Consider the following grammar. I have issues with the operator priority, for instance: res=2*a+b has a similar parse tree as res=2*(a+b). I know where the problem is, but no "beautiful" solution w...

How to handle nested comments in antlr4 lexer? ie I need to count the number of "/*" inside this token and close only after the same number of "*/" have been received. As an example, the D language...

I am trying to set up a simple project with Antlr in .net core 1.0 project using VS2017. Following https://github.com/sharwell/antlr4cs, added .g4 file to the project. The project file looks like ...

I am presently getting... error(56): AqlCommentTest.g4:12:4: reference to undefined rule: htmlCommentDeclaration error(56): AqlCommentTest.g4:13:4: reference to undefined rule: mdCommentDeclaratio...

Note: This is a self-answered question that aims to provide a reference about one of the most common mistakes made by ANTLR users. When I test this very simple grammar: grammar KeyValues; k...

I am developing a compiler using ANTLR and LLVM. I have already implemented a lexer and a parser using ANTLR 4's Eclipse IDE. I want to implement a semantic analyzer and a code generator using LLVM...

I've created this sample grammar using the ANTLR4 plugin in IntelliJ and when I use its tool chain to generate a visual representation for some invalid content (in this case an empty string), this ...

I am trying to split my ANTLR4 grammar in multiple files so i can test them more easily, i am using gradle as a build tool in a java project. Both grammar compile correctly by separate but when i ...

The view Parse Tree in Eclipse Oxygen is empty and white. I can compile my Hello.g4 grammar, see the Syntax Diagram but the Parse Tree view is empty. How can I fix it?

I am using antlr v4 for extracting parse tree of java programs for other purposes. I have started from this sample: ANTLR v4 visitor sample And I have tested the steps on given link to check if it...

I want to use Antlr to create parser and i followed instruction from Here after following all instruction while I am running following command antlr4 -visitor D:\T\arithmetic.g4 I am getting thi...

I have 2 simple lexer rules in my ANTLR4 grammar: fragment Attrs : '.' ARCH; fragment ARCH : 'IA32' | 'X64' | 'IPF' | 'EBC' | 'common'; The generated ATN with ANTLR4.7 is like this (Visual Studio...

I want to get the specific error message of ANTLR4's parser. And I found that there are two way to handle error: errorListener and errorHandler. // set error handler parser.removeErrorListeners();...

Is there a way to tell ANTLR4 to inline the parser rule? It seems reasonable to have such feature. After reading the book on ANTLR ("The Definitive ANTLR 4 Reference") I haven't found such possibi...

I'm trying to convert my grammar from v3 to v4 and having some trouble finding all the right pieces. In v3 to process a String, I used: public static DataExtractor create(String dataspec) { Char...

Are there any good CSS grammars out there for antlr4? I know there are some grammars for antlr3, but it turns out CSS is not trivial to parse without "lexer modes", which were added in v4. Why? Co...

With the help of this SO question How to create AST with ANTLR4? I was able to create the AST Nodes, but I'm stuck at coding the BuildAstVisitor as depicted in the accepted answer's example. I hav...

I am trying to use a 3rd party typescript library(antlr - https://github.com/tunnelvisionlabs/antlr4ts) in my angular 2 project created using angular-cli. It's failing with this error class constru...

Writing a pretty-printer for legacy code in an older language. The plan is for me to learn parsing and unparsing before I write a translator to output C++. I kind of got thrown into the deep end wi...

I am using ANTLR4 with Python and I am currently using the following code for parsing: lexer = MyGrammarLexer(FileStream(path)) stream = CommonTokenStream(lexer) parser = MyGrammarParser(stream) r...

This is a demo code label: var id let id = 10 goto label If allowed keyword as identifier will be let: var var let var = 10 goto let This is totally legal code. But it seems very hard to do t...

I would like to read expressions with Antlr4 and the perform some modifications on them. For example, if grammar is arithmetic, I would modify expression, representing 2 * (3 + 1) with 2 * 4 ...

I've got an ANTLR 4 grammar and built a lexer and parser from that. Now I'm trying to instantiate that parser in such a way that it will parse until it encounters an error. If it encounters an erro...

If I have an AST and modify it, can I use StringTemplates to generate the source code for the modified AST? I have successfully implemented my grammar for Antlr4. It generates the AST of a source ...

We're starting a project where we will need to parse python source files in a C++ application. I've used Antlr2 a while back to generate a few compilers, but this is the first time I'm using Antlr4...