The answer, it turns out, is to use LanguagePrimitives.PhysicalEquality: let isSameObject = LanguagePrimitives.PhysicalEquality let a = [1; 2; 3] let b = [1; 2; 3] let a’ = a printfn “%A” (isSameObject a b) // Prints “false” printfn “%A” (isSameObject a a’) // Prints “true” There was precisely one question I could find on Stack … Read more
I’d definitely prefer learning F# with the #light syntax. The non-light version is sometimes useful for understanding some tricks about the F# syntax, but the #light syntax gives you much pleasant experience. For example – using #light let add a b c = let ab = a + b printfn “%d” ab c – ab … Read more
If you complete your pattern-matchings with a constructor [] and not the catch-all _, the compiler will have a chance to tell you to look again at the function with a warning the day someone adds a third constructor to lists. My colleagues and I, working on a large OCaml project (200,000+ lines), force ourselves … Read more
F# 3 has auto-implemented properties so you can declare properties without declaring the backing field. Example taken from Properties(F#) on MSDN: type MyClass() = member val MyProperty = “” with get, set
I think the main use for the AutoOpen attribute is when you want to make some let-bound values available when the user of your library opens a namespace. This is where the attribute is very useful, because I think libraries should generally export all definitions in namespaces, but for some purposes you need to export … Read more
The Microsoft CLR has a 2GB maximum object size limit, even the 64 bit version. (I’m not sure whether this limit is also present in other implementations such as Mono.) The limitation applies to each single object — not the total size of all objects — which means that it’s relatively easy to workaround using … Read more
Assuming that there is a typo in your sources as DWright pointed out, I’d say that this error may arise just from the fact that by this code you define a static class MyModuleB with exposed method parameter of an external type MyCsharpType. This is how the Fsharp code translates to IL (from ILSpy – … Read more
That’s the Kleisli composition operator for monads. It allows you to compose functions with signatures like ‘a -> M<‘b> and ‘b -> M<‘c’> where M is monadic: in your case the Result<‘t> from the linked article. >=> is really just a function composition, but >> wouldn’t work here since the return type of the first … Read more
In the non-interactive F# code that’s not supposed to be compatible with OCaml, you shouldn’t need to ever need double semicolon. In the OCaml compatible mode, you would use it at the end of a top-level function declaration (In the recent versions, you can switch to this mode by using files with .ml extension or … Read more
As far as I know, F# doesn’t have any built-in operator equivalent to C# as so you need to write some more complicated expression. Alternatively to your code using match, you could also use if, because the operator 😕 can be use in the same way as is in C#: let res = if (inputValue … Read more