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Accessing Interface Properties
f#

hello, i am new to F# and have this problem:

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type InterfaceA =
    abstract Evaluate : unit -> double 

type InterfaceB =
    inherit InterfaceA
    abstract value : double

type Implementation(v) = 
    interface InterfaceB with
        member this.value = v
        member this.Evaluate() = this.value

In the last line, it says: property value is not defined.

Why?

(Indentation is ok, but i was not displayed well here... tryed with <code> but did not work) Thanks!

.

The type of 'this' is 'Implementation', and in F#, you need to explicitly upcast to interfaces to call interface members:

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type InterfaceA =
    abstract Evaluate : unit -> double 

 

type InterfaceB = 
    inherit InterfaceA 
    abstract Value : double 

 

type Implementation(v) =
    interface InterfaceB with
        member this.Value = v 

        member this.Evaluate() = (this :> InterfaceB).Value
By on 6/7/2011 10:51 AM ()

Thanks!!!

By on 6/7/2011 10:53 AM ()

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