Infer function template parameters

[Steven Schveighoffer]

On Thu, 20 Sep 2012 15:57:47 -0400, Jonas Drewsen <jdrewsen at nospam.com>  
wrote:

> In foreach statements the type can be inferred:
>
> foreach (MyFooBar fooBar; fooBars) writeln(fooBar);
> same as:
> foreach (foobar; fooBars) writeln(fooBar);
>
> This is nice and tidy.
> Wouldn't it make sense to allow the same for function templates as well:
>
> auto min(L,R)(L a, R b)
> {
>      return a < b;
> }
>
> same as:
>
> auto min(a,b)
> {
>      return a < b;
> }
>
> What am I missing (except some code that needs chaging because only  
> param type and not name has been specified in t?

Although I like it, I wonder if it works in D's context free grammar.   
Timon probably would know best...

I came up with this code, which compiles today:

import std.stdio;
alias int x;

void foo(x) {}

void foo2(string x) {writeln(x);}

void main()
{
     foo(1);
     foo2("hello");
}

Under your proposal, if we shorten foo2 to foo2(x), what happens?  Does it  
become just like foo?  Or does it turn into a template?  Or is it an error?

Note that just because some syntax isn't valid doesn't mean it should be  
utilized for a valid use.  That can result in code compiling and meaning  
something completely different than you expect.

-Steve