Fantomas.FCS 5.0.0-beta-003

This is a prerelease version of Fantomas.FCS.
There is a newer version of this package available.
See the version list below for details.
dotnet add package Fantomas.FCS --version 5.0.0-beta-003
                    
NuGet\Install-Package Fantomas.FCS -Version 5.0.0-beta-003
                    
This command is intended to be used within the Package Manager Console in Visual Studio, as it uses the NuGet module's version of Install-Package.
<PackageReference Include="Fantomas.FCS" Version="5.0.0-beta-003" />
                    
For projects that support PackageReference, copy this XML node into the project file to reference the package.
<PackageVersion Include="Fantomas.FCS" Version="5.0.0-beta-003" />
                    
Directory.Packages.props
<PackageReference Include="Fantomas.FCS" />
                    
Project file
For projects that support Central Package Management (CPM), copy this XML node into the solution Directory.Packages.props file to version the package.
paket add Fantomas.FCS --version 5.0.0-beta-003
                    
#r "nuget: Fantomas.FCS, 5.0.0-beta-003"
                    
#r directive can be used in F# Interactive and Polyglot Notebooks. Copy this into the interactive tool or source code of the script to reference the package.
#addin nuget:?package=Fantomas.FCS&version=5.0.0-beta-003&prerelease
                    
Install as a Cake Addin
#tool nuget:?package=Fantomas.FCS&version=5.0.0-beta-003&prerelease
                    
Install as a Cake Tool

Fantomas

Fantomas logo

F# source code formatter, inspired by scalariform for Scala, ocp-indent for OCaml and PythonTidy for Python.

Build Status Github Actions Discord

Quick install

How to use

Command line tool / API

Use this command to install Fantomas as a .NET 5 SDK global tool:

dotnet tool install -g fantomas

For detailed guidelines, please read Fantomas: How to use.

FAKE build system

Fantomas can be easily integrated with FAKE build system.<br /> Check out the sample.

JetBrains Rider

The resharper-fsharp uses fantomas under the hood to format the source code. No need for any additional plugins.

Using the latest version inside Rider

For technical reasons Rider cannot always use the latest version of Fantomas found on NuGet. As a workaround you could install fantomas locally with dotnet tool install fantomas-tool and configure it as an External tool.

Rider external tool window

Rider action window

This will have an impact on your editing experiencing in Rider, the external change to the file by the command line application might trigger more internal logic inside Rider than necessary. It could be noticeable in regards to the default formatting experience.

Visual Studio Code

The recommended way to use Fantomas is by using the Ionide plugin. Fantomas is integrated in FSAutoComplete which is the language server used by Ionide.

Alternatively, you can install the fantomas-fmt extension.

Visual Studio

The F# Formatting extension sets up Fantomas as the default formatter for F# files, configurable from Visual Studio's options.

Visual Studio for Mac

Install fantomas locally with dotnet tool install fantomas-tool and configure it as an [External tool]

VS Mac external tool window

Online

Try the Fantomas online.

Early builds

Every once in a while an alpha or beta version is published to https://www.nuget.org/. Our previous MyGet feed is now deprecated.

Benchmarks

Some figures can be found at https://fsprojects.github.io/fantomas/ <br/> We use BenchmarkDotNet to collect data for each build on the master branch.

Purpose

This project aims at formatting F# source files based on a given configuration. Fantomas will ensure correct indentation and consistent spacing between elements in the source files. We assume that the source files are parsable by F# compiler before feeding into the tool. Fantomas follows two F# style guides: the F# code formatting guidelines from Microsoft by default and the G-Research F# code formatting guidelines via various settings.

Use cases

The project is developed with the following use cases in mind:

  • Reformatting an unfamiliar code base. It gives readability when you are not the one originally writing the code. To illustrate, the following example

     type Type
         = TyLam of Type * Type
         | TyVar of string
         | TyCon of string * Type list
         with override this.ToString () =
                 match this with
                 | TyLam (t1, t2) -> sprintf "(%O -> %O)" t1 t2
                 | TyVar a -> a
                 | TyCon (s, ts) -> s
    

    will be rewritten to

     type Type =
         | TyLam of Type * Type
         | TyVar of string
         | TyCon of string * Type list
         override this.ToString() =
             match this with
             | TyLam(t1, t2) -> sprintf "(%O -> %O)" t1 t2
             | TyVar a -> a
             | TyCon(s, ts) -> s
    
  • Converting from verbose syntax to light syntax. Feeding a source file in verbose mode, Fantomas will format it appropriately in light mode. This might be helpful for code generation since generating verbose source files is much easier. For example, this code fragment

     let Multiple9x9 () =
         for i in 1 .. 9 do
             printf "\n";
             for j in 1 .. 9 do
                 let k = i * j in
                 printf "%d x %d = %2d " i j k;
             done;
         done;;
     Multiple9x9 ();;
    

    is reformulated to

     let Multiple9x9() =
         for i in 1..9 do
             printf "\n"
             for j in 1..9 do
                 let k = i * j
                 printf "%d x %d = %2d " i j k
    
     Multiple9x9()
    
  • Formatting F# signatures, especially those generated by F# compiler and F# Interactive.

