Listex -- regular expressions for other sequences

Use Case

You have a list of objects (dictionaries, hashes, js objects), of which you want some subset. You would use a regular expression if these were strings, but they aren't!

Let listex help!

Same great concepts you love from regexen, generalized out to match functions over objects!

Example

>>> from listex import Listex, Some
>>> mylist = [dict(x=1), dict(a=1,b=3), dict(x=1), dict(a=1,x=[1,2,3])]
>>> print list(Listex(dict(a=1)).search(mylist))
[(1, 2), (3, 4)]  # the listex matched at 1 and 3

What exactly is Regular Expression?

(see http://swtch.com/~rsc/regexp/regexp1.html)

allowed:

• s[*+?]
• s|t
• st

precedence

• (weakest)
• alternation
• concatenation
• repetition
• parens
• (stongest)

NO backreferences! backreferences aren't pure re's and can require exponential cost.

TODO / Scope

• expose simple regular expressions over objects (grouping, counts, greedy/non-greedy)
• better 'chainable' language for listexen
• javascript implemention
• full test suite
• improve search implementation / runtime