fantomas 5.0.0-alpha-008

This is a prerelease version of fantomas.
There is a newer version of this package available.
See the version list below for details.
dotnet tool install --global fantomas --version 5.0.0-alpha-008
                    
This package contains a .NET tool you can call from the shell/command line.
dotnet new tool-manifest
                    
if you are setting up this repo
dotnet tool install --local fantomas --version 5.0.0-alpha-008
                    
This package contains a .NET tool you can call from the shell/command line.
#tool dotnet:?package=fantomas&version=5.0.0-alpha-008&prerelease
                    
nuke :add-package fantomas --version 5.0.0-alpha-008
                    

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 net6.0 is compatible.  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. 
Compatible target framework(s)
Included target framework(s) (in package)
Learn more about Target Frameworks and .NET Standard.

This package has no dependencies.

Version Downloads Last Updated
7.0.3 13,193 7/4/2025
7.0.2 18,401 5/28/2025
7.0.1 33,355 2/21/2025
7.0.0 41,253 1/10/2025
7.0.0-beta-001 256 12/30/2024
7.0.0-alpha-004 1,000 12/12/2024
7.0.0-alpha-003 754 11/29/2024
7.0.0-alpha-002 304 11/2/2024
7.0.0-alpha-001 160 9/16/2024
6.3.16 53,483 10/29/2024
6.3.15 29,015 9/14/2024
6.3.14 405 9/14/2024
6.3.13 1,479 9/10/2024
6.3.12 11,776 9/5/2024
6.3.11 25,350 8/16/2024
6.3.10 151,411 7/12/2024
6.3.9 55,954 6/9/2024
6.3.8 1,558 6/6/2024
6.3.7 2,620 6/1/2024
6.3.6 456 6/1/2024
6.3.5 1,150 5/30/2024
6.3.4 40,690 4/16/2024
6.3.3 10,955 4/12/2024
6.3.2 661 4/12/2024
6.3.1 13,635 3/30/2024
6.3.0 15,396 3/15/2024
6.3.0-beta-001 1,197 3/7/2024
6.3.0-alpha-008 871 3/1/2024
6.3.0-alpha-007 2,078 1/27/2024
6.3.0-alpha-006 870 1/9/2024
6.3.0-alpha-005 1,248 12/22/2023
6.3.0-alpha-004 2,052 12/6/2023
6.3.0-alpha-003 1,507 11/15/2023
6.3.0-alpha-002 953 11/7/2023
6.3.0-alpha-001 799 11/3/2023
6.2.3 156,690 11/2/2023
6.2.2 33,980 10/18/2023
6.2.1 11,041 9/18/2023
6.2.0 24,811 8/29/2023
6.1.3 1,567 8/25/2023
6.1.2 15,730 7/23/2023
6.1.1 79,010 6/29/2023
6.1.0 7,603 6/28/2023
6.1.0-alpha-006 1,155 6/20/2023
6.1.0-alpha-005 1,081 6/20/2023
6.1.0-alpha-004 904 6/19/2023
6.1.0-alpha-003 1,169 6/2/2023
6.1.0-alpha-002 1,042 5/2/2023
6.1.0-alpha-001 1,047 5/2/2023
6.0.8 2,132 6/20/2023
6.0.7 1,363 6/20/2023
6.0.6 1,540 6/19/2023
6.0.5 5,445 6/6/2023
6.0.4 1,389 6/2/2023
6.0.3 13,210 5/14/2023
6.0.2 4,325 5/5/2023
6.0.1 92,389 4/19/2023
6.0.0 67,449 4/13/2023
6.0.0-beta-001 1,567 4/5/2023
6.0.0-alpha-010 7,862 4/3/2023
6.0.0-alpha-009 888 3/31/2023
6.0.0-alpha-008 2,136 3/27/2023
6.0.0-alpha-007 1,415 3/27/2023
