verbal_expressions.py

import re


def re_escape(fn):
    def arg_escaped(this, *args, **kwargs):
        t = [isinstance(a, VerEx) and a.s or re.escape(str(a)) for a in args]
        return fn(this, *t, **kwargs)
    return arg_escaped

    
def group(val, name=None):
    prefix = '?P<{0}>'.format(name) if name else ''
    return '(' + prefix + val + ')'
    

class VerEx(object):
    '''
    --- VerbalExpressions class ---
    the following methods behave different from the original js lib!

    - end_of_line
    - start_of_line
    - or
    when you say you want `$`, `^` and `|`, we just insert it right there.
    No other tricks.

    And any string you inserted will be automatically grouped
    except `tab` and `add`.
    '''
    def __init__(self):
        self.s = ''
        self.modifiers = {'I': 0, 'M': 0}

    def __getattr__(self, attr):
        ''' any other function will be sent to the regex object '''
        regex = self.regex()
        return getattr(regex, attr)

    def __str__(self):
        return self.s

    def add(self, value):
        self.s += value
        return self

    def regex(self):
        ''' get a regular expression object. '''
        return re.compile(self.s, self.modifiers['I'] | self.modifiers['M'])
    compile = regex

    def source(self):
        ''' return the raw string'''
        return self.s
    raw = value = source

    # ---------------------------------------------

    def anything(self, name=None):
        return self.add(group('.*', name))

    @re_escape
    def anything_but(self, value):
        return self.add(group('[^' + value + ']*'))

    def end_of_line(self):
        return self.add('$')

    @re_escape
    def maybe(self, value):
        return self.add(group(value) + "?")

    def start_of_line(self):
        return self.add('^')

    @re_escape
    def find(self, value):
        return self.add(group(value))
    then = find

    # special characters and groups

    @re_escape
    def any(self, value):
        return self.add(group("[" + value + "]"))
    any_of = any

    def line_break(self):
        return self.add(group(r"\n|(\r\n)"))
    br = line_break

    @re_escape
    def range(self, *args):
        from_tos = [args[i:i+2] for i in range(0, len(args), 2)]
        return self.add(group("[" + ''.join(['-'.join(i) for i in from_tos]) + "]"))

    def tab(self):
        return self.add(r'\t')

    def word(self, name=None):
        return self.add(group(r"\w+", name))
        
    def number(self, name=None):
        return self.add(group(r"\d+", name))

    def OR(self, value=None):
        ''' `or` is a python keyword so we use `OR` instead. '''
        self.add("|")
        return self.find(value) if value else self

    def replace(self, string, repl):
        return self.sub(repl, string)

    # --------------- modifiers ------------------------

    # no global option. It depends on which method
    # you called on the regex object.

    def with_any_case(self, value=False):
        self.modifiers['I'] = re.I if value else 0
        return self

    def search_one_line(self, value=False):
        self.modifiers['M'] = re.M if value else 0
        return self