https://gist.github.com/pocketberserker/8972681　をリファクタリング？してみた

ninja.fsx

type Emotion =
| Love
| Hate

type User = string

type Conversation = {
    Affinity: Map<User * User, Emotion>
    Message: Map<User * Emotion, string>
}

let template u1 u2 msg = sprintf "%s「%s？」\n%s「%s！」" u2 msg u1 msg

let inverse = function
    | Love -> Hate
    | Hate -> Love

//let generateSimple (u1: User) (u2: User) conversation : string option =
//    if conversation.Affinity |> Map.containsKey (u1, u2) then
//        let emotion = conversation.Affinity.[(u1, u2)]
//        if conversation.Message |> Map.containsKey (u1, emotion) then
//            Some (template u1 u2 (conversation.Message.[(u1, emotion)]))
//        else None
//    else None

let generateSimple u1 u2 conversation : string option = 
    conversation.Affinity |> Map.tryFind (u1, u2)
    |> Option.bind (fun emotion ->
        conversation.Message |> Map.tryFind (u1, emotion)
        |> Option.map (template u1 u2))

//let generateComplex (u1: User) (u2: User) conversation : string option =
//    let { Affinity = affinity; Message = message } = conversation
//    if affinity |> Map.containsKey (u1, u2) && affinity |> Map.containsKey (u2, u1) then
//        let emotion1 = affinity.[(u1, u2)]
//        let emotion2 = affinity.[(u2, u1)]
//        if emotion1 = emotion2 then
//            if message |> Map.containsKey (u1, inverse(emotion1)) then
//                Some (template u1 u2 (message.[(u1, inverse(emotion1))]))
//            elif message |> Map.containsKey (u1, emotion1) then
//                Some (template u1 u2 (message.[(u1, emotion1)]))
//            else None
//        else None
//    else None

let generateComplex (u1: User) (u2: User) conversation : string option =
    let { Affinity = affinity; Message = message } = conversation
    [for us in [u1, u2; u2, u1] -> affinity |> Map.tryFind us |> Option.toList]
    |> List.concat |> Seq.countBy id |> Seq.toList
    |> function
    | (e, 2)::[] ->
        [inverse; id] |> Seq.tryPick (fun f -> message |> Map.tryFind (u1, f e))
        |> Option.map (template u1 u2)
    | _ -> None

let affinity =
    Map.ofList
        [
            (("fuga", "pocketberserker"), Love)
            (("pocketberserker", "fuga"), Love)
            (("fuga", "hoge"), Hate)
        ]

let message =
    Map.ofList
        [
            (("pocketberserker", Love), "F#")
            (("fuga", Love), "Smalltalk")
            (("fuga", Hate), "静的型付き")
        ]

let conv = { Affinity = affinity; Message = message }

// シンプルなgenerate
conv |> generateSimple "pocketberserker" "fuga" |> printfn "%A\n" // Some "fuga「F#？」\npocketberserker「F#！」"
conv |> generateSimple "fuga" "pocketberserker" |> printfn "%A\n" // Some "pocketberserker「Smalltalk？」\nhoge「Smalltalk！」")
conv |> generateSimple "fuga" "hoge" |> printfn "%A\n" // Some "fuga「静的型付き？」\nhoge「静的型付き！」")
conv |> generateSimple "hoge" "fuga" |> printfn "%A\n" // None
conv |> generateSimple "pocketberserker" "hoge" |> printfn "%A\n" // None

// 複雑なgenerate
conv |> generateComplex "pocketberserker" "fuga" |> printfn "%A\n" // Some "fuga「F#？」\npocketberserker「F#！」"
conv |> generateComplex "fuga" "pocketberserker" |> printfn "%A\n" // Some "pocketberserker「Smalltalk？」\nhoge「Smalltalk！」")
conv |> generateComplex "fuga" "hoge" |> printfn "%A\n" // None
conv |> generateComplex "hoge" "fuga" |> printfn "%A\n" // None
conv |> generateComplex "pocketberserker" "hoge" |> printfn "%A\n" // None