6.0.0-alpha-006 1,562 3/17/2023
6.0.0-alpha-005 2,436 2/24/2023
6.0.0-alpha-004 9,788 2/22/2023
6.0.0-alpha-003 3,051 2/4/2023
6.0.0-alpha-002 973 2/1/2023
6.0.0-alpha-001 1,101 1/24/2023
5.2.4 6,294 3/17/2023
5.2.3 5,718 3/6/2023
5.2.2 14,144 2/21/2023
5.2.1 84,179 2/4/2023
5.2.0 6,950 1/19/2023
5.2.0-alpha-012 1,237 1/14/2023
5.2.0-alpha-011 1,460 1/12/2023
5.2.0-alpha-010 1,170 12/30/2022
5.2.0-alpha-009 1,096 12/29/2022
5.2.0-alpha-008 1,351 12/28/2022
5.2.0-alpha-007 1,083 12/26/2022
5.2.0-alpha-006 1,091 12/22/2022
5.2.0-alpha-005 1,214 12/16/2022
5.2.0-alpha-004 1,326 12/8/2022
5.2.0-alpha-003 1,115 12/6/2022
5.2.0-alpha-002 1,056 12/4/2022
5.2.0-alpha-001 1,004 11/30/2022
5.1.5 26,213 12/22/2022
5.1.4 28,575 11/30/2022
5.1.3 8,302 11/14/2022
5.1.2 1,644 11/10/2022
5.1.1 4,145 11/7/2022
5.1.0 2,831 11/4/2022
5.1.0-beta-002 1,070 10/29/2022
5.1.0-beta-001 1,437 10/19/2022
5.1.0-alpha-007 1,110 10/14/2022
5.1.0-alpha-006 1,085 10/14/2022
5.1.0-alpha-005 1,220 10/7/2022
5.1.0-alpha-004 1,230 10/7/2022
5.1.0-alpha-003 1,238 10/2/2022
5.1.0-alpha-002 1,127 9/29/2022
5.1.0-alpha-001 1,170 9/18/2022
5.0.6 25,985 10/13/2022
5.0.5 10,563 10/7/2022
5.0.4 2,266 10/4/2022
5.0.3 11,164 9/29/2022
5.0.2 8,533 9/22/2022
5.0.1 6,631 9/18/2022
5.0.0 21,340 9/16/2022
5.0.0-beta-010 31,974 9/10/2022
5.0.0-beta-009 10,683 9/2/2022
5.0.0-beta-008 3,103 8/30/2022
5.0.0-beta-007 1,705 8/19/2022
5.0.0-beta-006 3,023 8/12/2022
5.0.0-beta-005 5,152 8/3/2022
5.0.0-beta-004 2,401 7/27/2022
5.0.0-beta-003 3,794 7/26/2022
5.0.0-beta-002 1,983 7/19/2022
5.0.0-beta-001 2,975 7/15/2022
5.0.0-alpha-011 1,710 7/8/2022
5.0.0-alpha-010 2,297 6/27/2022
5.0.0-alpha-009 96,499 6/21/2022
5.0.0-alpha-008 3,160 5/28/2022
5.0.0-alpha-007 1,921 5/16/2022
5.0.0-alpha-006 1,951 5/13/2022
5.0.0-alpha-005 1,422 5/7/2022
5.0.0-alpha-004 1,522 5/7/2022
5.0.0-alpha-003 1,989 5/6/2022
5.0.0-alpha-002 828 4/4/2022
5.0.0-alpha-001 783 3/19/2022
4.7.9 11,507 5/2/2022
4.7.8 10,638 4/25/2022
4.7.7 1,256 4/20/2022
4.7.6 1,523 4/4/2022
4.7.5 1,386 3/27/2022
4.7.4 1,351 3/25/2022
4.7.3 4,918 3/12/2022
4.7.2 1,270 3/11/2022
4.7.1 1,268 3/8/2022
4.7.0 1,394 3/4/2022
4.6.6 1,307 3/4/2022
4.6.5 2,052 2/18/2022
4.6.4 1,822 2/11/2022
4.6.3 1,866 2/8/2022
4.6.2 1,846 2/6/2022
4.6.1 1,845 2/1/2022
4.6.0 2,346 1/14/2022
4.6.0-beta-001 906 1/8/2022
4.6.0-alpha-011 891 12/29/2021
4.6.0-alpha-010 909 12/4/2021
4.6.0-alpha-009 3,537 11/24/2021
4.6.0-alpha-008 1,320 11/19/2021
4.6.0-alpha-007 937 11/7/2021
4.6.0-alpha-006 305 11/3/2021
4.6.0-alpha-005 317 10/27/2021
4.6.0-alpha-004 297 10/20/2021
4.6.0-alpha-003 282 10/5/2021
4.6.0-alpha-002 290 9/7/2021
4.6.0-alpha-001 262 8/11/2021
