Thourghts.md

About the name.

As opposed to Janus, which allows for expressions that are not bidirectional in its inputs and outputs. RFun seems to have this bidirectionality, which seems to be stronger property than being reversible. First, I want to define bidirectionality and reversibility, and if we the former is stronger, and we really need it to be efficient, it would be more concise to call it the language BCPL for Bidirectional Concurrent Programming Language.

Todo.

Some things are initially unnessesary (such as a type checker). We will deal with introducing reversible concurrency/actors first, and then deal with such things later. However, it is nice to have a list of such things, as the ideas for them might pop up during development of the main features.

• A type system?
• Typed communication?
• Unspawn.
• Unbox.
• A typeconstuctor per Recive statement?
• Two different semantics for unrecieve/unsend.
• What will the first paper be about?

Backlog.

It makes sense to see what kinds of analysis can be made from the Core RFun language, before trying to do something more complicated. However, as most analysis are most naturally expressed as type-and-effect systems, the first thing todo, is to expand with algebraic datatypes.

The next thing we need is to expand with lambda, and introduce reversible lambda (which is not the ansilla curry). We can then express the ansilla as an extra program transformation.

Near summer, the sessiontype project should then have moved towards something implementable, and then we need to introduce spawn.