fantomas 5.0.0-alpha-003

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There is a newer version of this package available.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-003
                    
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-003
                    
This package contains a .NET tool you can call from the shell/command line.
#tool dotnet:?package=fantomas&version=5.0.0-alpha-003&prerelease
                    
nuke :add-package fantomas --version 5.0.0-alpha-003
                    

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 "(%s -> %s)" (t1.ToString()) (t2.ToString())
                 | 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 "(%s -> %s)" (t1.ToString()) (t2.ToString())
             | 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
7.0.2 3,988 5/28/2025
7.0.1 26,013 2/21/2025
7.0.0 32,767 1/10/2025
7.0.0-beta-001 234 12/30/2024
7.0.0-alpha-004 948 12/12/2024
7.0.0-alpha-003 601 11/29/2024
7.0.0-alpha-002 281 11/2/2024
7.0.0-alpha-001 137 9/16/2024
6.3.16 42,568 10/29/2024
6.3.15 27,079 9/14/2024
6.3.14 326 9/14/2024
6.3.13 1,366 9/10/2024
6.3.12 10,778 9/5/2024
6.3.11 23,765 8/16/2024
6.3.10 116,098 7/12/2024
6.3.9 47,417 6/9/2024
6.3.8 1,428 6/6/2024
6.3.7 2,449 6/1/2024
6.3.6 386 6/1/2024
6.3.5 1,080 5/30/2024
6.3.4 37,347 4/16/2024
6.3.3 9,394 4/12/2024
6.3.2 579 4/12/2024
6.3.1 13,287 3/30/2024
6.3.0 15,082 3/15/2024
6.3.0-beta-001 1,169 3/7/2024
6.3.0-alpha-008 848 3/1/2024
6.3.0-alpha-007 2,052 1/27/2024
6.3.0-alpha-006 847 1/9/2024
6.3.0-alpha-005 1,228 12/22/2023
6.3.0-alpha-004 1,935 12/6/2023
6.3.0-alpha-003 1,485 11/15/2023
6.3.0-alpha-002 938 11/7/2023
6.3.0-alpha-001 785 11/3/2023
6.2.3 150,031 11/2/2023
6.2.2 33,053 10/18/2023
6.2.1 10,829 9/18/2023
6.2.0 24,746 8/29/2023
6.1.3 1,512 8/25/2023
6.1.2 15,468 7/23/2023
6.1.1 78,797 6/29/2023
6.1.0 7,565 6/28/2023
6.1.0-alpha-006 1,123 6/20/2023
6.1.0-alpha-005 1,047 6/20/2023
6.1.0-alpha-004 861 6/19/2023
6.1.0-alpha-003 1,139 6/2/2023
6.1.0-alpha-002 1,005 5/2/2023
6.1.0-alpha-001 1,010 5/2/2023
6.0.8 2,104 6/20/2023
6.0.7 1,309 6/20/2023
6.0.6 1,499 6/19/2023
6.0.5 5,351 6/6/2023
6.0.4 1,353 6/2/2023
6.0.3 13,053 5/14/2023
6.0.2 4,274 5/5/2023
6.0.1 84,386 4/19/2023
6.0.0 61,131 4/13/2023
6.0.0-beta-001 1,526 4/5/2023
6.0.0-alpha-010 7,828 4/3/2023
6.0.0-alpha-009 846 3/31/2023
6.0.0-alpha-008 2,099 3/27/2023
6.0.0-alpha-007 1,376 3/27/2023
6.0.0-alpha-006 1,516 3/17/2023
6.0.0-alpha-005 2,397 2/24/2023
6.0.0-alpha-004 9,511 2/22/2023
6.0.0-alpha-003 3,009 2/4/2023
