by on May 6, 2012
A few days ago I wondered how to implement the Singleton pattern in F#. After a few failed attempts I came up with the following:
// Singleton type with a private parameterless constructor
type MySingleton private() =
// other bindings
// private static instance of the MySingleton type
static let mutable instance = lazy(MySingleton())
// public getter property
static member Instance with get() = instance
// other membersThe point I had the most trouble with was the correct definition of a static let binding. So in order to make a let binding static in a type definition just put a static in front of it - that’s all.