Changelog

All notable changes to this project will be documented in this file. Funcky adheres to Semantic Versioning.

Funcky 3.4.0 | Funcky.Async 1.3.0 | Funcky.XUnit 2.0.2

This update is mainly to update to .NET 8 but also has several smaller improvements.

Native AOT

Both Funcky and Funcky.Async have been annotated to be compatible with Native AOT. The only exception is OptionJsonSerializer which is not compatible with Native AOT.

.NET 8

We use the new C#12 and .NET features in the code, and expose new features through our API.

  • .NET 8 added new overloads to their TryParse APIs. These changes are reflected in Funcky's ParseOrNone APIs.
    • ParseByteOrNone overloads with ReadOnlySpan<byte> and string?
    • ParseSByteOrNone overloads with ReadOnlySpan<byte>
    • ParseSingleOrNone overloads with ReadOnlySpan<byte>
    • ParseDoubleOrNone overloads with ReadOnlySpan<byte>
    • ParseDecimalOrNone overloads with ReadOnlySpan<byte>
    • ParseInt16OrNone overloads with ReadOnlySpan<byte>
    • ParseInt32OrNone overloads with ReadOnlySpan<byte>
    • ParseInt64OrNone overloads with ReadOnlySpan<byte>
    • ParseUInt16OrNone overloads with ReadOnlySpan<byte>
    • ParseUInt32OrNone overloads with ReadOnlySpan<byte>
    • ParseUInt64OrNone overloads with ReadOnlySpan<byte>
    • ParseNumberOrNone<TNumber> overloads
    • ParseOrNone<TParsable> overloads

String Extensions

We implemented a few of the IEnumerable extensions which are very useful on strings.

  • Chunk on string.
  • SlidingWindow on string.

Monads

  • Implemented UpCast for the monds Option, Either, Result and System.Lazy.
  • Implemented InspectEmpty on IEnumerable and IAsyncEnumerable
  • Implemented ToAsyncEnumerable extension on Option

IEnumerator

  • MoveNextOrNone extension on IEnumerator<T>

Consistency

  • FindIndexOrNone and FindLastIndexOrNone extensions on List

Funcky 3.3.0 | Funcky.Analyzers 1.3.0 | Funcky.Xunit 2.0.1

This is a relatively minor release focuses on convenience for our monads Option, Either and Result.

GetOrElse and OrElse for all

We've added GetOrElse and OrElse to Either and Result bringing them on par with Option.
The corresponding analyzer now also correctly suggests using these methods instead of Match for Result and Either.

Inspect for the error case

All three alternative monads Option, Either and Result now support inspecting the «error» case:

  • Option.InspectNone - executes a side effect only when the option is None.
  • Either.InspectLeft - executes a side effect only when the either is on the Left side.
  • Result.InspectError - executes a side effect only when the result is an Error.

These methods are particularly useful for logging warnings/errors.

Funcky.XUnit

  • Funcky.XUnit is only compatible with XUnit 2.4, this is now correctly declared.

Funcky 3.2.0 | Funcky.Async 1.2.0

List Pattern for Option

We've added support for C# 11's List Patterns to Option<T>. This means that you can use regular switch expressions / statements to match on options:

var greeting = person switch
{
    { FirstName: var firstName, LastName: [var lastName] } => $"Hello {firstName} {lastName}",
    { FirstName: var firstName } => $"Hi {firstName}",
};

record Person(string FirstName, Option<string> LastName);

Discard

The new Discard.__ field provides a short-hand for Unit.Value to be used with switch expressions.

using static Funcky.Discard;

return __ switch
{
    _ when user.IsFrenchAdmin() => "le sécret",
    _ when user.IsAdmin() => "secret",
    _ => "(redacted)",
};

Retry with Exception

We've added overloads to the Retry and RetryAsync functions that allow retrying a function as long as an exception is thrown.

