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There is a newer version of this package available.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 5,604 5/28/2025
7.0.1 26,837 2/21/2025
7.0.0 34,599 1/10/2025
7.0.0-beta-001 238 12/30/2024
7.0.0-alpha-004 953 12/12/2024
7.0.0-alpha-003 624 11/29/2024
7.0.0-alpha-002 289 11/2/2024
7.0.0-alpha-001 142 9/16/2024
6.3.16 44,276 10/29/2024
6.3.15 27,284 9/14/2024
6.3.14 338 9/14/2024
6.3.13 1,375 9/10/2024
6.3.12 10,910 9/5/2024
6.3.11 23,941 8/16/2024
6.3.10 120,281 7/12/2024
6.3.9 48,235 6/9/2024
6.3.8 1,440 6/6/2024
6.3.7 2,480 6/1/2024
6.3.6 397 6/1/2024
6.3.5 1,087 5/30/2024
6.3.4 37,750 4/16/2024
6.3.3 9,489 4/12/2024
6.3.2 586 4/12/2024
6.3.1 13,310 3/30/2024
6.3.0 15,141 3/15/2024
6.3.0-beta-001 1,173 3/7/2024
6.3.0-alpha-008 859 3/1/2024
6.3.0-alpha-007 2,060 1/27/2024
6.3.0-alpha-006 855 1/9/2024
6.3.0-alpha-005 1,232 12/22/2023
6.3.0-alpha-004 1,940 12/6/2023
6.3.0-alpha-003 1,492 11/15/2023
6.3.0-alpha-002 942 11/7/2023
6.3.0-alpha-001 790 11/3/2023
6.2.3 150,994 11/2/2023
6.2.2 33,128 10/18/2023
6.2.1 10,840 9/18/2023
6.2.0 24,755 8/29/2023
6.1.3 1,522 8/25/2023
6.1.2 15,494 7/23/2023
6.1.1 78,820 6/29/2023
6.1.0 7,569 6/28/2023
6.1.0-alpha-006 1,129 6/20/2023
6.1.0-alpha-005 1,053 6/20/2023
6.1.0-alpha-004 871 6/19/2023
6.1.0-alpha-003 1,142 6/2/2023
6.1.0-alpha-002 1,011 5/2/2023
6.1.0-alpha-001 1,014 5/2/2023
6.0.8 2,107 6/20/2023
6.0.7 1,320 6/20/2023
6.0.6 1,509 6/19/2023
6.0.5 5,379 6/6/2023
6.0.4 1,360 6/2/2023
6.0.3 13,074 5/14/2023
6.0.2 4,281 5/5/2023
6.0.1 85,325 4/19/2023
6.0.0 61,883 4/13/2023
6.0.0-beta-001 1,534 4/5/2023
6.0.0-alpha-010 7,833 4/3/2023
6.0.0-alpha-009 858 3/31/2023
6.0.0-alpha-008 2,109 3/27/2023
6.0.0-alpha-007 1,379 3/27/2023
6.0.0-alpha-006 1,526 3/17/2023
6.0.0-alpha-005 2,407 2/24/2023
6.0.0-alpha-004 9,521 2/22/2023
6.0.0-alpha-003 3,020 2/4/2023
6.0.0-alpha-002 937 2/1/2023
6.0.0-alpha-001 1,067 1/24/2023
5.2.4 6,253 3/17/2023
5.2.3 5,670 3/6/2023
5.2.2 13,868 2/21/2023
5.2.1 78,728 2/4/2023
5.2.0 6,917 1/19/2023
5.2.0-alpha-012 1,200 1/14/2023
5.2.0-alpha-011 1,424 1/12/2023
5.2.0-alpha-010 1,136 12/30/2022
5.2.0-alpha-009 1,062 12/29/2022
5.2.0-alpha-008 1,313 12/28/2022
