[antlr-interest] ANTLRv3 emits literal DOWN instead of Token.Down
Kalen Petersen
khp at cypress.com
Tue Dec 4 10:01:50 PST 2007
Gavin Lambert wrote:
> At 14:53 4/12/2007, Kalen Petersen wrote:
> [...]
> >grammar DownBug;
> >
> >bug_rule
> > : ^('+' bug_rule)
> > | '+' bug_rule
> > | ZERO
> > ;
>
> Hmm. I'm surprised that even compiles. That doesn't seem like a
> valid construct to me -- you're using ^ like an AST node (which
> shouldn't work outside a rewrite rule or tree parser).
This came originally from a rewrite grammar working on an AST, it's
true. In the process of removing gobs of extraneous other code, I also
removed those options. Originally, it was actually two rules from an
expression grammar, one for postfix '++' and the other for prefix '++'.
Hopefully that justifies this as a little less crazy or just invalid code.
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