Need help implementing new commands in groovysh

Question

I've found very little info on building new commands for Groovysh. I'd like to use it as a normal part of my dev environment, to some degree replacing cmd.exe().

I did notice that there is a "register" command in groovysh that allows you to register new commands. After finding nothing I ended up looking at the source code for the existing commands and came up with this:

import org.codehaus.groovy.tools.shell.*

class test extends CommandSupport
{
    public static final String COMMAND_NAME = 'findall'

    // Printed when you use the help command specifying 'find' as an argument
    String help="Help"
    String usage="Usage"

    // Printed when you use the help command with no arguments
    String description="Description"    

    public test(org.codehaus.groovy.tools.shell.Groovysh shell)
    {
            super(shell, COMMAND_NAME, 'find')
    }
    Object execute(List<String> args)
    {
        return "Commanded "+args+" "+args.size()
    }

}

This does most of what I want, but I have a couple problems with it. First of all, the thing passed to "execute" is pre-parsed in an ugly way. If I try to find a string like "test strange spacing" I get ["test, strange, spacing"] I can use the quotes to rebuild what was supposed to be quoted as a single string but I can't replace the extra spaces"

The second issue is that I'd like to use tab completion. I can see that there are getCompleter and makeCompleters commands but there is no info on what a completer is... the javadocs link to a page that doesn't exist.

There are completers in the JLine library but I'm not sure they are the same thing (I tend to doubt it because JLine is inaccessible from groovysh, if you needed to use those to write scripts, you'd think they would be accessible)

If anyone knows of a blog that instructs you on how to do this kind of stuff--or has a few minimal examples laying around I'd appreciate the help.

Answer 1

You have deciphered groovy source pretty well. You can return jline completeres in overridden createCompleters method. You can also use completeres from org.codehaus.groovy.tools.shell.util.

import jline.console.completer.StringsCompleter
import org.codehaus.groovy.tools.shell.CommandSupport
import org.codehaus.groovy.tools.shell.Groovysh
import org.codehaus.groovy.tools.shell.util.SimpleCompletor;

public class GroovyshCmd extends CommandSupport {
    public static final String COMMAND_NAME = ':mycmd'
    public static final String SHORTCUT = ':my'

    protected GroovyshCmd(Groovysh shell) {
        super(shell, COMMAND_NAME, SHORTCUT)
    }

    @Override
    public List<Completer> createCompleters() {
        //return [new SimpleCompletor((String[])["what", "ever", "here"]), null]
        return [new StringsCompleter("what", "ever", "here"), null]
    }

    @Override
    public Object execute(List<String> args) {
        println "yo"
    }
}

I agree this is needlessly overcomplicated.