#!/usr/bin/python
"""<http://infomesh.net/2002/eep/>"""

import re

class Article: 
   def __init__(self, s): 
      s, self.r = str(s), str(s)
      if s[0] == '"': self.v, self.t = s[1:], 'Literal'
      elif s[0] == '?': self.v, self.t = s[1:], 'Univar'
      elif s[0] == '_': self.v, self.t = s[2:], 'Exivar'
      elif s[0] == '<': self.v, self.t = s[1:-1], 'URI'
      else: self.v, self.t, self.r = s, 'URI', '<%s>' % s
   def __repr__(self): return self.r
   def set(self, s): self.__init__(s)

def parse(s, t=[]): 
   if len(s) == 0: raise 'Document has no content'
   rc, a = re.compile(r'(\#[^\n]*)'), r'(<.*?>|_:\S+|\?\S+|"(?:\\"|[^"])*")[ \t]'
   rw, rt, y = re.compile(r'[ \t]+'), r'[ \t]*%s%s%s*.[ \t]*' % (a, a, a), t[:]
   for line in s.replace('\r\n', '\n').replace('\r', '\n').split('\n'): 
      if re.compile(rt).match(line):
          x = re.compile(rt).findall(line)[0]
          y.append([Article(x[0]), Article(x[1]), Article(x[2])])
      elif rc.match(line) or rw.match(line) or (len(line) == 0): continue
      else: raise 'Line is invalid', line
   return y

def query(q, triples, r=[]): 
   result = r[:]
   for t in triples: 
      if (((q[0].t == 'Univar') or (t[0].r == q[0].r)) 
          and ((q[1].t == 'Univar') or (t[1].r == q[1].r)) 
          and ((q[2].t == 'Univar') or (t[2].r == q[2].r))): result.append(t)
   return result

if __name__=="__main__": 
   print __doc__