Why is my ANTLR grammar file for Java not compiling?

I have been given an ANTLR grammar for a subset of the Java compiler known as the static Java compiler. I am trying to extend the grammar to include more of Java's features, for instance, I just added the grammar for For Loops.

Using Eclipse and an ANTLR plugin, I then did 'Compile ANTLR grammar'. Instead of compiling it produced two errors on the first bit of code:

grammar ExtendedStaticJava;

options { backtrack=true; memoize=true; }

@header
{
package sjc.parser.extended;
import java.math.BigInteger;

/**
 * Extended StaticJava parser.
 * @author <myname>
 */
}

// the rest of the grammar has been excluded.

The first error is on line 1: 'Unexpected Token: grammar' The second error is on line 5: 'Unexpected char: @'

Why does it not recognize this basic ANTLR syntax? My first thought was that I was missing something in the classpath, but I went to the project's properties and made sure that the following JARs were included under Libraries:

• antlr-2.7.7.jar
• stringtemplate开发者_Python百科-3.2.1.jar
• antlr.jar
• antlr-runtime-3.0.1.jar

Any ideas or suggestions?

antlr-2.7.7.jar is wrong: your grammar is in ANTLR v3+ syntax. Remove all:

• antlr-2.7.7.jar
• stringtemplate-3.2.1.jar
• antlr.jar
• antlr-runtime-3.0.1.jar

from your project/classpath and only stick this ANTLR v3 JAR in it (which contains everything you need: runtime, stringtemplate, the works!).

Good luck!

EDIT

Personally, I do my IDE integration with an Ant build script. I generate a lexer and parser like this:

<target name="generate.parser" depends="init" description="Generates the lexer, parser and tree-walker from the grammar files.">
    <echo>Generating the lexer and parser...</echo>
    <java classname="org.antlr.Tool" fork="true" failonerror="true">
        <arg value="-fo" />
        <arg value="${main.src.dir}/${parser.package}" />
        <arg value="${parser.grammar.file}" />
        <classpath refid="classpath" />
    </java>
    <!-- snip -->
</target>

and the classpath refid looks like:

<path id="classpath">
    <!-- snip -->
    <fileset dir="lib">
        <include name="*.jar" />
    </fileset>
</path>

and the lib/ directory contains the ANTLR v3 JAR (no other ANTLR JARs! (sorry for hammering on that :)))

You have probably installed the AntlrEclipse plugin. This indeed uses Antlr 2.7.something. There is however a plugin available that works with v3, Antlr IDE. This plugin is a little bit more advanced as it allows you to configure the Antlr version (3+) and can show a railroad view and has an interpreter.

Note If you are using Eclipse Juno, you will need to install the DLTK from the Indigo repositorties, as 4.0.0 is to new for the antlr plugin

I had this issue as well.

At some point during my attempts to get antlr running I had added some version of the jar file to my classpath windows environment variable. I removed this entry, and it resolved my issue.