Polyfill-based transformation library

[westonpace]

Discussions have come up in the past that we might want something like the following:

Starting with a source expression (coming from some producer) and a list of supported functions (from some consumer) simplify an expression so that it can run on the consumer by replacing unknown functions with known functions using a polyfill. For example, if a consumer does not know about the "between" function but it does know "<, <=, >, >=, AND" then you can replace between with those operators.

Generally such a discussion is accompanied by the idea of creating a library of these "polyfills" in some kind of format / extensible fashion (e.g. yaml files?)

So this module would be something that takes in an expression, a library of polyfills, and a desired output state and generates the output state.