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I wish PragProg would do a (whole) book one Haskell. The current ones just aren't very good. Books such as "Real World Haskell", the "gentle guide" and "Yet An

I wish PragProg would do a (whole) book one Haskell. The current ones just aren't very good. Books such as "Real World Haskell", the "gentle guide" and "Yet Another Haskell Tutorial" all manage the rather unbelievable feat of making many Haskell concepts unnecessarily complex, unintuitive and hard to understand -- not something you want for a language that is already on the complex side. For example, RWH goes into an absurdly complicated sample scenario (a parser, iirc) to introduce the reader to monads, and never slows down to go back to first principles. YAHT does the same thing. Monads have a reputation for being hard to understand, but I think this is mostly the fault of the current literature; monads are conceptually simple, yet every book manages to botch their explanation, making the learning curve particularly steep for non-FP programmers.

acomar 14y ago
Have you tried Learn You A Haskell? It's a gentle and humorous introduction to the language, and I rather like it's take on the more important typeclasses. As for monads in particular, I think the best introduction is "You Could Have Invented Monads."
tmhedberg 14y ago
Have you tried Learn You a Haskell for Great Good (http://learnyouahaskell.com/ http://learnyouahaskell.com/)? It's not as comprehensive or full of practical examples as something like RWH, but as an introductory text, I think it does a better job than any other Haskell book I've come across at keeping challenging concepts understandable.
- SkyMarshal 14y ago
  As an introductory text it actually does a better job than just about anything I've read. I'd rank it up there with The Little Schemer series for learning some aspects of functional programming. Miran is very good at explaining and writing.
- lobster_johnson 14y ago
  I had forgotten all about that. I agree, it's very good. Its chapter on monads is decent, iirc. But the book is also quite light, being a basic intro to the language, and doesn't get into a lot of things you'd want to learn in order to actually get stuff done (concurrent programming, networking etc.).
deleted 14y ago
[deleted]
stonemetal 14y ago
What example do you think would be good?
- lobster_johnson 14y ago
  This [1] was the explanation which finally made monads "click" for me. You can think of the IO monad as a way to force a compile-time dependency between I/O operations by having each IO-performing function take a "baton" value (the "IO" instance) as an argument, as well as return it. The explanation of how Haskell retains the appearance of purity in the face of impure I/O by passing an instance of RealWorld around is genius. That's a brilliant way to start out explaining monads, and it's something simple that you can use to explain the other monads such as the state monad (which the IO monad is built on). [1] http://www.haskell.org/haskellwiki/IO_inside http://www.haskell.org/haskellwiki/IO_inside
agumonkey 14y ago
Most of the mathematical culture inherited by haskell can be learned somehow elsewhere. Disclaimer, I'm quite a noob, but I'm pretty sure sicp/little schemer are good complementary sources on the spirit of haskell. About monads, seeing them outside of Haskell is a great way to see smaller steps. Articles like http://dorophone.blogspot.fr/2011/04/deep-emacs-part-1.html http://dorophone.blogspot.fr/2011/04/deep-emacs-part-1.html , or this video http://www.youtube.com/watch?v=ObR3qi4Guys http://www.youtube.com/watch?v=ObR3qi4Guys I hope it will help you
spacemanaki 14y ago
I think parsers are a decent way to introduce monads, and I really like the way Graham Hutton's Programming Haskell does it, by demonstrating parsing without even using the word monad, and then in a later chapter on IO, saying "oh hey and this thing is called a monad and we used it once before!" And I disagree a bit about RWH... I'm in the middle of it now I think it's great, filled with meaty examples that aren't too complicated at all and are generally pretty concrete. Maybe I'm just not far enough in yet? There are bits where it goes off into the weeds (the chapter on JSON goes so far as to fiddle about with character encoding IIRC) but I just can't imagine a PragProg book could do much better, without sacrificing depth.
- boothead 14y ago
  I actually find parsing to be a better example of Applicative than Monad.
- T_S_ 14y ago
  Hutton's book is excellent (and thin!). Work through that and you will learn about some deep stuff without even realizing it.
  - paulcc 14y ago
    I agree, and it's the one I recommend for experienced programmers. It has a K&R-like succinctness and clarity. That said, it is about programming in Haskell and not about programming with Haskell; hence this series of articles where I try to look at the wider picture and some pragmatic issues.
    - gtani 14y ago
      Simon Thompson's text (3rd ed) is also a good learning text. It was updated in 3rd ed for GHC
- Evbn 14y ago
  RWH is way obsolete. Its own authors have written libraries that deprecate the ones they recommend in the book.
lobster_johnson 14y ago
Please don't downvote just because you disagree with someone's opinion.
paulcc 14y ago
I agree that a more pragmatic approach is needed, which is why I started writing this series on FP. What else would you like to see in such a book? http://forums.pragprog.com/posts/30455 http://forums.pragprog.com/posts/30455
- lobster_johnson 14y ago
  Your link doesn't work (404). Personally, I like the "Learn You A Haskell" style, of carefully and very gently building up the basic language, with examples that are as simple as possible and deal with only the issue being discussed. My problem with Real World Haskell is that it combines learning the language with building stuff. So when it gets to something like monads, there are way too much noise surrounding the core concept being explained. It's fine to show practical examples, but not everything should be built on them. Aside from that, I like the practically-oriented stuff in RWH. I would like to see an article on doing concurrent, parallel, distributed systems (Erlang-style) in Haskell.
paulcc 14y ago
Did anyone notice that I only mentioned monads once in the article? (NB a mistake upstream meant some material was dropped. There was a nice para there about "I remember the time before monads... We did the same stuff, only it was a bit clumsier...") Monads are a useful technique, but they aren't everything!

