Feather.ErrorHandling 2.1.0

.NET 10.0 This package targets .NET 10.0. The package is compatible with this framework or higher. 
dotnet add package Feather.ErrorHandling --version 2.1.0
                    


                    

                
NuGet\Install-Package Feather.ErrorHandling -Version 2.1.0
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="Feather.ErrorHandling" Version="2.1.0" />
For projects that support PackageReference, copy this XML node into the project file to reference the package. 
<PackageVersion Include="Feather.ErrorHandling" Version="2.1.0" />
                    


                            Directory.Packages.props
                        

                    

                
<PackageReference Include="Feather.ErrorHandling" />
                    


                            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 Feather.ErrorHandling --version 2.1.0
                    


                    

                
#r "nuget: Feather.ErrorHandling, 2.1.0"
#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 Feather.ErrorHandling@2.1.0
#: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=Feather.ErrorHandling&version=2.1.0
                    


                            Install as a Cake Addin
                        

                    

                
#tool nuget:?package=Feather.ErrorHandling&version=2.1.0
                    


                            Install as a Cake Tool

<img src="https://github.com/FeatherTools/.github/blob/main/profile/feather-logo-200.png" alt="FeatherTools Logo" width="100" height="100"> Error-Handling

NuGet NuGet Downloads Checks

Library for proper error handling with Option, Result, AsyncResult and their computation expressions.

Inspiration

Install

paket add Feather.ErrorHandling

Note: You can also use this library in a Fable project.

Validation

validation {} is applicative. It evaluates every binding joined with and! and collects all of their failures. You can bind a Result<'T, 'Failure> or a Validation<'T, 'Failure> directly.

open Feather.ErrorHandling

type Person = { Name: string; Age: int }

type PersonError =
    | NameEmpty
    | InvalidAge
    | AgeNegative
    | Underage

module Int32 =
    let tryParse (s: string) =
        match System.Int32.TryParse(s) with
        | true, value -> Some value
        | false, _ -> None

let validateName name = if name = "" then Error NameEmpty else Ok name

let createPerson name age: Validation<Person, PersonError> = validation {
    let! name = validateName name
    and! age = result {  // only one specific error may come from the result
        let! age = age |> Int32.tryParse |> Result.ofOption InvalidAge
        if age < 0 then return! Error AgeNegative
        if age < 18 then return! Error Underage

        return age
    }

    return { Name = name; Age = age }
}

createPerson "Alice" "30"     // Ok { Name = "Alice"; Age = 30 }
createPerson "Alice" "thirty" // Error [ InvalidAge ]
createPerson "" "-1"          // Error [ NameEmpty; AgeNegative ]
createPerson "Alice" "16"     // Error [ Underage ]

A Validation<'T, 'Failure> is a Result<'T, 'Failure list>, so when a stage should run only if the previous one succeeded, bind the stages in an outer result {}.

Release

  1. Increment version in ErrorHandling.fsproj
  2. Update CHANGELOG.md
  3. Commit new version and tag it

Development

Requirements

Build

./build.sh build

Tests

./build.sh -t tests
Product Compatible and additional computed target framework versions.
.NET net10.0 is compatible.  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.

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GitHub repositories

This package is not used by any popular GitHub repositories.

Version Downloads Last Updated
2.1.0 40 9/25/2026
2.0.0 16,188 12/4/2025
1.0.0 1,808 11/26/2025