[rybosome]

That's functional programming for you. It's definitely less efficient, but there are other major advantages. For one thing, given the propagation of immutable data, things can be parallelized effortlessly - look at 'pmap' in Clojure for example. Once you're familiar with the style, it's significantly more concise and readable.

That being said, a systems programming language may not be the right place for FP concepts.

[coolsunglasses]

>That's functional programming for you.

Uhm, what? No it's not.

Haskell has stream fusion, thereby generating assembler that looks a lot like the optimal imperative version.

[burntsushi]

This is kind of misleading. Stream fusion isn't baked into Haskell; you need to use a library. [1,2]

    [1] - https://ghc.haskell.org/trac/ghc/ticket/915
    [2] - http://hackage.haskell.org/package/stream-fusion

[coolsunglasses]

http://hackage.haskell.org/package/text-0.1/docs/Data-Text-F...

http://hackage.haskell.org/package/vector-0.9.1/docs/Data-Ve...

Except it's bloody everywhere in the libraries you use and you can design your own libraries around it.

A language powerful enough that things like this can be done in libraries instead of in the compiler is a good thing.

[microtonal]

But, many of the commonly used libraries already use stream fusion, e.g. vector and text.

[rybosome]

Very cool - I was not aware of this feature. Fwiw, I'm actually something of an FP zealot; I failed to make a stronger case in my comment because I'm tired of arguing, and I'm concerned that I'm being obnoxious.

[saryant]

Scala gets around this with "views": store the higher-order functions until the collection actually needs to be used and then apply them all at once, without any intermediate data structure.

http://docs.scala-lang.org/overviews/collections/views.html

[krakensden]

> things can be parallelized effortlessly

If you're not using a language with Clojure's nifty datastructures, "effortlessly" probably isn't much better than OpenMP.

[atilaneves]

D is a systems programming language with FP concepts and they work quite well. Also, it has generics / templates / parametric polymorphism that are more powerful and easier to use than C++.

[chongli]

Right, but it still employs a machine model of computation. This is fundamentally different from FP's language model.

https://existentialtype.wordpress.com/2011/03/16/languages-a...

[Dewie]

> That being said, a systems programming language may not be the right place for FP concepts.

It's good enough for Rust.

[pcwalton]

Note that the Rust compiler doesn't do any stream fusion; rather the functional idioms are designed around iterators, which provide a functional interface that relatively easily and predictably compiles down to code that's as efficient as the corresponding for loop.

[rybosome]

I wondered about that - Rust looks like the one systems programming language I would actually enjoy using, but I don't know enough about it to have an informed opinion.