On Tue, 29 Sep 2009 18:19:08 -0700, you wrote:

On Tue, Sep 29, 2009 at 5:24 PM, Casey Hawthorne wrote:

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I read somewhere that for 90% of a wide class of computing problems, you only need 10% of the source code in Haskell, that you would in an imperative language.

If this is true, it needs to be pushed.

And if by changing a few lines of source code one can develop a whole family of similar applications, that needs to be pushed, also.

If you look through the archives here and elsewhere on the net, I think you'll see that technical superiority isn't the driving force for language adoption. It can help, but other factors seem to play a more significant role, usually dependent on context in which the languages became popular. At times it can seem like luck, but then I'm reminded of what Louis Pasteur said about luck and prepared minds.

It is good that you're talking about Haskell though. Continue to discuss it with your peers and show them fun and cool things you've written using Haskell. I think this is more compelling for the uninitiated than statements about perceived technical power of the language. I've heard people explain this as, "showing is better than telling."

Cheers, Jason

Hmmmmmmm! Like those people that are paid to go into coffee houses with some new technology, and then people see what they're doing and wander over and ask them questions about it.

"showing is better than telling."

It's even being used by marketers/sellers. :) -- Regards, Casey

Yep, LINQ makes C# more enjoyable :-) Scala and haXe also look nice, a bit of a mix between OCaml/F#, C#/Java and Haskell. Besides the fact that hacking in Haskell is a great deal of fun, the main reason I see for learning Haskell: it makes you a better programmer. After a couple of years of playing with Haskell, I can now solve problems that I couldn't before. It's of course hard to tell if Haskell is the reason here, or just experience, but I feel it really is Haskell (actually, functional programming). Haskell made me see the world in a different way (and if I see Oleg's and co's code, I still have an infinitely long road ahead. The main reason why you should not learn Haskell: it's a bit of a drug; after you learned Haskell, programming in an "industrial strength" language suddenly feels like a waste of time, time better spent learning more Haskell... On Wed, Sep 30, 2009 at 10:26 AM, Deniz Dogan wrote:

2009/9/30 Andrew Coppin :

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(Mr C++ argues that homo sapiens fundamentally think in an imperative way, and therefore functional programming in general will never be popular.

Sounds more like Mr C++ fundamentally thinks in an imperative way because that's what he is used to.

I recently started working with C# and struggled for way too long with for/foreach loops to do things that in Haskell could be expressed using only folding, mapping and filtering. When I realised that those ideas actually exist in System.Linq I suddenly started liking the language a bit more.

txtCommaSeparatedNames.Text.Split(',').Select(x => x.Trim()).Where(x => x.Length > 0).Select(x => Convert.ToInt32(x)).ToList();

Ah, the joy of FP.

-- Deniz Dogan _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Deniz Dogan wrote:

2009/9/30 Andrew Coppin :

...

(Mr C++ argues that homo sapiens fundamentally think in an imperative way, and therefore functional programming in general will never be popular.

Sounds more like Mr C++ fundamentally thinks in an imperative way because that's what he is used to.

This may or may not be true. It would be interesting to see some research on this. Without that, I think we cannot decide either way. Cheers, Jochem -- Jochem Berndsen | jochem@functor.nl | jochem@牛在田里.com

Peter Verswyvelen wrote:

I really doubt people tend to think in either way. It's not even sure our thinking can be modeled with computing no?

Well, try this: Go ask a random person how you add up a list of numbers. Most of them will say something about adding the first two together, adding the third to that total, and so forth. In other words, the step by step instructions. Very few of them will answer that the sum of an empty list is defined to be zero, and the sum of a non-empty list is defined to be the first number plus the sum of the list tail. Then again, few non-programmers will set anything about creating a counter variable and initialising it to zero either; this is a programming "artifact". (Humans don't think like this internally, but most programming languages conceptually require it.) Nobody has much difficulty with this, so maybe the only problem with Haskell is that everybody learns to program "the other way" first, before they get to Haskell...

