sharp) A .NET scripting language from Microsoft Research. Based on the ML language and its OCaml derivative, F# brings ML to the .NET Framework, offering the speed of C# (C Sharp) with the advantages of interactive scripting. Using the F# extension to Visual Studio, programmers work with the language in a familiar development environment.
Why the Number Sign?
Because it is similar to the sharp music notation symbol, the number sign (#) is used. See .NET Framework