CODEWITHSUNDEEP
f#pipeline
Jon49
Jon49

Reputation: 4606

Pipeline List with Constant Parameters

I'm trying to create a pipeline that consists of the main parameter being a list with a constant.

As a simple example

type ClockType = | In | Out
let ClockMap index offset = 
    match index with
    | index when index + offset % 2 = 0 -> In
    | _ -> Out
 let MapIt offset = [0 .. 23] |> List.map offset

It works when I take out the offset. I've tried doing a tuple but then it doesn't like the int list. What is the best way to go about this?

I'm just learning F# so bear with me.

Upvotes: 0

Views: 104

Answers (1)

ildjarn
ildjarn

Reputation: 62995

Is this what you're after?

type ClockType = In | Out
let clockMap offset index = if (index + offset) % 2 = 0 then In else Out
let mapIt offset = [0 .. 23] |> List.map (clockMap offset)

Output would be:

mapIt 3 |> printfn "%A"
// [Out; In; Out; In; Out; In; Out; In; Out; In; Out; In; Out; In; Out; In; Out;
//  In; Out; In; Out; In; Out; In]

If so, there were multiple issues:

  • clockMap's parameters were backwards
  • % has higher precedence than +
  • clockMap was never being called (and offset needs to be partially applied to clockMap)

The change from match to if was purely for readability, and idiomatically, non-literal let bound values start with lowercase characters (type names and class properties/methods start with uppercase).

Upvotes: 3

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