Licheng Fang wrote: > Oh, please do have a look at the second link I've posted. There's a > table comparing the regexp engines. The engines you've tested probably > all use an NFA implementation.
Unfortunately, the stuff about NFA's is wrong. Friedl's awful book was the first time I saw this confusion about what NFA is; I don't know if he originated the mess or just propagated it. "Nondeterministic finite automata" is well defined in theory of computation. The set of languages accepted by NFA's is exactly the same as the set accepted by DFA's. What Python uses is search-and-backtrack. Unfortunately such engines don't have much theory behind them, and it's hard to reason generally about what they do. -- --Bryan -- http://mail.python.org/mailman/listinfo/python-list
