Since Visual Studio won't calculate code metrics for F# projects, this script will calculate some some rough stats.

RoughMetrics.fsx

open System
open System.IO

let find_files dir = Directory.GetFiles( dir, "*.fs?", SearchOption.AllDirectories )

let not_start    (s:string) p = not <| s.StartsWith p
let has_type     (s:string)   = if s.Contains @"type"   then 1 else 0
let has_module   (s:string)   = if s.Contains @"module" then 1 else 0
let has_binding  (s:string)   = if s.Contains @"let"    ||
                                   s.Contains @"member" then 1 else 0

type Statistics =   {   ``Num Of Lines    `` : int  ;  ``Num Of Files    `` : int;
                        ``Num Of Chars    `` : int  ;  ``Num Of Types    `` : int;
                        ``Num Of Modules  `` : int  ;  ``Num Of Bindings `` : int;   
                    } 
let generate_stats =
    find_files 
    >>  Array.filter (fun f -> f.EndsWith ".fs" || f.EndsWith ".fsx" || f.EndsWith ".fsi")
    >>  Array.fold   (fun acc f -> 
            let contents = 
                f   |> File.ReadAllLines
                    |> Array.filter ( fun s -> not <| String.IsNullOrWhiteSpace s)
                    |> Array.map    ( fun s -> s.Trim()                          )
                    |> Array.filter ( fun s -> not_start s "open" &&
                                                not_start s @"///" &&
                                                not_start s @"//"                )
            {   ``Num Of Lines    `` = acc.``Num Of Lines    `` + Array.length contents             ; 
                ``Num Of Files    `` = acc.``Num Of Files    `` + 1                                 ;
                ``Num Of Chars    `` = acc.``Num Of Chars    `` + Array.sumBy String.length contents;
                ``Num Of Types    `` = acc.``Num Of Types    `` + Array.sumBy has_type      contents;
                ``Num Of Modules  `` = acc.``Num Of Modules  `` + Array.sumBy has_module    contents;
                ``Num Of Bindings `` = acc.``Num Of Bindings `` + Array.sumBy has_binding   contents;
            }   
        ) 
        {   ``Num Of Lines    `` = 0; ``Num Of Files    `` = 0; 
            ``Num Of Chars    `` = 0; ``Num Of Types    `` = 0; 
            ``Num Of Modules  `` = 0; ``Num Of Bindings `` = 0;    
        }   
;;

Path.GetDirectoryName __SOURCE_DIRECTORY__ |> generate_stats ;;
@"C:\Users\jared\Github\Clones\visualfsharp\src\fsharp" |> generate_stats ;;