I welcome any comments about v4 that makes those findings obsolete. Therefore, ANTLR doesn't save as much time as one might think. Lastly, the lexing (creating the tokens) and parsing (creating the AST) is a very tiny percentage of the total development of a quality compiler. In short, ANTLR is great for prototyping a parser but any industrial-grade parser released into the wild with programmers' expectations of helpful error messages would require a hand-written parser. It would be very hard to replicate how Chrome/Firefox/Safari/IE doesn't choke on broken HTML by using ANTLR to generate an HTML parser.
A pathological example would be the numerous "broken HTML" pages being successfully parsed by browsers. The common theme to the 2 bullet points above is that a high quality compiler written by hand will hold multiple "states" of information and an ANTLR grammar file doesn't really have an obvious way to express that knowledge. However, it's not easy to use the hooks to generate high quality diagnostic error messages.Ģ) ANTLR was not good for speculative parsing or probabilistic parsing which would be the basis of today's generation of tools such as "Intellisense" not giving up on parsing when there's an unclosed brace or missing variable declaration. With a grammar specification, it easily generates a parser that accepts or rejects a piece of source code.
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"antlr4.I last played around with ANTLR in 2012 (when it was version 3) and I discovered that there's a "bigger picture" to the parser generator universe that most tutorials don't talk about:ġ) ANTLR is a good tool for generating "happy path" parsers. These settings are inside the file settings.json in the.
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The code in the companion repository already include the proper settings to do so. Among other things, it can automatically call the ANTLR tool to generate the lexer and parser from your grammar each time you save it. The extension simplifies your life when using ANTLR.
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If you use Visual Studio Code, you can install a wonderful extension: ANTLR4 grammar syntax support. So, if you type cpp or CPP for the language option you will get an error: you have to type Cpp.
Pay attention to the case of the characters: the options in ANTLR are case-sensitive. Java -jar /usr/local/lib/antlr-4.9.2-complete.jar -Dlanguage=Cpp If you need more specific instructions you can look them up in the Setup section of the ANTLR Mega Tutorial.Īt the end of the setup, you should be able to use the Java ANTLR tool to generate a C++ parser.
The only requirement for the tool is that you have installed at least Java 1.7. The runtime must be available both to the developer and to the user. There is instead a different runtime for every target language. The tool is always the same, no matter which language you are targeting: it is a Java program that you need on your development machine.
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The tool will be needed just by you, the developer, while the runtime will be included in the final software using your language.