WIP: Nameof operator by forki · Pull Request #13 · dotnet/fsharp

forki · 2015-01-14T08:47:03Z

This pull request was moved from https://visualfsharp.codeplex.com/SourceControl/network/forks/forki/fsharp/contribution/7698 (see discussion there)

https://fslang.uservoice.com/forums/245727-f-language/suggestions/5900625-add-nameof-operator-to-follow-c-vb-update suggests we implement a "nameof" operator which is something similar to the typeof operator.

This feature was "approved in principle" by Don.

Small outline:

I added a nameof to env.fs
In opt.fs we rewrite the typed AST to const string expressions with the name
In check.fs we raise compiler errors for all unknown cases
prim-types.fs shows we will throw if we couldn't inline the nameof operator
src/fsharp/FSharp.Core.Unittests/NameOfTests.fs contains samples for all the known cases

Open questions:

How can we write unittests for the cases we don't want to support?
- I'd like to write a test which shows tha "nameof(6)" fails with compiler error
The C# spec for nameof shows cases that retrieve names for types. Do we want this too?
...

Related information:

C#/VB spec for nameof: https://roslyn.codeplex.com/discussions/570551
Mads showing the nameof operator: http://channel9.msdn.com/Events/Visual-Studio/Connect-event-2014/116 (at 5:35)

Latkin: F# 4.0 triage – This PR is not being considered for F# 4.0, but will be left open for the time being to allow for community feedback.

KevinRansom · 2015-01-14T09:15:12Z

Thanks for moving this over Steffen.

From: Steffen Forkmann [mailto:notifications@github.com]
Sent: Wednesday, January 14, 2015 12:47 AM
To: Microsoft/visualfsharp
Subject: [visualfsharp] Nameof operator (#13)

ThispPull request was moved from https://visualfsharp.codeplex.com/SourceControl/network/forks/forki/fsharp/contribution/7698 (see discussion there)

https://fslang.uservoice.com/forums/245727-f-language/suggestions/5900625-add-nameof-operator-to-follow-c-vb-update suggests we implement a "nameof" operator which is something similar to the typeof operator.

This feature was "approved in principle" by Don.

Small outline:

I added a nameof to env.fs
In opt.fs we rewrite the typed AST to const string expressions with the name
In check.fs we raise compiler errors for all unknown cases
prim-types.fs shows we will throw if we couldn't inline the nameof operator
src/fsharp/FSharp.Core.Unittests/NameOfTests.fs contains samples for all the known cases

Open questions:

How can we write unittests for the cases we don't want to support?
I'd like to write a test which shows tha "nameof(6)" fails with compiler error
The C# spec for nameof shows cases that retrieve names for types. Do we want this too?
...

Related information:

C#/VB spec for nameof: https://roslyn.codeplex.com/discussions/570551
Mads showing the nameof operator: http://channel9.msdn.com/Events/Visual-Studio/Connect-event-2014/116 (at 5:35)

Latkin: F# 4.0 triage – This PR is not being considered for F# 4.0, but will be left open for the time being to allow for community feedback.

You can merge this Pull Request by running

git pull https://github.com/forki/visualfsharp nameof

Or view, comment on, or merge it at:

#13

Commit Summary

Implementing basic nameof scenarios
Use the same function for check.fs and opt.fs
Fix check.fs types
Add QA tests which show expected compile errors
Add more unit tests
Don't allow to use nameof on applied or partially applied functions
Add some tests for name lookup of operators
Don't allow to use nameof(1+2)
Dogfood the nameof operator in FSharp.Core
NameOf should not work on applied functions
Revert problematic FSharp.Core files
Show we can find the name of members that are defined below
Prefix error cases with E_
Show user-defined nameof wins.
Don' report get_ for properties in nameof
Show that nameof can't be used as a function
Show how we can use nameof in pattern matching
Use nameof in quotation
Add a generic function as nameof test
Show methods with get_ work in nameof
Better structure in nameof tests

