Data model

Serde works by taking .NET code, transforming it into the Serde data model, and then translating it into the various output formats. The Serde data model is a subset of the .NET type system, focused on only the pieces that can be translated to serialization output formats.

In code, the Serde data model is split into two sides: .NET types and output formats. .NET types implement the ISerialize<T>, IDeserialialize<T>, and ISerdeInfo interfaces. Output formats implement the ISerializer and IDeserializer interfaces.

The Serde data model is as follows:

• Primitive types
  • bool
  • I8, I16, I32, and I64 (sbyte, short, int, and long)
  • U8, U16, U32, and U64 (byte, ushort, uint, and ulong)
  • F32 and F64 (float and double)
  • decimal
  • string
  • DateTime
• Contiguous array of bytes
  • Serialization: ReadOnlyMemory<byte>
  • Deserialization: IBufferWriter<byte>
• Custom types
  • Structs, classes, and records.
• Lists
  • A sequence of elements, like an array or a list. The length does not need to be known ahead-of-time.
• Dictionaries
  • A variable-size key-value pair. The length does not need to be known ahead-of-time.
• Nullable types
  • Both nullable reference types and nullable value types are supported. All reference types not marked as nullable (? suffix) are assumed to be non-null.
• Enums
• Unions
  • Sometimes referred to as "polymorphic types." C# does not yet have built-in support for discriminated unions, but the source generator will match a particular pattern anyway. To write a union type, use an abstract record type, with nested records that inherit from the parent record. The parent record must only have private constructors. For example,

[StaticCs.Closed] // Optional library for annotating union types
[GenerateSerde]
abstract partial record UnionBase
{
    private UnionBase() { }

    public partial record DerivedA(int A) : UnionBase;
    public partial record DerivedB(string B) : UnionBase;
}