[RFC FS-1003] Nameof operator redux

[dsyme]

Brings #2290 up-to-date with master

Implementation of RFC FS-1003

Testing verified:

• handle cases where nameof already resolves to something user-defined, to avoid being a breaking change
• works in quotations
• works with method parameters
• works with local variables
• works with local (nested) functions
• works with local curried functions
• works with local tupled functions
• can get name from inside a local function (needs to be let rec)
• can get member names
• can get static member names
• can get static property names
• can get names that quoted in ``
• can be used in pattern matching
• can be used with generic functions/types
• when used like a function, let f = nameof ;; f x
• when used with pipe operator, x |> nameof
• can get names of operators like +, |>, typeof, nameof, ...
• works in attributes
• works with namespaces, nameof System.Diagnostics
• works with types, nameof System.String
• works with modules, nameof List

Not necessary to test (it will work:

• works with provided symbol names, i.e. generated by type providers

Feature limitation:

• the feature will not work with type arguments, let f<'t> (x : 't) = nameof 't

[jwosty]

I am very much looking forward to having this. I just want to thank everyone who has put work into this!

[dsyme]

Closing in favour of #6809 from feature branch

[The-Futurist]

@cartermp

Could someone please let us know if or when the new nameof capability will become available?

VS 2019 tells me I have this:

Visual F# Tools 10.4 for F# 4.6 16.3.0-beta.19455.1+0422ff293bb2cc722fe5021b85ef50378a9af823
Microsoft Visual F# Tools 10.4 for F# 4.6

Thanks

[KevinRansom]

@Korporal,

It is currently available as a language preview.

So in a dotnetsdk .fsproj project file use:

<LangVersion>Preview</LangVersion>

for fsi
use

fsi /LangVersion:Preview

or
dotnet fsi --langversion:preview

Hope this helps

Kevin

[The-Futurist]

This is helpful, much appreciated.