Stefan O'Rear
I'm building a tracer/debugger that shows the structure of the heap, using a redex trail-like data structure,
- Freja, the first of the Haskell debuggers, operated in exactly this way, using an instrumented GHC (maybe it was HBC? the paper didn't say) runtime system.
Actually, Freja had its own nearly-complete compiler for Haskell. We tried to persuade Henrik to release it more widely as "hhc" (hardly a haskell compiler), but he did not have enough time to support it properly. Freja/hhc was a native code compiler (sparc only). It was the first Haskell compiler to deal properly with mutually recursive modules (you could include many modules into a single source file). The more serious deficiency was a lack of typeclasses (but I believe Henrik fixed that in later versions). Regards, Malcolm