[antlr-interest] Syntactic anti-predicates

[Steve Bennett]

On 2/12/08, Gerald B. Rosenberg <gbr at newtechlaw.com> wrote:
>
>  Won't this do the trick?
>
>  table:
>     LEFT_BRACE PIPE ws? table_format? NL
>     ( ( ws? PIPE RIGHT_BRACE )=> ws? PIPE RIGHT_BRACE | table_line )+
>  ;

It's close, but matches too much input on data like:

{|
|foo
|}
|blah

That last row (|blah) should not be matched by the table rule. Sort of
comes back to the need for the anti-predicate: the only way to
terminate a loop is for everything in it to fail, and it can be a bit
awkward arranging for that to take place.

Steve