code: def exact_match(self):
          
          #We don't have to worry about grouping or anything else fancy. Just
          #loop through forward and back until we hit a character that can't be
          #part of a variable or function name.
          if self._exact_match is None:
              i = self.pos[1] - 1
              start = None
              end = None
              line = self.current_line
              terminators = ['(', ')', '\n', ' ', '=', '%', ',']
              while i >= 0 and start is None:
                  if line[i] in terminators:
                      start = i + 1
                  i -= 1
  
              i = self.pos[1]
              while i < len(line) and end is None:
                  if line[i] in terminators:
                      end = i
                  i += 1
  
              self._exact_match = line[start:end].lower()
  
          return self._exact_match
docs: Returns the symbol under the cursor looking both directions as part
          of a definition lookup for an exact match.