error vs Maybe in Collections package

Robert Dockins robdockins at fastmail.fm
Tue Jun 6 11:16:22 EDT 2006


On Jun 6, 2006, at 9:57 AM, David F. Place wrote:

> It bothers me that the functions findMin, findMax, deleteFindMin  
> and deleteFindMax are error when applied to the empty set in  
> various types of collections.   Shouldn't they return Maybe?


FYI, Edison has operations that generalize 'deleteFind*' (named  
viewMin/viewMax) which call 'fail' in an arbitrary monad when applied  
to an empty collection; obviously, these can be instantiated at type  
'Maybe'.

http://www.eecs.tufts.edu/~rdocki01/docs/edison/Data-Edison- 
Coll.html#v%3AminView


> --------------------------------
> David F. Place
> mailto:d at vidplace.com


Rob Dockins

Speak softly and drive a Sherman tank.
Laugh hard; it's a long way to the bank.
           -- TMBG



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