On Wed, Sep 30, 2009 at 03:43:12PM +0100, Andrew Coppin wrote:

Well, try this: Go ask a random person how you add up a list of numbers. Most of them will say something about adding the first two together, adding the third to that total, and so forth. In other words, the step by step instructions. Very few of them will answer that the sum of an empty list is defined to be zero, and the sum of a non-empty list is defined to be the first number plus the sum of the list tail.

Maybe they would say that you have to go adding each number to the others, i.e. they're thinking with a fold. -- Felipe.

On Wed, Sep 30, 2009 at 11:10:19PM -0400, John Dorsey wrote:

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Well, try this: Go ask a random person how you add up a list of numbers. Most of them will say something about adding the first two together, adding the third to that total, and so forth. In other words, the step by step instructions.

You word the (hypothetical) question with a bias toward imperative thinking. You're asking "How do you do this action?"

Why isn't the question "What is the sum of a list of numbers?", which is biased toward the declarative?

Indeed! Surely a person asked to "sum a list of numbers" such as [45,82,78] will do exactly this: 45 + 82 + 78, proceeding to add 82 to 45, noting the intermediate sum, and then adding 78 to that. It's certainly a fold, though our (non-programmer) subject here probably wouldn't call it that. Generalizing this pattern to non-arithmetical situations is an 'FP trick' (or pattern, or what-have-you). Also, he or she would probably not understand what we know as 'foldl' or 'foldr' immediately because the idea of a 'starting value' is not that clear -- the task statement of 'add a list of numbers' seems to presuppose that there are numbers to be added, i.e. the list is not empty. Assuredly the subject would not (mentally) count how many numbers were in the list, set up a 'counter', and then execute an addition operation that many times, storing the result in a 'temporary variable'. In both cases our anonymous non-programmer understands the idea of recursive/iterative addition, but does not know about the general pattern of 'fold' or 'for(...) { ... }'. These are learned from programming books. Most of these books teach some imperative language, so, many programmers get used to the one and then have some difficulty re-tooling mentally for the other. I know I did when I first began using Haskell, but now the lack of folds in, say, C really hurts. :) Whoever commented earlier in the thread that learning haskell is bad for your brain because you pine for it when you program in other languages was right on.

2009/10/1 Andrew Coppin :

John Dorsey wrote:

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...

Well, try this: Go ask a random person how you add up a list of numbers.  Most of them will say something about adding the first two together,  adding the third to that total, and so forth. In other words, the step  by step instructions.

You word the (hypothetical) question with a bias toward imperative thinking.  You're asking "How do you do this action?"

Why isn't the question "What is the sum of a list of numbers?", which is biased toward the declarative?

Sure. But what is a computer program? It's a *list of instructions* that tells a computer *how to do something*. And yet, the Haskell definition of sum looks more like a definition of what a sum is rather than an actual, usable procedure for *computing* that sum. (Of course, we know that it /is/ in fact executable... it just doesn't look it at first sight.)

Well, we are not writing computer programs directly, even in C, that's what compilers are for. That's why I find arguments about the sequential essence of computer programs to be weak.

Whatever; I'm leaning more and more towards the concept that FP is only hard for people who already learned some other way...

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2009/10/1 Andrew Coppin :

Eugene Kirpichov wrote:

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2009/10/1 Andrew Coppin :

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Sure. But what is a computer program? It's a *list of instructions* that tells a computer *how to do something*. And yet, the Haskell definition of sum looks more like a definition of what a sum is rather than an actual, usable procedure for *computing* that sum. (Of course, we know that it /is/ in fact executable... it just doesn't look it at first sight.)

Well, we are not writing computer programs directly, even in C, that's what compilers are for. That's why I find arguments about the sequential essence of computer programs to be weak.

It might be a better argument to say that human thinking is fundamentally sequential; parallel computers have been around for a little while now...

I don't buy this argument, either; human thinking is far too broad a concept to say that it is simply "sequential". If it were sequential, it could barely express non-sequential concepts, and natural languages would have rather few of them, which we all know is false.

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-- Eugene Kirpichov Web IR developer, market.yandex.ru

Tom Tobin wrote:

On Thu, Oct 1, 2009 at 3:26 AM, Andrew Coppin wrote:

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It might be a better argument to say that human thinking is fundamentally sequential; parallel computers have been around for a little while now...

