The core datastructures and algorithms of yarrow are complete. Below is a short list of features to be added to the library.
Efficient construction of diagrams from Σ-expressions (see [WZ23] sections 7 and 8)
Documentation for the functor module
Provide an interface for implementing functors of optics and differentiability (see [WZ23] section 10)
Rewriting of diagrams
Rewriting of diagrams is a long-term goal, and may not appear soon. Other features are intended to arrive shortly.