Debug arguments?

[bearophile via Digitalmars-d]

Sometimes you want to give arguments to a function that are only 
used for debug builds. So is it a good idea to introduce debug 
arguments (only allowed as trailing arguments, like the arguments 
with a default value)?

import std.stdio;
void foo(ref int x, debug int y) {
    x++;
    debug writeln(y);
}
void main() {
    int a, b;
    foo(a, debug b);
}


That is equivalent to code like:

import std.stdio;
debug {
    void foo(ref int x, int y) {
        x++;
        writeln(y);
    }
} else {
    void foo(ref int x) {
        x++;
    }
}
void main() {
    int a, b;
    debug {
        foo(a, b);
    } else {
        foo(a);
    }
}


This avoids to pass useless arguments, and it documents (in the 
code) that certain arguments are not used in a function in 
non-debug builds.

(The "debug" at the calling point is not necessary, but it 
documents better the meaning of the code).

Bye,
bearophile