File Changes

M src/fsharp/FSComp.txthttps://github.com/WIP: Nameof operator #13/files#diff-0 (1)
M src/fsharp/FSharp.Core.Unittests/FSharp.Core.Unittests.fsprojhttps://github.com/WIP: Nameof operator #13/files#diff-1 (1)
A src/fsharp/FSharp.Core.Unittests/NameOfTests.fshttps://github.com/WIP: Nameof operator #13/files#diff-2 (202)
M src/fsharp/FSharp.Core.Unittests/SurfaceArea.4.0.fshttps://github.com/WIP: Nameof operator #13/files#diff-3 (1)
M src/fsharp/FSharp.Core/Linq.fshttps://github.com/WIP: Nameof operator #13/files#diff-4 (2)
M src/fsharp/FSharp.Core/Query.fshttps://github.com/WIP: Nameof operator #13/files#diff-5 (6)
M src/fsharp/FSharp.Core/array.fshttps://github.com/WIP: Nameof operator #13/files#diff-6 (314)
M src/fsharp/FSharp.Core/array2.fshttps://github.com/WIP: Nameof operator #13/files#diff-7 (16)
M src/fsharp/FSharp.Core/array3.fshttps://github.com/WIP: Nameof operator #13/files#diff-8 (8)
M src/fsharp/FSharp.Core/math/n.fshttps://github.com/WIP: Nameof operator #13/files#diff-9 (2)
M src/fsharp/FSharp.Core/math/z.fshttps://github.com/WIP: Nameof operator #13/files#diff-10 (24)
M src/fsharp/FSharp.Core/prim-types.fshttps://github.com/WIP: Nameof operator #13/files#diff-11 (3)
M src/fsharp/FSharp.Core/prim-types.fsihttps://github.com/WIP: Nameof operator #13/files#diff-12 (4)
M src/fsharp/FSharp.Core/seq.fshttps://github.com/WIP: Nameof operator #13/files#diff-13 (238)
M src/fsharp/check.fshttps://github.com/WIP: Nameof operator #13/files#diff-14 (28)
M src/fsharp/check.fsihttps://github.com/WIP: Nameof operator #13/files#diff-15 (1)
M src/fsharp/env.fshttps://github.com/WIP: Nameof operator #13/files#diff-16 (5)
M src/fsharp/opt.fshttps://github.com/WIP: Nameof operator #13/files#diff-17 (15)
A tests/fsharpqa/Source/Conformance/Expressions/DataExpressions/NameOf/E_NameOfAdditionExpr.fshttps://github.com/WIP: Nameof operator #13/files#diff-18 (7)
A tests/fsharpqa/Source/Conformance/Expressions/DataExpressions/NameOf/E_NameOfAppliedFunction.fshttps://github.com/WIP: Nameof operator #13/files#diff-19 (8)
A tests/fsharpqa/Source/Conformance/Expressions/DataExpressions/NameOf/E_NameOfAsAFunction.fshttps://github.com/WIP: Nameof operator #13/files#diff-20 (7)
A tests/fsharpqa/Source/Conformance/Expressions/DataExpressions/NameOf/E_NameOfDictLookup.fshttps://github.com/WIP: Nameof operator #13/files#diff-21 (8)
A tests/fsharpqa/Source/Conformance/Expressions/DataExpressions/NameOf/E_NameOfIntConst.fshttps://github.com/WIP: Nameof operator #13/files#diff-22 (7)
A tests/fsharpqa/Source/Conformance/Expressions/DataExpressions/NameOf/E_NameOfIntegerAppliedFunction.fshttps://github.com/WIP: Nameof operator #13/files#diff-23 (8)
A tests/fsharpqa/Source/Conformance/Expressions/DataExpressions/NameOf/E_NameOfParameterAppliedFunction.fshttps://github.com/WIP: Nameof operator #13/files#diff-24 (9)
A tests/fsharpqa/Source/Conformance/Expressions/DataExpressions/NameOf/E_NameOfPartiallyAppliedFunction.fshttps://github.com/WIP: Nameof operator #13/files#diff-25 (8)
A tests/fsharpqa/Source/Conformance/Expressions/DataExpressions/NameOf/E_NameOfStringConst.fshttps://github.com/WIP: Nameof operator #13/files#diff-26 (7)
A tests/fsharpqa/Source/Conformance/Expressions/DataExpressions/NameOf/env.lsthttps://github.com/WIP: Nameof operator #13/files#diff-27 (9)
M tests/fsharpqa/Source/test.lsthttps://github.com/WIP: Nameof operator #13/files#diff-28 (2)

