Language Plugin for a Thymeleaf like templating language

Hello,

I recently spotted that an adapter for ANTLR based grammers was created to use them in IntelliJ plugins and therefore stared developing a plugin for a templating language called HTL which is similar to Thymeleaf. Although I can understand the basics of custom language plugins after reading through the SimplePlugin in your DevGuide I have problems understanding how this could work in a templating language. I tried to inject my language into the HTML attributes which works fine for highlighting, however I got stuck when dealing with references. How should I handle variables or references to Java beans defined in an HTML attribute? What I would like to achieve is to have code completion for Java getters in my HTL Expressions for the following case:

<div data-sly-use.bean="com.htl.language.JavaBean">
    <h1 data-sly-text="${bean.textFromBean}">Title</h1> <!-- completion for getters -->
</div>

public class JavaBean {
    public String getTextFromBean() {
        return "Some text from a bean";
    }
}

Does anyone have some experience with similar language plugins or are there even some examples somewhere?