For more complex examples, please take a look at F# outputs of 20 language shootout programs and 10 CodeReview.SE source files.

Why the name "Fantomas"?

There are a few reasons to choose the name as such. First, it starts with an "F" just like many other F# projects. Second, Fantomas is my favourite character in the literature. Finally, Fantomas has the same Greek root as "phantom"; coincidentally F# ASTs and formatting rules are so mysterious to be handled correctly.

Contributing Guidelines

See the Contribution Guidelines.

Credits

We would like to gratefully thank the following persons for their contributions.

License

The library and tool are available under Apache 2.0 license. For more information see the License file.

Product Compatible and additional computed target framework versions.
.NET net5.0 was computed.  net5.0-windows was computed.  net6.0 was computed.  net6.0-android was computed.  net6.0-ios was computed.  net6.0-maccatalyst was computed.  net6.0-macos was computed.  net6.0-tvos was computed.  net6.0-windows was computed.  net7.0 was computed.  net7.0-android was computed.  net7.0-ios was computed.  net7.0-maccatalyst was computed.  net7.0-macos was computed.  net7.0-tvos was computed.  net7.0-windows was computed.  net8.0 was computed.  net8.0-android was computed.  net8.0-browser was computed.  net8.0-ios was computed.  net8.0-maccatalyst was computed.  net8.0-macos was computed.  net8.0-tvos was computed.  net8.0-windows was computed.  net9.0 was computed.  net9.0-android was computed.  net9.0-browser was computed.  net9.0-ios was computed.  net9.0-maccatalyst was computed.  net9.0-macos was computed.  net9.0-tvos was computed.  net9.0-windows was computed.  net10.0 was computed.  net10.0-android was computed.  net10.0-browser was computed.  net10.0-ios was computed.  net10.0-maccatalyst was computed.  net10.0-macos was computed.  net10.0-tvos was computed.  net10.0-windows was computed. 
.NET Core netcoreapp2.0 was computed.  netcoreapp2.1 was computed.  netcoreapp2.2 was computed.  netcoreapp3.0 was computed.  netcoreapp3.1 was computed. 
.NET Standard netstandard2.0 is compatible.  netstandard2.1 was computed. 
.NET Framework net461 was computed.  net462 was computed.  net463 was computed.  net47 was computed.  net471 was computed.  net472 was computed.  net48 was computed.  net481 was computed. 
MonoAndroid monoandroid was computed. 
MonoMac monomac was computed. 
MonoTouch monotouch was computed. 
Tizen tizen40 was computed.  tizen60 was computed. 
Xamarin.iOS xamarinios was computed. 
Xamarin.Mac xamarinmac was computed. 
Xamarin.TVOS xamarintvos was computed. 
Xamarin.WatchOS xamarinwatchos was computed. 
Compatible target framework(s)
Included target framework(s) (in package)
Learn more about Target Frameworks and .NET Standard.

NuGet packages (2)

Showing the top 2 NuGet packages that depend on Fantomas.FCS:

Package Downloads
Fantomas.Core

This library aims at formatting F# source files based on a given configuration. Fantomas will ensure correct indentation and consistent spacing between elements in the source files. Some common use cases include: (1) Reformatting a code base to conform a universal page width (2) Converting legacy code from verbose syntax to light syntax (3) Formatting auto-generated F# signatures.

WoofWare.Whippet.Fantomas

Helpers for accessing Fantomas syntax trees.

GitHub repositories

This package is not used by any popular GitHub repositories.

