//[snippet:Core Definition]
#nowarn "42"

open System

[<MeasureAnnotatedAbbreviation>] type bool<[<Measure>] 'm> = bool
[<MeasureAnnotatedAbbreviation>] type uint64<[<Measure>] 'm> = uint64
[<MeasureAnnotatedAbbreviation>] type Guid<[<Measure>] 'm> = Guid
[<MeasureAnnotatedAbbreviation>] type string<[<Measure>] 'm> = string
[<MeasureAnnotatedAbbreviation>] type TimeSpan<[<Measure>] 'm> = TimeSpan
[<MeasureAnnotatedAbbreviation>] type DateTime<[<Measure>] 'm> = DateTime
[<MeasureAnnotatedAbbreviation>] type DateTimeOffset<[<Measure>] 'm> = DateTimeOffset

module private Unsafe =
    let inline cast<'a, 'b> (a : 'a) : 'b = (# "" a : 'b #)

type UnitOfMeasure =

    static member inline tag<[<Measure>]'m> (x : bool) : bool<'m> = Unsafe.cast x
    static member inline tag<[<Measure>]'m> (x : int) : int<'m> = Unsafe.cast x
    static member inline tag<[<Measure>]'m> (x : int64) : int64<'m> = Unsafe.cast x
    static member inline tag<[<Measure>]'m> (x : uint64) : uint64<'m> = Unsafe.cast x
    static member inline tag<[<Measure>]'m> (x : float) : float<'m> = Unsafe.cast x
    static member inline tag<[<Measure>]'m> (x : decimal) : decimal<'m> = Unsafe.cast x
    static member inline tag<[<Measure>]'m> (x : Guid) : Guid<'m> = Unsafe.cast x
    static member inline tag<[<Measure>]'m> (x : string) : string<'m> = Unsafe.cast x
    static member inline tag<[<Measure>]'m> (x : TimeSpan) : TimeSpan<'m> = Unsafe.cast x
    static member inline tag<[<Measure>]'m> (x : DateTime) : DateTime<'m> = Unsafe.cast x
    static member inline tag<[<Measure>]'m> (x : DateTimeOffset) : DateTimeOffset<'m> = Unsafe.cast x

    static member inline untag<[<Measure>]'m> (x : bool<'m>) : bool = Unsafe.cast x
    static member inline untag<[<Measure>]'m> (x : int<'m>) : int = Unsafe.cast x
    static member inline untag<[<Measure>]'m> (x : int64<'m>) : int64 = Unsafe.cast x
    static member inline untag<[<Measure>]'m> (x : uint64<'m>) : uint64 = Unsafe.cast x
    static member inline untag<[<Measure>]'m> (x : float<'m>) : float = Unsafe.cast x
    static member inline untag<[<Measure>]'m> (x : decimal<'m>) : decimal = Unsafe.cast x
    static member inline untag<[<Measure>]'m> (x : Guid<'m>) : Guid = Unsafe.cast x
    static member inline untag<[<Measure>]'m> (x : string<'m>) : string = Unsafe.cast x
    static member inline untag<[<Measure>]'m> (x : TimeSpan<'m>) : TimeSpan = Unsafe.cast x
    static member inline untag<[<Measure>]'m> (x : DateTime<'m>) : DateTime = Unsafe.cast x
    static member inline untag<[<Measure>]'m> (x : DateTimeOffset<'m>) : DateTimeOffset = Unsafe.cast x

    static member inline cast<[<Measure>]'m1, [<Measure>]'m2> (x : bool<'m1>) : bool<'m2> = Unsafe.cast x
    static member inline cast<[<Measure>]'m1, [<Measure>]'m2> (x : int<'m1>) : int<'m2> = Unsafe.cast x
    static member inline cast<[<Measure>]'m1, [<Measure>]'m2> (x : int64<'m1>) : int64<'m2> = Unsafe.cast x
    static member inline cast<[<Measure>]'m1, [<Measure>]'m2> (x : uint64<'m1>) : uint64<'m2> = Unsafe.cast x
    static member inline cast<[<Measure>]'m1, [<Measure>]'m2> (x : float<'m1>) : float<'m2> = Unsafe.cast x
    static member inline cast<[<Measure>]'m1, [<Measure>]'m2> (x : decimal<'m1>) : decimal<'m2> = Unsafe.cast x
    static member inline cast<[<Measure>]'m1, [<Measure>]'m2> (x : Guid<'m1>) : Guid<'m2> = Unsafe.cast x
    static member inline cast<[<Measure>]'m1, [<Measure>]'m2> (x : string<'m1>) : string<'m2> = Unsafe.cast x
    static member inline cast<[<Measure>]'m1, [<Measure>]'m2> (x : TimeSpan<'m1>) : TimeSpan<'m2> = Unsafe.cast x
    static member inline cast<[<Measure>]'m1, [<Measure>]'m2> (x : DateTime<'m1>) : DateTime<'m2> = Unsafe.cast x
    static member inline cast<[<Measure>]'m1, [<Measure>]'m2> (x : DateTimeOffset<'m1>) : DateTimeOffset<'m2> = Unsafe.cast x
//[/snippet]
//[snippet:Examples]
[<Measure>] type m
[<Measure>] type n

let x = UnitOfMeasure.tag<m> "string"
let y = UnitOfMeasure.cast<m,n> x
let z = UnitOfMeasure.untag y
//[/snippet]