毕设&课设&项目&实训-基于知识图谱的智能问答机器人.zip

REfO ==== Lacking a proper name, REfO stands for "Regular Expressions for Objects". It's a python library that supplies a functionality very similar to the python `re` module (regular expressions) but for arbitrary sequences of objects instead of strings (sequences of characters). In addition to that, it's possible to match each object in a sequence with not only equality, but an arbitrary python function. For example, if you have a sequence of integers you can make a regular expression that asks for a even number followed by a prime number followed by a 3-divisible number. This software was written by Rafael Carrascosa while working at Machinalis in the first months of 2012. Contact: rcarrascosa@machinalis.com or rafacarrascosa xyz gmail.com (replace " xyz " with "@") [](https://travis-ci.org/gjhiggins/refo) How to use it ------------- The syntax is a little bit different than python's re, and similar to that of pyparsing, you have to more-or-less explicitly build the syntax tree of your regular expression. For instance: `"ab"` is `Literal("a") + Literal("b")` `"a*"` is `Star(Literal("a"))` `"(ab)+|(bb)*?"` is: a = Literal("a") b = Literal("b") regex = Plus(a + b) | Star(b + b, greedy=False) You can also assign a group to any sub-match and later on retrieve the matched content, for instance: regex = Group(Plus(a + b), "foobar") | (b + b) m = match(regex, "abab") print m.span("foobar") # prints (0, 4) For more, check out the examples in the examples folder. How we use it ------------- At Machinalis we use REfO for applications similar to that in `examples/words.py`, check it out! About the implementation ------------------------ I use a Thompson-like virtual machine aproach, which ensures polynomial time worst-case complexity. See `examples/poly_time.py` for an example of this. The implementation is heavily based on Russ Cox notes, see http://swtch.com/~rsc/regexp/regexp2.html for the source. If you go to read the code, some glossary: - RE -- regular expression - VM -- virtual machine - Epsilon transitions -- All VM instructions that do not consume a symbol or stop the thread (for example an Accept). Acknowledgements ---------------- Thanks Russ Cox for sharing the awesome info and insights on your web site. Thanks Javier Mansilla for reviewing the code and being enthusiastic about it. Thanks Machinalis for everything :)