Example from IoRetrier:

// Retries an action until the file is no longer in use.
Task RetryWhileFileIsInUseAsync(IRetryPolicy policy, Action action)
    => RetryAsync(ActionToUnit(action), exception => exception is IOException && exception.HResult == FileInUseHResult, policy);

New Extensions

  • EnumerableExtensions.MinByOrNone
  • EnumerableExtensions.MaxByOrNone
  • ImmutableListExtensions.IndexOfOrNone
  • ImmutableListExtensions.LastIndexOfOrNone
  • ListExtensions.IndexOfOrNone

Funcky 3.1.0 | Funcky.Async 1.1.0 | Funcky.Analyzers 1.2.0

New APIs

  • ✨ OptionExtensions.ToNullable ✨
  • StreamExtenions.ReadByteOrNone
  • New overloads for ElementAtOrNone that take an Index.
  • New overload for JoinToString that takes an IEnumerable<string>.

.NET 7

  • .NET 7 added new overloads to their TryParse APIs. These changes are reflected in Funcky's ParseOrNone APIs.
  • The ParseOrNone methods include the new [StringSyntax] attribute from .NET 7.

Analyzers

The new Option.Match analyzer suggests simpler alternatives over custom Matches including the all-new ToNullable extension.

Funcky 3.0.0 | Funcky.Async 1.0.0 | Funcky.XUnit 2.0.0

There's a handy Migration Guide available.

New APIs

  • Result.GetOrThrow
  • EnumerableExtensions.GetNonEnumeratedCountOrNone

PriorityQueue

  • PriorityQueueExtensions.DequeueOrNone
  • PeekOrNone

Traversable

The new Traverse and Sequence extension methods allow you to «swap» the inner and outer monad (e.g. Result<Option<T>> -> Option<Result<T>>)

Memoize

The new Memoize extension function returns an IBuffer / IAsyncBuffer.
This new type represents ownership over the underlying enumerator (and is therefore IDisposable).

CycleRange and RepeatRange have also been changed to return an IBuffer.

ParseExtensions

The parse extensions have been improved with the goal of aligning more with the BCL. Many of the changes are breaking.

  • The functions now use BCL type names instead of C# type names (e.g. ParseIntOrNone has been renamed to Parse)
  • The parameter names and nullability have been changed to align with the BCL.
  • Added HttpHeadersNonValidatedExtensions

IReadOnlyList / IReadOnlyCollection

Funcky now communicates materialization in the IEnumerable<T> extensions by returning IReadOnlyList or IReadOnlyCollection. This reduces «multiple enumeration» warnings.

  • Materialize
  • Chunk
  • Partition
  • Shuffle
  • SlidingWindow
  • Split
  • Transpose
  • Sequence.Return

Disallowing null Values

Our Option<T> type has always disallowed null values. This has been extended to our other monads: Result<T>, Either<L, R> and Reader<E, R>.

Breaking Changes

  • Option.None() has been changed to a property. There's an automatic fix available for this.
  • Our Match functions now differentiate between Func and Action. The Action overloads have been renamed to Switch.
  • The return type of EnumerableExtensions.ForEach has been changed to Unit.
  • Many parameter names and generic type names have been renamed in an attempt to unify naming across Funcky.
  • All Action extensions have been moved to a new class ActionExtensions.
  • EitherOrBoth has been moved to the Funcky namespace.
  • The retry policies have been moved to the Funcky.RetryPolicies namespace.
  • Partition returns a custom Partitions struct instead of a tuple.

Obsoleted APIs Removed

APIs that have been obsoleted during 2.x have been removed:

  • ObjectExtensions.ToEnumerable
  • Funcky.GenericConstraints.RequireClass and RequireStruct
  • All Try* APIs (TryGetValue, TryParse*, etc.). These APIs use the OrNone suffix instead.
  • Sequence.Generate has been superceded by Sequence.Successors
  • CartesianProduct

JSON Converter

We have removed the implicit System.Text.Json converter for Option<T>. This means that you'll have to register the OptionJsonConverter yourself.
⚠️ Test this change carefully as you won't get an error during compilation, but rather at runtime.

