Why are let bindings not permitted in a discriminated union? I assume it has to do with let bindings being executed in a default constructor?
On a secondary note any suggestions on how I could rewrite AI_Choose
would be appreciated. I want to keep the weighted priority in a tuple with the AI. My idea is to have AI_Weighted_Priority
inherit AI_Priority
and override Choose. I don't want to deal with zipping lists of different lengths (bad practice imo.)
open AI
type Condition =
| Closest of float
| Min
| Max
| Average
member this.Select (aiListWeight : list<AI * float>) =
match this with
| Closest(x) ->
aiListWeight
|> List.minBy (fun (ai, priority) -> abs(x - priority))
| Min -> aiListWeight |> List.minBy snd
| Max -> aiListWeight |> List.maxBy snd
| Average ->
let average = aiListWeight |> List.averageBy snd
aiListWeight
|> List.minBy (fun (ai, priority) -> abs(average - priority))
type AI_Choose =
| AI_Priority of list<AI> * Condition
| AI_Weighted_Priority of list<AI * float> * Condition
// I'm sad that I can't do this
let mutable chosen = Option<AI>.None
member this.Choose() =
match this with
| AI_Priority(aiList, condition) ->
aiList
|> List.map (fun ai -> ai, ai.Priority())
|> condition.Select
|> fst
| AI_Weighted_Priority(aiList, condition) ->
aiList
|> List.map (fun (ai, weight) -> ai, weight * ai.Priority())
|> condition.Select
|> fst
member this.Chosen
with get() =
if Option.isNone chosen then
chosen <- Some(this.Choose())
chosen.Value
and set(x) =
if Option.isSome chosen then
chosen.Value.Stop()
chosen <- Some(x)
x.Start()
interface AI with
member this.Start() =
this.Chosen.Start()
member this.Stop() =
this.Chosen.Stop()
member this.Reset() =
this.Chosen <- this.Choose()
member this.Priority() =
this.Chosen.Priority()
member this.Update(gameTime) =
this.Chosen.Update(gameTime)