Proposal: Add &&& and *** to Data.Tuple

[Henrik Nilsson]

Hi Josef,

Thanks for the thorough and thoughtful reply.
You do make a number of good points, and if people in general
think this is a good proposal, I don't want to be the one
killing it.

However, I have thought a bit more about what really bothers
me about the proposal, and I think it is this. You say:

 > The other side of the coin is what to name the functions. For this
 > proposal I chose the same names as their generalized counterparts. I
 > can see why that worries people although I don't share that feeling.
 > We have a module system whose purpose is (among other things) to
 > handle names. It does so rather well, consider for instance Data.Map
 > and Data.Set which I use extensively in my everyday programming. They
 > have a lot of function names in common and which also clashes with
 > Prelude names and other libraries. It's not a problem to have several
 > functions having the same name. It's actually a feature which lessens
 > the burden of remembering a ton of names and which shows that their
 > intended semantics is, if not equal, then strongly related.

Yes. If it truly were the case that we were talking about different
*functions* having the same name, I wouldn't be concerned. Data.Map
and Data.Set are good examples. But here we are talking about reusing
the name of a method, i.e. an already overloaded entity, as a function.
That does bother me, for some reason. I guess one level of overloading
too many for my taste. (Maybe my brain just cannot cope! ;-)
I'd be equally concerned if someone suggested using well-established
methods from, say, the Monad class for something else.

Part of it is also that the fact that an entity belongs to a class
notionally representing some mathematical structure implies a
"moral obligation" that instances of that entity should conform
to the structure, even if Haskell does not enforce this. Using
such a name for something else breaks or at least weakens that
conceptual link, which I think would be a pity.

Sorry that I don't have time to give a more in-depth reply at this
point.

Best,

/Henrik

-- 
Henrik Nilsson
School of Computer Science and Information Technology
The University of Nottingham
nhn at cs.nott.ac.uk

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