Re: [Haskell-beginners] Haskell as a useful practical 'tool' for intelligent non-programmers

On 04/29/2012 02:35 AM, Mike Meyer wrote:

On Sun, 29 Apr 2012 01:20:22 -0400 Michael Orlitzky wrote:

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They're wrapped in Proc objects, but those objects can be treated like any other in the language. Everything else is just syntactic sugar on top of Procs.

That makes *Procs* first class object, not functions.

What's the difference? You're not passing around the actual function, in any language.

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This is not conceptually any different to me than in Haskell or C; you have a name for the thing, distinct from the thing itself, and you have to ask for function application via (f x), f(x), f.call(x), or whatever.

And if having the same set of concepts were all that mattered, we'd still PERFORMing blocks of code. The syntax of a language makes some things easier to do, and some things harder - that's why there's more than one of them. Writing HOFs is harder in ruby than in a language with first-class functions, because you can't pass a function to a function. You have to decide which of the workarounds you want to use (blocks or lambdas or Methods or Procs or ...). If you want to use a function from the standard library - you have to wrap it in order to pass it to your HOF. Since "all of the above" isn't a valid choice, if you're trying to use a library of HOFs (assuming such exist in Ruby - and if they don't, that's yet another reason Ruby isn't a good way to get to Haskell), you may wind up wrapping some things multiple times, or wrap the results of your HOFs, or ... well, you get the idea.

None of this makes Ruby any better or worse for anything other than writing code in a functional style. There are perfectly usable languages that can't do HOFs at all. That you can do it at all makes Ruby a better choice than them for writing functional code. But it requires a lot of code that's nothing more than boilerplate, which makes it worse than languages that don't require such.

Of course, if you don't think boilerplate makes things harder, and all that matters is having the same concepts, then I expect you won't argue if I claim that there's no reason to pick Ruby over Java for writing OO code. After all, they have the same concepts, just with different syntactic sugar and more or less boilerplate.

We were never talking about easy, only possible. I can pass around functions just fine if I declare them with Proc.new and call them with p[x]. Nobody actually does this in practice because classes provide implicit state, and that combined with blocks solves almost all real use cases.