[antlr-interest] Removing global backtracking
Johannes Luber
jaluber at gmx.de
Sun Feb 10 05:39:13 PST 2008
Andreas Bartho schrieb:
> Hello,
>
> inspired by the recent discussion about global backtracking I tried to
> remove global backtracking from my grammar. My plan was to enable
> backtracking for each rule individually, then turn global backtracking
> off and try to disable individual backtracking for one rule at a time to
> identify the rules that cause problems.
> However, this does not work. ANTLR reports for a number of rules that
> multiple alternatives can match a given input (even for rules that have
> only one alternative).
> Isn't global backtracking and local backtracking for each rule supposed
> to be equivalent? If not, how do they differ?
> I tried version 3.01 and the latest intermediate built.
>
> Andreas
>
I believe that this behavior means that you have an
if-then-else-ambiguity in your grammar. Usually their default behaviour
is the required one.
Johannes
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