https://issues.dlang.org/show_bug.cgi?id=16446

          Issue ID: 16446
           Summary: Captures does not expose named captures for iteration
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: enhancement
          Priority: P1
         Component: phobos
          Assignee: nobody@puremagic.com
          Reporter: justin@economicmodeling.com

The Captures struct maintains an internal list of named subexpressions in _names but it is private and the public API offers no way to discover which named subexpressions exist, only indexing when the subexpression's name is already known.  Ideal usage scenario would look like this:

string sample = "ABCDEFG";
auto re = regex( getExpressionFromuser() );
auto captures = sample.matchFirst(re);

foreach (string name, string hit; captures.namedSubExpressions)
    writeln(name, ": ", hit);

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