Macros
- Macros are inlined each time they are called.
- Macros can have untyped parameters.
- Macros are allowed to use
var to infer the type of any variable.
- Macros must start with
@ when they use expression parameters.
- Expression parameters start with a
# and copy the passed expression every time they are used, similar to C macro parameters except the expression must be valid before it is copied.
import std::io;
macro void @swap(#x, #y)
{
var temp = #x;
#x = #y;
#y = temp;
}
fn void main()
{
int a = 0;
int b = 1;
io::printfn("%d", a);
@swap(a, b);
io::printfn("%d", a);
// @swap(1, 2); // This will error because it will evaluate to `1 = 2`
}
