A C++ Pattern Matching Library based on lstrlib.c

[steve donovan <steve.j.donovan@...>]

I'll always be a admirer of the Lua pattern matching library, and
started thinking about how one could design a C++ library that
provided a similar interface.  Initially I was wrapping POSIX regexps,
but with a twist: the ugly '\\' can be written as '%' and nasties like
[[:alpha:]] can be written as '%a'. (This is a surface transformation
and of course the semantics remains unaltered.)  During my experiments
I found that the GNU regex implementation is pretty bad at dealing
with large chunks of text (my test corpus was _The Adventures of
Sherlock Holmes_ from the Gutenberg project.). So I've extracted the
pattern matcher from lstrlib.c, and made an alternative wrapper for
that as well.

So, the relevance here is: first, can we get a fluid Lua-like
interface, and what adjustments need to be made? Second, re-using
parts of Lua can be fun! [1] is the practical result and [2] is the
discussion.

Rxp words("%a+",Rx::lua);  // simple Lua-style regexps
 for (auto M:  words.gmatch(text)) {
     if (M[0].size() > 6)
         cout << M[0] << "\n";
 }

;)

steve d.

[1] https://github.com/stevedonovan/rx-cpp
[2] http://steved-imaginaryreal.blogspot.com/2015/05/what-can-c-libraries-learn-from-lua.html