acomar 14y ago

Have you tried Learn You A Haskell? It's a gentle and humorous introduction to the language, and I rather like it's take on the more important typeclasses. As for monads in particular, I think the best introduction is "You Could Have Invented Monads."

tmhedberg 14y ago

Have you tried Learn You a Haskell for Great Good (http://learnyouahaskell.com/ http://learnyouahaskell.com/)? It's not as comprehensive or full of practical examples as something like RWH, but as an introductory text, I think it does a better job than any other Haskell book I've come across at keeping challenging concepts understandable.

SkyMarshal 14y ago
As an introductory text it actually does a better job than just about anything I've read. I'd rank it up there with The Little Schemer series for learning some aspects of functional programming. Miran is very good at explaining and writing.
lobster_johnson 14y ago
I had forgotten all about that. I agree, it's very good. Its chapter on monads is decent, iirc. But the book is also quite light, being a basic intro to the language, and doesn't get into a lot of things you'd want to learn in order to actually get stuff done (concurrent programming, networking etc.).

deleted 14y ago

[deleted]

stonemetal 14y ago

What example do you think would be good?

lobster_johnson 14y ago
This [1] was the explanation which finally made monads "click" for me. You can think of the IO monad as a way to force a compile-time dependency between I/O operations by having each IO-performing function take a "baton" value (the "IO" instance) as an argument, as well as return it. The explanation of how Haskell retains the appearance of purity in the face of impure I/O by passing an instance of RealWorld around is genius. That's a brilliant way to start out explaining monads, and it's something simple that you can use to explain the other monads such as the state monad (which the IO monad is built on). [1] http://www.haskell.org/haskellwiki/IO_inside http://www.haskell.org/haskellwiki/IO_inside

agumonkey 14y ago

Most of the mathematical culture inherited by haskell can be learned somehow elsewhere. Disclaimer, I'm quite a noob, but I'm pretty sure sicp/little schemer are good complementary sources on the spirit of haskell. About monads, seeing them outside of Haskell is a great way to see smaller steps. Articles like http://dorophone.blogspot.fr/2011/04/deep-emacs-part-1.html http://dorophone.blogspot.fr/2011/04/deep-emacs-part-1.html , or this video http://www.youtube.com/watch?v=ObR3qi4Guys http://www.youtube.com/watch?v=ObR3qi4Guys I hope it will help you

spacemanaki 14y ago

I think parsers are a decent way to introduce monads, and I really like the way Graham Hutton's Programming Haskell does it, by demonstrating parsing without even using the word monad, and then in a later chapter on IO, saying "oh hey and this thing is called a monad and we used it once before!" And I disagree a bit about RWH... I'm in the middle of it now I think it's great, filled with meaty examples that aren't too complicated at all and are generally pretty concrete. Maybe I'm just not far enough in yet? There are bits where it goes off into the weeds (the chapter on JSON goes so far as to fiddle about with character encoding IIRC) but I just can't imagine a PragProg book could do much better, without sacrificing depth.

boothead 14y ago
I actually find parsing to be a better example of Applicative than Monad.
T_S_ 14y ago
Hutton's book is excellent (and thin!). Work through that and you will learn about some deep stuff without even realizing it.
- paulcc 14y ago
  I agree, and it's the one I recommend for experienced programmers. It has a K&R-like succinctness and clarity. That said, it is about programming in Haskell and not about programming with Haskell; hence this series of articles where I try to look at the wider picture and some pragmatic issues.
  - gtani 14y ago
    Simon Thompson's text (3rd ed) is also a good learning text. It was updated in 3rd ed for GHC
Evbn 14y ago
RWH is way obsolete. Its own authors have written libraries that deprecate the ones they recommend in the book.

lobster_johnson 14y ago

Please don't downvote just because you disagree with someone's opinion.

paulcc 14y ago

I agree that a more pragmatic approach is needed, which is why I started writing this series on FP. What else would you like to see in such a book? http://forums.pragprog.com/posts/30455 http://forums.pragprog.com/posts/30455

lobster_johnson 14y ago
Your link doesn't work (404). Personally, I like the "Learn You A Haskell" style, of carefully and very gently building up the basic language, with examples that are as simple as possible and deal with only the issue being discussed. My problem with Real World Haskell is that it combines learning the language with building stuff. So when it gets to something like monads, there are way too much noise surrounding the core concept being explained. It's fine to show practical examples, but not everything should be built on them. Aside from that, I like the practically-oriented stuff in RWH. I would like to see an article on doing concurrent, parallel, distributed systems (Erlang-style) in Haskell.

paulcc 14y ago

Did anyone notice that I only mentioned monads once in the article? (NB a mistake upstream meant some material was dropped. There was a nice para there about "I remember the time before monads... We did the same stuff, only it was a bit clumsier...") Monads are a useful technique, but they aren't everything!