Hello Andy and Mark,
Thanks for the review! There has actually been more progress since I pushed that branch. I hit a point in the CPS->RTL stuff where I had trouble because I didn't know how to do things (like mutable variables) in RTL. So I've actually ported the compiler to GLIL in a branch on my computer. I also have a working Tree-IL->CPS compiler for some of Tree-IL (it's not done yet).
I thought that might be a better way forward because CPS and RTL are, to a certain extent, separate ideas. I'll push my wip-cps branch, which contains a Tree-IL->CPS compiler and a CPS->GLIL compiler. What I'm working on now is actually how to represent mutable variables in CPS. I think having explicit environment structures would be nice (and fit with Kennedy's paper), but I haven't figured out the details yet.
I realize it might be confusing to start with CPS->RTL, then switch to CPS->GLIL, then switch back later when the RTL branch is ready. If you'd rather do it that way, we can skip the CPS->GLIL phase.
* Yes, passes might be good. I had thought of writing some generic control-flow operators like 'compute-fixpoint' and then writing other things in terms of those.
* Using tree-il first sounds good to me.
* I also think that CPS should have some construct which says 'do these things in any order'. I haven't put one in yet, mostly because the compiler wouldn't take advantage of it anyway.