Ant and Groovy integration (Gravy)

Hi,

Here's a little hack that I think represents a stabler pattern for integrating
Ant and Groovy at the infrastructural layer.

Problem:
- Groovy bundles some Ant jars and loads them in classloader A
- Many real Ant builds use different versions of Ant and/or 3rd party Ant tasks
such as XDoclet, XMLTask, PMD, JUnit, Beanshell scripts, etc., which are often
installed in ANT_HOME/lib or are referenced in build script classpaths. 
- Adding 3rd party jars for Ant builds to the Groovy classpath using the -cp or
-classpath options on the command line causes conflicts because of the
classloader hierarchy
- Groovy currently ships minimal Ant 1.6.1 jars and JUnit's jar for the Ant
junit task, but this is ad hoc and arbitrary and leave Ant and JUnit version
upgrade issues unanswered.
- Groovy's AntBuilder needs minimal Ant jars to work at all with built-in tasks

Solution:
- Define clear integration points to decouple Groovy and Ant
- use groovy-classworlds.conf to put ANT_HOME/lib first in the Groovy 
classpath. 

Advantages:
- allows me to use Groovy to execute a whole bunch of existing build scripts I
have with no changes
- allows me to re-use existing Ant installation infrastructure we have on every
desktop or in every project in source control
- minimal changes to Groovy scripts/config

Check it out:

Change to $GROOVY_HOME/conf/groovy-classworlds.conf
# NEW: Load all libs under ANT_HOME first
load ${ant.home}/lib/*

# Load required libraries
load ${groovy.home}/lib/*.jar


Then in the bin/groovy script, I added a -D to set ant.home to ANT_HOME:
    exec $JAVACMD $JAVA_OPTS \
        -classpath "$CP" \
        -Dprogram.name="$PROGNAME" \
        -Dclassworlds.conf="$CLASSWORLDS_CONF" \
        -Dgroovy.home="$GROOVY_HOME" \
        -Dant.home="$ANT_HOME" \                   <-- NEW
        -Dtools.jar="$TOOLS_JAR" \
        org.codehaus.classworlds.Launcher "$@"

Hope someone finds this useful. I've got some more stuff to share soon, but need
to vet it out a bit here first.

Thanks,
Scott Stirling
Framingham, MA