digitalmars.D.bugs - [Issue 4582] New: distinct field names constraint for std.typecons.Tuple
- d-bugmail puremagic.com (41/41) Aug 04 2010 http://d.puremagic.com/issues/show_bug.cgi?id=4582
- d-bugmail puremagic.com (12/12) Oct 07 2010 http://d.puremagic.com/issues/show_bug.cgi?id=4582
- d-bugmail puremagic.com (8/8) Oct 07 2010 http://d.puremagic.com/issues/show_bug.cgi?id=4582
http://d.puremagic.com/issues/show_bug.cgi?id=4582 Summary: distinct field names constraint for std.typecons.Tuple Product: D Version: D2 Platform: All OS/Version: All Status: NEW Keywords: patch Severity: enhancement Priority: P2 Component: Phobos AssignedTo: nobody puremagic.com ReportedBy: bearophile_hugs eml.cc It's better to put guards as template constraints at the std.typecons.Tuple, so erroneous Tuple template instantiations fail at the instantiation point, giving a more useful error message in the user code instead giving an error inside the std.typecons module (this is one of the main purposes of template constraints). This code guards against duplicated field names: private template Iota(int stop) { // this is useful in general static if (stop <= 0) alias TypeTuple!() Iota; else alias TypeTuple!(Iota!(stop-1), stop-1) Iota; } private bool distinctFieldNames(T...)() { enum int tlen = T.length; // can't move this below, probably DMD bug foreach (i1; Iota!(tlen)) static if (is(typeof(T[i1]) : string)) foreach (i2; Iota!(tlen)) static if (i1 != i2 && is(typeof(T[i2]) : string)) if (T[i1] == T[i2]) return false; return true; } // ............... struct Tuple(T...) if (distinctFieldNames!(T)()) { -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Aug 04 2010
http://d.puremagic.com/issues/show_bug.cgi?id=4582 Andrei Alexandrescu <andrei metalanguage.com> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |ASSIGNED CC| |andrei metalanguage.com AssignedTo|nobody puremagic.com |andrei metalanguage.com 08:02:31 PDT --- Excellent. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Oct 07 2010
http://d.puremagic.com/issues/show_bug.cgi?id=4582 Thank you. But I think some tests/benchmarks may be done to make sure this extra test doesn't slow down too much the compilation of programs that define many tuple types. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Oct 07 2010