macros.mkd

Macros

Macros programming relies on extensions such as Typeof, auto, and Statement Expressions.

There are still a couple of problems

1. Multi-line macros are annoying

2. Collision of variable names

#define foo(x)              \
({                          \
    __auto_type a = (x);    \
})

int main()
{
    int a = 1;
    foo(a);
}

3. Semicolons can not appear as part of arguments

#define min(x, y)           \
({  __auto_type _x = (x);   \
    __auto_type _y = (y);   \
    (_x < _y) ? _x : _y;    \
})

4. No pattern matching of expression

5. Compound expressions can not be used safely in macros because curly brackets are not parsed:

foo((int[]){ 0, 0 })

6. Compound expressions can not be used safely inside Statement Expressions

Life time of a compound expressions used in a macro written using a statement expression ends, so can not be returned.

New kind of macros?

#macro foo(x * y)
  mul(x, y)
#endmacro