[Haskell-cafe] Why?

[John D. Earle]

Magnus, thank you. It at least gives me a lead. I can focus on the 
significance of laziness and what role it may have on purity. That the 
language is lazy gives me no anxiety as I see laziness as natural. I see 
Haskell as having proven that laziness is viable; a language can be lazy and 
fast and memory efficient. I am trying to put the puzzle pieces together and 
from what I can gather purity may be a perceived outcome of combinatory 
logic with Occam's razor. So perhaps the motivation is scientific. Unless 
you absolutely must don't go there. Science is an evolutionary process. You 
go from Newtonian mechanics to Relativity. Relativity is more complicated 
than Newtonian mechanics, but it was proven that the additional complexity 
was needed.

--------------------------------------------------
From: "Magnus Therning" <magnus at therning.org>
Sent: 10 Thursday December 2009 0507
To: "John D. Earle" <JohnDEarle at cox.net>
Cc: "Haskell Cafe" <haskell-cafe at haskell.org>
Subject: Re: [Haskell-cafe] Why?

> On Thu, Dec 10, 2009 at 12:01 PM, John D. Earle <JohnDEarle at cox.net> 
> wrote:
>> This is a matter that I genuinely at the present time do not grasp and I 
>> am
>> hoping that some of you who are more familiar with the Haskell language 
>> may
>> be able to help enlighten me. I feel the question to be an important one.
>> What material benefit does Haskell derive from being a "pure" functional
>> language as opposed to an impure one? Please provide examples as I 
>> require
>> instruction.
>>
>> The following is what I believe to be true at the present time. It seems 
>> to
>> be that the decision was made because it was a matter of taste under the
>> belief that computer scientists can and often are superstitious and their
>> superstitions can and often do materially interfere with progress. What I 
>> am
>> saying is that at the present time perhaps due to my ignorance I am
>> unfamiliar with how this benefits the language in a material sense. It
>> appears to be a philosophical matter, a matter of identity, what Haskell
>> stands for.
>>
>> The sort of decision that Apple computer and Microsoft made not to go 
>> down
>> the POSIX road seems relevant. Historically, Apple did not embrace POSIX.
>> Windows continues to stand for Windows, that is the graphical user
>> interface.
>
> As I understand it it all started with laziness.  I don't know if
> laziness is impossible without purity, but talks and papers tend to
> say something like "laziness has kept Haskell pure".
>
> /M
>
> -- 
> Magnus Therning                        (OpenPGP: 0xAB4DFBA4)
> magnus＠therning．org          Jabber: magnus＠therning．org
> http://therning.org/magnus         identi.ca|twitter: magthe