Can I write a function which returns the name of the function given as the argument?
let funName f: string =
// returns the name of f.
For example, if I pass printfn as an argument to funName, it returns "printfn".
> funName printfn;;
val it : string = "printfn"
EDIT: I wanted to write a function doc which returns the XML documentation associated with the given function.
let doc f = // returns the XML documentation of the function `f`.
To retrieve the summary of the function using something like NuDoq, I wanted to know the name of the function.
I cannnot imagine why you would want to do this and I do not think that there's a way to do this with reflection, but F# Code Quotations might get you halfway there.
open Microsoft.FSharp.Quotations
let rec funName = function
| Patterns.Call(None, methodInfo, _) -> methodInfo.Name
| Patterns.Lambda(_, expr) -> funName expr
| _ -> failwith "Unexpected input"
let foo () = 42
funName <@ foo @> // "foo"
But note that certain predefined library functions have a divergent internal name.
funName <@ printfn @> // "PrintFormatLine"
funName <@ id @> // "Identity"
Note that as of F# 4.0, class types can automatically quote their arguments, simplifying the call site compared to kaefer's answer:
open Microsoft.FSharp.Quotations
type DocumentGetter =
static member GetName([<ReflectedDefinition>]x:Expr<_->_>) =
match x with
| DerivedPatterns.Lambdas(_, Patterns.Call(_,methodInfo,_)) ->
methodInfo.Name
let f x y = x + y
DocumentGetter.GetName f