Moved to Funcky.Async

All APIs related to IAsyncEnumerable and Task have been moved to the new Funcky.Async package:

  • AsyncEnumerableExtensions
  • Functional.RetryAsync -> AsyncFunctional.RetryAsync
  • Option<Task> and Option<ValueTask> awaiters

Funcky.Async

AsyncSequence

This class exposes all of the same factory functions as Sequence, but for IAsyncEnumerable:

  • Return
  • Successors
  • Concat
  • Cycle
  • CycleRange
  • FromNullable
  • RepeatRange

New IAsyncEnumerable extensions

We've worked hard towards the goal of parity between our extensions for IEnumerable and IAsyncEnumerable:

  • AdjacentGroupBy
  • AnyOrElse
  • AverageOrNoneAsync / MaxOrNoneAsync / MinOrNoneAsync
  • Chunk
  • ConcatToStringAsync
  • ExclusiveScan
  • InclusiveScan
  • Inspect
  • Interleave
  • Intersperse
  • JoinToStringAsync
  • MaterializeAsync
  • Memoize
  • Merge
  • NoneAsync
  • PartitionAsync
  • PowerSet
  • Sequence / SequenceAsync / Traverse / TraverseAsync
  • ShuffleAsync
  • SlidingWindow
  • Split
  • Transpose
  • WhereNotNull
  • WithIndex / WithLast / WithPrevious / WithFirst
  • ZipLongest

Funcky.Xunit

  • Breaking: The Is prefix has been dropped from assertion methods for consistency with XUnit's naming scheme for assertion methods.

Funcky 2.7.1

Deprecations

  • Option.None<T>(): We originally introduced the Option.None<T> method as a future proof replacement to Option<T>.None for use in method groups, because Funcky 3 changes Option<T>.None to a property. This turned out to be confusing to users especially because both method are always suggested in autocomplete.

Funcky 2.7.0 | Funcky.XUnit 1.0.0 | Funcky.Analyzers 1.1.0

This release is the last non-breaking release for Funcky before 3.0.

Deprecations

  • EnumerableExtensions.CartesianProduct will be removed in Funcky 3.
  • To align our naming with that of the BCL, the ParseOrNone methods that return a type that has a keyword in C# int, long, etc. use the name of the BCL type instead.
    Example: ParseIntOrNone becomes ParseInt32OrNone.
    The old methods will be removed in Funcky 3.
  • In preparation for Funcky 3 we deprecated Option<T>.None when used as method group. Use Option.None<T> instead.

New ParseOrNone extensions

With the help of a source generator we have added a lot of new ParseOrNone methods for various types from the BCL:

  • Unsigned integer types
  • DateOnly, TimeOnly
  • Version
  • Support for ReadOnlySpan<T> as input
  • ... and more

Convenience for Either and Result

  • Added implicit conversions for Either and Result.
  • Implement Inspect for Either and Result.
  • Added Partition for IEnumerable<Either> and IEnumerable<Result>.
  • Added ToString on Either and Result.
  • Implement ToEither on Option.

IEnumerable<T> extensions

  • AnyOrElse
  • Prefix sum: InclusiveScan and ExclusiveScan

Analyzers

This release adds two new analyzer rules:

  • λ1003: Warning when certain methods, such as Match are used without argument labels
  • λ1004: Warning that suggests .ConcatToString() over .JoinToString("")

Both of these warnings come with corresponding code fixes.

Funcky.Xunit

  • Breaking: Funcky.Xunit now uses the Funcky namespace, instead of Funcky.Xunit.
  • Add assertion methods for testing Either: FunctionalAssert.IsLeft and FunctionalAssert.IsRight.

Funcky 2.6.0 | Funcky.Analyzers 1.0.0

Analyzers

This release comes with a new package Funcky.Analyzers, which we'll use to guide users of Funcky

New extensions

  • Add extensions DequeueOrNone and PeekOrNone on Queue and ConcurrentQueue.
  • Add extension ConcatToString as an alias for string.Concat.
  • Add overload to WhereSelect with no parameter.
  • Add methods to convert from Either to Option: #439
    • LeftOrNone: Returns the left value or None if the either value was right.
    • RightOrNone: Returns the right value or None if the either value was left.
  • Extension functions for System.Range to allow the generations of IEnumerable<T>s from Range-Syntax: 
    foreach(var i in 1..5) { }

// negative numbers are not supported
from x in 5..2
from y in 1..3
select (x, y)

Improvements to Sequence

  • Sequence.Return now accepts multiple parameters: 
    Sequence.Return(1, 2, 3)
  • ⚠️ Sequence.Generate has been deprecated in favour of the newly added Sequence.Successors function which includes the first element (seed) in the generated sequence.

