Expressions module, support of Strings

I've been looking at the Expressions module, a really impressive piece of
work!

The "JavaScript" sub-package only appears to support an extreme subset of
JavaScript, one where the only data type is a double.  I don't see that it
supports Strings/text, to include passing Strings to methods and resolving
String data from a binding.  Can someone confirm this?  What would it take
to expand that?

I can see that Javascript.g4 (Antlr grammar) references a "STRING" but
can't make out if/how it's used in JavaScriptCompiler.

~ David Smiley
Apache Lucene/Solr Search Developer
http://www.linkedin.com/in/davidwsmiley