CODEWITHSUNDEEP
optimizationantlr4productionvisitors
Fabrice NEYRET
Fabrice NEYRET

Reputation: 734

antlr4: code production vs visitors

My grammar contains production code. Is it really possible to mix this with visitors ? (my problem is to implement if cond then block endif )

In terms of performances, is there a difference between production code in grammar vs visitors ? (I have to re-evaluate several programs 30-60 times per second, in the browser on Javascript target. I understood direct production code was closer to compiled code but maybe I'm wrong).

Upvotes: 1

Views: 204

Answers (1)

GRosenberg
GRosenberg

Reputation: 5991

Actions of the type shown only affect the content of the parse-tree -- an e context node will be created with a return field having the Action computed value. Consequently, there is no bar to subsequently walking the parse tree with a visitor.

Using a visitor (without using the embedded Actions) can achieve the same end results.

Using a visitor will incur some overhead - impossible to say whether it would be significant without testing (using the Java/Antlr runtime, evaluating a relatively complex grammar with multiple walkers over a fairly lengthy source text, takes 3ms average in a warm environment - YMWV).

Upvotes: 1

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