How do I create an extension method (F#)? [duplicate]

Answer 1

For an F# extension that can be called from F#:

type System.String with
  member x.Right(index) = x.Substring(x.Length - index)

Note that as of Beta 1, this doesn't result in a C#-compatible extension method.

For generating extension methods visible from C# (but not usable as extension methods in F#), see the link in Brian's edit to the original post.