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exony-craigminihan edited this page Feb 26, 2014 · 4 revisions

Installation Walkthrough

Note from Sam: This installation guide is adapted from Setting Up ANTLR4 C# Target in Visual Studio 2012 (Revised) from phurst.

This is a (revised) attempt at a full summary of the steps needed to get ANTLR4 to generate a C# lexer, parser, and listener for a very simple grammar. The C# target is designed to work as a Visual Studio (VS) add-in only and cannot be used from the command line.

Terence Parr is the author of ANTLR and Sam Harwell is the author of the C# language target for ANTLR. Any errors in this document are mine alone.

STEP 1

Goal: A working Java RE installation and creation of the registry entries the ANTLR4 C# target uses to locate the java.exe executable.

  • Install the Java JRE (http://java.com/en/download/manual.jsp )

  • Run regedit and examine the HKEY_LOCAL_MACHINE\SOFTWARE key. It should contain a JavaSoft subkey:

      HKEY_LOCAL_MACHINE\SOFTWARE\JavaSoft

I run Windows 7 64-bit. I found the above registry key was only created when I manually installed the 64-bit version of the JRE. It was not created by the 32-bit installer or the installer that runs when you click on the "Free Java Download" button on the java.com page.

The ANTLR4 C# target, needs the java runtime, and will not run without this registry key, so keep installing versions of java till you get one.

Note from Sam: you should be able to install the 32-bit JDK on a 64-bit system and, so long as you tell the installer to install the JRE as well, the ANTLR4 C# Target will find the java runtime.

STEP 2

Goal: ANTLR Language Support extension installed in VS.

STEP 3

Goal: NuGet package manager at version 2.5 or greater.

  • Run Visual Studio 2012.
  • Click on Tools → Extensions and Updates... in the menu.
  • Select Updates → Visual Studio Gallery in the left hand panel.
  • If the NuGet Package Manager appears, click the Update button. In my case it updated from version 2.2.40116.9051 to 2.6.40627.9000. Your goal is to get a NuGet version of 2.5 or more.
  • Restart Visual Studio.

STEP 4

Goal: A VS solution and project.

  • Run Visual Studio 2012
  • Create a new solution called ANTLR4Test with a new Console Application project in it called Hello.

STEP 5

Goal: ANTLR4 NuGet package installed in Hello project.

  • In Solution Explorer, right click the Hello project folder and select Manage NuGet Packages... in the context menu. A dialog pops up.
  • In the left hand panel select NuGet official package source, or nuget.org.
  • At the top, select Include Prerelease in the left hand combo box.
  • In the search panel at top right type ANTLR4.
  • The ANTLR 4 package will appear in the central list. Install it.

This package must be installed in each project that uses the ANTLR C# target.

STEP 6

Goal: A simple ANTLR Grammar.

  • In Solution Explorer, right click the Hello project and select Add → New Item in the context menu. A dialog pops up.

  • Select Visual C# Items → ANTLR in the left hand panel.

  • Select ANTLR4 Combined Grammar in the center panel.

  • Enter the name Hello.g4 at the bottom.

  • Click the Add Button.

  • Open the Hello.g4 file and replace all its text with the following:

    grammar Hello;
r  : HELLOWORD ID EOF;    // match keyword hello followed by an identifier
HELLOWORD : 'hello';
ID : [a-z]+ ;             // match lower-case identifiers
WS : [ \t\r\n]+ -> skip ;

STEP 7

Goal: A program to parse the Hello.g4 grammar, parse a text string, and traverse the parsed tokens.

  • Create a new class called MyVisitor as follows:

    using Antlr4.Runtime.Tree;

public class MyVisitor : HelloBaseVisitor<object> {
    public override object VisitR([NotNull] HelloParser.RContext context) {
        Console.WriteLine("HelloVisitor VisitR");
        context
            .children
            .OfType<TerminalNodeImpl>()
            .ToList()
            .ForEach(child => Visit(child));
        return null;
    }

    private void Visit(TerminalNodeImpl node) {
        Console.WriteLine(" Visit Symbol={0}", node.Symbol.Text);
    }
}

  • Open the Program.cs file.

  • Add the following using statement at the top of the file:

    using Antlr4.Runtime;

  • Replace all the class text with the following:

    class Program {
    private static void Main(string[] args) {
        (new Program()).Run();
    }
    public void Run() {
        try {
            Console.WriteLine("START");
            RunParser();
            Console.Write("DONE. Hit RETURN to exit: ");
        } catch (Exception ex) {
            Console.WriteLine("ERROR: " + ex);
            Console.Write("Hit RETURN to exit: ");
        }
        Console.ReadLine();
    }
    private void RunParser() {
        AntlrInputStream inputStream = new AntlrInputStream("hello world\n");
        HelloLexer helloLexer = new HelloLexer(inputStream);
        CommonTokenStream commonTokenStream = new CommonTokenStream(helloLexer);
        HelloParser helloParser = new HelloParser(commonTokenStream);
        HelloParser.RContext rContext = helloParser.r();
        MyVisitor visitor = new MyVisitor();
        visitor.VisitR(rContext);
    }
}

    If you have ReSharper installed you will probably see syntax errors reported by IntelliSense in AddParseListener and RContext. These are, due to a bug in ReSharper. Ignore the "errors" for now or disable ReSharper via the Tools → Options → ReSharper → General tab.

  • Build the program. It should build successfully.

STEP 8

Goal: Run the program with the expected result.

  • Run the Hello program.

  • You should see the following output in the console window:

    START
HelloVisitor VisitR
Visit Symbol=hello
Visit Symbol=world
DONE. Hit RETURN to exit:

The program parsed the text hello world and chopped it up into 2 terminal tokens, as you can see above.

STEP 9

Goal: Understand how it works (only a bit though).

  • Look in the ANTLR4\Hello\obj\Debug directory and observe the following files:

    • HelloBaseListener.cs
    • HelloBaseVisitor.cs
    • HelloLexer.cs
    • HelloLexer.tokens
    • HelloListener.cs
    • HelloParser.cs
    • HelloVisitor.cs

USEFUL LINKS

http://antlr.org/

http://tunnelvisionlabs.com/products/demo/antlrworks

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