6.0.0-alpha-002 931 2/1/2023
6.0.0-alpha-001 1,062 1/24/2023
5.2.4 6,243 3/17/2023
5.2.3 5,662 3/6/2023
5.2.2 13,857 2/21/2023
5.2.1 77,969 2/4/2023
5.2.0 6,911 1/19/2023
5.2.0-alpha-012 1,195 1/14/2023
5.2.0-alpha-011 1,414 1/12/2023
5.2.0-alpha-010 1,122 12/30/2022
5.2.0-alpha-009 1,050 12/29/2022
5.2.0-alpha-008 1,305 12/28/2022
5.2.0-alpha-007 1,044 12/26/2022
5.2.0-alpha-006 1,049 12/22/2022
5.2.0-alpha-005 1,174 12/16/2022
5.2.0-alpha-004 1,287 12/8/2022
5.2.0-alpha-003 1,062 12/6/2022
5.2.0-alpha-002 1,012 12/4/2022
5.2.0-alpha-001 960 11/30/2022
5.1.5 25,873 12/22/2022
5.1.4 27,855 11/30/2022
5.1.3 8,059 11/14/2022
5.1.2 1,587 11/10/2022
5.1.1 4,105 11/7/2022
5.1.0 2,796 11/4/2022
5.1.0-beta-002 1,024 10/29/2022
5.1.0-beta-001 1,393 10/19/2022
5.1.0-alpha-007 1,070 10/14/2022
5.1.0-alpha-006 1,029 10/14/2022
5.1.0-alpha-005 1,173 10/7/2022
5.1.0-alpha-004 1,186 10/7/2022
5.1.0-alpha-003 1,194 10/2/2022
5.1.0-alpha-002 1,080 9/29/2022
5.1.0-alpha-001 1,119 9/18/2022
5.0.6 25,692 10/13/2022
5.0.5 10,457 10/7/2022
5.0.4 2,220 10/4/2022
5.0.3 10,991 9/29/2022
5.0.2 8,489 9/22/2022
5.0.1 6,534 9/18/2022
5.0.0 21,302 9/16/2022
5.0.0-beta-010 29,919 9/10/2022
5.0.0-beta-009 10,431 9/2/2022
5.0.0-beta-008 3,063 8/30/2022
5.0.0-beta-007 1,656 8/19/2022
5.0.0-beta-006 2,974 8/12/2022
5.0.0-beta-005 5,111 8/3/2022
5.0.0-beta-004 2,354 7/27/2022
5.0.0-beta-003 3,749 7/26/2022
5.0.0-beta-002 1,936 7/19/2022
5.0.0-beta-001 2,925 7/15/2022
5.0.0-alpha-011 1,655 7/8/2022
5.0.0-alpha-010 2,238 6/27/2022
5.0.0-alpha-009 93,901 6/21/2022
5.0.0-alpha-008 3,105 5/28/2022
5.0.0-alpha-007 1,880 5/16/2022
5.0.0-alpha-006 1,900 5/13/2022
5.0.0-alpha-005 1,383 5/7/2022
5.0.0-alpha-004 1,478 5/7/2022
5.0.0-alpha-003 1,938 5/6/2022
5.0.0-alpha-002 782 4/4/2022
5.0.0-alpha-001 738 3/19/2022
4.7.9 11,449 5/2/2022
4.7.8 10,595 4/25/2022
4.7.7 1,212 4/20/2022
4.7.6 1,480 4/4/2022
4.7.5 1,336 3/27/2022
4.7.4 1,302 3/25/2022
4.7.3 4,868 3/12/2022
4.7.2 1,224 3/11/2022
4.7.1 1,226 3/8/2022
4.7.0 1,347 3/4/2022
4.6.6 1,253 3/4/2022
4.6.5 2,006 2/18/2022
4.6.4 1,777 2/11/2022
4.6.3 1,821 2/8/2022
4.6.2 1,802 2/6/2022
4.6.1 1,799 2/1/2022
4.6.0 2,304 1/14/2022
4.6.0-beta-001 862 1/8/2022
4.6.0-alpha-011 842 12/29/2021
4.6.0-alpha-010 861 12/4/2021
4.6.0-alpha-009 3,494 11/24/2021
4.6.0-alpha-008 1,273 11/19/2021
4.6.0-alpha-007 896 11/7/2021
4.6.0-alpha-006 256 11/3/2021
4.6.0-alpha-005 275 10/27/2021
4.6.0-alpha-004 255 10/20/2021
4.6.0-alpha-003 235 10/5/2021
4.6.0-alpha-002 248 9/7/2021
4.6.0-alpha-001 222 8/11/2021
