CODEWITHSUNDEEP
f#
Scott Nimrod
Scott Nimrod

Reputation: 11595

How can I use the compiler to infer the type of a static member?

How can I use the compiler to infer the type of a static member?

In C# 6.0, the compiler can infer the type of a static property or method by providing the "using static <namespace>.<class>" directive.

Thus, I want to write as little code as possible.

I have the following static members:

module Mock

type Profile() =

    static member SomeUserName = "some_user_name"
    static member SomePassword = "some_password"

I then define some types and a function:

open Mock

(*Types*)
type User =        User of string
type Password =    Password of string
type Credentials = { User:User; Password:Password }

(*Functions*)
let login credentials =
    false

I then have the following test:

[<Test>]
let ``sign in`` () =

    // Setup
    let credentials = { User=     User     Profile.SomeUserName
                        Password= Password Profile.SomePassword } 
    // Test
    credentials |> login 
                |> should equal true

I would like to remove the Profile type qualifier from SomeUserName and SomePassword and do this instead:

// Setup
let credentials = { User=     User     SomeUserName
                    Password= Password SomePassword }

Do I have to explicitly specify a type of a static member?

Upvotes: 1

Views: 71

Answers (1)

TheInnerLight
TheInnerLight

Reputation: 12184

The obvious solution, as Fyodor Soikin points out, is to simply make Profile a module.

module Profile =
    let someUserName = "some_user_name"
    let somePassword = "some_password"

Then you can just:

open Profile

let credentials = { 
    User = User someUserName;
    Password = Password somePassword 
    }

Incidentally, while it may not be possible to open static classes in F# at the moment, this looks set to change in future versions - this feature has been "approved in principle". See the user voice item for more.

Upvotes: 5

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