redprl / sml-telescopes Goto Github PK

Currently, the bottleneck of RedPRL is the the telescope library. It needs a deque, which is implemented as a list now. There are many plausible approaches:

1. Deques as pairs of lists: constant amortized time.
2. Deques as four lists: constant time in the worst case. See Okasaki's thesis.
3. Deques as finger trees: constant time even with persistency.

The issue of (1) is that, depending on how we use telescopes, the amortized analysis might not apply. (3) looks clean but needs polymorphic recursion which AFAIK will be ugly in SML.

This was only needed in Classic JonPRL because we were dealing with names in a rather fast-and-loose way. In Red JonPRL, we have no need for this, so we should remove it.

See https://github.com/RedPRL/sml-redprl/blob/bdf2b484058644b28cc4f8a65808c88dcc3384b4/src/redprl/refiner_kit.fun#L69-L93, for example.

• switch order of arguments
• curry more stuff to make it a bit easier to use