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Why do I get this error while generating code in ANTLR?
[16:06:38] error(10): internal error: C:\Users\user\Desktop\test.g : java.lang.ClassCastException: org.antlr.runtime.tree.CommonTree cannot be cast to org.antlr.tool.GrammarAST
org.antlr.grammar.v3.CodeGenTreeWalker.rules(CodeGenTreeWalker.java:1467)
org.antlr.grammar.v3.CodeGenTreeWalker.grammarSpec(CodeGenTreeWalker.java:1441)
org.antlr.grammar.v3.CodeGenTreeWalker.grammar_(CodeGenTreeWalker.java:509)
org.antlr.codegen.CodeGenerator.genRecognizer(CodeGenerator.java:421)
org.antlr.Tool.generateRecognizer(Tool.java:655)
org.antlr.Tool.process(Tool.java:468)
org.antlr.works.generate.CodeGenerate.generate(CodeGenerate.java:104)
org.antlr.works.generate.CodeGenerate.run(CodeGenerate.java:185)
java.lang.Thread.run(Unknown Source)
The syntax is very simple, just for testing:
grammar test;
ID : ('a'..'z'|'A'..'Z'|'_') ('a'..'z'|'A'..'Z'|'0'..'9'|'_')*
;
Any ideas?
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What is ANTLR? ANTLR (ANother Tool for Language Recognition) is a powerful parser generator for reading, processing, executing, or translating structured text or binary files. Terence Parr is a tech lead at Google and until 2022 was a professor of data science / computer science at Univ.
A language is specified using a context-free grammar expressed using Extended Backus–Naur Form (EBNF). ANTLR can generate lexers, parsers, tree parsers, and combined lexer-parsers.
ANTLR or ANother Tool for Language Recognition is a lexer and parser generator aimed at building and walking parse trees. It makes it effortless to parse nontrivial text inputs such as a programming language syntax. In this post, we'll get into the basics of getting ANTLR up and running in a dev environment.
ANTLR is a powerful parser generator that you can use to read, process, execute, or translate structured text or binary files. It's widely used in academia and industry to build all sorts of languages, tools, and frameworks. Twitter search uses ANTLR for query parsing, with over 2 billion queries a day.
You specified a mixed grammar (lexer and parser), but you did not specify a parser rule.
Either add one or use lexer grammar test;
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