Improvements to Option

  • Add Option.FromBoolean to create an Option<T> from a boolean.

Improvements to Result

The behaviour of the Result.Error constructor has been changed regarding exceptions with an already set stack trace. The original stack trace is now preserved. Previously this resulted in the stacktrace being replaced (.NET < 5.0) or an error (.NET ≥ 5.0).

Improvements to Either

  • Add Either.Flip to swaps left with right.

Tooling

  • Funcky automatically adds global usings for the most important namespaces of funcky when the FunckyImplicitUsings property is set. This requires .NET SDK ≥ 6.0 and C# ≥ 10.0.
  • Funcky now supports trimming for self-contained deployments.
  • Option<T> now works with the new System.Text.Json source generation.
  • The Funcky package now supports Source Link and deterministic builds.
  • The symbols package is now finally working again.

Funcky 2.5.0

Reader Monad

This release includes the Reader monad including a bunch of factory methods and convenience extensions.

public static Reader<Enviroment, IEnumerable<string>> DefaultLayout(IEnumerable<DateTime> month)
    => from colorizedMonthName in ColorizedMonthName(month)
       from weekDayLine in WeekDayLine()
       from weeksInMonth in month
        .GroupBy(GetWeekOfYear)
        .Select(FormatWeek)
        .Sequence()
       select BuildDefaultLayout(colorizedMonthName, weekDayLine, weeksInMonth);

Improved Action Extensions

Funcky now supports Curry, Uncurry and Flip for Actions too.
This release also adds the inversion of ActionToUnit: UnitToAction

More Extensions for IEnumerable<T>

  • Intersperse: Adds a given item in between all items of an enumerable.
  • JoinToString: Alias for string.Join.
  • WithPrevious: Similar to WithFirst/Last/Index but with the predecessor of each item.
  • ForEach: Add an overload to ForEach that accepts a Unit-returning Func.

Additional Factory Methods

  • EitherOrBoth.FromOptions creates an EitherOrBoth from two options.
  • Lazy.FromFunc creates a Lazy<T> from a Func.
    This is sugar over the Lazy<T> constructor, with the additional benefit of supporting type inference.
  • Lazy.Return creates a Lazy<T> from a value.
    This is sugar over the Lazy<T> constructor, with the additional benefit of supporting type inference.

Documentation Improvements

This release comes with a few small documentation improvements. Funcky users will now also see the [Pure] attributes which were previously not emitted.

Funcky 2.4.1

  • Remove upper bounds on all Microsoft.Bcl.* dependencies. Between the 2.3.0 and 2.4.0 release an overly restrictive upper bound was accidentally introduced for Microsoft.Bcl.AsyncInterfaces.

Funcky 2.4.0

Try* → *OrNone

We've renamed all Try* methods, such as TryParse, TryGet value to *OrNone. The old methods are still available, but marked as obsolete and will be removed in 3.0.0.

Factory methods for IEnumerable<T>

This release adds some new factory methods for creating IEnumerable<T> to the Sequence class:

  • Sequence.RepeatRange: Generates a sequence that contains the same sequence of elements the given number of times
  • Sequence.Cycle: Cycles the same element over and over again as an endless generator.
  • Sequence.CycleRange: Generates a sequence that contains the same sequence of elements over and over again as an endless generator
  • Sequence.Concat

More Extension Methods

for IEnumerable<T>

  • Materialize: Materializes all the items of a lazy enumerable.
  • PowerSet: Returns a sequence with the set of all subsets
  • Shuffle: Returns the given sequence in random Order in O(n).
  • Split: Splits the source sequence a separator.
  • ZipLongest: Zips two sequences with different lengths.

for string

  • SplitLazy: Splits a string by separator lazily.
  • SplitLines: Splits a string by newline lazily.

for Func

  • Curry
  • Uncurry
  • Flip
  • Compose

EitherOrBoth

EitherOrBoth is a new data type that can represent Left, Right and Both. It is used in ZipLongest.

