The purpose of this post is to mention where the F# language, compilation and editing support in Xamarin Studio comes from and how you can contribute to this tooling (and the same for Emacs too), and is posted on behlaf of Dave Thomas, a major F# commuity contributor.
Develop Android and iOS applications.
Develop F# components to be used across multiple platforms, including components to be used in C#-fronted Android and iOS applications.
The F# language tooling, on-the-fly-checking and editing support in Xamarin Studio and Emacs is based on the code in the "FSharpBinding" project. This project is "F# Editing Support for Open Editors" and incorproates components from the F# open edition. For Xamarin Studio, a Xamarin Studio addin is pushed to http://addins.monodevelop.com/ and picked up by versions with a commpatible version number. For Emacs, the packages are pushed to MELPA.
You can help plan the future of the FSharpBinding project by participating in the FSharpBinding User Voice.
The Xamarin Studio support for iOS and Android programming with F# is via two additional components called Xamarin.iOS and Xamarin.Android. You can find the details from Xamarin here: http://docs.xamarin.com/guides/cross-platform/fsharp/. These components include templates based on the sources here: https://github.com/xamarin/md-xamarin-fsharp-addins.
Please contribute to this great project and help bring F# to both Emacs users and 2.5 Billion devices.
Can Microsoft just pay for ReSharper support in Visual Studio instead? That is what people really need (at least me).