[Haskell-cafe] Re: Is "take" behaving correctly?
ketil at ii.uib.no
Thu Sep 13 09:16:05 EDT 2007
On Thu, 2007-09-13 at 13:56 +0100, Neil Mitchell wrote:
> > tail = fromJust . tailMay
> The error messages suffer [..]
> That's why I supplied tailNote
Still, given tailMay, we have:
tailDef xs = maybe xs id . tailMay
tailNote msg = tailDef (error msg)
tailSafe = tailDef 
tail = tailNote "tail: empty list"
which I suppose was Lutz's point?
(My rather ugly preference is to #define tail so that an error message
contains source code location.)
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