parser.py 文件源码

def parse_match_expr(self):
        expr = ast.MatchExpression(self.cur_tok, None, None)

        if not self.expect(token.LPAREN):
            return None

        self.next()
        expr.expr = self.parse_expr(LOWEST)

        if not self.expect(token.RPAREN):
            return None

        if not self.expect(token.LBRACE):
            return None

        expr.arms = self.parse_match_arms()
        if not expr.arms:
            return None

        return expr