Have the loop also be a syntax parameter.
Avoid unnecessary loop variable.
Typo.
New transducer macro.

Closer to traversal macro.

Lots of repetition that will need to be cleaned up.
Add reverse.

Doesn't work for stateful builables, elements are added before recurring.

Will need to revise the transducer macro.
Rewrite transducer, which fixes reverse.

Transducers now have separate bodies for structural and stateful building.

Previous version, in addition to not working, had too much magic.
Transducer: separate sets of accumulators for structural and stateful building.
Extra transducer tests.
Start of cleanup.
More cleanup.
Cleanup.
Add an abstraction for building.

Not sure it's worth it.
Abstract between building and transducer.
More abstraction.
Typo.
Implement the full API for range.