DIP78 - macros without syntax extensions

[Kagamin via Digitalmars-d]

On Wednesday, 27 May 2015 at 11:53:00 UTC, Jacob Carlborg wrote:
> DIP50 would require a minimal amount of syntax change, the only 
> thing is prefixing a function with the "macro" keyword. DIP78 
> on the other hand, it's not so easy to see that a function 
> declaration is actual a macro declaration.

Well, that's the point: the function is a normal function, only 
some of its parameters require specially prepared arguments, this 
can't be missed as soon as arguments are passed to the respective 
parameters.

> In that case I would prefer the "macro" keyword. It's already a 
> reserved, for exactly this purpose, so it will be backwards 
> compatible.

Well, maybe, I just didn't need the keyword.

> One thing that would be more complex in DIP50 would be the 
> "Context" class. Although I'm not sure if that's needed in 
> DIP78 as well.

No, passing of Context is not proposed.

>> Maybe a macro should be called with a special syntax,
>> e.g. myAssert!(a==b);
>
> I have thought of that too. But I haven't been able to come up 
> with a syntax that looks good and doesn't conflict with any 
> existing syntax/symbol. The above syntax is already used for 
> template instantiation.

I mean, the template instantiation syntax can inform the compiler 
that the expression is evaluated at compile time with possible 
code generation, so that the compiler is prepared to what macro 
will do. This resembles similarity between macros and templates. 
If macros can use existing syntax of a function call, I see no 
problem if they use another existing syntax.