Getting started with Haskell

Answer 1

I suggest that you first start by reading BONUS' tutorial, And then reading Real World Haskell (online for free). Join the #Haskell IRC channel, on irc.freenode.com, and ask questions. These people are absolutely newbie friendly, and have helped me a lot over time. Also, right here on SO is a great place to get help with things you can't grasp! Try not to get discouraged, once it clicks, your mind will be blown.

BONUS' tutorial will prime you up, and get you ready for the thrill ride that Real World Haskell brings. I wish you luck!

Answer 2

Here's a good book that you can read online: Real World Haskell

Most of the Haskell programs I've done have been to solve Project Euler problems.

Once piece of advice I read not too long ago was that you should have a standard set of simple problems you know how to solve (in theory) and then whenever you try to learn a new language you implement those problems in that language.

Answer 3

To add on others' answers - there is one useful that will help you when coding (for example when solving project Euler problems): Hoogle. You can use either the command line interface or the web interface.

Command Line

After you installed the Haskell platform be sure to cabal install hoogle

Hoogle usage example:

You have a function f x = 3 * x + 1 and you want to apply it on (5 :: Int), then apply it on the result and on that result and so on and get an infinite list of those values. You suspect there might already exist a function to assist you (not specifically for your f though).

That function would be of type (a -> a) -> a -> [a] if it takes f 5 or a -> (a -> a) -> [a] if it takes 5 f (we assume the function is for general types and not just Ints)

$ hoogle "a -> (a -> a) -> [a]"
Prelude iterate :: (a -> a) -> a -> [a]

yep, the function you need already exists and it's called iterate. you use it by iterate func 5!

Web interface

The result for the same example can be found here.

Answer 4

Graham Hutton's Programming in Haskell is concise, reasonably thorough, and his years of teaching Haskell really show. It's almost always what I recommend people start with, regardless of where you go from there.

In particular, Chapter 8 ("Functional Parsers") provides the real groundwork you need to start dealing with monads, and I think is by far the best place to start, followed by All About Monads. (With regard to that chapter, though, do note the errata from the web site, however: you can't use the do form without some special help. You might want to learn about typeclasses first and solve that problem on your own.)

This is rarely emphasized to Haskell beginners, but it's worth learning fairly early on not just about using monads, but about constructing your own. It's not hard, and customized ones can make a number of tasks rather more simple.

Answer 5

Try writing easy programs in it.

You can find sample tasks in various textbooks, probably.

I wouldn't recommend sticking to Haskell/FP textbooks, just try to do simple things with it: calculations, string manipulations, file access.

After I solved a dozen, I've broke the ice :)

After that, read a lot on advanced concepts (Monads, Arrows, IO, recursive data structures), because haskell is infinite and there are a lot of them.

Answer 6

Don't try to read all the monad tutorials with funny metaphors. They will just get you mixed up even worse.