has lambdas, and C#3 adds closures and more type inferencing, so  
>> C#3+ supports the following syntaxes:
>> (int i) => { return i % 3 == 1; } // C#2
>> i => i % 3 == 1 // C#3
>> i => { return i % 3 == 1; } // C#3, with statements too
>> To define a delegate o delegate closure:
>> Func<int> foo = i => { return i % 3 == 1; };
>> Func<int> foo = i => i % 3 == 1;
>> Func<int> bar = () => 2;
>> But this isn't allowed:
>> Func<void> bar = () => 2;
>
> Yeah, C# lambdas are the killer feature. Slick, readable, C-compatible.  
> Anders knows his job. Let's face it: delegate literals suck a little,  
> mixins as delegates suck a lot, the former is too verbose, the latter  
> just sucks.

I don't like C# lambda syntax (although it is not half as bad as C++ lambda syntax).

I believe D delegate syntax is superior due to its natural and unambiguous syntax.
But yes, it could be made shorter by improving type deduction:

int delegate(int) inc = (i) { i + 1; }

Which would be the same as

int delegate(int) inc = (int i) { return i + 1; }

where i's type is deduced from inc's type and the only expression (i + 1) made a return value:

auto x = inc(5); // yields 6

Here is an another example:

void foo(void delegate(ref int i) inc);

Could be used as follows:

foo( (i) { ++i; } );

as opposed to

foo( (ref int i) { ++i; } );

I can put this enhancement request into bugzilla if anyone likes it.