By the way, if what you're actually looking for on a high level is a Haskell-like string matching engine, it might be better to go back to the original sources.  Look up Kleene's work on string pattern matching; while regexes derive from it, its more direct descendants are the pattern matching mechanisms in SNOBOL and Icon.  I've thought for a while that the right way to do it in Haskell is not parsing a program encoded as a string/regex, but instead a monadic "Kleene machine"; but I've never managed to work out a decent functional implementation (too many irons in the fire, not enough spoons to even keep track of them much less do something useful with them).
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brandon s allbery                                      allbery.b@gmail.com
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