Generating ANTLR4 grammar files with package declaration in gradle

Question

I try to use the gradle antlr plugin, but run into several problems.

I have a grammar file called wls.g4:

grammar WlsScript;

@header {
   package hu.pmi.wls.antlr.ws;
} 

program
  : 'statementList'? EOF
  ;

// Several more grammar and lexer rules

(Note: I made the statementList to a keyword only to make a correct grammer without including the whole grammar. ;-))

This file is located in /src/main/antlr (as the default source folder of the antlr production grammar files).

Here is the snippet from build.gradle:

project('common') {

    apply plugin: 'antlr'

    dependencies {
       // Some dependencies

       antlr "org.antlr:antlr4:4.5"
    }
} 

When I use the generateGrammarSource gradle task (comming from antlr plugin) to generate the source files it generates the files in build/generated-src/antlr/main folder which is the default.

What goes wrong, that it doesn't create the folders of the java package (hu/pmi/wls/antlr/ws in our case) so the source will be incorrectly located in Eclipse.

My primary question is how could I force the task to generate source files in a package-structured way? In other words, how can I configure the gradle task to use the package declaration from grammar?

Thanks!

Answer 1

I had the exact same question and I was able to change the outputDirectory used by the AntlrTask to get the package name in there.

generateGrammarSource {
    outputDirectory = new File("${project.buildDir}/generated-src/antlr/main/net/example".toString())
}

I found no easy way to extract the grammar package from the files so had to hardcode it in the task.