error vs Maybe in Collections package

Robert Dockins robdockins at
Wed Jun 7 17:03:51 EDT 2006

On Jun 7, 2006, at 4:44 PM, Jean-Philippe Bernardy wrote:

> Good idea. I added a ticket.
> If there is no taker I'll try to do it this weekend.

I've just realized that I typo'd the Edison names for these  
operations.  It would be unfortunate to introduce needless name  
differences, so I'd like to point out that the Edison names for these  
operations are actually:




> Cheers,
> JP.
> On 6/6/06, Robert Dockins <robdockins at> wrote:
>> 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'.
>> Coll.html#v%3AminView

Rob Dockins

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

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