4 ms·

Why can't we have the expressiveness of CL or Haskell with the performance of C++?

by capisce 14y ago

jeremiep 14y ago
We do, its called the D programming language.
- shadowfox 14y ago
  That feels a little surprising to me. Last time I looked at D it was nowhere close to CL or Haskell in expressiveness? (It was certainly better than C and less complicated than C++). Has there been significant improvements in the past couple of years?
  - CountHackulus 14y ago
    There really has. D 1.0 has 20 days of life left, and D 2.0 is really amazing. It has the C++ idea of "it's only there if you want it" but taken to an amazing degree. Yes, it's a little more verbose than most FP languages, but honestly, if you're interested in verbosity, go use J or Coke. The thing I like about D is that there's no surprises, everything works the way you'd expect it to. You can guess at what code should look like, and chances are it'll work.
- Peaker 14y ago
  map (head &&& length) . sort . group filterM (const [True, False]) Can you show how you implement these in D? If you want, I can explain these or give other examples of expressiveness I don't think you'll find in D.
  - deleted 14y ago
    [deleted]
  - tel 14y ago
    That is one of the best implementations of powerset I've seen in a while. Thank you for that!
  - roryokane 14y ago
    Links explaining these Haskell code snippets: http://stackoverflow.com/a/10410997/578288 http://stackoverflow.com/a/10410997/578288 – the `map` snippet converts a flat list into a multiset represented as a list of `(count, element)` tuples http://stackoverflow.com/a/5378799/578288 http://stackoverflow.com/a/5378799/578288 – the `filterM` snippet returns the powerset of its list argument (http://en.wikipedia.org/wiki/Power_set http://en.wikipedia.org/wiki/Power_set)
  - orlandu63 14y ago
    I think you mean group . sort
    - Peaker 14y ago
      Oops, quick-typing on my phone can have problematic results :-)
- gtani 14y ago
  Can you detail, or point to background info? There've been type system debates between proponents of Haskell, ocaml, SML, scala, and F#, i've never seen a D to Haskell comparison, and I've never seen D mentioned as a "free theorems" language. Maybe in this vid: http://channel9.msdn.com/Blogs/Charles/Alexandrescu-Bright-Meijer-Moran-Pure-versus-Native-and-much-more http://channel9.msdn.com/Blogs/Charles/Alexandrescu-Bright-M... Here's a scala to haskell http://www.cs.ox.ac.uk/jeremy.gibbons/publications/scalagp.pdf http://www.cs.ox.ac.uk/jeremy.gibbons/publications/scalagp.p...
roryokane 14y ago
We can, theoretically. We just haven't yet developed algorithms that are clever enough to make the correct optimizations to code in enough of the cases where such optimizations are possible. There are patterns in our code that we humans can write out when we write our code in C++, but that we haven't yet formalized and implemented for the computer to do.

Why can't we have the expressiveness of CL or Haskell with the performance of C++?

by capisce 14y ago

Why can't we have the expressiveness of CL or Haskell with the performance of C++?

jeremiep 14y ago

We do, its called the D programming language.

shadowfox 14y ago
That feels a little surprising to me. Last time I looked at D it was nowhere close to CL or Haskell in expressiveness? (It was certainly better than C and less complicated than C++). Has there been significant improvements in the past couple of years?
- CountHackulus 14y ago
  There really has. D 1.0 has 20 days of life left, and D 2.0 is really amazing. It has the C++ idea of "it's only there if you want it" but taken to an amazing degree. Yes, it's a little more verbose than most FP languages, but honestly, if you're interested in verbosity, go use J or Coke. The thing I like about D is that there's no surprises, everything works the way you'd expect it to. You can guess at what code should look like, and chances are it'll work.
Peaker 14y ago
map (head &&& length) . sort . group filterM (const [True, False]) Can you show how you implement these in D? If you want, I can explain these or give other examples of expressiveness I don't think you'll find in D.
- deleted 14y ago
  [deleted]
- tel 14y ago
  That is one of the best implementations of powerset I've seen in a while. Thank you for that!
- roryokane 14y ago
  Links explaining these Haskell code snippets: http://stackoverflow.com/a/10410997/578288 http://stackoverflow.com/a/10410997/578288 – the `map` snippet converts a flat list into a multiset represented as a list of `(count, element)` tuples http://stackoverflow.com/a/5378799/578288 http://stackoverflow.com/a/5378799/578288 – the `filterM` snippet returns the powerset of its list argument (http://en.wikipedia.org/wiki/Power_set http://en.wikipedia.org/wiki/Power_set)
- orlandu63 14y ago
  I think you mean group . sort
  - Peaker 14y ago
    Oops, quick-typing on my phone can have problematic results :-)
gtani 14y ago
Can you detail, or point to background info? There've been type system debates between proponents of Haskell, ocaml, SML, scala, and F#, i've never seen a D to Haskell comparison, and I've never seen D mentioned as a "free theorems" language. Maybe in this vid: http://channel9.msdn.com/Blogs/Charles/Alexandrescu-Bright-Meijer-Moran-Pure-versus-Native-and-much-more http://channel9.msdn.com/Blogs/Charles/Alexandrescu-Bright-M... Here's a scala to haskell http://www.cs.ox.ac.uk/jeremy.gibbons/publications/scalagp.pdf http://www.cs.ox.ac.uk/jeremy.gibbons/publications/scalagp.p...

roryokane 14y ago

We can, theoretically. We just haven't yet developed algorithms that are clever enough to make the correct optimizations to code in enough of the cases where such optimizations are possible. There are patterns in our code that we humans can write out when we write our code in C++, but that we haven't yet formalized and implemented for the computer to do.