CODEWITHSUNDEEP
f#c#-to-f#
Dax Fohl
Dax Fohl

Reputation: 10781

Parameter names in abstract tupled function

Related to No argument names in abstract declaration?, how would you do this with a C#-style tupled argument? So if I wanted 

abstract member createEmployee : (string * string) -> Employee

how would I be able to communicate whether it should be

1-   member this.createEmployee(firstName, lastName) = ...
2-   member this.createEmployee(lastName, firstName) = ...

Use case: creating an interface in F# to be used from C#.

Upvotes: 2

Views: 94

Answers (3)

Dax Fohl
Dax Fohl

Reputation: 10781

abstract createEmployee: firstName:string * lastName:string -> Employee

compiles to create C# invocation semantics and the names appear both in C# and F# intellisense in Visual Studio 2013.

Upvotes: 7

Be Brave Be Like Ukraine
Be Brave Be Like Ukraine

Reputation: 7735

There are two ways to do that:

  1. Use Named Arguments as described in MSDN

    member this.createEmployee(firstName: string, lastName: string) = ...

// external code
MyClass.createEmployee(firstName = "John", lastName = "Smith")
MyClass.createEmployee(lastName = "Smith", firstName = "John")

  2. Make your class member accept a structure as an argument:

    type EmployeeName =
   struct 
      val firstName: string
      val lastName: string
   end 

member this.createEmployee2(employeeName: EmployeeName) = ...

// external code
MyClass.createEmployee2 {firstName = "John"; lastName = "Smith"}
MyClass.createEmployee2 {lastName = "Smith"; firstName = "John"}

The choice is yours; the former allows for optional arguments (consider middleName or salutation) while the latter allows for storing the structure together (e.g. if you need to process it further).

Upvotes: 3

Random Dev
Random Dev

Reputation: 52270

I think the easiest way is to go like this:

type FirstName = FirstName of string
type LastName  = LastName of string

...

abstract member createEmployee : (FirstName * LastName) -> Employee

remark:

you probably want it to be

abstract member createEmployee : FirstName * LastName -> Employee

instead as there are slight differences ;)

Upvotes: 3

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