F# Interactive is great for exploring new API's. What would be even more helpful is if I could change what an object prints. By default, they just print their full class name. It would be awesome if I could have certain classes print something more meaningfull.

The InteractiveSession object (fsi) has a function called AddPrinter which does exactly what you are looking for.

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> type Point = { x:int; y:int };;

type Point = {x: int;
              y: int;}

> let p = {x=1;y=2};;

val p : Point

> p;;
val it : Point = {x = 1;
                  y = 2;}
> fsi.AddPrinter( fun (p:Point) -> sprintf "(%i,%i)" p.x p.y );;
val it : unit = ()
> p;;
val it : Point = (1,2)
>

It sounds like you want your classes to implement the StructuredFormat.IFormattable interface, see [link:www.intellifactory.com]

Stephan