------- Comment #3 from  2009-03-22 16:50 -------
(In reply to comment #2)
> judging from compiler error messages, ref is not a type modifier, it's a
> function attribute, so brackets won't help. 

I'm a little confused - if that were the case, surely it would work?

Moreover, what is there preventing ref from becoming a type modifier, if this
would fix the problem?

It should also be noted, that
> others function attributes' grammar is also ambiguous.
> ---
> nothrow int function() foo();
> ---
> What is nothrow here?

So there's actually an advantage to the suffix notation for function

> ---
> const int foo();
> ---
> What is const here?
> ---
> int foo(ref int function() goo);
> ---
> This one would probably give no error.

But that is a case that really is ambiguous.

> Is it keyword saving issue? Semantically different things have the same 
> syntax.
> If Walter wants context-dependent keywords, he should mark those contexts
> better.
> I would like to see function attributes at predictable, easy-to-spot 
> locations,
> so it would be no chanse to mess storage class with function attributes. There
> are already good places for function attributes (after function) and storage
> class attributes (before type). If the attributes will be restricted to
> corresponding places, there will be no ambiguity (except const).
> ---
> int foo(ref int function() goo); //ref parameter
> int goo(int function() ref foo); //return byref function
> ---

I don't really like this.  The ref essentially means the same thing, it's just
whether it applies to the parameter or the return.  In the latter, it's being
moved further from what it applies to: the return type.

IIRC, the equivalent C++ syntax is

int foo(int (*&goo)());  // ref parameter
int goo(int& (*foo)());  // ref return in parameter

It isn't exactly clear, but at least it's unambiguous.  If D got the & notation
for reference, we would have

int foo(int function()& goo);  // ref parameter
int goo(int& function() foo);  // ref return in parameter

Indeed, we could have ref take the place of & in this notation

int foo(int function() ref goo);  // ref parameter
int goo(int ref function() foo);  // ref return in parameter

and so the syntax of ref/& would become consistent with that of *.

We could do it like this, or we could make ref a type modifier along the lines
of const.  Take your pick.


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