Re: why tail recursion matters and why Java isn't it, was Re: lispperformance was Re: problems with lisp

[Pascal Costanza <address@hidden>]

Matthias Felleisen wrote:
> 
> 
> On Thursday, September 4, 2003, at 02:08 PM, Pascal Costanza wrote:
> 
>> Matthias Felleisen wrote:
>>
>>> On Wednesday, September 3, 2003, at 01:11 AM, Peter Seibel wrote:
>>>
>>>> What's unnatural about looping? If I find certain algorithms easier to
>>>> think of in terms of a loop (do this, do that, then go back to the
>>>> beginning unless I'm done) what does that mean? That I'm a programming
>>>> illiterate? That I'm *really* thinking in terms of recursion but don't
>>>> know it because I've somehow trained my brain to unnaturally translate
>>>> my Platonic recursive ideas into an "iterative" form before they reach
>>>> my consciousness?
>>>
>>> To understand how program design truly works, you need to go "pure".
>>
>>
>> "Purity" is an aesthetic category. In your example, you have purity as 
>> a premise (a minimal set of language features) and purity as result (a 
>> program that behaves in a "pure" way). If you think that purity is 
>> beautiful, it's no wonder that you like both the premise and the result.
>>
>> However, there are other possible aesthetic categories.
> 
> 
> 1. I don't have an example.

For? (sorry, I don't understand what you mean here...)

> 2. "Going pure" means to conduct a Gedankenexperiment. I don't propose to
> program in this pure style. But I do propose to construct programs from 
> first
> ("natural") principles. Then you step back and see what you have learned.
> 
> I have done both, have you? -- Matthias

Yes


Pascal

-- 
Pascal Costanza               University of Bonn
mailto:costanza@web.de        Institute of Computer Science III
http://www.pascalcostanza.de  Römerstr. 164, D-53117 Bonn (Germany)