Reuse of Grails taglibs in the markup template engine

taglib_reuse.groovy

    void testGrailsTagLibCompatibility() {
        TemplateConfiguration config = new TemplateConfiguration()
        MarkupTemplateEngine engine = new MarkupTemplateEngine(this.class.classLoader, config)
        def template = engine.createTemplate '''g.emoticon(happy:'true') { 'Hi John' }
'''
        StringWriter rendered = new StringWriter()
        def model = [:]
        def tpl = template.make(model)
        model.g = new TagLibAdapter(tpl)
        model.g.registerTagLib(SimpleTagLib)
        tpl.writeTo(rendered)
        assert rendered.toString() == "Hi John :-)"
    }

    class SimpleTagLib {
        def emoticon = { attrs, body ->
            out << body() << (attrs.happy == 'true' ? " :-)" : " :-(")
        }
    }