Rust as a gateway drug to Haskell

Post by jnordwick » Wed, Jun 14, 2017, 7:41 AM UTC

toprerules wrote: post #15

The similarities are striking. Both have a problem with undocumented or experimental modules for everyday tasks, both use compiler plugins to make sure that every package is using its own superset of the language (although in Rust this only applies to nightly), both tout lofty goals while rarely producing production grade systems. Rust is the first toe dip into the world of blog posts heralding the"coming of the age…

Post by decafbad » Wed, Jun 14, 2017, 7:45 AM UTC

Post by delhanty » Wed, Jun 14, 2017, 8:21 AM UTC

wyager wrote: post #29

delhanty wrote: post #25

Earlier quoted context omitted.

> .. you can write vastly more complicated programs that are, say, 80% as fast as hand-optimized C for only 10% of the effort of hand-optimized C. Computer Language Benchmarks of GHC versus C don't seem to be close to matching your 80% as fast claim [1]. Also, the 10% of the effort of hand-optimized C bit - seem to recall there was a caveat - "if you happen to Don Stewart" [2]. The following is just my vague, uninfor…

The benchmarks game falls squarely under the umbrella of "short, simple programs", not the sort of real-world stuff where you would benefit from having a language that scales well. That said, Haskell performs pretty well in the toy benchmarks anyway. Your comparison between Haskell and Go is about market size, not language design. I suspect you would have a similarly hard time finding Rust devs as Haskell devs (i.e.…

Post by delhanty » Wed, Jun 14, 2017, 8:29 AM UTC

wyager wrote: post #29

delhanty wrote: post #25

Earlier quoted context omitted.

> .. you can write vastly more complicated programs that are, say, 80% as fast as hand-optimized C for only 10% of the effort of hand-optimized C. Computer Language Benchmarks of GHC versus C don't seem to be close to matching your 80% as fast claim [1]. Also, the 10% of the effort of hand-optimized C bit - seem to recall there was a caveat - "if you happen to Don Stewart" [2]. The following is just my vague, uninfor…

The benchmarks game falls squarely under the umbrella of "short, simple programs", not the sort of real-world stuff where you would benefit from having a language that scales well. That said, Haskell performs pretty well in the toy benchmarks anyway. Your comparison between Haskell and Go is about market size, not language design. I suspect you would have a similarly hard time finding Rust devs as Haskell devs (i.e.…

Post by louthy » Wed, Jun 14, 2017, 8:37 AM UTC

DaiPlusPlus wrote: post #26

pjmlp wrote: post #7

> More advanced type systems, however, allow to specify the generic constraints explicitly. Well, Java allows it, even if it looks a bit unglier than the Rust example. > T min (T a, T b) { if (a.compareTo(b) > 0) { return b; } else { return a; } } And even without general availability of concepts (already in gcc 6.x), one can achieve it in C++ via if constrexpr .

The difference with Rust is that you can apply a trait to an extant type you don't "own" - you can't do that in Java or C#: you would need to use the decorator-pattern (boilerplate ahoy!). C++'s checks are closer to duck-typing in practice.

    public interface Eq
    {
        bool Equals(A x, A y);
    }

    public interface Ord : Eq
    {
        bool GreaterThan(A x, A y);
        bool GreaterThanOrEq(A x, A y);
        bool LessThan(A x, A y);
        bool LessThanOrEq(A x, A y);
    }

    public struct OrdInt : Ord
    {
        public bool Equals(int x, int y) => x == y;
        public bool GreaterThan(int x, int y) => x > y;
        public bool GreaterThanOrEq(int x, int y) => x >= y;
        public bool LessThan(int x, int y) => x  x 
    {
        public bool Equals(string x, string y) => x == y;
        public bool GreaterThan(string x, string y) => x.CompareTo(y) > 0;
        public bool GreaterThanOrEq(string x, string y) => x.CompareTo(y) >= 0;
        public bool LessThan(string x, string y) => x.CompareTo(y)  x.CompareTo(y) (x);
            BubbleSort(y);
        }

        public static void BubbleSort(A[] values) where OrdA : struct, Ord
        {
            bool swap;
            do
            {
                swap = false;

                for (var i = 0; i