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Pattern Match System.Tuple`2 Type ?
f#

How do I pattern match the System.Tuple'2 type? I'm using the just released Visual Studio 10 beta.

let matchType (o:obj) =
match o.GetType() with
| t when t = typeof<string> -> printfn "It is a string."
| t when t = typeof<Tuple<_,_>> -> printfn "It is a Tuple!"
| t -> printfn "Unmatched type: %A" t

matchType "Hello"
matchType (3,4)

Running that in FSI gives me:

It is a string.
Unmatched type: System.Tuple`2[System.Int32,System.Int32]

.

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open System
let matchType (o:obj) =
    match o.GetType() with
    | t when t = typeof<string> -> printfn "It is a string."
    | t when t = typeof<Tuple<_,_>> -> printfn "It is a Tuple<obj,obj>!"
    | t when t = typeof<Tuple<int,int>> -> printfn "It is a Tuple<int,int>!"
    | t when t.GetGenericTypeDefinition() = typedefof<Tuple<_,_>> -> printfn "It is a Tuple<?,?>!"
    | t -> printfn "Unmatched type: %A" t

matchType "Hello"
matchType (box 3, box 4)
matchType (3,4)
matchType (3.1,4.1)
By on 5/24/2009 12:57 AM ()

Yes, helps out a lot! Thanks.

By on 5/24/2009 11:19 AM ()

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