@inproceedings{Hood00,
  author = {Andy Gill},
  title = {Debugging {H}askell by observing intermediate data structures},
  booktitle = {Proceedings of the 2000 ACM SIGPLAN {W}orkshop on Haskell, Technical report of the University of Nottingham},
  year = {2000},
  abstract = {Haskell has long needed a debugger. Although there has been much research into the topic of debugging lazy functional programs, no robust tool has yet come from the Haskell community that can help debug full Haskell - until now. This paper describes a portable debugger for full Haskell, building only on commonly implemented extensions. It is based on the concept of observation of intermediate data structures, rather than the more traditional stepping and variable examination paradigm used by traditional imperative debuggers.}
}