Sat Apr 20 08:31:45 EDT 2019

Extend types gradually

There are now at least two things that would benefit from
parameterization in the type system:

- Bit types

- Substrate (e.g. mul or no mul)

These can probably be introduced gradually by writing the old in terms
of the new, and then moving the library written in terms of old to

This in itself is not the issue right now: bit types are values passed
in at instantiation time, and substrate is just Seq, but with some
parts eliminated (exposed as errors).

Seq is dataflow + sequential feedback.  It cannot by itself express
other types of hierarchy, such as running a program on a CPU.  This
needs to be captured by "recursive" Seq.