manually when debugging. Most of my expriments are related to the tickets I filled in: checking whether I can have some cheap workarourd till they are implemented or whether they actually help as much as I hope.
That means that for anything more complicated I need access directly to the representation of the same code which is just being debugged. From your response it looks that if I needed something more again I'll just need to create my own version of GHCi driver and reuse the rest through GHC API. If there is some tutorial how to build custom GHCi driver or something else at a higher level (i.e. not the GHC API docs directly), please, let me know.
No tutorial that I'm aware of, and recent changes to the GHC API mean that some of the example code out there isn't up to date, either. But there is currently a small example of a modified GHCi on hackage (likely to be folded into the main line later). ghci-haskeline This package reimplements ghci using the GHC API and the Haskeline package for line input in command-line programs. Just a copy&modify of some of the GHCi sources, including a Main.hs to call the modified code. Claus