parameters: (self, p)
docstring: expression : LEFT_PARENTHESE search_text RIGHT_PARENTHESE
                    | column
                    | value
docstring_summary: expression : LEFT_PARENTHESE search_text RIGHT_PARENTHESE
                    | column
                    | value
docstring_tokens: expression : LEFT_PARENTHESE search_text RIGHT_PARENTHESE | column | value
function: def p_expression(self, p):
      '''expression : LEFT_PARENTHESE search_text RIGHT_PARENTHESE
                    | column
                    | value'''
      if len(p) == 2:
        p[0] = p[1]
      else:
        p[0] = p[2]
function_tokens: def p_expression ( self , p ) : if len ( p ) == 2 : p [ 0 ] = p [ 1 ] else : p [ 0 ] = p [ 2 ]