4.5.12 1,712 1/8/2022
4.5.11 2,499 12/29/2021
4.5.10 2,745 12/4/2021
4.5.9 7,639 11/24/2021
4.5.8 1,857 11/19/2021
4.5.7 1,686 11/7/2021
4.5.6 1,474 11/3/2021
4.5.5 1,641 10/27/2021
4.5.4 1,550 10/5/2021
4.5.3 3,034 9/7/2021
4.5.2 1,687 8/11/2021
4.5.1 3,562 7/24/2021
4.5.0 3,461 7/7/2021
4.5.0-beta-005 1,005 7/6/2021
4.5.0-beta-004 980 7/5/2021
4.5.0-beta-003 1,019 7/5/2021
4.5.0-beta-002 1,011 6/27/2021
4.5.0-beta-001 1,508 6/5/2021
4.5.0-alpha-020 966 5/26/2021
4.5.0-alpha-019 966 5/22/2021
4.5.0-alpha-018 999 5/21/2021
4.5.0-alpha-017 962 5/15/2021
4.5.0-alpha-016 942 5/9/2021
4.5.0-alpha-015 1,038 5/8/2021
4.5.0-alpha-014 1,072 4/30/2021
4.5.0-alpha-013 991 4/27/2021
4.5.0-alpha-012 984 4/23/2021
4.5.0-alpha-011 1,080 4/20/2021
4.5.0-alpha-010 1,005 4/14/2021
4.5.0-alpha-009 1,018 4/11/2021
4.5.0-alpha-008 1,007 4/8/2021
4.5.0-alpha-007 1,025 4/8/2021
4.5.0-alpha-006 976 4/5/2021
4.5.0-alpha-005 1,011 4/3/2021
4.5.0-alpha-004 1,033 4/2/2021
4.5.0-alpha-003 1,065 3/28/2021
4.5.0-alpha-002 1,044 3/22/2021
4.5.0-alpha-001 2,669 2/26/2021
4.4.0 13,579 2/25/2021
4.4.0-beta-008 1,089 2/19/2021
4.4.0-beta-007 1,082 2/12/2021
4.4.0-beta-006 1,061 2/12/2021
4.4.0-beta-005 1,125 2/9/2021
4.4.0-beta-004 1,108 2/5/2021
4.4.0-beta-003 1,560 1/30/2021
4.4.0-beta-002 1,088 1/23/2021
4.4.0-beta-001 1,501 1/22/2021
4.4.0-alpha-008 1,265 1/15/2021
4.4.0-alpha-007 1,771 12/26/2020
4.4.0-alpha-006 1,194 12/25/2020
4.4.0-alpha-005 1,263 12/23/2020
4.4.0-alpha-004 1,290 12/22/2020
4.4.0-alpha-003 1,297 12/18/2020
4.4.0-alpha-002 1,263 12/17/2020
4.4.0-alpha-001 1,169 12/17/2020
4.3.0 6,043 12/17/2020
4.3.0-beta-002 1,227 12/11/2020
4.3.0-beta-001 1,183 12/7/2020
4.3.0-alpha-007 1,190 11/21/2020
4.3.0-alpha-006 1,184 11/20/2020
4.3.0-alpha-005 1,139 11/16/2020
4.3.0-alpha-004 1,634 11/12/2020
4.3.0-alpha-003 1,227 11/10/2020
4.3.0-alpha-002 1,207 10/26/2020
4.3.0-alpha-001 1,233 10/23/2020
4.2.0 5,092 9/25/2020
4.2.0-alpha-004 1,378 9/23/2020
4.2.0-alpha-003 1,179 9/21/2020
4.2.0-alpha-002 1,240 9/19/2020
4.2.0-alpha-001 1,285 9/18/2020
4.1.1 1,879 9/17/2020
4.1.0 2,096 9/10/2020
4.1.0-beta-004 1,333 9/5/2020
4.1.0-beta-003 1,258 9/4/2020
4.1.0-beta-002 1,613 9/4/2020
4.1.0-beta-001 1,242 9/3/2020
4.1.0-alpha-001 1,209 9/1/2020
4.0.0 4,276 8/27/2020
4.0.0-beta-003 1,286 8/21/2020
4.0.0-beta-002 1,322 8/7/2020
4.0.0-beta-001 1,625 7/20/2020
4.0.0-alpha-014 1,442 7/14/2020
4.0.0-alpha-013 1,251 7/11/2020
4.0.0-alpha-012 2,089 7/6/2020
4.0.0-alpha-011 1,100 6/25/2020
4.0.0-alpha-010 1,486 6/18/2020
4.0.0-alpha-009 1,148 6/12/2020
4.0.0-alpha-008 1,283 6/2/2020
4.0.0-alpha-007 1,155 6/1/2020
4.0.0-alpha-006 2,421 5/23/2020
4.0.0-alpha-005 2,260 5/16/2020