5.2.0-alpha-007 1,048 12/26/2022
5.2.0-alpha-006 1,057 12/22/2022
5.2.0-alpha-005 1,185 12/16/2022
5.2.0-alpha-004 1,297 12/8/2022
5.2.0-alpha-003 1,076 12/6/2022
5.2.0-alpha-002 1,019 12/4/2022
5.2.0-alpha-001 968 11/30/2022
5.1.5 25,913 12/22/2022
5.1.4 27,933 11/30/2022
5.1.3 8,088 11/14/2022
5.1.2 1,603 11/10/2022
5.1.1 4,109 11/7/2022
5.1.0 2,800 11/4/2022
5.1.0-beta-002 1,033 10/29/2022
5.1.0-beta-001 1,402 10/19/2022
5.1.0-alpha-007 1,077 10/14/2022
5.1.0-alpha-006 1,045 10/14/2022
5.1.0-alpha-005 1,184 10/7/2022
5.1.0-alpha-004 1,197 10/7/2022
5.1.0-alpha-003 1,207 10/2/2022
5.1.0-alpha-002 1,089 9/29/2022
5.1.0-alpha-001 1,128 9/18/2022
5.0.6 25,707 10/13/2022
5.0.5 10,466 10/7/2022
5.0.4 2,230 10/4/2022
5.0.3 11,002 9/29/2022
5.0.2 8,493 9/22/2022
5.0.1 6,583 9/18/2022
5.0.0 21,307 9/16/2022
5.0.0-beta-010 30,248 9/10/2022
5.0.0-beta-009 10,469 9/2/2022
5.0.0-beta-008 3,072 8/30/2022
5.0.0-beta-007 1,668 8/19/2022
5.0.0-beta-006 2,983 8/12/2022
5.0.0-beta-005 5,123 8/3/2022
5.0.0-beta-004 2,361 7/27/2022
5.0.0-beta-003 3,756 7/26/2022
5.0.0-beta-002 1,947 7/19/2022
5.0.0-beta-001 2,934 7/15/2022
5.0.0-alpha-011 1,669 7/8/2022
5.0.0-alpha-010 2,251 6/27/2022
5.0.0-alpha-009 93,985 6/21/2022
5.0.0-alpha-008 3,121 5/28/2022
5.0.0-alpha-007 1,885 5/16/2022
5.0.0-alpha-006 1,906 5/13/2022
5.0.0-alpha-005 1,392 5/7/2022
5.0.0-alpha-004 1,485 5/7/2022
5.0.0-alpha-003 1,950 5/6/2022
5.0.0-alpha-002 793 4/4/2022
5.0.0-alpha-001 746 3/19/2022
4.7.9 11,460 5/2/2022
4.7.8 10,603 4/25/2022
4.7.7 1,218 4/20/2022
4.7.6 1,485 4/4/2022
4.7.5 1,345 3/27/2022
4.7.4 1,312 3/25/2022
4.7.3 4,876 3/12/2022
4.7.2 1,230 3/11/2022
4.7.1 1,231 3/8/2022
4.7.0 1,353 3/4/2022
4.6.6 1,267 3/4/2022
4.6.5 2,013 2/18/2022
4.6.4 1,782 2/11/2022
4.6.3 1,826 2/8/2022
4.6.2 1,806 2/6/2022
4.6.1 1,808 2/1/2022
4.6.0 2,310 1/14/2022
4.6.0-beta-001 869 1/8/2022
4.6.0-alpha-011 853 12/29/2021
4.6.0-alpha-010 869 12/4/2021
4.6.0-alpha-009 3,501 11/24/2021
4.6.0-alpha-008 1,279 11/19/2021
4.6.0-alpha-007 901 11/7/2021
4.6.0-alpha-006 265 11/3/2021
4.6.0-alpha-005 284 10/27/2021
4.6.0-alpha-004 265 10/20/2021
4.6.0-alpha-003 248 10/5/2021
4.6.0-alpha-002 252 9/7/2021
4.6.0-alpha-001 226 8/11/2021
