It's a Common Lisp library for advanced forms of iteration.

It is inspired by iterate, and is in fact mostly a rewrite of it using a proper code walker.

Iterate has various issues around code walking. It was causing us trouble when we used it inside delimited continuations, or inside the Lisp -> SQL query compiler in hu.dwim.perec (e.g. iterate is not extending the lexical environment with the variables it is introducing).

Iterate doesn't retain the identity of the cons cells, and due to that jumping to the source location inside an iterate form doesn't work in Slime. This codebase retains the identities whenever possible.

It was also quite a lot of fun working on it. The ultimate goal was to put together a library that has an improved API compared to Iterate, and also a compatibility layer so that it can be used as a drop-in replacement for Iterate.

Written by attila@lendvai.name.

The primary communication channel is the facilities on the project's GitHub page.

Unfortunately, it's at around 80% completion, and I haven't worked on it for years.

You're welcome to take over development if you feel inspired!

Whatever is finished is of good quality, and the infrastructure is also solid. It has good unit tests, too. In short, all the depth-work is probably done, but there's more breadth-work to be done.