How to Get the F# Name of a Module, Function, etc. From Quoted Expression Match

Question

I continue to work on a printer for F# quoted expressions, it doesn't have to be perfect, but I'd like to see what is possible. The active patterns in Microsoft.FSharp.Quotations.Patterns and Microsoft.FSharp.Quotations.DerivedPatterns used for decomposing quoted expressions will typically provide MemberInfo instances when appropriate, these can be used to obtain the name of a property, function, etc. and their "declaring" type, such as a module or static class. The problem is, I only know how to obtain the CompiledName from these instances but I'd like the F# name. For example,

> <@ List.mapi (fun i j -> i+j) [1;2;3] @> |> (function Call(_,mi,_) -> mi.DeclaringType.Name, mi.Name);;
val it : string * string = ("ListModule", "MapIndexed")

How can this match be rewritten to return ("List", "mapi")? Is it possible?

FYI, here is my final polished solution from Stringer Bell and pblasucci's help:

let moduleSourceName (declaringType:Type) =
    FSharpEntity.FromType(declaringType).DisplayName

let methodSourceName (mi:MemberInfo) =
    mi.GetCustomAttributes(true)
    |> Array.tryPick 
            (function
                | :? CompilationSourceNameAttribute as csna -> Some(csna)
                | _ -> None)
    |> (function | Some(csna) -> csna.SourceName | None -> mi.Name)

//usage:
let sourceNames =
    <@ List.mapi (fun i j -> i+j) [1;2;3] @> 
    |> (function Call(_,mi,_) -> mi.DeclaringType |> moduleSourceName, mi |> methodSourceName);

Answer 1

You can use F# powerpack for that purpose:

open Microsoft.FSharp.Metadata
...
| Call(_, mi, _) ->
    let ty = Microsoft.FSharp.Metadata.FSharpEntity.FromType(mi.DeclaringType)
    let name = ty.DisplayName // name is List

However, I don't think if it's possible to retrieve function name with powerpack.

Edit:

As hinted by pblasucci, you can use CompilationSourceName attribute for retrieving source name:

let infos = mi.DeclaringType.GetMember(mi.Name)
let att = infos.[0].GetCustomAttributes(true)
let fName =
    (att.[1] :?> CompilationSourceNameAttribute).SourceName // fName is mapi