4.5.12 1,670 1/8/2022
4.5.11 2,456 12/29/2021
4.5.10 2,697 12/4/2021
4.5.9 7,596 11/24/2021
4.5.8 1,807 11/19/2021
4.5.7 1,640 11/7/2021
4.5.6 1,429 11/3/2021
4.5.5 1,588 10/27/2021
4.5.4 1,499 10/5/2021
4.5.3 2,997 9/7/2021
4.5.2 1,642 8/11/2021
4.5.1 3,506 7/24/2021
4.5.0 3,412 7/7/2021
4.5.0-beta-005 959 7/6/2021
4.5.0-beta-004 936 7/5/2021
4.5.0-beta-003 980 7/5/2021
4.5.0-beta-002 969 6/27/2021
4.5.0-beta-001 1,464 6/5/2021
4.5.0-alpha-020 918 5/26/2021
4.5.0-alpha-019 925 5/22/2021
4.5.0-alpha-018 962 5/21/2021
4.5.0-alpha-017 921 5/15/2021
4.5.0-alpha-016 892 5/9/2021
4.5.0-alpha-015 988 5/8/2021
4.5.0-alpha-014 1,033 4/30/2021
4.5.0-alpha-013 950 4/27/2021
4.5.0-alpha-012 944 4/23/2021
4.5.0-alpha-011 1,035 4/20/2021
4.5.0-alpha-010 953 4/14/2021
4.5.0-alpha-009 964 4/11/2021
4.5.0-alpha-008 963 4/8/2021
4.5.0-alpha-007 987 4/8/2021
4.5.0-alpha-006 934 4/5/2021
4.5.0-alpha-005 966 4/3/2021
4.5.0-alpha-004 982 4/2/2021
4.5.0-alpha-003 1,025 3/28/2021
4.5.0-alpha-002 989 3/22/2021
4.5.0-alpha-001 2,621 2/26/2021
4.4.0 13,427 2/25/2021
4.4.0-beta-008 1,039 2/19/2021
4.4.0-beta-007 1,027 2/12/2021
4.4.0-beta-006 1,016 2/12/2021
4.4.0-beta-005 1,075 2/9/2021
4.4.0-beta-004 1,061 2/5/2021
4.4.0-beta-003 1,512 1/30/2021
4.4.0-beta-002 1,045 1/23/2021
4.4.0-beta-001 1,451 1/22/2021
4.4.0-alpha-008 1,219 1/15/2021
4.4.0-alpha-007 1,714 12/26/2020
4.4.0-alpha-006 1,140 12/25/2020
4.4.0-alpha-005 1,210 12/23/2020
4.4.0-alpha-004 1,243 12/22/2020
4.4.0-alpha-003 1,246 12/18/2020
4.4.0-alpha-002 1,219 12/17/2020
4.4.0-alpha-001 1,121 12/17/2020
4.3.0 5,928 12/17/2020
4.3.0-beta-002 1,177 12/11/2020
4.3.0-beta-001 1,134 12/7/2020
4.3.0-alpha-007 1,145 11/21/2020
4.3.0-alpha-006 1,138 11/20/2020
4.3.0-alpha-005 1,092 11/16/2020
4.3.0-alpha-004 1,585 11/12/2020
4.3.0-alpha-003 1,174 11/10/2020
4.3.0-alpha-002 1,153 10/26/2020
4.3.0-alpha-001 1,182 10/23/2020
4.2.0 5,044 9/25/2020
4.2.0-alpha-004 1,330 9/23/2020
4.2.0-alpha-003 1,131 9/21/2020
4.2.0-alpha-002 1,198 9/19/2020
4.2.0-alpha-001 1,245 9/18/2020
4.1.1 1,830 9/17/2020
4.1.0 2,046 9/10/2020
4.1.0-beta-004 1,279 9/5/2020
4.1.0-beta-003 1,216 9/4/2020
4.1.0-beta-002 1,567 9/4/2020
4.1.0-beta-001 1,188 9/3/2020
4.1.0-alpha-001 1,167 9/1/2020
4.0.0 4,232 8/27/2020
4.0.0-beta-003 1,239 8/21/2020
4.0.0-beta-002 1,270 8/7/2020
4.0.0-beta-001 1,585 7/20/2020
4.0.0-alpha-014 1,395 7/14/2020
4.0.0-alpha-013 1,204 7/11/2020
4.0.0-alpha-012 2,050 7/6/2020
4.0.0-alpha-011 1,054 6/25/2020
4.0.0-alpha-010 1,427 6/18/2020
4.0.0-alpha-009 1,106 6/12/2020
