• via Digitalmars-d-bugs (33/33) Jul 08 2016 https://issues.dlang.org/show_bug.cgi?id=16255

via Digitalmars-d-bugs <digitalmars-d-bugs puremagic.com> writes:

https://issues.dlang.org/show_bug.cgi?id=16255

          Issue ID: 16255
           Summary: std.algorithm.iteration.each on opApply doesn't
                    support ref
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: normal
          Priority: P1
         Component: phobos
          Assignee: nobody puremagic.com
          Reporter: schveiguy yahoo.com

Look at this code:

struct S
{
   int x;
   int opApply(int delegate(ref int _x) dg) { return dg(x); }
}

void main()
{
   S s;
   foreach(ref a; s) ++a;
   assert(s.x == 1);
}

If we replace the foreach loop with an each call, we would do:

s.each!"++a";

Except it doesn't work. When each accepts the iterable, it accepts it by value.
It should accept it by reference (if it's a class, it could take the class
reference by value). Otherwise, the point of using ref throughout each is kind
of useless.

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