Hoed-0.5.0: Lightweight algorithmic debugging.

Safe HaskellNone




debug :: Q [Dec] -> Q [Dec] Source #

A handy TH wrapper for debugging functions, offering more information than obs

  debug [d|
    quicksort [] = []
    quicksort (x:xs) = quicksort lt ++ [x] ++ quicksort gt
        where (lt, gt) = partition (<= x) xs

expands to:

  quicksort = observe "quicksort" quicksort'
  quicksort' [] = []
  quicksort' (x:xs) = quicksort lt ++ [x] ++ quicksort gt
        where (observe "lt" -> lt, observe "lt" -> gt) = partition (<= x) xs

The additional information may lead to unnecessary questions in algorithmic debugging, obs is the recommended wrapper for that purpose.

obs :: Q [Dec] -> Q [Dec] Source #

A handy TH wrapper for observing functions.

  obs [d|
    trimPat :: Exp S -> Pat S -> Pat S
    trimPat vs = filterPat ((member freeVars vs) . void)

is equivalent to:

  trimPat = observe "trimPat" trimPat'
  trimPat' vs = filterPat ....

obs accepts multiple declarations, and all the functions inside will be wrapped as above, while the rest of declarations will stay unchanged. As such it can be used to observe entire modules.