Building Antlr4 programs is a laborious task. To build a program, you must:

• Install Java. You need to use Java version 11 or newer because the tool requires it.
• Download the Antlr4 Tool .jar from the download area.
• Run the tool on you grammar. Many manually run the tool, but there are plenty of questions how to do that because it is different over the OS you are running. If you modify the grammar, but forget to regenerate the parser and lexer, you end up with a version skew.
• For C#, you need to set up a <PackageReference> for the runtime Antlr4.Runtime.Standard. If you are not careful, you may generate the parser and lexer with a different version of the tool from the runtime.

Harwell's excellent Antlr4cs, was published in NuGet to simplify the build of C# Antlr programs. It was publiched as three packages:

• Antlr4 (which is a thin package that simply requires the two following packages)
• Antlr4.CodeGenerator
• Antlr4.Runtime.

They were the official items for C# Antlr programs until Antlr4.Runtime.Standard became the official runtime for C#, which completely replaces Antlr4.Runtime since ANTLR 4.7.

Unfortunately, since then, there is no "official" build package for C# Antlr programs. Antlr4BuildTasks replaces the old Antlr4cs support with an updated and cleaned up build tool.

More details can be found in this file.

You shouldn't use Harwell's packages any more if you want to use ANTLR 4.7 and above.

Antlr4BuildTasks is a third-party set of build rules published in Nuget as a package for builds of C# projects containing Antlr4 grammars, using the official Antl4.Runtime.Standard package.

When added as a <PackageReference> to your C# project, Antlr4BuildTasks provides the rules to compile .g4's into parser code via the Antlr4 Tool using Java, and compiled by the C# compiler, for a seemless build for Antlr4 grammars using C#.

Antlr4BuildTasks automatically downloads a Java Runtime Environment (JRE) and the Antlr tool jar file to generate the parser and lexer. You do not need to set up anything. It can be used either at the command line or within Visual Studio, and on Windows, Linux or Mac. The JRE is only required to build your project, and never required or used after the build.

To use this package, add the Antlr4BuildTasks and Antlr4.Runtime.Standard packages to your project. csproj file as shown below, otherwise you can use the "NuGet Package Manager":

<ItemGroup>
    <PackageReference Include="Antlr4.Runtime.Standard" Version="4.13.1" />
    <PackageReference Include="Antlr4BuildTasks" Version="12.8" PrivateAssets="all" />
</ItemGroup>

Then, you will need to tag each Antlr4 grammar file you want the Antlr tool to process. You can change the "Build Action" property for the .g4 file from "None" to "ANTLR 4 grammar". Or, you can add the following lines to your .csproj file for your "MyGrammar.g4" file:

<ItemGroup>
    <Antlr4 Include="MyGrammar.g4" />
</ItemGroup>

Notes:

• <PrivateAssets>all</PrivateAssets> is added to the package reference so that when you run dotnet publish, the Antlr4BuildTasks.dll is not included in your app; it's only used to build your application. Antlr4BuildTasks.dll is not currently digitally signed.
• Antlr4BuildTasks downloads a JRE for your OS and places it in $USERPROFILE/.jre/ on Windows and $HOME/.jre/ on Linux. The package also downloads the Antlr4 tool JAR file and places it in $USERPROFILE/.m2/ on Windows and $HOME/.m2/ on Linux.
• You can use a pattern for the Include attribute, e.g., <Antlr4 Include="*.g4"/>.

You can set the arguments to the Antlr Tool in Visual Studio by modifying the properties for each grammar file. Or, you can modify the .csproj file to include the parameters you are interested in setting:

<ItemGroup>
    <Antlr4 Include="MyGrammar.g4">
        <Listener>false</Listener>
        <Visitor>false</Visitor>
        <GAtn>true</GAtn>
        <Package>foo</Package>
        <Error>true</Error>
    </Antlr4>
</ItemGroup>

The <Antlr4> item supports the following parameters that are passed onto the Antlr tool:

• <Listener> -- A bool that specifies whether you want an Antlr Listener class generated by the tool.
• <Visitor> -- A bool that specifies whether you want an Antlr Visitor class generated by the tool.
• <GAtn> -- A bool that specifies whether you want Antlr to generate the ATN Dot diagrams.
• <Package> -- An C# identifier that specifies the namespace to wrap the generated classes in.
• <Error> -- Use this to specify whether you want the tool to flag warnings as errors and stop a build.
• <LibPath> -- A string that specifies the path for token and grammar files for the Antlr tool.
• <Encoding> -- A string that specifies the encoding of the input grammars.
• <DOptions> -- A list of <option>=<value>, passed to the Antlr tool. E.g., language=Java. Multiple options can be specified using a semi-colon separating each.
• <JavaExec> -- A semi-colon separated list of one of the following: Full path name of the Java executable, or PATH indicating to search PATH for an executable, or DOWNLOAD to download and use the <JavaDownloadDirectory>.
• <AllowAntlr4cs> -- Allow both <PackageReference> to Antlr4.Runtime and Antlr4.Runtime.Standard. (NB, you will need to handle aliasing of one package. See #32)
• <JavaDownloadDirectory> -- Full path of directory for downloaded JRE compressed and uncompressed files.
• <AntlrToolJarDownloadDir> -- Full path of the directory for download and use Antlr4 tool jar. If not set the default value is $USERPROFILE/.m2/ and $HOME/.m2/ to Windows and Linux respectively.
• <Log> -- Adds'-Xlog' to Antlr4 Tool call, which turns on logging.
• <LongMessages> -- Add '-long-messages' to Antlr4 Tool call, which turns on long messages.

The Antlr4 tool generates files that produce a lot of compiler warnings for code set with CLSCompliant=false. This package adds in code to ignore these warnings so you don't need to modify your .csproj file.

In the .csproj file, change items from

<ItemGroup>
    <Antlr4 Update="arithmetic.g4">
        etc etc etc
    </Antlr4>
</ItemGroup>

to

<ItemGroup>
    <Antlr4 Include="arithmetic.g4" />
</ItemGroup>

Change package references from

<ItemGroup>
    <PackageReference Include="Antlr4.CodeGenerator" Version="4.6.6">
        <PrivateAssets>all</PrivateAssets>
        <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
    </PackageReference>
    <PackageReference Include="Antlr4.Runtime" Version="4.6.6" />
</ItemGroup>

to

<ItemGroup>
    <PackageReference Include="Antlr4BuildTasks" Version="12.8" PrivateAssets="all" />
    <PackageReference Include="Antlr4.Runtime.Standard" Version="4.13.1" />
</ItemGroup>

Antlr4BuildTasks examines PropertyGroup AntlrProbePath, a string of URI separated by semicolon, to find the version of the Antlr JAR file that you are looking for. Antlr4BuildTasks will look for a .jar with version as specified in the Antlr4.Runtime.Standard PackageReference (e.g., 4.13.1). I recommend that you just use the PackageReference's defined above.

The package here has little to do with VS other than builds under VS can use Antlr4BuildTasks for a seemless build. You will just need to add the package references and other items to the .csproj file as outlined above.

If you are looking for a set of templates to create a console application that uses Antlr4, then see Antlr4Templates.

• Fix for #77.

• Fix for Eclipse Temurin OpenJDK.

• Fix for #75. WebClient, obsolete, has been replaced.

• Fix for #49. The pattern recognition for valid versions of Java has been updated.

• Security update. Clean up builds. Published now in Release configuration.

• Added new parameter <AntlrToolJarDownloadDir> to set the location to download the Antlr4 tool jar.