Fantomas.Core 9.0.0-alpha-001

This is a prerelease version of Fantomas.Core.
dotnet add package Fantomas.Core --version 9.0.0-alpha-001
                    
NuGet\Install-Package Fantomas.Core -Version 9.0.0-alpha-001
                    
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.Core" Version="9.0.0-alpha-001" />
                    
For projects that support PackageReference, copy this XML node into the project file to reference the package.
<PackageVersion Include="Fantomas.Core" Version="9.0.0-alpha-001" />
                    
Directory.Packages.props
<PackageReference Include="Fantomas.Core" />
                    
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.Core --version 9.0.0-alpha-001
                    
#r "nuget: Fantomas.Core, 9.0.0-alpha-001"
                    
#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.
#:package Fantomas.Core@9.0.0-alpha-001
                    
#:package directive can be used in C# file-based apps starting in .NET 10 preview 4. Copy this into a .cs file before any lines of code to reference the package.
#addin nuget:?package=Fantomas.Core&version=9.0.0-alpha-001&prerelease
                    
Install as a Cake Addin
#tool nuget:?package=Fantomas.Core&version=9.0.0-alpha-001&prerelease
                    
Install as a Cake Tool

Fantomas

Fantomas logo

GitHub CI Status Discord Nuget (with prereleases) llms.txt llms-full.txt

An opinionated F# source code formatter.

dotnet tool install fantomas

Documentation is available at https://fsprojects.github.io/fantomas/docs/

If you point a coding agent at Fantomas, give it llms.txt for an index of the documentation, or llms-full.txt for all of it in one file.

Reporting a bug

Report bugs through the online tool, which opens an issue with everything needed to reproduce it.

With a coding agent, the fantomas-report skill shrinks the file Fantomas failed on to a minimal sample and opens the same issue form for you to review:

npx skills add fsprojects/fantomas --skill fantomas-report -g

See Reporting a bug for more.

Contributing Guidelines

See the Contribution Guidelines and our contributors documentation

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 (5)

Showing the top 5 NuGet packages that depend on Fantomas.Core:

Package Downloads
Myriad.Core

Core Myriad library used for developing plugins

Fantomas.Extras

Utility package for Fantomas

WoofWare.Whippet.Fantomas

Helpers for accessing Fantomas syntax trees.

Fabulous.AST

Fabulous.AST, an Abstract Syntax Tree (AST) Domain Specific Language (DSL) for F#.

Partas.Feliz.Generator

Package Description

GitHub repositories

This package is not used by any popular GitHub repositories.

Version Downloads Last Updated
9.0.0-alpha-001 0 10/15/2026
8.0.10 36 10/14/2026
8.0.9 29 10/14/2026
8.0.8 118 10/9/2026
8.0.7 182 10/5/2026
8.0.6 119 10/1/2026
8.0.5 209 9/25/2026
8.0.4 146 9/23/2026
8.0.3 121 9/23/2026
8.0.2 379 9/22/2026
8.0.1 124 9/21/2026
8.0.0 276 9/15/2026
8.0.0-beta-003 95 9/12/2026
8.0.0-beta-002 103 9/8/2026
8.0.0-beta-001 133 9/1/2026
8.0.0-alpha-026 161 8/29/2026
8.0.0-alpha-025 117 8/28/2026
8.0.0-alpha-024 102 8/28/2026
8.0.0-alpha-023 114 8/28/2026
8.0.0-alpha-022 122 8/27/2026
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### Changed

- Fantomas checks that its output keeps every `//` and `(* *)` comment of the file. A format run searches its result for each of them, and does not write a result that is missing one, even when it is valid F#. The daemon that editors use refuses such output too, and output that is not valid F#, where it used to send both to the editor. `fantomas doctor` has a `Comments` step that checks, more thoroughly than a format run can afford, that the result keeps every comment and directive of the file under every define combination, a `Parse` step that lists the define combinations the file is parsed under, and ends on a `Verdict`: what a format run would do with the file. `CodeFormatter.FormatDocumentWithValidationsAsync` takes the checks to run as `Validations`, and `FormatResult` has a new field, `Issues`, with what they found, so code that constructs a `FormatResult` has to set it. `DefineParseException.Combinations` holds the defines of each combination that failed, rather than their names. [#1353](https://github.com/fsprojects/fantomas/issues/1353)
- On Linux x64, the `fantomas` tool is an executable compiled with Native AOT. It starts in milliseconds rather than first starting the .NET runtime. The `fantomas` package only names the packages per platform: `fantomas.linux-x64` and, for Alpine, `fantomas.linux-musl-x64` hold the executable, and every other platform installs `fantomas.any`, the tool as it shipped before. [#3171](https://github.com/fsprojects/fantomas/issues/3171)