[antlr-interest] Intentional?: Can't label (tokens*)
Steve Bennett
stevagewp at gmail.com
Wed Dec 5 04:09:37 PST 2007
On 12/5/07, Brendon McLean <antlr at twistedprotein.com> wrote:
> I was wondering whether the labelling of parenthesised tokens should
> be allowed?
>
> Currently, you can construct a grammar like this:
>
> postincdec : varref op=('++' | '--') -> (^POSTFIX_EXPR $op)
Looks like what I did wrong in my previous post. How should one write this?
postincdec : varref (op='++' | op='--') -> ^(POSTFIX_EXPR $op)
(I assume you meant ^ before the other parentheses).
Incidentally, I find it odd that it's illegal to parenthesise the AST structure:
... -> (foo);
seems to be illegal. It's not particularly useful, but you expect it
to be ignored.
Steve
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