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Learn You a Haskell for Great Good

learnyouahaskell.com

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Re: Learn You a Haskell for Great Good

#51

Post by [deleted] »

nilkn wrote: post #17
ikkyu wrote: post #5

Haskell looks very interesting but I can't help but ask 'why do I need it?'. Currently I am learning Java since I want to get a jr.developer job later on and Ruby for some scripting and personal projects(maybe even Rails later). So Java is used in industry, Ruby is used in web and metasploit/ronin (something that I like to mess with), but what about Haskell? I am genuinely curious what Haskell can offer. I always see…

> I always see it mentioned on Reddit but I have yet to come across any notable project written with it. xmonad, one of the best tiling window managers for Linux, is written in Haskell (and is open source).

[deleted]

Re: Learn You a Haskell for Great Good

#52

Post by ihm »

davidw wrote: post #24
ikkyu wrote: post #5

Haskell looks very interesting but I can't help but ask 'why do I need it?'. Currently I am learning Java since I want to get a jr.developer job later on and Ruby for some scripting and personal projects(maybe even Rails later). So Java is used in industry, Ruby is used in web and metasploit/ronin (something that I like to mess with), but what about Haskell? I am genuinely curious what Haskell can offer. I always see…

If you want to look at an interesting functional language that has some very solid real world uses, have a look at Erlang, and its own "Learn you ..." here: http://learnyousomeerlang.com/ Which is a fantastic book, clearly written as a labor of love. Erlang doesn't have Haskell's type system and doesn't seem to be of much interest for CS research types, but it's awesome for developing certain kinds of system. I am cu…

One thing that I love to do in Haskell, and which Haskell is especially suited to, is writing interpreters and parsers. The other week I wrote a brainfuck interpreter (https://github.com/imeckler/skellfuck) in a couple of hours. Parsec, along with monads and functors, make this kind of thing a real joy to write.

Re: Learn You a Haskell for Great Good

#53

Post by davidw »

ihm wrote: post #52
davidw wrote: post #24

Earlier quoted context omitted.

If you want to look at an interesting functional language that has some very solid real world uses, have a look at Erlang, and its own "Learn you ..." here: http://learnyousomeerlang.com/ Which is a fantastic book, clearly written as a labor of love. Erlang doesn't have Haskell's type system and doesn't seem to be of much interest for CS research types, but it's awesome for developing certain kinds of system. I am cu…

One thing that I love to do in Haskell, and which Haskell is especially suited to, is writing interpreters and parsers. The other week I wrote a brainfuck interpreter ( https://github.com/imeckler/skellfuck ) in a couple of hours. Parsec, along with monads and functors, make this kind of thing a real joy to write.

That still seems like something of a second order problem in that you're solving your own problem that you might need in order to solve a customer's problem.

Re: Learn You a Haskell for Great Good

#54

Post by nbouscal »

ccdan wrote: post #42
adimitrov wrote: post #31

Earlier quoted context omitted.

The designers of Haskell (and Haskell is one of the few successful design-by-committee languages,) were not doing things "your way" (where I assume you are a working programmer, with knowledge of some or even many traditional imperative languages.) They were PL researchers. Used to ML, Common Lisp, Ada, and, most importantly, Mathematics and Category and Type Theory. `data` introduces an algebraic data type , so it m…

Huge mistake on their part, typical of math people. High level programming languages have to be as close as possible to human languages (English) not to some obscure mathematical concepts and notation that most people don't care about. Actually math notation itself (cryptic, inconsistent, ambiguous) is a horrible result of math people's communication handicap and ineptitude.

No. The math notation that is used across all branches of mathematics is consistent and unambiguous (the notation of formal logic, naive set theory, etc). The only ambiguity typically comes from traversing different branches of the discipline, which is inevitable considering how many branches there are and how deep they go.

Furthermore, mathematics is all about communication. The language of mathematics exists to codify concepts so that they can be talked about concisely. Being able to say 'group' instead of 'set with an associative binary operation with identities' is essential if you want to be able to build on top of that concept without taking an hour to read one theorem.

The handicap in communication isn't on the mathematics end, it's on your end. You seem to expect them to be able to explain structures to you that took years of work to build by using the same language that you use to talk about sports or social events. The reality is that you are not the target audience of their communication, and they are okay with that. You should be too.