4.0.0-alpha-008 1,229 6/2/2020
4.0.0-alpha-007 1,104 6/1/2020
4.0.0-alpha-006 2,376 5/23/2020
4.0.0-alpha-005 2,211 5/16/2020
4.0.0-alpha-004 1,522 5/4/2020
4.0.0-alpha-003 1,173 5/3/2020
4.0.0-alpha-002 1,216 4/26/2020
4.0.0-alpha-001 1,111 4/20/2020
3.3.0 12,987 2/28/2020
3.3.0-beta-002 2,052 2/21/2020
3.3.0-beta-001 1,223 2/18/2020
3.2.0 21,255 2/3/2020
3.2.0-beta-002 1,791 1/7/2020
3.2.0-beta-001 1,352 12/26/2019
3.1.0 10,739 11/27/2019
3.0.0 5,089 10/11/2019
3.0.0-beta-006 1,938 10/2/2019
3.0.0-beta-005 1,122 9/27/2019
3.0.0-beta-004 1,700 9/18/2019
3.0.0-beta-003 1,257 9/13/2019
3.0.0-beta-002 16,777 7/20/2019
3.0.0-beta-001 5,986 7/12/2019
2.9.2 25,849 2/2/2019
2.9.1 5,048 11/20/2018
2.9.0 11,478 10/17/2018
2.8.1 2,885 9/12/2018
2.8.0 6,215 7/7/2018
2.7.1 5,106 5/2/2018
2.7.0 2,760 5/2/2018
2.6.1 45,892 4/22/2017
2.5.0 3,119 2/19/2017
2.4.0 3,239 10/24/2016
2.3.0 2,891 7/9/2016
2.2.0 2,630 4/24/2016
2.1.0 2,527 4/1/2016
2.0.2 9,271 11/15/2015
1.11.0 3,065 9/12/2015
1.10.0 2,422 8/29/2015
1.9.0 2,878 8/10/2015
1.8.0-beta 2,047 7/19/2015
1.7.0 2,533 6/10/2015
1.6.0 3,419 10/25/2014
1.5.0 2,887 9/18/2014
1.4.0 3,239 7/1/2014
1.3.0 2,735 5/17/2014
1.2.0 2,763 4/21/2014
1.1.0 2,664 3/29/2014
1.0.7 2,623 3/12/2014
1.0.5.1 2,718 1/15/2014
1.0.5 2,447 1/7/2014
1.0.4 2,523 11/16/2013
1.0.3 2,538 10/6/2013
1.0.2 2,482 8/16/2013
1.0.1 2,672 7/22/2013
1.0.0 5,772 7/16/2013
0.9.9.2 2,875 7/2/2013
0.9.9.1 2,645 6/22/2013
0.9.8 2,640 6/14/2013
0.9.7 2,586 6/7/2013
0.9.6 2,579 5/31/2013
0.9.5 2,662 5/23/2013
0.9.4 2,511 5/19/2013
0.9.3 2,536 5/9/2013
0.9.2 2,562 5/3/2013
0.9.1 2,775 4/26/2013
0.9.0 2,563 4/19/2013
0.8.9 2,620 4/12/2013
0.8.8 2,583 4/11/2013
0.8.7 2,503 4/9/2013
0.8.6 2,521 4/4/2013
0.8.5 2,620 4/2/2013
0.8.4 2,535 4/1/2013
0.8.3 2,603 4/1/2013
0.8.2 2,486 4/1/2013
0.8.1 2,672 3/31/2013
0.8.0 2,611 3/31/2013

### Changed
* Don't add space between type of array and square brackets. [#2192](https://github.com/fsprojects/fantomas/issues/2192)
* Adjusted formatting of quotation expressions to latest F# style guide. [#661](https://github.com/fsharp/fslang-design/issues/661)
* Use F# compiler from the source files. [#2217](https://github.com/fsprojects/fantomas/issues/2217)
* Rename Fantomas to Fantomas.Core and fantomas-tool to fantomas. [#2174](https://github.com/fsprojects/fantomas/issues/2174)
* Update logo. [#2229](https://github.com/fsprojects/fantomas/pull/2229)

### Fixed
* Idempotency problem with multiline quotation expressions. [#2203](https://github.com/fsprojects/fantomas/issues/2203)