[Haskell-cafe] Array.Diff, strange oversight or myopia ?

Chaddaï Fouché chaddai.fouche at gmail.com
Sun Sep 2 09:24:50 EDT 2007

Data.Array.Diff don't have an instance for DiffUArray Bool, which is
strange by itself since IOUArray Bool exists and it's the only
IOUArray that is not mirrored in Diff.
But ok, why not, I guess it might be a small oversight, so I go on to
create the missing instance IArray (IOToDiffArray IOUArray) Bool on
the model of the instances in the source of Array.Diff. Ok, Diff
exports readDiffArray, newDiffArray and replaceDiffArray for this
exact purpose, seems it will be straightforward... except that
boundsDiffArray is not exported and you can't rewrite it since it
needs to take apart the DiffArrayData type which is not exported
either !

So how can I do this (short of copying and renaming an alternative
Array.Diff or changing the library in my installation of GHC) ? And is
there something obvious I missed due to a sudden case of myopia ?


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