A Groovy mustache(1) replacement

Mustache.groovy

#!/usr/bin/env groovy

@Grab(group='com.github.jknack', module='handlebars', version='4.0.3')
@Grab(group='org.yaml', module='snakeyaml', version='1.16')
@Grab(group='org.slf4j', module='slf4j-simple', version='1.7.14')

import org.yaml.snakeyaml.Yaml;
import com.github.jknack.handlebars.Handlebars;
import com.github.jknack.handlebars.Template;


if (args.length == 2) {
    String i = args[0];
    String t = args[1];
    if (i == t) return usage();
    Yaml yaml = new Yaml()
    InputStream input = i == '-' ? System.in : new File(args[0]).newInputStream();
    String file = t == '-' ? System.in : new File(args[1]).text;
    Object o = yaml.load(input)
    Handlebars handlebars = new Handlebars();
    Template template = handlebars.compileInline(file);
    Writer w = System.out.newWriter();
    template.apply(o, w);
    w.flush();
}
else {
    return usage();
}

def usage() {
    println "Usage: Mustache.groovy INPUT FILE"
    return 1
}