nemesis wrote:
> Darren New <dne### [at] sanrrcom> wrote:
>> You're saying "a hastable is for lookups. It doesn't have an order.
>> Therefore, Python is right to base its data structures on hash tables."
> 
> It's supposed to be a hashtable.

What is "supposed" to be a hashtable? And why do you say it's "supposed" to 
be a hashtable?

> If you don't want a hashtable, you shouldn't use it.

Of course not. Because it *is* a hashtable, whether that's what you want or 
not.

>> Well, there ya go. So why isn't that built in, like it is in PHP, since it
>> allows both random and sequential lookups? :-)
> 
> Because Python, Scheme and Haskell attempt to use the correct approaches.  Form
> follows function.

And what is incorrect about PHP's approach?  Why is Python more "correct" 
than PHP?  (Note: "because it uses hashtables" is a circular argument.)

>> So, it's OK for a mathematical set to maintain order when it's simpler,
> 
> A math set has no order.  I was saying the notation of functions over set
> domains employs the convention of lists of arguments because it's simpler to
> notate than named arguments out of order.

I understand that. You're missing my point. You're arguing that keyed data 
structures in a programming language should not preserve insertion order. 
I'm asking you why that is the case, and you're answering "Because!"

I'm just trying to figure out why you think a structure with a superset of 
the functionality that a hashtable provides is a bad thing.

> and that ought to be a good thing.

Why?  Do you actually *have* a reason beyond "because"? Or is this a 
faith-based argument?

If you need a hashtable, PHP's arrays give that to you. If you need a list, 
PHP's arrays give that to you. If you need order-preserving keyed-access 
data structures, PHP's arrays gives that to you, and Python doesn't. If you 
need order-preserving keyed-access data structures in Python, you have to 
implement it yourself. I'd say that's a bad thing, for all the same reasons 
that having non-standardized implementations of any application-independent 
data structures in any language is a bad thing.

-- 
   Darren New, San Diego CA, USA (PST)
   There's no CD like OCD, there's no CD I knoooow!

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