Roadmap

Nicer API

Right now, you need to expand using a Map<String, VariableValue>, instantiate your VariableValues yourself, etc.

Try and find an API like what this implementation does.

Dot support?

In theory, the RFC allows this kind of variable spec: foo.bar. If foo is some kind of dictionary, then this would mean "key bar in dictionary foo".

However, this is not defined anywhere.

Macros?

The RFC also defines $, ( and ) as reserved for macro use (supposedly using sequences of $(...), other combinations don't really make any sense). Support this? How?

Use parboiled

This tool is great; it can help quite a lot if used correctly. The parboiled core itself lacks some useful features, such as customizable error messages. But when it is done, all the power of parboiled belong to us.

https://github.com/sirthias/parboiled