Will macros work with expressions?

[Don Clugston]

Reiner Pope wrote:
> Jari-Matti Mäkelä wrote:
>> Robert Fraser wrote:
>>> Jari-Matti Mäkelä Wrote:
>>
>>>> If I understood it correctly, the macros only do a simple substitution
>>>> using their parameters, hide symbols when necessary (hygiene) and then
>>>> attach the generated code to the AST.
>>> I think that's about right, but remember that their parameters can
>>> specialize on any pattern and extract parts of the expression, which I
>>> think is the most exciting feature.
>>
>> Ah, good point. That would make overloading and recursive calls the 
>> primary
>> control flow constructs then. 
> 
> Such an environment is not pleasant as it involves large code overheads. 
> It's what's required in C++ template metaprogramming; D made this *much* 
> nicer by introducing static if. 

And even better (perfect in many cases) with CTFE.

> Please don't take a step backwards with macros.

This was the reaction I had too. There's really no need for macros to provide 
new functionality, they just need to provide syntax sugar for what we can 
already do with string mixins.