It seems doable to have some kind of function transformer (adaptor?) for this.
from: int foo(int a = 0, int b = 1, double c = 0.0, bool d = false) { return 1;} alias namedParams!foo nfoo; nfoo("d", true); // a = 0, b = 1, c = 0.0, d = true nfoo("d", true, "b", 100); // a=0, b=100, c=0.0, d=true nfoo(1, 2, "d", true); // a=1, b=2, c=0.0, d=true That is, it expects some values, then string/values couples. Downside: in the above example, if foo accepts a string argument in first or second position the "d" will be passed down as an argument... or, using AA syntax: nfoo(1, ["d":true],["b":100]); Would that be palatable? Because I think it's doable. To obtain the arguments names: int foo(int a, int b, double c = 0.0, bool d = true) { return 1;} template Name(alias foo) if (isCallable!foo) { enum string Name = S!(foo.stringof); } template S(string s) // this template is just a trick because foo.stringof directly displeases DMD { enum string S = s; } writeln(Name!foo); // "int(int a, int b, double c = 0, bool d = true)" So this gives me: - the arguments names - which ones have default values - what is that default value The difficulty here is correctly parsing the ( ,,,) part, without getting desoriented by argument types that themselves use (,), like templated types. Philippe