Haskell Foldable Wats (Was: Add conspicuously missing Functor instances for tuples)
Henning Thielemann
lemming at henning-thielemann.de
Tue Feb 23 08:33:31 UTC 2016
On Wed, 17 Feb 2016, Bart Massey wrote:
> The whole point of importing Data.List (either directly or from the
> Prelude) is to get functions that work on lists.
Foldable and Traversable generalizations in Data.List are an interim
solution, driven by the habit of some programmers to import complete
Data.List without qualification and expecting that coinciding names in
Data.List and Prelude actually refer to the same function. It would have
been better to first warn about these cases, eliminate them and then
implement FTP (if at all).
Summarized, generalizing list functions in Prelude was a concession to
programmers who are too lazy to import from Data.Foldable and
Data.Traversable and generalizing functions in Data.List was a concession
to programmers who are too lazy to import identifiers explicitly or with
qualification from Data.List.
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