4.5.12 1,676 1/8/2022
4.5.11 2,463 12/29/2021
4.5.10 2,704 12/4/2021
4.5.9 7,601 11/24/2021
4.5.8 1,814 11/19/2021
4.5.7 1,646 11/7/2021
4.5.6 1,436 11/3/2021
4.5.5 1,599 10/27/2021
4.5.4 1,508 10/5/2021
4.5.3 3,002 9/7/2021
4.5.2 1,647 8/11/2021
4.5.1 3,522 7/24/2021
4.5.0 3,426 7/7/2021
4.5.0-beta-005 966 7/6/2021
4.5.0-beta-004 942 7/5/2021
4.5.0-beta-003 984 7/5/2021
4.5.0-beta-002 974 6/27/2021
4.5.0-beta-001 1,474 6/5/2021
4.5.0-alpha-020 928 5/26/2021
4.5.0-alpha-019 934 5/22/2021
4.5.0-alpha-018 968 5/21/2021
4.5.0-alpha-017 927 5/15/2021
4.5.0-alpha-016 897 5/9/2021
4.5.0-alpha-015 1,001 5/8/2021
4.5.0-alpha-014 1,043 4/30/2021
4.5.0-alpha-013 960 4/27/2021
4.5.0-alpha-012 952 4/23/2021
4.5.0-alpha-011 1,040 4/20/2021
4.5.0-alpha-010 965 4/14/2021
4.5.0-alpha-009 979 4/11/2021
4.5.0-alpha-008 969 4/8/2021
4.5.0-alpha-007 993 4/8/2021
4.5.0-alpha-006 944 4/5/2021
4.5.0-alpha-005 975 4/3/2021
4.5.0-alpha-004 996 4/2/2021
4.5.0-alpha-003 1,029 3/28/2021
4.5.0-alpha-002 1,001 3/22/2021
4.5.0-alpha-001 2,627 2/26/2021
4.4.0 13,454 2/25/2021
4.4.0-beta-008 1,049 2/19/2021
4.4.0-beta-007 1,041 2/12/2021
4.4.0-beta-006 1,024 2/12/2021
4.4.0-beta-005 1,082 2/9/2021
4.4.0-beta-004 1,066 2/5/2021
4.4.0-beta-003 1,517 1/30/2021
4.4.0-beta-002 1,054 1/23/2021
4.4.0-beta-001 1,459 1/22/2021
4.4.0-alpha-008 1,230 1/15/2021
4.4.0-alpha-007 1,728 12/26/2020
4.4.0-alpha-006 1,147 12/25/2020
4.4.0-alpha-005 1,222 12/23/2020
4.4.0-alpha-004 1,251 12/22/2020
4.4.0-alpha-003 1,255 12/18/2020
4.4.0-alpha-002 1,227 12/17/2020
4.4.0-alpha-001 1,130 12/17/2020
4.3.0 5,936 12/17/2020
4.3.0-beta-002 1,188 12/11/2020
4.3.0-beta-001 1,144 12/7/2020
4.3.0-alpha-007 1,154 11/21/2020
4.3.0-alpha-006 1,149 11/20/2020
4.3.0-alpha-005 1,100 11/16/2020
4.3.0-alpha-004 1,592 11/12/2020
4.3.0-alpha-003 1,183 11/10/2020
4.3.0-alpha-002 1,163 10/26/2020
4.3.0-alpha-001 1,193 10/23/2020
4.2.0 5,050 9/25/2020
4.2.0-alpha-004 1,339 9/23/2020
4.2.0-alpha-003 1,141 9/21/2020
4.2.0-alpha-002 1,205 9/19/2020
4.2.0-alpha-001 1,250 9/18/2020
4.1.1 1,839 9/17/2020
4.1.0 2,055 9/10/2020
4.1.0-beta-004 1,290 9/5/2020
4.1.0-beta-003 1,222 9/4/2020
4.1.0-beta-002 1,574 9/4/2020
4.1.0-beta-001 1,200 9/3/2020
4.1.0-alpha-001 1,174 9/1/2020
