Re: PIZZA time again :-)

From: mAsterdam <mAsterdam_at_vrijdag.org>
Date: Sat, 03 Sep 2005 01:59:44 +0200
Message-ID: <4318e74c$0$11070$e4fe514c@news.xs4all.nl>

dawn wrote:
> mAsterdam wrote:

>>dawn wrote:
>>>mAsterdam wrote:
>>>>>>Assume
>>>>>>1. there is a meaningful (or at least consequential)
>>>>>>difference between:
>>>>>>
>>>>>>	toppings([salami, mozarella, onions]).
>>>>>>		and
>>>>>>	toppings([mozarella, onions, salami]).

[snip]

>>>>Consider
>>>>
>>>>	merge(ListOfLists, MergedList).
>>>>
>>>>Now
>>>>
>>>>merge ([[salami, mozarella, onions][mozarella, onions, salami]], M).
>>>>
>>>>should fail because salami is before mozarella in the first list,
>>>>and after it in the second. It can't preserve the order.
>>>
>>>I don't know how you define a merge when there isn't
>>>an ordering defined on the type.
>>>Is there such a function?  Your lists are ordered here,
>>>but your domain/type is not, unless you choose something
>>>like alpha order.
>>
>>That is another way of asking the same question.
>>What should 'merge' do when the order is not
>>in the values (as it would be if we took the
>>ordering defined on the type) but just in
>>their position, relative to other values.
>>It is what I'm trying to find out.

>
> Perhaps it should do the same thing as a sort on a set where no
> ordering has been defined - ?

Which would be - in the context of lists? Could you please (try to) translate what you mean onto the realm of lists?

>>>I can imagine an interleave function that alternates ingredients from
>>>both lists and yields a pizza with salami on it twice (I think I'll
>>>pass on it, however).  --dawn
>>
>>So that is not the desired behaviour.
>>The resulting pizza will be richer than the
>>originals, but I would like to see one you
>>would like to eat.

>
> I'd like plenty of mozarella, olives (black or green), tomatoes, and
> maybe even some pepperoni on either a whole wheat crust or a thin crust
> -- oh, and pineapple too. The ordering does make a difference, as does
> the city in which I'm eating the pizza -- in Chicago I'm OK with
> reversing the order and adding sausage to the pizza. I'm sitting in
> the biggest pork producing county in the U.S. right now and people
> order pizza with "swine" on it here.
>
> I talked students through a pizza example from the Head Frist Design
> Patterns book last year -- a fun book for anyone wanting to teach or
> learn OO design patterns.
>
> cheers! --dawn

You already know you are welcome to enjoy the best pizzas in Amsterdam whenever you feel like coming here :-) Received on Fri Sep 02 2005 - 18:59:44 CDT