On Jun 7, 11 03:00, Steven Schveighoffer wrote:
Someone wrote a very compelling argument for ufcs (uniform function call
syntax) for ranges, and that is, given a slew of range functions, and a
slew of ranges, it is nice to use a fluent programming syntax to specify
wrappers for ranges without having to extend each range type. For example:
take(10,stride(2,cycle([3,2,5,3])));
vs.
[3,2,5,3].cycle().stride(2).take(10);
And I thought damn it would be nice if ranges could implement ufcs, but
other types that you didn't want to allow infinite extendability could
avoid it. That gave me an idea :)
import std.stdio;
struct ufcs
{
auto opDispatch(string name, T...)(T args) // appropriate if compiles
constraint here
{
mixin("return ." ~ name ~ "(this, args);");
}
}
int foo(ufcs x, int y)
{
writefln("it works! %d", y);
return y+1;
}
void main()
{
ufcs u;
auto x = u.foo(1);
assert(x == 2);
}
And it does indeed work (2.053)...
So we can have ufcs without any changes to the compiler, and we also
make it a *choice* for people who don't want to allow infinite
extendability, and don't want to deal with possible compiler ambiguities.
The opDispatch could even be a mixin itself (I think).
What do you think?
-Steve
Maybe better
auto ref opDispatch(string name, T...)(auto ref T args) {
mixin("return ." ~ name ~ "(this, args);");
}
so that ref-returns and ref-parameters can be handled as well. Doesn't
work for 'lazy' though. It also cannot preserve 'pure'-ity,
'nothrow'-ness and '@safe'-ty of the original function.
