The vocabulary/lexicon generation

Generating code should start from a Go struct with annotations, or from a JSON-LD context document.

The steps should be something like this:

Structure

We need to validate the struct’s compatibility with the Vanilla AP objects:

• the properties must match the position and type of one of the Object, Actor, IntransitiveActivity, Activity, Link, etc.
• the struct must validate against the JSON-LD contexts that the developer chooses for them.

Helper functions

Generate helper functions in the lexicon package:

• Initializer function: vocab.New<Type>
  • Perhaps fluent API builders - with generics - would provide a better UX? lexicon.Builder[lexicon.Object]().Type(lexicon.NoteType)
• Generate function type With<Type>Fn that’s used as parameters for On<StructName>
• Generate functions: On<StructName>, and To<StructName>
  • Perhaps change To<StructName> to return *StructName, bool instead of error
• Generate MarshalJSON/UnmarshalJSON, GobEncode/GobDecode
• Add type switch cases to the IsObject, IsActor, IsActivity, IsIntransitiveActivity, IsLink
• Add type switch cases to the ToObject, ToActor, ToActivity, ToIntransitiveActivity, ToLink
• Add type switch cases to the IsNil function.

Types constraints

Accumulate types for generated objects and add their types to the slices for:

• ActorTypes: struct has Inbox/Outbox properties
• ActivityTypes: struct has Actor/Object properties
• IntransitiveActivityTypes: struct has Actor property but no Object property
• LinkTypes: no ID property, but has a Href property.
• CollectionTypes: struct has Items/OrderedItems and TotalItems (perhaps Next ?).
• ObjectTypes: what’s left? - This is the default when there’s nothing else annotated.

Accumulate types into the interfaces that can be used by generic code (Actors, Objects, etc).

Codecs for JSON/Binary representations