[Haskell-cafe] Re: Channel9 Interview: Software Composability and theFu ture of Languages

[Magnus Therning]

On Wed, Jan 31, 2007 at 13:36:02 +0200, Yitzchak Gale wrote:
>Bulat Ziganshin wrote:
>>>FP way is to represent everything as
>>>function, imperative way is to represent everything as algorithm.
>
>Magnus Therning wrote:
>>Neither way may be "natural", but imperative thinking is extremely
>>common in society, I'd say much more than "functional" thinking.  Just
>>think of cooking recipes, IKEA instructions, all the algorithms taught
>>in math classes in grade school.
>
>Those are not imperative thinking - they are sequential thinking. There
>is nothing non-functional about describing an algorithm in sequential
>form.

Sequential thinking would be related to procedural programming, that is
ordering of statements are important but there's no state.  Functional
programming is declarative, no order and no state.  So, to be strict I'd
say that sequential form _is_ non-functional.  At least if FOLDOC is
correct and I read and understood things properly.

I'm assuming that imperative implies state _and_ order.

>Imperative means requiring that the steps always be followed exactly.
>People do not follow the steps of a recipe exactly - they just use the
>recipe to understand what needs to be prepared. Same with your other
>examples.

When cooking we have a state--the kitchen/workbench/dish.  We have a
sequence of steps--the recipe.

Yes, it's possible to re-arrange that sequence, cooks do that all the
time, based on experience.  But that's just optimisation. The
optimisation done by a C-compiler doesn't change the nature of the
language from imperative to procedural or declarative, does it?

>That's why I think that the oposite is true - declarative style is more
>natural. Just describe what you want to be computed.  If that is best
>described as a sequence of steps, fine, if not, not.  But in either
>case, you are not forcing a CPU to follow the steps blindly.

The world has state!  Just see what a "stink" that has created in the
pure functional language camp!  Your arguments have actually strenthened
my conviction that we as humans find imperative to be more "natural"
than both sequential and declarative. :-)  Just too bad that in this
case "natural" doesn't correspond with "best" :-(

/M

-- 
Magnus Therning                             (OpenPGP: 0xAB4DFBA4)
magnus at therning.org             Jabber: magnus.therning at gmail.com
http://therning.org/magnus
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