Patch Links:

—
Reply to this email directly or view it on GitHubhttps://github.com//pull/13.

ctaggart · 2015-01-16T20:45:13Z

Looking forward to this functionality being added at some point. I think it will be a great addition. I could really use it for some logging I'm doing right now.

forki · 2015-01-16T21:27:23Z

Could you please describe your scenario with a small code sample?

dsyme · 2015-01-21T13:14:52Z

This won't be in F# 4.0, and needs further work, so I suggest we "archive" this PR for now by closing it, and then revisiting it later.

dungpa · 2015-01-21T13:16:55Z

Could you add some sort of labels e.g. "archived", "deferred", etc. so that it is easier to track these issues?

dsyme · 2015-01-21T13:29:50Z

Yes, we would need an "archived" label. The feature is still in http://fslang.uservoice.com of course, which sort of acts as a root for all future feature work on the core language/library

forki · 2015-01-21T13:34:20Z

(just a small technical note: the branch should be kept in at least one repo, otherwise it might get lost after closing)

latkin · 2015-01-21T18:11:01Z

"archived" it is

xperiandri · 2015-07-19T23:55:16Z

What is the status of this feature?
Does someone do any work on this?

forki · 2015-07-20T06:14:42Z

I created a prototype, but there are many open edge cases.
On Jul 20, 2015 1:55 AM, "Andrii Chebukin" notifications@github.com wrote:

What is the status of this feature?
Does someone do any work on this?

—
Reply to this email directly or view it on GitHub
#13 (comment)
.

ghost · 2015-11-24T12:07:34Z

Look forward to this feature. I assume it will work also doing interop with C# code.

ghost · 2015-12-01T09:25:25Z

Example usecase:
[<ReflectedDefinition(true)>]
let foo (x) = ...

let fooType = foo.GetType().DeclaringType.GetMethod(nameof(foo))

forki · 2015-12-01T09:27:57Z

@bluemmc yes there are many usecases, but team decided against it for now.

ghost · 2015-12-01T09:30:54Z

Yes, could read that it would not make it for F# 4.0 - but that is out now. What about next F# versions - has that been decided ?

forki · 2015-12-01T09:34:46Z

@KevinRansom @otawfik-ms @NumberByColors ?

7sharp9 · 2016-01-29T08:27:42Z

Would of been nice to have the open edge cases listed so that anyone interested could look at them etc.

forki · 2016-01-29T08:32:45Z

Unfortunately I can't reopen this after @latkin closed it.

IIRC we had some discussion over there. It was mostly that we don't support all the positions where nameof can be used in C# (e.g. in attributes)

forki · 2016-01-29T08:34:04Z

From the discussion here you can tell that the interest inside ms is rather low ;-)

ghost · 2016-01-29T08:41:03Z

Yes, unfortunately no response from the F# team.

Nameof is the one of few place where C# has a strong advantage language-wise. It is highly annoying that F# still forces developers to use a string anti-pattern when referencing stuff.

@dsyme Is it possible to clarify if there are any plans for Nameof support in F# ?

enricosada · 2016-01-29T08:53:45Z

well, i think this pr it's dead (need rebase anyway).
But i think it's possibile to reboot a [WIP] pr if someone want to try implement it.

It's a really nice feature to have, and a good base implementation by @forki

forki · 2016-01-29T09:25:57Z

Ok I will try to rebase. Then we can let it rot again.

ghost · 2016-01-29T09:31:23Z

RE: IIRC we had some discussion over there. It was mostly that we don't support all the positions where nameof can be used in C# (e.g. in attributes)

@forki Would be better to release something a partial fix, rather then letting it rot as you write. Hopefully the F# team can see the benefits of your contribution after a rebase and another look?

