Executive summary: I wrote a simple implementation of an algorithm… that wasn’t tail-recursive. I compiled it with OCaml under Linux. It worked fine, and finished in 0.14 seconds. It was then time to port to F#. I translated the code (direct translation) to F#. I compiled under Windows, and run it – I got a … Read more
By this discription about Blittable and Non-Blittable Types in the link below you could try the System.Double in place of float, because they do not require conversion when they are passed between managed and unmanaged code wich means no more special handling by the interop marshaler with a plus in performance: https://msdn.microsoft.com/en-us/library/75dwhxf7%28v=vs.110%29.aspx I did a … Read more
If you’re using .NET 4.0, you can just use File.ReadLines. > let readLines filePath = System.IO.File.ReadLines(filePath);; val readLines : string -> seq<string>
(**) and pown are two different things. When you see (**), you can think of the mathematical formula using logarithms. When you see pown, it’s just a series of multiplications. I understand it can be surprising/confusing at first, because most other languages don’t make such a difference (mainly because integers are often implicitly converted to … Read more
Regarding “Haskell’s equally powerful inference”, I don’t think Haskell has to deal with OO-style dynamic subtyping (type classes can do some similar stuff, but type classes are easier to type/infer) method overloading (type classes can do some similar stuff, but type classes are easier to type/infer) That is, I think F# has to deal with … Read more
Perl style regex matching let (=~) input pattern = System.Text.RegularExpressions.Regex.IsMatch(input, pattern) It lets you match text using let test = “monkey” =~ “monk.+” notation.
What is the F# language created to accomplish? The F# research project sought to create a variant of the OCaml language running on top of the .Net platform. A related project at MSR Cambridge, SML.NET, did the same for Standard ML. (OCaml and Standard ML are both variants of the ML language.) The motivations for … Read more
The point-free style is considered by some author as the ultimate functional programming style. To put things simply, a function of type t1 -> t2 describes a transformation from one element of type t1 into another element of type t2. The idea is that “pointful” functions (written using variables) emphasize elements (when you write \x … Read more
Parameterized active patterns to the rescue! let (|Prefix|_|) (p:string) (s:string) = if s.StartsWith(p) then Some(s.Substring(p.Length)) else None match “Hello world” with | Prefix “The” rest -> printfn “Started with ‘The’, rest is %s” rest | Prefix “Hello” rest -> printfn “Started with ‘Hello’, rest is %s” rest | _ -> printfn “neither”
C# the language isn’t, but .NET the framework may be. The Contracts library + the static analysis tools being introduced in .NET 4 might introduce these: Microsoft is using [Immutable] and [Pure] inside .NET 3.5 framework right now. For example, see [Microsoft.Contracts.Immutable] and [Microsoft.Contracts.Pure] inside .NET 3.5, in the System.Core.dll. Unfortunately, they’re internal. However, Microsoft.Contracts.* … Read more