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. It's widely used to build languages, tools, and frameworks. From a grammar, ANTLR generates a parser that can build and walk parse trees.
Terence Parr is a tech lead at Google and until 2022 was a professor of data science / computer science at Univ. of San Francisco. He is the maniac behind ANTLR and has been
working on language tools since 1989.Check out Terence impersonating a machine learning droid: explained.ai
Quick Start
To try ANTLR immediately, jump to the new ANTLR Lab!
To install locally, use antlr4-tools, which installs Java and ANTLR if needed and creates antlr4 and antlr4-parse executables:
(Windows must add ..\LocalCache\local-packages\Python310\Scripts to the PATH). See the Getting Started doc. Paste the following grammar into file Expr.g4 and, from that directory, run the antlr4-parse command. Hit control-D on Unix (or control-Z on Windows) to indicate end-of-input. A window showing the parse tree will appear.
$ pip install antlr4-tools
(Windows must add ..\LocalCache\local-packages\Python310\Scripts to the PATH). See the Getting Started doc. Paste the following grammar into file Expr.g4 and, from that directory, run the antlr4-parse command. Hit control-D on Unix (or control-Z on Windows) to indicate end-of-input. A window showing the parse tree will appear.
grammar Expr; prog: (expr NEWLINE)* ; expr: expr ('*'|'/') expr | expr ('+'|'-') expr | INT | '(' expr ')' ; NEWLINE : [\r\n]+ ; INT : [0-9]+ ; |
$ antlr4-parse Expr.g4 prog -gui 10+20*30 ^D $ antlr4 Expr.g4 # gen code $ ls ExprParser.java ExprParser.java |
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