enricosada · 2016-01-29T09:32:58Z

i really hope not @forki, it's a really nice feature.
And now VS 2015 shipped, so less problems

forki · 2016-01-29T09:38:06Z

rebased version at #908

merge from master

append extension methods in GetRelevantMethodsForTrait

…crete (a) Adds a parametrized [<Theory>] over the six axes (naked-generic ctor, generic extension, static generic-type member, optional-tail, paramarray-tail) proving rule #13 fires for each. Backed by a differential default-vs-preview corpus (62 snippets): every already-successful default resolution is byte-for-byte preserved under preview (20 single-applicable rows OK:A->OK:A), incomparable cases stay ambiguous (ERR->ERR), and the feature only converts FS0041 ambiguity into success (40 rows ERR->OK). Proves ground-truth #8: (a) never flips a resolution. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

…t-plan Correctness (blocking back-compat regression): moreConcreteRule (#13, preview) ran before nullableOptionalInteropRule (#14, F#5.0 default-on) and propertyOverrideRule (#15, always-on). A resolution those default-on rules settle could be silently re-decided by #13 under preview -> overload+result-type flip. Move moreConcreteRule to the END of allTiebreakRules so it only breaks ties nothing else resolved (its intended FS0041 case). Pre-dates Phase 6 (also hit generic methods); Phase 6 widened its reach to ctors/generic-type members. Reuse: paramsMentionComparableTypeVar now takes ParamData list and uses the plural freeInTypesLeftToRight instead of List.exists over the singular walk. Compactness: shared private paramDataType accessor replaces three inlined ParamData(...) destructurings across moreConcreteRule and the FS0041 explainer. Test-plan: delete two facts that duplicated matrix rows; add instance-method-generic-type matrix row; add ORPA-beats-concreteness guard and two back-compat guards proving a later shipped rule still decides successful resolutions (static + ctor). Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

forki added 21 commits January 14, 2015 09:47

Implementing basic nameof scenarios

fbc3328

Use the same function for check.fs and opt.fs

8fde5ed

Fix check.fs types

1dea9a7

Add QA tests which show expected compile errors

4d143aa

Add more unit tests

8b89dde

Don't allow to use nameof on applied or partially applied functions

2fd9498

Add some tests for name lookup of operators

c57cfdc

Don't allow to use nameof(1+2)

c0beb95

Dogfood the nameof operator in FSharp.Core

8a46d36

NameOf should not work on applied functions

9663c8f

Revert problematic FSharp.Core files

427f888

Show we can find the name of members that are defined below

2d60881

Prefix error cases with E_

8d2d721

Show user-defined nameof wins.

0a92ef4

Don' report get_ for properties in nameof

0ba200b

Show that nameof can't be used as a function

827bef8

Show how we can use nameof in pattern matching

7c1713c

Use nameof in quotation

fa063b0

Add a generic function as nameof test

4adfe45

Show methods with get_ work in nameof

e74f2ab

Better structure in nameof tests

005e740

forki force-pushed the nameof branch from 9a469a3 to 005e740 Compare January 14, 2015 08:49

dsyme changed the title ~~Nameof operator~~ WIP: Nameof operator Jan 17, 2015

latkin added the archived label Jan 21, 2015

latkin closed this Jan 21, 2015

forki mentioned this pull request Jan 29, 2016

[WIP] F# RFC-1003 - Implementing nameof operator #908

Closed

18 tasks

nelak pushed a commit to nelak/visualfsharp that referenced this pull request Nov 27, 2016

Merge pull request dotnet#13 from Microsoft/master

c802cca

merge from master

vasily-kirichenko mentioned this pull request Jan 18, 2017

Re-implement nameof operator #2287

Closed

forki mentioned this pull request Sep 24, 2017

[WIP] [FS-1003] Nameof operator reimplementation #2290

Closed

kevmal pushed a commit to kevmal/visualfsharp that referenced this pull request Mar 22, 2019

Merge pull request dotnet#13 from kevmal/ext1

e11da64

append extension methods in GetRelevantMethodsForTrait

nojaf pushed a commit to nojaf/fsharp that referenced this pull request Nov 14, 2022

Merge pull request dotnet#13 from safesparrow/heuristic_otel_formatting3

e550115

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forki commented Jan 14, 2015

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KevinRansom commented Jan 14, 2015

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ctaggart commented Jan 16, 2015

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forki commented Jan 16, 2015

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dsyme commented Jan 21, 2015

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