Monad.Return

This release adds a Return method for all monad types in Funcky:

  • Option.Return
  • Either<TLeft>.Return
  • Result.Return

OptionEqualityComparer

To support more advanced comparison scenarios, OptionEqualityComparer has been added similar to the already existing OptionComparer.

Smaller Improvements

  • Added a missing Match overload to Either that takes Actions
  • Added additional overloads for Functional.True and Functional.False for up to four parameters.

Funcky 2.3.0

  • net5.0 has been added to Funcky's target frameworks.

Improvements to Option<T>

  • Option<T> is now implicitly convertible from T. 
    public static Option<int> Answer => 42;
  • Option adds support for System.Text.Json:
    The custom JsonConverter is picked up automatically when serializing/deserializing. None is serialized as null and Some(value) is serialized to whatever value serializes to.

Factory methods for IEnumerable<T>

This release adds factory methods for creating IEnumerable<T> with the static class Sequence:

  • Sequence.Return: Creates an IEnumerable<T> with exactly one item.
  • Sequence.FromNullable: Creates an IEnumerable<T> with zero or one items.
  • Sequence.Generate: Creates an IEnumerable<T> using a generation function and a seed.

More Extension Methods for IEnumerable<T>

This release adds a bunch of new extension methods on IEnumerable<T>:

  • AdjacentGroupBy
  • AverageOrNone
  • CartesianProduct
  • Chunk
  • ElementAtOrNone
  • Interleave
  • MaxOrNone
  • Merge
  • MinOrNone
  • Pairwise
  • Partition
  • SlidingWindow
  • TakeEvery
  • Transpose
  • WithFirst
  • WithIndex
  • WithLast

IAsyncEnumerable<T> Support

This release adds a couple of extension methods that provide interoperability with Option<T> to IAsyncEnumerable<T>:

  • WhereSelect
  • FirstOrNoneAsync
  • LastOrNoneAsync
  • SingleOrNoneAsync
  • ElementAtOrNoneAsync

A couple of the new extension methods on IEnumerable<T> have async counterparts:

  • Pairwise
  • TakeEvery

The naming of the extension methods and their overloads follows that of System.Linq.Async.

Improved IQueryable Support

This release adds specialized extension methods for IQueryable<T> that are better suited especially for use with EF Core:

  • FirstOrNone
  • LastOrNone
  • SingleOrNone

Dependencies

To support .NET Standard, Funcky conditionally pulls in dependencies that provide the missing functionality:

  • Microsoft.Bcl.AsyncInterfaces for .NET Standard 2.0
  • System.Collections.Immutable and System.Text.Json for .NET Standard 2.0 and 2.1
  • The version constraints for all these packages have been relaxed to allow 5.x.

Improvements

  • ConfigureAwait(false) is now used everywhere await is used.
  • The IRetryPolicy implementations now use correct Timespan with double multiplication when targeting .NET Standard 2.0.

Deprecations

  • ObjectExtensions.ToEnumerable has been deprecated in favor of Sequence.FromNullable.
  • RequireClass and RequireStruct have been obsoleted with no replacement.

Funcky 2.2.0 | Funcky.xUnit 0.1.3

  • Added overload to Functional.Retry with a IRetryPolicy.
  • Added None overload that takes no predicate.

Funcky 2.1.1 | Funcky.xUnit 0.1.2

  • Re-release of previous release with correct assemblies.

Funcky 2.1.0 | Funcky.xUnit 0.1.1

  • Add Inspect method to Option akin to IEnumerable.Inspect.
  • Add ToTheoryData extension for IEnumerable<T> for xUnit.
  • Add Unit.Value as a way to a get a Unit value.
  • Add Functional.Retry which retries a producer until Option.Some is returned.

