Summary

Teach compiler that fold and map with clean procedure is itself clean

Metadata

• Id: 714e930f5bfdc04b1b856f00fe73e94fb73595ad
• Trac id: 1323
• Type: defect
• Reporter: sjamaan
• Owner:
• Cc:
• Status: new
• Component: compiler
• Estimated difficulty: hard
• Resolution:
• Priority: major
• Milestone: someday
• Version: 4.11.0
• Changetime: 2016-08-29 12:30:29 UTC
• Created: 2016-08-29 12:30:29 UTC
• Keywords: optimisations

Description

It looks like CHICKEN currently doesn't understand that `fold` and `map` are `#:clean` if the argument procedure is `#:clean`. This prevents it from recognising that something like `(fold + 0 (iota 10000))` is foldable.

We could hardcode these procedures, but I'd prefer not to, so this might require some kind of new annotation in `types.db`.

This idea was inspired by http://pramode.in/2016/08/25/rust-add-billion-numbers/ - if Rust can do it, so can we!