Tutorial

This tutorial is a single thread that builds a small application end-to-end. The five chapters cover:

1. First model: defining a class, instantiating it, and reading its fields.
2. Fields and types: defaults, descriptions, the dx.field(...) metadata constructor, and the built-in scalar types.
3. Validation: per-field validators, class-level axioms, and the shape of a ValidationError.
4. Serialisation: model_dump, model_dump_json, the inverse model_validate and model_validate_json paths, plus JSON Schema export.
5. Writing a migration: defining a Lens between two versions of a Model and registering it for use by dx.migrate.

By the end you will have a working set of Models, a registered migration, a JSON Schema artefact, and a feel for the day-to-day operations didactic supports.

The tutorial assumes Python 3.14 and pip install didactic.