Is there a way to find out either the string, begin/end iterator or even the position of the regex string that created a sub_match?

Lets say I have a regex parser that allows a dynamically defined regex to be passed (say, user defined, from a config file).

So A user might pass: Bla (.*) blerk (.*) ([[:digit:]]+) Bla .* ([[:alpha:]]*)

Or pretty much any regex (actually, in my case, this is not completely true, however lets just say for argument's sake ...).

Now assuming another arbitary string is passed to this function, and it matches the user-passed regex. How do I find out what the REGEX was that matched this particular sub_match (or the position in the passed regex).

For example, if the second regex above was passed, I know by looking at it that matches[1] was 'created' by ([[:digit:]]+) and matches[2] was 'created' by ([[:alpha:]]*). However programatically, I cannot find out.

Why can sub_match not include a mfirst and msecond parameter (and mstr() function), that like first and second (and str()), will point to the beginning and end, but of the regex string instead of the 'input' string.

Because no-one has ever asked for it before. If it were to be done the information would be stored inside the basic_regex object (because it's strictly a property of the regular expression, so there's no need to clutter up the sub_match object with that information. However, it would slow down regex parsing and compilation quite a bit, because it would involve dynamic memory structures (something I've been trying to eliminate as far as possible for performance reasons). Whatever this won't be in 1.33, after that I guess it depends on whether there is demand from anyone else for this, you seem to be a little unusual in needing this at present. John.