digitalmars.D.bugs - [Issue 4168] New: More handy std.conv.to for std.algorithm.map
- d-bugmail puremagic.com (57/57) May 09 2010 http://d.puremagic.com/issues/show_bug.cgi?id=4168
- d-bugmail puremagic.com (12/12) Aug 15 2010 http://d.puremagic.com/issues/show_bug.cgi?id=4168
http://d.puremagic.com/issues/show_bug.cgi?id=4168 Summary: More handy std.conv.to for std.algorithm.map Product: D Version: future Platform: All OS/Version: All Status: NEW Severity: enhancement Priority: P2 Component: Phobos AssignedTo: nobody puremagic.com ReportedBy: bearophile_hugs eml.cc Conversion of an array of strings to an array of integers is a common usage of map (for example the array of strings can come from the splitting of a line read from a text file), but this code doesn't work: import std.algorithm: map; import std.conv: to; void main() { auto number = to!int("10"); // OK auto strings = ["10", "20"]; auto data = map!(to!int)(strings); // ERR } DMD 2.045 shows: test.d(6): Error: template instance to!(int) does not match any template declaration You must give both types to the to!, something that you usually don't need to give (see the 'number' variable in the first example): import std.algorithm: map; import std.conv: to; void main() { auto strings = ["10", "20"]; auto data = map!(to!(int, string))(strings); // OK } So to make to!() more handy when used with a map!() Phobos2 can define two to! This is a test that shows how it can be done (here I have used the name 'foo' instead of 'to', but in std.conv it will keep its 'to' name): import std.stdio: writeln; import std.conv: to; import std.algorithm: array, map; template foo(Tout) { Tout foo(Tin)(Tin x) { return to!(Tout, Tin)(x); } } Tout foo(Tout, Tin)(Tin x) { return to!(Tout, Tin)(x); } void main() { auto strings = ["10", "20"]; auto data = map!(foo!int)(strings); // OK writeln(foo!int("10")); // OK writeln(foo!(int, string)("20")); // OK } -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
May 09 2010
http://d.puremagic.com/issues/show_bug.cgi?id=4168 David Simcha <dsimcha yahoo.com> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |RESOLVED CC| |dsimcha yahoo.com Resolution| |FIXED Fixed 2.048. Your test program now compiles. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Aug 15 2010