class_docstr: Uses a regular expression to extract tokens from text.
  
  >>> rex = RegexTokenizer()
  >>> [token.text for token in rex(u("hi there 3.141 big-time under_score"))]
  ["hi", "there", "3.141", "big", "time", "under_score"]
code: def __eq__(self, other):
      if self.__class__ is other.__class__:
          if self.expression.pattern == other.expression.pattern:
              return True
      return False
  
imports: from whoosh.compat import u, text_type
  from whoosh.analysis.acore import Composable, Token
  from whoosh.util.text import rcompile
label_desc: Use image node_id 2 for calling the RegexTokenizer obj's underlying member method code with example usage: obj.__eq__(other) and returns: False, True