ANTLR4 Gradle Template

Template for ANTLR4 projects using Gradle and its ANTLR plugin.

In addition to the default behaviour of the ANTLR plugin, this template uses the package declaration from the grammar file.

Getting Started

You can use the template exactly as described in the documentation of the ANTLR plugin for Gradle. The main steps are basically:

1. Clone this project
2. Store your ANTLR grammar file in src/main/antlr or src/test/antlr
3. Run generateGrammarSource respectively generateTestGrammarSource
4. Find the generated code in src-gen/main/java or src-gen/test/java

Features

Folders for generated code

The folders for the generated code are defined in the variables GENERATED_MAIN and GENERATED_TEST inside the build.gradle and can be easily changed. The default folders are src-gen/main/java and src-gen/test/java.

Grammars with different packages

There is no problem in providing multiple grammar files with different package names in their package declarations.

First the template uses the ANTLR plugin to generate the code as intended by the plugin (everything goes in the same folder). In a second step it will move the generated files into their correct packages.

Example

In src/main/antlr, this project contains the sample grammar from the ANTLR homepage, extended with a package declaration:

grammar Expr;

@header {
    package org.antlr.samples.antlr4example;
} 

prog:    (expr NEWLINE)* ;
expr:    expr ('*'|'/') expr
    |    expr ('+'|'-') expr
    |    INT
    |    '(' expr ')'
    ;
NEWLINE : [\r\n]+ ;
INT     : [0-9]+ ;

By running the Gradle task generateGrammarSource ANTLR will generate Lexer and Parser and move the files to src-gen/main/java/org/antlr/samples/antlr4example. Each *.java-file will have the correct package name (package org.antlr.samples.antlr4example;).