Perhaps *conscious* human thinking is sequential — yet our brains are massively parallel processors, and have been around for quite a long time. ;-)

This is very true. And it's just as well; I read somewhere that the maximum firing rate of a neuron gives the human brain an effective "clock frequency" of about 100 MHz - which isn't terribly fast. But it's massively parallel, as you say. Actually, I just had a flash of inspiration: Maybe the reason programmers tend to think sequentially is because programmers tend to be *men*. Maybe the way to hardness the multicores is to get more women into programming? :-D

On Oct 2, 2009, at 11:14 AM, Richard O'Keefe wrote:

Human *verbalisation* is fundamental, human *thinking* is not.

Sigh. Accidentally lean on the wrong key and half your text disappears. Human *verbalisation* is fundamentally sequential. Human *thinking* is not. I don't know any sign language myself, but I am aware that since people have faces and two hands, there is a limited amount of concurrency in some sign languages. (E.g., you can give place and manner at the same time.)

On Oct 1, 2009, at 8:53 PM, Andrew Coppin wrote:

Sure. But what is a computer program?

It depends on the computer. Classical machines do one thing, data flow machines do another, reduction machines another. I once saw a tiny machine at a UK university where the hardware was a combinator reduction gadget. It wasn't combinators on top of conventional instructions, the hardware did nothing _but_ combinators. A computer program, in short, is *whatever we want it to be*. (Within reasonable limits.)

Andrew Coppin writes:

Peter Verswyvelen wrote:

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I really doubt people tend to think in either way. It's not even sure our thinking can be modeled with computing no?

Well, try this: Go ask a random person how you add up a list of numbers.

Although the question of how we "naturally" think often comes up, I'm not sure it's a very important one. In my experience, the natural thing for humans appear rather to be the absence of thinking, and instead slouching in front of the TV eating unhealthy food. After all, we give people who program computers several years of education to learn about unnatural things like counters and temporary variables, or recursion and folds. The question shouldn't be what comes more natural for average Joe, but rather what skills can we teach a reasonably bright student in three to five years that will make her the most effective programmer. (That's what the question should be, of course what the question really *is* is what curriculum can we present that looks entertaining, fashionable, and trivial enough that enough high-school kids will apply for the department not to be starved of funds... ) -k -- If I haven't seen further, it is by standing in the footprints of giants

On 2009-10-01 08:53 +0100 (Thu), Andrew Coppin wrote:

Sure. But what is a computer program? It's a *list of instructions* that tells a computer *how to do something*.

Some are. Some aren't, as proven by the Haskell definition of sum, which is certainly a "program." I like to think of a program as a specification. A list of instructions can certainly qualify, but so can other things, depending on what's interpreting and executing that specification. On 2009-10-01 08:59 +0100 (Thu), Andrew Coppin wrote:

Although, to all the people who ask "why is Ruby so popular?", I might suggest "because it's easy to learn"...

From reading a lot of the code out there (particularly disasters such as Rails), I suspect a lot of Ruby programmers don't get much past

Actually, Ruby isn't terribly easy to learn. If you have previous experience in another imperative or OO language, you'll pick up the parts of Ruby that are similar to that fairly quickly, but you're not really learning anything so much as just doing a simple translation of a few concepts you already know. You're still going to run into problems with a number of standard Ruby constructions, probably not be writing clean or idiomatic code, and you'll be a long way from writing DSLs. In particular, you're likely to be writing highly repetitive code which could easily be refactored into something much smaller and nicer. (I'm constantly seeing people who have programmed in Ruby for years come up with six- to ten-line chunks of code that are could be replaced with a single line if they, e.g., only know that there was such as thing as a "modulo" function.) this level. cjs -- Curt Sampson +81 90 7737 2974 Functional programming in all senses of the word: http://www.starling-software.com

В сообщении от 30 сентября 2009 15:58:40 Jochem Berndsen написал:

Deniz Dogan wrote:

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2009/9/30 Andrew Coppin :

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(Mr C++ argues that homo sapiens fundamentally think in an imperative way, and therefore functional programming in general will never be popular.

Sounds more like Mr C++ fundamentally thinks in an imperative way because that's what he is used to.

