[Issue 2305] New: ".sort" on array of struct can use templated "opCmp"

[d-bugmail at puremagic.com]

http://d.puremagic.com/issues/show_bug.cgi?id=2305

           Summary: ".sort" on array of struct can use templated "opCmp"
           Product: D
           Version: unspecified
          Platform: PC
               URL: http://codepad.org/63qU9Ndr
        OS/Version: Windows
            Status: NEW
          Severity: enhancement
          Priority: P2
         Component: DMD
        AssignedTo: bugzilla at digitalmars.com
        ReportedBy: tsalm at free.fr


Actually, to sort an array of "struct", ".sort" don't use a templated opCmp
method.

Here is an example that illustrate the problem (same as in the url) :

import tango.io.Stdout;

struct A{
 int i;
 static A opCall(int j){ A a; a.i=j; return a; }
 int opCmp(T)(T b) { static if (is(T:A)||is(T:A*)) return (i-b.i); else return
false;}
}

struct B{ // opposite ordering
 int i;
 static B opCall(int j){ B res; res.i=j; return res; }
 int opCmp(T)(T b) { static if (is(T:B)||is(T:B*)) return -(i-b.i); else return
false; }
}

void main()
{
 int a=1,b=2;

 A a2=A(a),b2=A(b);
 Stdout("A")(a2.opCmp(b2))(" ")(a2<b2).newline;
 auto aa2=[a2,b2];

 B a3=B(a),b3=B(b);
 Stdout("B")(a3.opCmp(b3))(" ")(a3<b3).newline;
 auto aa3=[a3,b3];

 aa2.sort;
 aa3.sort;

 foreach(v;aa2) Stdout( v.i )(" ");
 Stdout.newline;
 foreach(v;aa3) Stdout( v.i )(" ");
 Stdout.newline;
}


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