Tree walking evaluator for the formula engine #658
Description
What's needed?
Our current postfix expression evaluator is not suitable for performing arbitrary non-binary operations. And we have (had) multiple operations that don't fit the binary evaluator requirement clearly.
- Averager (not binary, can average multiple things. going away in Drop formula step Averager #645)
- Clamper (unary operation)
- Max/Min (needs to be decomposed to a binary operation, like
Max(Max(a, b), c), and needs changes to the operator priority.)
We need is a new design concept based on a tree-walking evaluator, that would allow for the composition of arbitrary operations - binary or otherwise, seamlessly, without causing additional async cycles, just from adding an implementation for the operation, without having to touch the evaluator's internals, like we're having to do with operator priority in the current expression evaluator.
The specifics can be decided after 1.0. This is just internal refactoring of the Formula Builder, Evaluator and Steps. So it can be done after 1.0
Proposed solution
No response
Use cases
No response
Alternatives and workarounds
No response
Additional context
No response