The weirdest assertion that you made is that high-level programming languages ought to be as close as possible to human languages. The two categories of languages exist to communicate fundamentally and widely different groups of concepts. Words represent categories of analogous concepts, and the relevant categories in human life are nothing like the relevant categories in programming. In Haskell, 'functor', 'applicative functor', and 'monad' are highly relevant categories. They pop up everywhere and can be leveraged with great benefit. In human life these concepts are far less common, and thus do not merit words in the common vernacular. Were we to use a programming language modeled on English, we would miss the benefit of these abstractions, trading them for categories like 'dog' and 'car' which have very little practical use in typical programming.

Re: Learn You a Haskell for Great Good

#55

Post by GhotiFish »

I really liked LYAH, but it only starts out good. Once you hit Chapter 9. I/O. Prepare to fall off the rails. It only gets worse and worse and worse from that point onwards.

I don't think that's really the books fault as much as it is Haskells. I also think it's why you hear ALOT of people swearing Haskell is actually very easy, because everything up to chapter 9 is not very complicated at all.

I'm sure there are some very tallented people where this isn't true, but I get the impression that the people who are saying it's easy haven't gotten to the point where you can actually do things with Haskell, or developed a program with Haskell, or inter-operate with other libraries using Haskell, or tested their metal against the Parsing Combinators in Haskell (let alone making your own set), or ect. ect. ect.

Chapters 1-8 aren't complicated in the slightest.

Chapter 9 is when it starts.

Haskell isn't easy.

Re: Learn You a Haskell for Great Good

#56

Post by nilkn »

nbouscal wrote: post #22
ikkyu wrote: post #5

Haskell looks very interesting but I can't help but ask 'why do I need it?'. Currently I am learning Java since I want to get a jr.developer job later on and Ruby for some scripting and personal projects(maybe even Rails later). So Java is used in industry, Ruby is used in web and metasploit/ronin (something that I like to mess with), but what about Haskell? I am genuinely curious what Haskell can offer. I always see…

There are two very different types of arguments typically made as to why to learn the more esoteric languages (Haskell, Lisp, Forth, others). The first is the more common: learning these languages exposes you to other ways of programming, which in turn makes you a better programmer no matter what language you're programming in. This is unquestionably true. Mainstream languages are constantly learning new things from…

> The other argument, which is made less often, is that you can actually write great software in these languages.

It's probably worth mentioning that Jane Street writes all their trading infrastructure these days in OCaml. They're probably one of the biggest industrial users of a functional language.

There's also Tsuru Capital, a trading firm of lesser note than Jane Street, which almost exclusively uses Haskell.

Mailrank's backend was also written in Haskell.

Re: Learn You a Haskell for Great Good

#57

Post by nilkn »

ccdan wrote: post #42
adimitrov wrote: post #31

Earlier quoted context omitted.

The designers of Haskell (and Haskell is one of the few successful design-by-committee languages,) were not doing things "your way" (where I assume you are a working programmer, with knowledge of some or even many traditional imperative languages.) They were PL researchers. Used to ML, Common Lisp, Ada, and, most importantly, Mathematics and Category and Type Theory. `data` introduces an algebraic data type , so it m…

Huge mistake on their part, typical of math people. High level programming languages have to be as close as possible to human languages (English) not to some obscure mathematical concepts and notation that most people don't care about. Actually math notation itself (cryptic, inconsistent, ambiguous) is a horrible result of math people's communication handicap and ineptitude.

I don't think it's ever a mistake for something to push standards higher, even if those standards are so high that it might turn off some talented people.

I also disagree overall with your assessment of mathematical notation. But it doesn't really matter because Haskell doesn't actually use any math notation. It does use some math terminology, though, and overall mathematicians are absurdly pedantic about terminology. Mathematicians may not be great at telling jokes at parties (though you may be surprised!), but it's their job to make sure they are writing in consistent and unambiguous ways.

Re: Learn You a Haskell for Great Good

#58

Post by jmilkbal »

klibertp wrote: post #49
tel wrote: post #41

Earlier quoted context omitted.

