The antlr4-maven-plugin does not appear to be document on the Antlr4 website.
That might get you nothing, like it did me. Try this:
mvn org.antlr:antlr4-maven-plugin:help -Ddetail=true
Produces:
[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building Maven Stub Project (No POM) 1
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- antlr4-maven-plugin:4.0:help (default-cli) @ standalone-pom ---
[INFO] ANTLR 4 Maven plugin 4.0
Maven plugin for ANTLR 4 grammars
This plugin has 2 goals:
antlr4:antlr4
Parses ANTLR 4 grammar files *.g4 and transforms them into Java source files.
Available parameters:
arguments
A list of additional command line arguments to pass to the ANTLR tool.
atn
If set to true then the ANTLR tool will generate a description of the ATN
for each rule in Dot format.
encoding
specify grammar file encoding; e.g., euc-jp
excludes
A set of Ant-like exclusion patterns used to prevent certain files from
being processed. By default, this set is empty such that no files are
excluded.
forceATN
Use the ATN simulator for all predictions.
includes
Provides an explicit list of all the grammars that should be included in
the generate phase of the plugin. Note that the plugin is smart enough to
realize that imported grammars should be included but not acted upon
directly by the ANTLR Tool. A set of Ant-like inclusion patterns used to
select files from the source directory for processing. By default, the
pattern **/*.g4 is used to select grammar files.
libDirectory
Specify location of imported grammars and tokens files.
listener
Generate parse tree listener interface and base class.
options
A list of grammar options to explicitly specify to the tool. These options
are passed to the tool using the -D