Miscellaneous F# Utilities

fs-util.fs

// Don't know why these functions aren't part of the language but there you are.

module Util

module String =
    let splitArray (delimiters: string list) (s: string) =
        s.Split((Array.ofList delimiters), System.StringSplitOptions.None)

    let splitArrayMax (delimiters: string list) max (s: string) =
        s.Split((Array.ofList delimiters), max, System.StringSplitOptions.None)
        
    let split delimiters s = splitArray delimiters s |> List.ofArray
    let splitMax delimiters max s = splitArrayMax delimiters max s |> List.ofArray
        
    let splitSeq delimiters s = splitArray delimiters s |> List.ofSeq
    let splitSeqMax delimiters max s = splitArrayMax delimiters max s |> List.ofSeq

module List =
    let distinct source =
        let folder acc item =
            if List.exists ((=) item) acc then
                acc
            else
                item :: acc
        match source with
        | [] -> []
        | [i] -> [i]
        | first :: rest -> List.fold folder [first] rest |> List.rev

    let distinctBy projection source =
        let folder acc item =
            let itemKey = projection item
            if List.exists (fun (_, key) -> key = itemKey) acc then
                acc
            else
                (item, itemKey) :: acc
        match source with
        | [] -> []
        | [i] -> [i]
        | first :: rest -> List.fold folder [first, projection first] rest |> List.rev |> List.map fst