What is this strange alias syntax?

[Steven Schveighoffer]

On Mon, 23 May 2011 09:32:47 -0400, Timon Gehr <timon.gehr at gmx.ch> wrote:

> Steven Schveighoffer wrote:
>> it's akin to
>> making:
>>
>> if(x);
>>
>> invalid. Yes, it's valid syntax, but it's almost certainly not what the
>> user wanted.  It's special cased for failure, to aid the developer in
>> writing less buggy programs.  This would be a similar change, and I
>> actually thought it was already in the compiler.
>
> It is in the compiler. It is actually not valid syntax anymore  
> (disallowed by
> grammar and caught by the parser).

When I said I thought it was already in the compiler, I meant the bizarro  
function type declaration, not the empty if statement.

> And it is not similar to removing function type
> alias. You can write if(x){} as a replacement if you need it.
>
> There is currently no alternative for the alias.

But why do you need a function type vs. a function pointer type?   
Especially since the function pointer type is easily built from the  
function type, and you can't actually use the function type until you turn  
it into a function pointer.

>
>>
>> I'll throw it back at you, do you see a good use case for it?  And no,
>> porting C code isn't a good use case.
>
> There are no alias in C code.
>
> I actually gave one:
> Timon Gehr wrote:
>> alias int func();
>>
>> int main(){
>>     static assert(is(typeof(main)==func);
>>     return 0;
>> }

static assert(is(typeof(&main) == int function());

More straightforward and descriptive.

> BTW:
>
> writeln(typeid(int function(int))); //int()*
>
> wtf?

That needs to be fixed, the runtime's TypeInfo.toString methods are not  
always accurate (I think this warrants a bugzilla report).

-Steve