• bearophile <bearophileHUGS lycos.com> Apr 04 2010

bearophile <bearophileHUGS lycos.com> writes:

Sorry for pulling out this old thread again, I have one thing to add.

 void convolve(const float[][] mat, enum float[][] mask, float[][] outmat);


A possible variant of "enum" arguments is "auto enum" arguments. If the given
value is a compile-time constant then the function becomes a template as
before. Otherwise if the given value is a run-time value, then the argument is
a normal function argument. So this code:

void foo(int a, auto enum int b) {}
void main() {
  int x = 10;
  enum int y = 10;
  foo(x, y);
  int z = 10;
  foo(x, z);
}


is syntax sugar for:

void foo_t(int b)(int a) {}
void foo(int a, int b) {}
void main() {
  int x = 10;
  enum int y = 10;
  foo_t!(y)(x);
  int z = 10;
  foo(x, z);
}

This allows for a cheap form of partial compilation :-)
It's "cheap" for the compiler because it's the programmer that tells the
compiler on what it can partially compile, so the compiler doesn't need to be
smart to guess as in a true partial compilation implementation.
In many situations I think this can be enough.

Bye,
bearophile