On Thursday, 1 September 2016 at 16:50:49 UTC, Steven
Schveighoffer wrote:
I agree. Note that if(isSomethingElse!T) may also need to have
if(!isSomething!T && isSomethingElse!T).
A suggestion in the past was to allow "else" clauses with if
constraints. I had envisioned:
void f(T)(T t) if(isSomething!T) {}
void f(T)(T t) else if(isSomethingElse!T) {}
void f(T)(T t) else {}
But someone also suggested this more DRY solution as well
(can't remember the thread for it):
void f(T)(T t) if(isSomething!T) {}
else if(isSomeghingElse!T) {}
else {}
Obviously this doesn't work across modules, but how does that
even work? You need some sort of ordering for an if/else
if/else scheme to work.
Having a "fallback" template could potentially define a way to
handle the default, but it doesn't fix the other issues.
I don't know if it's because of the current rules, or just
natural, but typically I'm not splitting my template functions
between many modules.
-Steve
I just thought of this, but cannot test if it works. If it does,
maybe it would be a suitable solution?
void f(T)(T t) if(isSomething!T) {}
void f(T)(T t) if(isSomethingElse!T) {}
//Taken if no other "overload" of f will intantiate with the
given T
void f(T)(T t) if(!__traits(compiles, alias _ = .f!T)) {}
