On Apr 19, 2010, at 10:59 AM, Daniels, Troy (US SSA) wrote:
> That fails when there are predicates in the rule that use the variables.
> Consider this rule, based on something that was discusses on the list a while
> ago.
>
> Fragment LETTER: 'a'..'z';
>
> OneToFiveLetters:
> @init {
> int i = 0;
> }
>
> ( {i<5}? LETTER {++i;} )+ ;
Predicates are difficult to implement because you can't really have the action
executed to you are sure that the entire rule matches. That means backtracking
if there are other rules that can match that input string. The solution is to
use the always executing {{++i;}} version of the action. because i it's a local
variable, the side effects are relevant.
Ter
List: http://www.antlr.org/mailman/listinfo/antlr-interest
Unsubscribe:
http://www.antlr.org/mailman/options/antlr-interest/your-email-address
--
You received this message because you are subscribed to the Google Groups
"il-antlr-interest" group.
To post to this group, send email to [email protected].
To unsubscribe from this group, send email to
[email protected].
For more options, visit this group at
http://groups.google.com/group/il-antlr-interest?hl=en.
