type CsvType(id, name, parentId) =

    member this.Id : int = id

    member this.Name : string = name

    member this.ParentId : int = parentId

​

type OutType(id, name, children) = 

    member this.Id : int = id

    member this.Name : string = name

    member this.Children : OutType list = children

​

let rec buildTree (data : CsvType list) value =

    data |>

    List.filter (fun row -> row.ParentId = value) |>

    List.map (fun row -> 

        OutType(row.Id, row.Name, (buildTree data row.Id)))

​

let csvData = [

    new CsvType(1, "Shinobi", 0);

    new CsvType(2, "Jubei Kibagami", 0);

    new CsvType(3, "Kagero", 2);

    new CsvType(4, "Splinter", 0);

    new CsvType(5, "Leonardo", 4);

    new CsvType(6, "Raphael", 4);

    new CsvType(7, "Donatello", 4);

    new CsvType(8, "Michelangelo", 4);

]

​

let tree = buildTree csvData 0