Question

Given i have the type:

type NewsMessage(identifier:string, headline:string)

and this record:

type NewsMessageParams = { 
    identifier:string
    headline:string 
}

Is there an implicit way to adapt the record into the class constructor?

Something like so:

let newsMessageParmas = {identifier=""; headline=""}
new NewsMessage(newsMessageParams) //this is where i need help

You can do this with tuples using the ||> syntax. I would like to do this with a record.

Answer 1

Something like this would work:

let toClass {identifier = i; headline = h} = NewsMessage(i, h)

// Usage
let newsMessageParams = {identifier = ""; headline = ""}
let newsMessage = newsMessageParams |> toClass

Note that object constructor isn’t first-class in F#, so you have more chances of using pipe operators if declaring NewsMessage as discriminated unions:

type NewsMessage = NewsMessage of string * string
let toTuple {identifier = i; headline = h} = i, h

let newsMessageParams = {identifier = ""; headline = ""}
let newsMessage = newsMessageParams |> toTuple |> NewsMessage