4.0.0-alpha-004 1,574 5/4/2020
4.0.0-alpha-003 1,218 5/3/2020
4.0.0-alpha-002 1,269 4/26/2020
4.0.0-alpha-001 1,167 4/20/2020
3.3.0 13,045 2/28/2020
3.3.0-beta-002 2,104 2/21/2020
3.3.0-beta-001 1,271 2/18/2020
3.2.0 21,307 2/3/2020
3.2.0-beta-002 1,838 1/7/2020
3.2.0-beta-001 1,399 12/26/2019
3.1.0 10,790 11/27/2019
3.0.0 5,136 10/11/2019
3.0.0-beta-006 1,990 10/2/2019
3.0.0-beta-005 1,173 9/27/2019
3.0.0-beta-004 1,742 9/18/2019
3.0.0-beta-003 1,305 9/13/2019
3.0.0-beta-002 16,836 7/20/2019
3.0.0-beta-001 6,059 7/12/2019
2.9.2 25,901 2/2/2019
2.9.1 5,102 11/20/2018
2.9.0 11,521 10/17/2018
2.8.1 2,940 9/12/2018
2.8.0 6,340 7/7/2018
2.7.1 5,229 5/2/2018
2.7.0 2,890 5/2/2018
2.6.1 46,012 4/22/2017
2.5.0 3,216 2/19/2017
2.4.0 3,330 10/24/2016
2.3.0 2,983 7/9/2016
2.2.0 2,727 4/24/2016
2.1.0 2,623 4/1/2016
2.0.2 9,369 11/15/2015
1.11.0 3,158 9/12/2015
1.10.0 2,515 8/29/2015
1.9.0 2,975 8/10/2015
1.8.0-beta 2,146 7/19/2015
1.7.0 2,630 6/10/2015
1.6.0 3,526 10/25/2014
1.5.0 2,990 9/18/2014
1.4.0 3,327 7/1/2014
1.3.0 2,835 5/17/2014
1.2.0 2,859 4/21/2014
1.1.0 2,763 3/29/2014
1.0.7 2,722 3/12/2014
1.0.5.1 2,831 1/15/2014
1.0.5 2,552 1/7/2014
1.0.4 2,613 11/16/2013
1.0.3 2,641 10/6/2013
1.0.2 2,584 8/16/2013
1.0.1 2,777 7/22/2013
1.0.0 5,879 7/16/2013
0.9.9.2 2,987 7/2/2013
0.9.9.1 2,754 6/22/2013
0.9.8 2,740 6/14/2013
0.9.7 2,686 6/7/2013
0.9.6 2,693 5/31/2013
0.9.5 2,767 5/23/2013
0.9.4 2,615 5/19/2013
0.9.3 2,644 5/9/2013
0.9.2 2,667 5/3/2013
0.9.1 2,883 4/26/2013
0.9.0 2,667 4/19/2013
0.8.9 2,728 4/12/2013
0.8.8 2,686 4/11/2013
0.8.7 2,606 4/9/2013
0.8.6 2,622 4/4/2013
0.8.5 2,727 4/2/2013
0.8.4 2,640 4/1/2013
0.8.3 2,704 4/1/2013
0.8.2 2,595 4/1/2013
0.8.1 2,781 3/31/2013
0.8.0 2,714 3/31/2013

### Changed
* Formatting of multi-constrained SRTP functions needs improvement. [#2230](https://github.com/fsprojects/fantomas/issues/2230)
* Try/With with a single clause. [#1881](https://github.com/fsprojects/fantomas/issues/1881)
* Long type argument with constraints is not respecting max_line_length. [#2266](https://github.com/fsprojects/fantomas/issues/2266)
* Long function argument with constraints is not respecting max_line_length. [#2267](https://github.com/fsprojects/fantomas/issues/2267)

### Removed
* Remove Fantomas.Extras. [#2269](https://github.com/fsprojects/fantomas/issues/2269)

### Fixed
* Superfluous space between negate and RationalConst. [#2265](https://github.com/fsprojects/fantomas/issues/2265)
* Idempotency problem with ParsedHashDirective in signature file. [#2258](https://github.com/fsprojects/fantomas/issues/2258)
* Keyword 'override' gets changed to 'member'. [#2221](https://github.com/fsprojects/fantomas/issues/2221)