Funcky 2.0.0

Breaking Changes

  • Remove Reader monad based on await.
  • Remove IToString.
  • Remove overload for Option.From that flattens passed Options.
  • Move ToEnumerable extension method to its own class. This is only a breaking change if you've used the extension method as normal method. In that case you need to change EnumerableExtensions.ToEnumerable to ObjectExtensions.ToEnumerable.
  • Rename Option.From to Option.FromNullable and remove overload that takes non-nullable value types.
  • Unify Option<T>.ToEnumerable and Yield to ToEnumerable
  • Rename OrElse overloads that return the item to GetOrElse which improves overload resolution.
  • The Each extension method on IEnumerable<T> has been renamed to ForEach.
  • Move the Ok constructor of Result<T> to a non-generic class. This allows for the compiler to infer the generic type. Old: Result<int>.Ok(10). New: Result.Ok(10).
  • Use Func<T, bool> instead of Predicate<T> in predicate composition functions (Functional.All, Functional.Any, Functional.Not), because most APIs in System use Func.
  • Functional.Any now returns false when the given list of predicates is empty.

Fixes

  • Fix incorrect Equals implementation on Option. Equals previously returned true when comparing a None value with a Some value containing the default value of the type.
  • Exception created by Result monad contains valid stack trace
  • Fix incorrect implementation on Result.SelectMany which called the selectedResultSelector even when the result was an error. As a result (pun intended) of the fix, ResultCombinationException is no longer needed and also removed.

Additions

  • Add IndexOfOrNone, LastIndexOfOrNone, IndexOfAnyOrNone and LastIndexOfAnyOrNone extension methods to string.
  • Added Curry, Uncurry and Flip to the Functional Class
  • Add extension method for HttpHeaders.TryGetValues, which returns an Option.
  • Add extension methods for getting Stream properties that are not always available, as Option: GetLengthOrNone, GetPositionOrNone, GetReadTimeoutOrNone, GetWriteTimeoutOrNone.
  • Add None extension method to IEnumerable.
  • Option<Task<T>>, Option<Task> and their ValueTask equivalents are now awaitable: 
    var answer = await Option.Some(Task.FromResult(42));

Improvements

  • Full nullable support introduced with C# 8.
  • Mark our functions as [Pure].
  • Implement IEquatable on Option, Result and Either.

Funcky 2.0.0-rc.2

  • Move the Ok constructor of Result<T> to a non-generic class. This allows for the compiler to infer the generic type. Old: Result<int>.Ok(10). New: Result.Ok(10).
  • Add IndexOfOrNone, LastIndexOfOrNone, IndexOfAnyOrNone and LastIndexOfAnyOrNone extension methods to string.
  • Rename OrElse overloads that return the item to GetOrElse which improves overload resolution.
  • Added Curry, Uncurry and Flip to the Functional Class
  • Remove IToString.
  • Mark our functions as [Pure].
  • Fix incorrect implementation on Result.SelectMany which called the selectedResultSelector even when the result was an error. As a result (pun intended) of the fix, ResultCombinationException is no longer needed and also removed.

Funcky 2.0.0-rc.1

  • Full nullable support introduced with C# 8
  • Rename Option.From -> Option.FromNullable and remove overload that takes non-nullable value types.
  • Use Func<T, bool> instead of Predicate<T> in predicate composition functions (Functional.All, Functional.Any, Functional.Not), because most APIs in System use Func.
  • Functional.Any now returns false when the given list of predicates is empty.
  • The Each extension method on IEnumerable<T> has been renamed to ForEach.
  • Unify Option<T>.ToEnumerable and Yield to ToEnumerable
  • Remove Reader monad based on await.
  • Exception created by Result monad contains valid stack trace

Funcky 1.8.0

  • Added overload for AndThen which flattens the Option
  • Add Where method to Option<T>, which allows filtering the Option by a predicate.
  • Add overload for Option<T>.SelectMany that takes only a selector.
  • Add WhereNotNull extension method for IEnumerable<T>.

Funcky 1.7.0

  • Add nullability annotations to everything except for Monads.Reader.
  • Add a function for creating an Option<T> from a nullable value: Option.From.
  • Either.Match now throws when called on an Either value created using default(Either<L, R>).
  • Add True and False functions to public API
  • Match of Result Monad accepts actions
  • Add FirstOrNone, LastOrNone and SingleOrNone extension functions

Funcky 1.6.0

  • Add ToEnumerable function to Option<T>.
  • Add WhereSelect extension function for IEnumerable<T>.
  • Add missing overload for nullary actions to ActionToUnit.