besser-generators

BESSER Generator Operations

Every BESSER generator implements the same shape:

class GeneratorInterface(ABC):
    def __init__(self, model, output_dir=None): ...
    def generate(self): ...

If output_dir is omitted, output goes to <cwd>/output/. The directory is created automatically (os.makedirs(..., exist_ok=True)).

Regeneration always overwrites. Every call to generate() replaces the output files entirely. This is by design — the model is the source of truth. Customizations belong in separate files (see "Safe customization" below). Once you have generated, the besser-user skill's "Verification checklist" covers what to check next (files exist, syntax parses, it runs).

Generate the baseline, then build on top. The point of these generators is that you don't hand-write the boilerplate. Regenerate the baseline freely and spend your effort only where the work is actually custom: extending and overriding in separate files so a re-run never clobbers it. Often the generated code is all you need; when it isn't, the "Safe customization" patterns below are how you build on top without fighting regeneration.

The output is equivalent across runs, but not byte-identical. Generators iterate unordered collections, so the same model can emit the same members in a different order each run — fields, columns, constructor arguments, table columns. Nothing changes semantically. Two consequences worth knowing: don't diff one regeneration against another expecting silence, and don't hard-code a column position when reading generated output (in a test, say) — look columns up by name.

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Generator picker

Per-generator detail (inputs, outputs, options, templates, gotchas) lives in references/. Find your target, then read the listed reference:

Want	Generator	Reference
Python data classes	PythonGenerator	python-and-data.md
Java classes	JavaGenerator	python-and-data.md
Pydantic models (with optional OCL→validator)	PydanticGenerator	python-and-data.md
JSON Schema (regular or NGSI-LD)	JSONSchemaGenerator	python-and-data.md
JSON data from an ObjectModel (instances)	JSONObjectGenerator	python-and-data.md
RDF Turtle vocabulary	RDFGenerator	python-and-data.md
SQLAlchemy ORM	SQLAlchemyGenerator	persistence.md
Raw SQL DDL	SQLGenerator	persistence.md
Supabase (Postgres + RLS) schema	SupabaseGenerator	persistence.md
FastAPI + ORM + Pydantic stack	BackendGenerator	api-and-web.md
Standalone REST API	RESTAPIGenerator	api-and-web.md
Django project	DjangoGenerator	api-and-web.md
Full-stack web app (React + FastAPI + Docker)	WebAppGenerator	api-and-web.md
Flutter mobile app	FlutterGenerator	api-and-web.md
Conversational agent / chatbot	BAFGenerator	agents-and-other.md
Quantum circuit	QiskitGenerator	agents-and-other.md
Terraform infrastructure	TerraformGenerator	agents-and-other.md
PyTorch / TensorFlow neural net	PytorchGenerator / TFGenerator	agents-and-other.md