TryGetExt.fsx

[<System.Runtime.CompilerServices.Extension>]
type ExtensionMethods() =
    [<System.Runtime.CompilerServices.Extension>]
    static member inline GetOption< ^a,'k,'v when 'a : (member TryGetValue : 'k * ('v byref) -> bool)>(this : ^a, key : 'k) =
        let mutable v = Unchecked.defaultof<'v>
        let scc = ( ^a : (member TryGetValue : 'k * ('v byref) -> bool) this, key, &v)
        if scc then
            Some v
        else
            None
    [<System.Runtime.CompilerServices.Extension>]
    static member inline GetOrDefault< ^a,'k,'v when 'a : (member TryGetValue : 'k * ('v byref) -> bool)>(this : ^a, key : 'k, defaultValue : 'v) =
        let mutable v = Unchecked.defaultof<'v>
        let scc = ( ^a : (member TryGetValue : 'k * ('v byref) -> bool) this, key, &v)
        if scc then
            v
        else
            defaultValue
    [<System.Runtime.CompilerServices.Extension>]
    static member inline Bind< ^a,'k,'v when 'a : (member TryGetValue : 'k * ('v byref) -> bool)>(this : ^a, key : 'k, f : 'v -> 'v option) =
        let mutable v = Unchecked.defaultof<'v>
        let scc = ( ^a : (member TryGetValue : 'k * ('v byref) -> bool) this, key, &v)
        if scc then
            f v
        else
            None
    [<System.Runtime.CompilerServices.Extension>]
    static member inline Return< ^a,'k,'v when 'a : (member TryGetValue : 'k * ('v byref) -> bool)>(this : ^a, v : 'v) = Some v