pkg
MagicMoux/TypeLogic.LiskovWingSubstitutionv1.0.0
.NET Std2.0
A .NET library implementing the Liskov/Wing Substitution Principle for type variance checking (including generic typeParameters constraints validation). Provides additional variance checking capabilities when working with GenericTypeDefinitions.
Get Started
$ dotnet add package TypeLogic.LiskovWingSubstitutionReadme
TypeLogic.LiskovWingSubstitution
A .NET library implementing the Liskov/Wing Substitution Principle for type variance checking (including generic typeParameters constraints validation).
This project emerged from previous R&D tests dealing with .NET generics: I needed an additional simple way to verify type variance against GenericTypeDefinition, complementing .NET's built-in type system capabilities.
What started as a proof-of-concept to simplify variance checking turned into a full-fledged library that extends .NET's type system that you may find educational or even practicalin some cases. The implementation is based from Barbara Liskov's and Jeannette Wing's work on behavioral subtyping, providing additional variance checking capabilities when working with GenericTypeDefinitions (especially in cases where non-generic Type inheritance is absent, as illustrated in the examples).
Features
- Type variance checking according to Liskov/Wing Substitution Principle
- Support for generic type parameter constraints
- Caching of type variance relationships for performance
- Instance-based variance checking
- Support for generic type definitions
- Full support for .NET Standard 2.0
Installation
The package can be installed via NuGet:
dotnet add package TypeLogic.LiskovWingSubstitution
Usage
Basic Type Variance Checking
using TypeLogic.LiskovWingSubstitution;
// Check if List<string> is variant of IEnumerable<object>
bool isVariant = typeof(List<string>).IsSubtypeOf(typeof(IEnumerable<object>));
// Check with runtime type information
bool isVariantWithType = typeof(List<string>).IsSubtypeOf(typeof(IEnumerable<object>), out Type runtimeType);