Version Downloads Last Updated
7.0.2 580 5/28/2025
7.0.1 2,909 2/21/2025
7.0.0 1,399 1/10/2025
7.0.0-beta-001 112 12/30/2024
7.0.0-alpha-004 135 12/12/2024
7.0.0-alpha-003 118 11/29/2024
7.0.0-alpha-002 127 11/2/2024
7.0.0-alpha-001 156 9/16/2024
6.3.16 3,563 10/29/2024
6.3.15 10,822 9/14/2024
6.3.14 187 9/14/2024
6.3.13 228 9/10/2024
6.3.12 338 9/5/2024
6.3.11 778 8/16/2024
6.3.10 1,087 7/12/2024
6.3.9 8,324 6/9/2024
6.3.8 202 6/6/2024
6.3.7 690 6/1/2024
6.3.6 195 6/1/2024
6.3.5 221 5/30/2024
6.3.4 2,230 4/16/2024
6.3.3 922 4/12/2024
6.3.2 197 4/12/2024
6.3.1 1,638 3/30/2024
6.3.0 610 3/15/2024
6.3.0-beta-001 187 3/7/2024
6.3.0-alpha-008 151 3/1/2024
6.3.0-alpha-007 180 1/27/2024
6.3.0-alpha-006 464 1/9/2024
6.3.0-alpha-005 191 12/22/2023
6.3.0-alpha-004 177 12/6/2023
6.3.0-alpha-003 962 11/15/2023
6.3.0-alpha-002 206 11/7/2023
6.3.0-alpha-001 144 11/3/2023
6.2.3 1,333 11/2/2023
6.2.2 18,464 10/18/2023
6.2.1 263 9/18/2023
6.2.0 7,498 8/29/2023
6.1.3 249 8/25/2023
6.1.2 300 7/23/2023
6.1.1 17,283 6/29/2023
6.1.0 276 6/28/2023
6.1.0-alpha-006 194 6/20/2023
6.1.0-alpha-005 205 6/20/2023
6.1.0-alpha-004 179 6/19/2023
6.1.0-alpha-003 282 6/2/2023
6.1.0-alpha-002 256 5/2/2023
6.1.0-alpha-001 204 5/2/2023
6.0.8 256 6/20/2023
6.0.7 246 6/20/2023
6.0.6 251 6/19/2023
6.0.5 11,449 6/6/2023
6.0.4 281 6/2/2023
6.0.3 341 5/14/2023
6.0.2 282 5/5/2023
6.0.1 347 4/19/2023
6.0.0 759 4/13/2023
6.0.0-beta-001 399 4/5/2023
6.0.0-alpha-010 402 4/3/2023
6.0.0-alpha-009 205 3/31/2023
6.0.0-alpha-008 226 3/27/2023
6.0.0-alpha-007 206 3/27/2023
6.0.0-alpha-006 359 3/17/2023
6.0.0-alpha-005 211 2/24/2023
6.0.0-alpha-004 210 2/22/2023
6.0.0-alpha-003 211 2/4/2023
6.0.0-alpha-002 211 2/1/2023
6.0.0-alpha-001 255 1/24/2023
5.2.4 1,505 3/17/2023
5.2.3 642 3/6/2023
5.2.2 557 2/21/2023
5.2.1 8,743 2/4/2023
5.2.0 974 1/19/2023
5.2.0-alpha-012 328 1/14/2023
5.2.0-alpha-011 250 1/12/2023
5.2.0-alpha-010 202 12/30/2022
5.2.0-alpha-009 202 12/29/2022
5.2.0-alpha-008 233 12/28/2022
5.2.0-alpha-007 215 12/26/2022
5.2.0-alpha-006 217 12/22/2022
5.2.0-alpha-005 227 12/16/2022
5.2.0-alpha-004 231 12/8/2022
5.2.0-alpha-003 207 12/6/2022
5.2.0-alpha-002 234 12/4/2022
5.2.0-alpha-001 208 11/30/2022
5.1.5 1,597 12/22/2022
5.1.4 789 11/30/2022
5.1.3 997 11/14/2022
5.1.2 1,013 11/10/2022
5.1.1 765 11/7/2022
5.1.0 770 11/4/2022
5.1.0-beta-002 237 10/29/2022
5.1.0-beta-001 277 10/19/2022
5.1.0-alpha-007 237 10/14/2022
5.1.0-alpha-006 235 10/14/2022
5.1.0-alpha-005 202 10/7/2022
5.1.0-alpha-004 222 10/7/2022
5.1.0-alpha-003 223 10/2/2022
5.1.0-alpha-002 254 9/29/2022
5.1.0-alpha-001 316 9/18/2022
5.0.6 1,935 10/13/2022
5.0.5 939 10/7/2022
5.0.4 885 10/4/2022
5.0.3 964 9/29/2022
5.0.2 820 9/22/2022
5.0.1 886 9/18/2022
5.0.0 13,990 9/16/2022
5.0.0-beta-010 305 9/10/2022
5.0.0-beta-009 675 9/2/2022
5.0.0-beta-008 533 8/30/2022
5.0.0-beta-007 415 8/19/2022
5.0.0-beta-006 289 8/12/2022
5.0.0-beta-005 275 8/3/2022
5.0.0-beta-004 251 7/27/2022
5.0.0-beta-003 304 7/26/2022
5.0.0-beta-002 289 7/19/2022
5.0.0-beta-001 281 7/15/2022
5.0.0-alpha-011 317 7/8/2022
5.0.0-alpha-010 312 6/27/2022
5.0.0-alpha-009 251 6/21/2022
5.0.0-alpha-008 256 5/28/2022
5.0.0-alpha-007 376 5/16/2022
5.0.0-alpha-006 304 5/13/2022
5.0.0-alpha-005 261 5/7/2022
5.0.0-alpha-004 320 5/7/2022
5.0.0-alpha-003 245 5/6/2022

### Changed

* * Show a better error message when the folder does not exist. [#2341](https://github.com/fsprojects/fantomas/issues/2341)
* * Update FCS to 'Use SynLongIdent in SynOpenDeclTarget.ModuleOrNamespace', commit c18989124a92cc26a736d89137254f1ca84d4880

### Fixed

* * global keyword is escaped with single-backticks when used as part of a namespace/module open. [#2274](https://github.com/fsprojects/fantomas/issues/2274)
* * global namespace should not be escaped. [#2366](https://github.com/fsprojects/fantomas/issues/2366)
* * Trivia between xml doc and type not restored. [#2143](https://github.com/fsprojects/fantomas/issues/2143)