4.0.0 4,239 8/27/2020
4.0.0-beta-003 1,247 8/21/2020
4.0.0-beta-002 1,278 8/7/2020
4.0.0-beta-001 1,591 7/20/2020
4.0.0-alpha-014 1,406 7/14/2020
4.0.0-alpha-013 1,214 7/11/2020
4.0.0-alpha-012 2,057 7/6/2020
4.0.0-alpha-011 1,062 6/25/2020
4.0.0-alpha-010 1,446 6/18/2020
4.0.0-alpha-009 1,113 6/12/2020
4.0.0-alpha-008 1,239 6/2/2020
4.0.0-alpha-007 1,112 6/1/2020
4.0.0-alpha-006 2,384 5/23/2020
4.0.0-alpha-005 2,218 5/16/2020
4.0.0-alpha-004 1,533 5/4/2020
4.0.0-alpha-003 1,181 5/3/2020
4.0.0-alpha-002 1,230 4/26/2020
4.0.0-alpha-001 1,124 4/20/2020
3.3.0 13,000 2/28/2020
3.3.0-beta-002 2,062 2/21/2020
3.3.0-beta-001 1,229 2/18/2020
3.2.0 21,262 2/3/2020
3.2.0-beta-002 1,800 1/7/2020
3.2.0-beta-001 1,360 12/26/2019
3.1.0 10,746 11/27/2019
3.0.0 5,094 10/11/2019
3.0.0-beta-006 1,946 10/2/2019
3.0.0-beta-005 1,131 9/27/2019
3.0.0-beta-004 1,706 9/18/2019
3.0.0-beta-003 1,264 9/13/2019
3.0.0-beta-002 16,784 7/20/2019
3.0.0-beta-001 6,005 7/12/2019
2.9.2 25,859 2/2/2019
2.9.1 5,055 11/20/2018
2.9.0 11,484 10/17/2018
2.8.1 2,893 9/12/2018
2.8.0 6,235 7/7/2018
2.7.1 5,123 5/2/2018
2.7.0 2,780 5/2/2018
2.6.1 45,914 4/22/2017
2.5.0 3,134 2/19/2017
2.4.0 3,254 10/24/2016
2.3.0 2,906 7/9/2016
2.2.0 2,648 4/24/2016
2.1.0 2,547 4/1/2016
2.0.2 9,291 11/15/2015
1.11.0 3,083 9/12/2015
1.10.0 2,437 8/29/2015
1.9.0 2,899 8/10/2015
1.8.0-beta 2,071 7/19/2015
1.7.0 2,553 6/10/2015
1.6.0 3,444 10/25/2014
1.5.0 2,910 9/18/2014
1.4.0 3,258 7/1/2014
1.3.0 2,761 5/17/2014
1.2.0 2,781 4/21/2014
1.1.0 2,680 3/29/2014
1.0.7 2,643 3/12/2014
1.0.5.1 2,747 1/15/2014
1.0.5 2,469 1/7/2014
1.0.4 2,539 11/16/2013
1.0.3 2,557 10/6/2013
1.0.2 2,500 8/16/2013
1.0.1 2,689 7/22/2013
1.0.0 5,788 7/16/2013
0.9.9.2 2,903 7/2/2013
0.9.9.1 2,666 6/22/2013
0.9.8 2,656 6/14/2013
0.9.7 2,603 6/7/2013
0.9.6 2,604 5/31/2013
0.9.5 2,684 5/23/2013
0.9.4 2,534 5/19/2013
0.9.3 2,554 5/9/2013
0.9.2 2,588 5/3/2013
0.9.1 2,794 4/26/2013
0.9.0 2,582 4/19/2013
0.8.9 2,638 4/12/2013
0.8.8 2,601 4/11/2013
0.8.7 2,525 4/9/2013
0.8.6 2,540 4/4/2013
0.8.5 2,642 4/2/2013
0.8.4 2,555 4/1/2013
0.8.3 2,621 4/1/2013
0.8.2 2,505 4/1/2013
0.8.1 2,688 3/31/2013
0.8.0 2,630 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)