Coding Practice for F#

Question

I have been dabbling with F# in Visual Studio 2010. I am a developer with more code/architecture design experience in object-oriented languages such as C# and Java.

T

Answer 1

Most of the time deforesting without a specific reason, generally performance, is a bad idea. Which one of these do you see as easier to read and less error prone? Deforesting taken out of context just adds complexity and/or coupling to your code.

let createPeople filter ppl =
    ppl 
    |> List.mapi (fun i x -> (i, x)) 
    |> List.filter filter
    |> List.map createPerson

let createPeople filter ppl =
    [ for (index, name) in ppl |> List.mapi (fun i x -> (i, x)) do
          if filter (index, name) then
              yield createPerson (index, string) ]

let createPeople filter ppl = 
    (ppl |> List.mapi (fun i x -> (i, x)), []) 
    ||> List.foldBack (fun P acc -> if filter P then (createPerson P)::acc else acc) 

Once you get used to the syntax function composition allows you to drop ppl.

let createPeople filter =
    List.mapi (fun i x -> (i, x)) 
    >> List.filter filter
    >> List.map createPerson

All of these use tupled data.

let filter (id, name) = 
    id % 2 = 1

let allFilter (id, name) = 
    true

let createPerson (id, name) = 
    ()