PolyType

PolyType is a practical generic programming library for .NET. It facilitates the rapid development of feature-complete, high-performance libraries that interact with user-defined types. This includes serializers, RPC frameworks, structured loggers, mappers, validators, parsers, random generators, and equality comparers. Its built-in source generator ensures that any library built on top of PolyType gets Native AOT support for free.

The project is a port of the TypeShape library for F#, adapted to patterns and idioms available in C#. The name PolyType is a reference to polytypic programming, another term for generic programming.

See the project website for additional background and API documentation.

Applications

The following projects have been based on PolyType:

• Nerdbank.MessagePack - a MessagePack library with performance to rival MessagePack-CSharp, and greater simplicity and additional features.
• “At Alvys, we built an EDI mapping engine to automate and accelerate EDI integrations. The engine had to be fast, configurable and portable across EDI versions. A crucial step is mapping the EDI segments model to an object model. For this, we used PolyType, which allowed us to easily build both the encoder and the decoder. We appreciated the emphasis on fundamentals and performance, as well as the plethora of examples. The result: a solution with only a fraction of the code and an order-of-magnitude increase in micro-benchmark performance compared to the previous solution that used a commercial EDI library.” — Leo Gorodinski

Project structure

The repo consists of the following projects:

• The core PolyType library containing:
  • The core abstractions defining the type model.
  • The reflection provider implementation.
  • The model classes used by the source generator.
• The PolyType.SourceGenerator project contains the built-in source generator implementation.
• The PolyType.Roslyn library exposes a set of components for extracting data models from Roslyn type symbols. Used as the foundation for the built-in source generator.
• PolyType.Examples containing library examples:
  • A serializer built on top of System.Text.Json,
  • A serializer built on top of System.Xml,
  • A serializer built on top of System.Formats.Cbor,
  • A ConfigurationBinder like implementation,
  • A dependency injection implementation,
  • A simple pretty-printer for .NET values,
  • A generic random value generator based on System.Random,
  • A JSON schema generator for .NET types,
  • An object cloning function,
  • A structural IEqualityComparer<T> generator for POCOs and collections,
  • An object validator in the style of System.ComponentModel.DataAnnotations.
  • A simple .NET object mapper.
• The applications folder contains sample Native AOT console applications.

CI Packages

CI builds of NuGet packages are available on feedz.io. To use the feed, add the following package source to your NuGet.config:

<configuration>
  <packageSources>
    <add key="feedz.io" value="https://f.feedz.io/eiriktsarpalis/PolyType/nuget/index.json" />
  </packageSources>