This may or may not be true. It would be interesting to see some research on this. Without that, I think we cannot decide either way. Cheers, Jochem

One of my first impressiions with haskell was absence of impendance mismatch between my thoughts and my code. This is not nessesarily true for everyone because people has different ways of thinking I beleive. P.S. And haskell doesn't have tendency to eat brain away like C++ does.

As one C++ expert I know is fond of telling me, "Haskell will only become popular when obscure mathematics becomes popular".

That might be true, but the calculus and even arithmetic were once considered obscure.

В сообщении от 30 сентября 2009 18:05:28 Peter Verswyvelen написал:

On Wed, Sep 30, 2009 at 3:56 PM, Kalani Thielen wrote:

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That might be true, but the calculus and even arithmetic were once considered obscure.

Mmm, to the average student calculus is still very obscure ;-)

Really? One professor said that it's possible to teach monkey to differentiate. In principle I agree with him (-;

On Wed, Sep 30, 2009 at 12:32 AM, Andrew Coppin

wrote:

Casey Hawthorne wrote:

...

I read somewhere that for 90% of a wide class of computing problems, you only need 10% of the source code in Haskell, that you would in an imperative language.

If this is true, it needs to be pushed.

And if by changing a few lines of source code one can develop a whole family of similar applications, that needs to be pushed, also.

:)

As one C++ expert I know is fond of telling me, "Haskell will only become popular when obscure mathematics becomes popular".

You can argue about whether or not this is true. Myself I think we just need to start documenting things more clearly. (E.g., Mr C++ apparently spent half an hour trying to figure out why an expression wouldn't parse. Turns out you have to write negative numbers in brackets. Which isn't hard, but you have to already know this.)

It's clear Haskell has become popular, and without the need for the obscure math. (though I have to admit, I find the math highly interesting, yet I'm quite the novice)

I might also point out that 90% of all desktop computers run Windows, and yet every single C library binding on Hackage fails to compile on Windows. That really needs to be fixed. (Not to mention some of the standard I/O functions doing slightly strange things because GHC is calling POSIX compatibility functions rather than native I/O functions. For example, doesDirectoryExist "C:\\" = False.)

YES

The lack of a big shiny whizzy-looking IDE probably stops quite a few people too. (I gather the Leksah guys are working on that one.)

I personally have found 2 IDEs to be "worth bothering with" in my entire life. One is Visual Studio. The other is Borland's Turbo C++ 3.0 IDE for DOS. (I even coerced it to run on my 16MHz 286.... geeze 16MHz was fast back then :-) )

Lack of a good way to write native-looking Windows GUI applications - or indeed any GUI applications without requiring a stack of DLLs - probably doesn't help either.

None of these look fundamentally insumountable to me.

(Mr C++ argues that homo sapiens fundamentally think in an imperative way, and therefore functional programming in general will never be popular. We shall see...)

I think that's a bunch of garbage :-). People think algorithmically, or we wouldn't design algorithms to deal with complexity. Algorithms very often have steps that are quite imperative, but many of the sub-pieces of a step are clearly pure and functional. Being able to see the difference in a set of instructions, and being able to isolate them, can be quite a powerful way to break a problem down to a manageable set of steps. If it wasn't, Functional Programming would have died long ago, and it clearly hasn't, and is gaining ground. See F#, Erlang, O'Caml, and Haskell. I don't think you can argue with the quantitative data that is the user base. The number of people in #haskell on freenode, or the subscribers on Reddit. People are paying attention and trying it out. Whether haskell will completely fail to "Avoid success at all costs" or not is hard to say :-). In fact, Intel is porting their concurrent collections libraries to Haskell now. How's that for an endorsement? (It *was* just a C++ library). Tell your friend to stick that in their pipe and smoke it... then pass it to me! :-) Dave

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On Wed, Sep 30, 2009 at 8:32 AM, Andrew Coppin wrote:

(Mr C++ argues that homo sapiens fundamentally think in an imperative way, and therefore functional programming in general will never be popular. We shall see...)

You could use the same argument against, say, utensils. Being "natural" or "intuitive" is a 100% irrelevant metric for any tool. What matters is if it's effective or not. -- Sebastian Sylvan