+def _if_expression_parser(index, tokens):
+ failure = (False, index, None)
+
+ if tokens[index].match == 'if':
+ index += 1
+ else:
+ return failure
+
+ success, index, condition_expression = _or_level_expression_parser(index, tokens)
+
+ if not success:
+ raise Exception('Expected condition after "if" on line {}'.format(tokens[index].line))
+
+ if tokens[index].match == 'do':
+ index += 1
+ else:
+ raise Exception('Expected "do" after "if" on line {}'.format(tokens[index].line))
+
+
+ success, index, if_statement_list = _zero_or_more_parser(tuple, _statement_parser)(index, tokens)
+ _, index, _ = consume_newlines(index, tokens)
+
+ if tokens[index].match == 'else':
+ index += 1
+ success, index, else_statement_list = _zero_or_more_parser(tuple, _statement_parser)(index, tokens)
+ _, index, _ = consume_newlines(index, tokens)
+ else:
+ else_statement_list = ()
+
+ if tokens[index].match == 'end':
+ index += 1
+ else:
+ raise Exception('Expected "end" after "if" on line {}'.format(tokens[index].line))
+
+ return (
+ True,
+ index,
+ FurIfExpression(
+ condition_expression=condition_expression,
+ if_statement_list=if_statement_list,
+ else_statement_list=else_statement_list,
+ ),
+ )
+
+_expression_parser = _or_parser(
+ _or_level_expression_parser,
+ _if_expression_parser, # This should always be at the top level
+)
+
+def _expression_statement_parser(index, tokens):
+ failure = (False, index, None)
+
+ success, index, expression = _expression_parser(index, tokens)
+
+ if not success:
+ return failure
+
+ return (True, index, FurExpressionStatement(expression=expression))
+
+BUILTINS = {'print', 'pow'}