f#

问题 Previously had a very compact and comprehensive answer for my question. I had it working for my custom type but now due to some reason I had to change it to string type which is now causing type mismatch errors. module AsyncResult = let bind (binder : 'a -> Async<Result<'b, 'c>>) (asyncFun : Async<Result<'a, 'c>>) : Async<Result<'b, 'c>> = async { let! result = asyncFun match result with | Error e -> return Error e | Ok x -> return! binder x } let compose (f : 'a -> Async<Result<'b, 'e>>) (g

问题 I have a hand-written CSS parser done in C# which is getting unmanageable and was trying to do it i FParsec to make it more mantainable. Here's a snippet that parses a css selector element made with regexes: var tagRegex = @"(?<Tag>(?:[a-zA-Z][_\-0-9a-zA-Z]*|\*))"; var idRegex = @"(?:#(?<Id>[a-zA-Z][_\-0-9a-zA-Z]*))"; var classesRegex = @"(?<Classes>(?:\.[a-zA-Z][_\-0-9a-zA-Z]*)+)"; var pseudoClassRegex = @"(?::(?<PseudoClass>link|visited|hover|active|before|after|first-line|first-letter))";

问题 I'm trying to figure out how to code this. Implement in F# a function that tests whether an element is a member of a given list. Here is the type I want. val memberof : ’a * ’a list -> bool when ’a : equality Here are examples of the function in action. memberof 1 [1;2;3];; error FS0003: This value is not a function and cannot be applied memberof (1,[1;2;3]);; val it : bool = true memberof (1, []);; val it : bool = false memberof (1,[2;3;4]);; val it : bool = false heres what i've put

问题 Similar to this question about clojure, is it possible to list the contents of a namespace or module in F#? When I open a namespace for a loaded DLL I'm not receiving an error that the namespace doesn't exist, but then when I try to use the documented functions I'm seeing errors that the namespace doesn't exist. I'm looking for a programatic way of listing values and methods and not relying on the IDE. For example if I loaded up the F# repl I'm looking for something similar to: > #r "mylib

问题 I have a unit test project that targets F# runtime 4.4.1. It has an app.config with the bindingRedirect section: <dependentAssembly> <Paket>True</Paket> <assemblyIdentity name="FSharp.Core" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" /> <bindingRedirect oldVersion="0.0.0.0-65535.65535.65535.65535" newVersion="4.4.1.0" /> </dependentAssembly> However, when I run tests I get a runtime error: Could not load file or assembly 'FSharp.Core, Version=4.3.0.0, Culture=neutral, PublicKeyToken

问题 I've made a scanner in F#. Currently it returns a list of bunch of tuples with type (Token, string). Ideally I'd like to return a list of tuples that might contain different types. For example: (Token, string) //if it's an identifier (Token, float) //if it's a float. (Token, int) //etc So, Basically I'd like to return type (Token, _) but I'm not sure how to specify this. Right now it just has errors complaining of mismatched types. I'm looking through my book, and wikibooks, but I'm not

问题 I'm trying to write a function that takes a list for example let list = [5;23;29;1] let x = max list // This will return 2 because 29 will be the max value and it's "indexed" at position 2 I'm not sure about how to go about writing the max function Since my list will only contain four elements I currently have some code like this let list = (1, newMap1 |> getScore) :: (2, newMap2 |> getScore) :: (3, newMap3 |> getScore) :: (4, newMap4 |> getScore) :: [] I consider this a terrible approach but

问题 let rec isolate (l:'a list) = match l with | [] -> [] | x::xs -> if memberof(x,xs) then remove (x,l) else isolate xs I've already created functions memberof and remove, the only problem is that when line 6 remove(x,l) executes it doesn't continue with isolate(xs) for continued search through the list. Is there a way to say, if x then f(x) and f(y) ? 回答1: As you are using F# immutable lists, the result of remove needs to be stored somewhere: let rec isolate (l:'a list) = match l with | [] -> [

问题 Closed . This question needs details or clarity. It is not currently accepting answers. Want to improve this question? Add details and clarify the problem by editing this post. Closed 3 years ago . I am trying to see if there are any instructions/documentation on how to use Glimpse in an F# project? I looked through the list of adapters they have on their website and I didn't see anything specific to F#. They have ones for ASP.NET MVC and EF but if you using something like Suave (https:/

问题 My question is this: How can I splice the expressions from a list into a quotation when I don't know the number and types of those expressions at design time? At the bottom I've included the full code for a type provider. (I've stripped the concept down to demonstrate the problem.) My issue occurs at these lines: let func = ProvidedMethod((*...*), InvokeCode = fun args -> <@@ let stringParts = args |> List.mapi (fun i arg -> if paramTypes.[i] = typeof<int> then sprintf "%i" (%%arg: int)... On