Alpine-DAV/ascent

expression filter that can call pipeline filters

Opened this issue · 2 comments

Add a overarching expression filter for use in pipelines, focused on derived field gen

We want the expression lang to be able to call pipeline filters that create derived fields to simplify implementation of expressions that wrap existing filters.

Will require a new path for expression eval.

Example:
#1358

Goal is: Any filter registered as a "transform" can be called via expression language.

Details to get this right involve param mapping and rules for derived fields vs general transforms.

Namely, derived fields need a common way to select the field output name.