Daniel Carrera wrote:
As a newbie... I agree that a newbie should be able to write this fairly early on:
main = do x <- getLine() putStrLn ("The answer is " ++ show(fib(read(x))))
I'd agree for some definition of 'early'. I'll elaborate: This entire discussion is about 'breaking a cyclic graph of conceptual dependencies'. Unfortunately, I don't think it can be done well in short amount of time. The above code snippet contains typeclasses (show, read, monadic IO, lists), syntactic sugar (do, <-). When you say a 'newbie' should be able to write that early on, I'd interpret that as 'a newbie should be able to regurgitate this early on' because the next thing a newbie might want to do is try to divide the result of fib by a float and wonder why he can't do that, or try to debug his fib implementation by trying to insert a putStrLn. There are numerous ways to frustration unless the newbie is comfortable with typeclasses, monads, etc. This happens all the time when somebody is learning a new language, but it's most problematic for haskell because the breadth of knowledge (of various concept of the language) a learner has to gather before he can dive deep (formulation, compilation, execution, debugging) into an actual (even trivial) program is larger than all popular languages out there. In every language, the most powerful features make their ways into the most basic elements (as they should so that the entire language benefits, but then, lists are monads?!?!). Learners of C++ with a C background are not as much troubled by "cout << yadda << endl;" even though there is operator overloading, references and the streams class hieararchy in that statement. You can close your eyes and pretend that cout is just magic and re-visit that node when you are comfortable with classes. I don't think we can break cycles easily like that in Haskell. The mental load is very high, and with concerns about language features vs complexity even in other languages (see http://lambda-the-ultimate.org/node/view/1155) I think we are observing a new phenomenon: languages worth learning from now on will be increasingly difficult (heck, even Perl is difficult now), and we'll have to do away with 'tutorials' mostly. In fact what we have are not really tutorials (YAHT is a small book! compare that with http://www.ocaml-tutorial.org/). I think it's a tall order for a 'tutorial' to teach Haskell (which may be why we end up reading 4-5 of them). In fact Hudak's Haskell book was the first introductory language book I'd ever bought. That's why I think tutorials can have be frustrating and it takes a well edited book and . Cheers, Koray