Scheme, Clojure, and most of Erlang are on an entirely different side of a fairly large chasm within the lay term "functional programming". Haskell, ML, Ada, Coq, and even some parts of Scala are just entirely different beasts. The underlying math is far more pronounced, leadi to new terminology and power.

Ada?! It's purely imperative, type-safe language, no? At least that was the impression I got when it was forced on me at university. Also, ML? I know OCaml a bit, but according to this comparison: http://adam.chlipala.net/mlcomp/ Standard ML has a "ref" type, which in effect allows mutable state. While it lack a bit of a syntactic sugar for this, OCaml's mutable record fields are implemented in terms of refs, so in t…

I use Ada (a proper noun) regularly. It is not a functional language, but encourages a lot of the same things that functional people like to talk about. Ada is a wonderful language to use. It's rather boring and uneventful and is not accompanied by buzz words, but most of the Ada folks I know (converts or otherwise) all suggest that they're accomplishing more in less time with fewer bugs than they get with other languages. A lot of the new, buzzy languages seem to be solving problems that Ada took care of in the 80s and 90s. It's definitely worth a look if only to improve your approaches to software.

Edited for fun and grammar!

Re: Learn You a Haskell for Great Good

#59

Post by digitalzombie »

jordigh wrote: post #12
tieTYT wrote: post #3

This is an amazing book. I highly recommend it as the first Haskell book you read. After it, you can check out Real World Haskell. To elaborate on why you shouldn't read (at least the online version of) Real World Haskell first: It has a lot of important topics that it covers that LYAH does not cover (like how to use cabal their package manager). But, it's not as good of a tutorial on the language and functional prog…

I started reading the online version, enjoyed it so much, I went ahead and boug ht the treeware version. And it's awesome . I felt so loved as a customer of No Starch Press. They sent me the book, let me download the ebook in three free formats (no DRM), plus I got a bunch of freebie stickers. The book itself is also quite remarkable to me in that I can read it and understand Haskell without needing a computer. I am…

=/ I never got freebie stickers from No Starch Press (probably cause I buy it through amazon). Their book quality is amazing, the paper and cover are very nice quality (unlike other publishers >=( ), I bought the learn you some erlang for great good, art of R programming, and the eloquent javascript.

Re: Learn You a Haskell for Great Good

#60

Post by ccdan »

nbouscal wrote: post #54
ccdan wrote: post #42

Earlier quoted context omitted.

Huge mistake on their part, typical of math people. High level programming languages have to be as close as possible to human languages (English) not to some obscure mathematical concepts and notation that most people don't care about. Actually math notation itself (cryptic, inconsistent, ambiguous) is a horrible result of math people's communication handicap and ineptitude.

No. The math notation that is used across all branches of mathematics is consistent and unambiguous (the notation of formal logic, naive set theory, etc). The only ambiguity typically comes from traversing different branches of the discipline, which is inevitable considering how many branches there are and how deep they go. Furthermore, mathematics is all about communication. The language of mathematics exists to cod…

>>No. The math notation that is used across all branches of mathematics is consistent and unambiguous (the notation of formal logic, naive set theory, etc). >>>Being able to say 'group' instead of 'set with an associative binary operation with identities' is essential >>>The reality is that you are not the target audience of their communication, and they are okay with that. You should be too.>>>The weirdest assertion that you made is that high-level programming languages ought to be as close as possible to human languages. The two categories of languages exist to communicate fundamentally and widely different groups of concepts. Words represent categories of analogous concepts, and the relevant categories in human life are nothing like the relevant categories in programming. In Haskell, 'functor', 'applicative functor', and 'monad' are highly relevant categories. They pop up everywhere and can be leveraged with great benefit.False. Computers and software are mainly used to emulate some real world stuff (objects, actions etc.) and to help people with real world stuff in a more automated way. They aren't used too much to prove theorems or some other math stuff. And pretty much no one cares about proving the so called "mathematical correctness" of a program - a concept that doesn't even make sense in most cases. Old misconception among FP advocates, even Dijkstra himself admitted that he was kinda wrong about how computer would evolve and what they'd used for. But the associated misconceptions live on. A language close to human language also helps avoiding errors. That's why you won't see functional languages in critical systems, but rather languages like Ada which is probably the closest programming language to human language. The claims of clarity of FP languages are pretty much at odds with the evidence the real world provides.
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