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> Condescending tutorials seem to be an integrated part of Haskell culture.

Could you perhaps link to one? I know of plenty of misguided tutorials that try to be helpful but aren't. I've never come across one I'd call "condescending".

> I can't recollect I have ever learned a programming concept through metaphors. The only way I have learned concepts is though solving tasks in a language and thereby learning to use the tools available.

Yet for some reason newcomers (reputedly) want to know what a monad is before trying to use one! I agree with you: they should go ahead and use one and not worry about what it is!

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It's not unique to Haskell, and I wouldn't say condescending. More like patronizing and a little infantile. 'Learn you a Haskell' is in the same tone.

Ultimately most of these are just imitations of the 'poignant guide to ruby' which is probably responsible for starting the trend of whimsical and zany programming guides.

You need to use the IO monad to write "hello world". So it is naturally the first question a newcomer will ask. But for example "Learn you a Haskell" http://learnyouahaskell.com/chapters postpones "hello world" to chapter 9, after explaining things like type classes. So the reader is expected to read and understand 9 chapters before writing the first program? This is ridiculous - I certainly wouldn't be able to learn anything that way.

I'm sorry, I don't understand which part of my comment you were replying to.

You are suggesting that newcomers to Haskell should not care about what a monad is. I'm pointing out that tutorials like "Learn you a Haskell" are trying to explain monads before even getting to "Hello World".

Well then, as you already know I agree with you that this is absurd!

> Yet for some reason newcomers (reputedly) want to know what a monad is before trying to use one! I agree with you: they should go ahead and use one and not worry about what it is!

> [...] trying to explain monads before even getting to "Hello World".

Chapter 9: Input and Output

Chapter 12: A Fistful of Monads

No, that doesn't seem to be the case to me.

Sure you need to use the IO monad to write "hello world" but you don't need to understand what it does in the background.

  #include <stdio.h>
  int main(int argc, char *argv[]) {
    printf("Hello World!\n"); 
    return 0;
  }

  class HelloWorld {
    static public void main(String args[]) {
      System.out.println("Hello World!");
    }
  }

  main :: IO ()
  main = print "hello world"

Hello worlds in C, Java and Haskell. I can write them and run them without needing to fully understand what's behind "*argv[]", "static public void" or "IO ()".

Let's be fair to Haskell and LyaH:

I've taught some Java classes. I can get people writing and running trivially useful code before explaining the concepts of "class" and "static". I explain that parts of the code will remain a mystery for a little while until I explain them, I promise to do so, and of course I fulfill that promise as soon as I can.

I feel neither Java nor Haskell are intrinsically bad just because there's no practical way to teach them completely on progressively layered concepts. Even (e.g.) Lisp has a risk of using special forms before understanding them.

Sure, but Learn You a Haskell seem to try to avoid saying "I will explain this mumbo jumbo later" by explaining everything up to type classes before getting to "hello world".

I guess I should write a Haskell tutorial which starts with "hello world" without trying to teach monads beforehand!

Skipping over syntax, I think it's something like:

To write any program in Haskell, you define `main`, the IO action that does the work of your program. `putStrLn` is a function that takes a String and returns an IO action that prints the string.

So we can write "hello world" simply:

    main = putStrLn "Hello, World"

I'm curious whether you actually think that's more useful than building understanding at the REPL.

> I'm curious whether you actually think that's more useful than building understanding at the REPL.

Again, I think this depends on you way of learning. For some people it might be possible to "build understanding" gradually over weeks until you are finally ready to write "hello world" having learnt all the fundamentals of the language. That just doesn't work for me. I need to learn through writing programs which actually does something.

But in the tutorial you are building programs that actually do something - plenty more than simply printing a fixed string. You're just doing it at the REPL instead of in a file.

You keep describing the alternative as if it's a bunch of theory before any practice. It's actually just a slightly different form of practice than maybe you are used to.

I am sympathetic to the notion that it might not work for you, but you haven't spoken at all to the actual distinction. If it really does make a big difference for you, I'm very interested in any unpacking you can do.

I do understand what a REPL is and have even used one from time to time. But from my perspective, a program which cannot interact with the outside world is literally useless.

It is not an accident that almost any tutorial for any language or framework or platform starts with "hello world". Because you want to start with the minimal but real, working program - and build from there.

I seriously don't see how a stand-alone "hello world" program is meaningfully "interact[ing] with the outside world" in a way that printing a string at the REPL is not. Stop ranting and posturing, and instead please try to unpack that.

In either case you are simply printing a string to the terminal. The standalone program is easier to compose in your shell, which in some contexts matters a lot, but I don't see that it does here. Where is the difference?

Further, if we define "interact with the outside world" in a way that excludes the programmer reading things off the screen, then it's plainly wrong that all such programs are "literally useless". Calculators, for instance, have delivered a tremendous amount of value. I've personally run something at a REPL (in various languages) plenty of times because I had actual use for the value to be printed and didn't need to persist the program.

The point of "Hello world" is that it is the simplest possible real, working program. It can be compiled and executed and you could deploy it to users or to a production environment if you wanted.

"A complex system that works is invariably found to have evolved from a simple system that worked."

I understand that from a certain theoretical perspective it is just the same thing to echo a string literal in a REPL, but from a software development perspective it is completely different.

> The standalone program is easier to compose in your shell, which in some contexts matters a lot, but I don't see that it does here.

I kind of see where you are coming from. You are assuming the program is only ever used by yourself. I understand this is just a different culture and hadn't even thought about that perspective.

To clarify, I am not critical of the language Haskell itself. I think it is great. It is mostly a criticism of the tutorials and general culture around the language.

For example Rust is another language which have a reputation for being hard to learn, due to novel and complex concepts like the borrow checker. But in my experience you see none of this "talking down" to the audience. They just explain how the stuff works with practical examples.

> So the reader is expected to read and understand 9 chapters before writing the first program?

Not at all. Haskell has a REPL, so anything involving output is defined as pure functions, then executed at the REPL. For example, here's Quicksort: http://learnyouahaskell.com/recursion#quick-sort That's from Chapter 5.

> I certainly wouldn't be able to learn anything that way.

Certainly not by only reading the table of contents, sure.

Again, this is about different ways of learning which ties into what is even the purpose of programming in the first place.

For academics, the purpose of a program is to exhibit some clever abstraction. So a quicksort which can't take any input to sort and can't produce any output is a perfectly fine program - almost the platonic ideal of a program.

But for developers, the purpose of programs is to do something useful. So learning how to read input and produce output is basically the first thing I want to learn when learning a new language or platform. Because then I can start building small toy programs, gradually doing more and more stuff and learning by tackling the challenges along the way. And implementing quicksort comes way down the line of things I need to learn to write a useful application.

> You need to use the IO monad to write "hello world".

This isn't actually true. You need to use a value of the `IO ()` type. Your program would still work if `IO` was not an instance of `Monad`. In a similar way, you also need to use a value of type `String` but you don't care that it implements `Read` or `Ord` or `Semigroup`.

This doesn't entirely invalidate the rest of what you've written - you do need some basic understanding of how to combine IO actions to do any more interesting IO.

But I feel like your presentation is still misleading. "Learn You A Haskell" starts with the REPL, and has you running code in the first tutorial.

LYAH is full of programs before chapter 9. It does this by living in ghci. Haskell is different - it makes sense for it to start somewhere else (somewhere more useful!) than hello world.

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