http://d.puremagic.com/issues/show_bug.cgi?id=6384
--- Comment #2 from [email protected] 2013-08-22 20:16:25 PDT --- There are actually at least two possible isComparable's that would be helpful in signature constraints. One checks if "a<b" compiles, the other checks if "a==b" compiles. I notice that some Phobos code uses is(typeof(a) : typeof(b)) in signature constraints, only to write if(a==b) in the function body, which is fallacious: just because a is implicitly convertible to b does not necessarily mean == is defined between them. More generally, code should really test for specific operations they need to use, instead of just assuming that is(A : B) implies A.init <op> B.init is valid. To that end, maybe we need isValidBinaryOp instead: template isValidBinaryOp(T1, string op, T2) { alias isValidBinaryOp = is(mixin("T1.init" ~ op ~ "T2.init") : bool); } then we could write signature constraints of the form: auto myFunc(T,U)(T t, U u) if (isValidBinaryOp!(T, "<", U)) { ... } -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
