CODEWITHSUNDEEP
antlr4
Nilo Paim
Nilo Paim

Reputation: 447

How to decide between Listener and Visitor?

I'm using Antlr4, C# version under Visual Studio. Works nicelly.

AFAIK (but I may be wrong) Listeners and Visitors are used for similar tasks.

So, how to decide between them? Or can I use both? Note that all the samples I've found uses Listener OR Visitor, but not both...

Upvotes: 1

Views: 1961

Answers (1)

xNappy
xNappy

Reputation: 158

In my opinion he visitor is a good choice because you have full control of the traversal

Here is quote from the book "The Definitive ANTLR 4 Reference"

The biggest difference between the listener and visitor mechanisms is that listener methods are called by the ANTLR-provided walker object, whereas visitor methods must walk their children with explicit visit calls. Forgetting to invoke visit() on a node’s children means those subtrees don’t get visited

If you translate the input to a lower level, e.g. virtual machine instructions, both patterns may be useful.

Upvotes: 1

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