abstract syntax tree - How can I build an AST using ANTLR4? -


i have antlr3 grammar builds abstract syntax tree. i'm looking upgrading antlr4. however, appears antlr4 builds parse trees , not abstract syntax trees. example, output=ast option no longer recognized. furthermore neither "ast" nor "abstract syntax" appears in text of "the definitive antlr4 reference".

i'm wondering if i'm missing something.

my application knows how crawl on ast produced antlr3. changing process parse tree isn't impossible bit of work. want sure it's necessary before start down road.

antlr 4 produces parse trees based on grammar instead of asts based on arbitrary ast operators and/or rewrite rules. allows antlr 4 automatically produce listener , visitor interfaces can implement in code using grammar.

the change can dramatic users upgrading existing applications version 3, whole new system easier use , (especially) maintain.


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