Davidson Corry:
> The only reason to have an 'out(result)' form is to declare that we
> intend to use the magic 'result' symbol in the post-condition testing.
This is not true. Currently 'result' has nothing magic, it's just a variable
name, you are free to change it:
int result;
int foo(int x, out int result)
out(y) {
assert(y > 0);
}
body {
result = 10;
return -1;
}
void main() {
int z;
auto s = foo(4, z);
}
> I think the thing to do is to just declare 'out' as we currently do [or
> 'scope(out)' as I am proposing], and treat the 'result' symbol magically
> in the post-condition code whether or not it is pre-declared -- that is,
> have the compiler find it and interpret it as the magic returned-value.
In some rare situations magic is acceptable, but it's dangerous, and in most
situations it's better to avoid it. Unless "result" becomes a keyword (so you
can't assign something to it by mistake), then the current syntax with
out(someConstVariableName) seems better.
Bye,
bearophile
