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Discussion on: F# Tip 1: Don't use classes

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Replies for: A hybrid way of doing this is to use type extensions. The golden rule is that you keep everything immutable, but streamline the code somewhat. The...

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Brian Berns • • Edited

Yes, type classes are definitely a cool way to support "dot" notation in F#. You can even have it both ways by defining a plain record type with a corresponding module of functions, as I did above, and then adding type extensions at the end:

type Car with
   member this.Drive(miles) = this |> Car.drive miles
   member this.Paint(color) = this |> Car.paint color

Usage:

car |> Car.drive 10   // F# style
car.Drive(10)         // C# style

BTW, when I do this, I usually use C# naming conventions for the type extensions: capitalize the first letter and put parens around the arguments, since they can't be curried (e.g. this.Drive(miles) instead of this.drive miles).