On Thu, Aug 28, 2008 at 12:23 PM, Terrence Brannon <[EMAIL PROTECTED]> wrote: > Hello, I'm using a tool (PLY) which apparently expects the tokens to > be created using r'' > > But because one token is a rather complex regular expression, I want > to create the regular expression programmatically. > > How can I generate a string and then create something of the same type > that the r'' function does?
The "r" prefix isn't a function or a type, it's merely a special literal syntax for strings that's handy when you're writing regexes and therefore have to deal with another level of backslash escaping. See the second to last paragraph of http://docs.python.org/ref/strings.html for more info. Regards, Chris > > Concretely, in the program below, consonant is not the same type as > t_NAME, but I assume that it needs to be for PLY to use it for > tokenizing: > > import re > > t_NAME = r'[a-zA-Z_][a-zA-Z0-9_]*' > > guttural = 'kh?|gh?|\"n' > palatal = '(?:chh?|jh?|\~n)' > cerebral = '\.(?:th?|dh?|n)' > dental = '(?:th?|dh?|n)' > semivowel = '[yrlv]' > sibilant = '[\"\.]?s' > aspirant = 'h' > > consonant = re.compile('|'.join([guttural , palatal , cerebral , > dental , semivowel , sibilant , aspirant])) > > print consonant > print t_NAME > -- > http://mail.python.org/mailman/listinfo/python-list > -- http://mail.python.org/mailman/listinfo/python-list
