EMFPy — Eclipse EMF / Ecore for Python

A Python port of the Eclipse Modeling Framework (EMF) Core metamodel and runtime.

It is derived from two references:

• TypeScript (EMFTs/emfts) — structure and a tested behavior suite that serves as the conformance oracle.
• Java (learn/org.eclipse.emf) — the original, authoritative semantics.

Status: core complete — Phases 0–8 done; the ported conformance suite is green (284 tests, ruff + mypy --strict clean). See PLAN.md for per-phase detail.

Features

• Dynamic EMF in pure Python: build metamodels programmatically, create instances, and use the reflective API (e_get / e_set / e_is_set / e_unset) — no code generation required.
• Self-describing Ecore metamodel + global package registry (resolve classifiers by nsURI).
• Notification framework: Adapter / Notifier / EContentAdapter, wired into EObject and EList.
• Resources: URI, Resource / ResourceSet, URI fragments (XPath / ID / //Name), cross-document proxies.
• Serialization: emfjson-compatible JSON and XMI (loads/saves real .ecore models) — both on the Python standard library (no required external deps).
• Bidirectional references: instance-level opposite maintenance (EMF eInverseAdd/ eInverseRemove semantics, including reparenting).
• Utilities: EcoreUtil (resolve/copy/containment), isinstance-based type guards, and an Eclipse-style plugin/extension registry with decorators.

Behavioral parity with the EMF references is verified by a 1:1 pytest port of the TypeScript suite (284 tests, all green).

Installation

pip install emf

From source:

git clone https://github.com/eclipse-fennec/emf.py.git
cd emf.py
pip install .

With optional lxml backend for faster XML parsing:

pip install emf[lxml]

Examples

Runnable demos live in examples/:

python examples/runtime_example.py        # build a metamodel, reflect, JSON round-trip
python examples/usage_example.py          # registry lookup + XMI round-trip
python examples/plugin_system_example.py  # extension points via decorators

Naming convention

Java/TypeScript are camelCase; EMFPy maps idiomatically:

EMF (TS/Java)	EMFPy
eGet / eSet / eIsSet / eUnset	e_get / e_set / e_is_set / e_unset
eClass() / eContainer() / eContents()	e_class() / e_container() / e_contents()
getName() / setName()	property .name
isContainment()	property .containment
Interfaces	ABCs (abc.ABC)
EList	collections.abc.MutableSequence subclass

Class names stay EMF-canonical (EObject, EClass, BasicEObject, DynamicEObject, …).

Development

python -m venv .venv && source .venv/bin/activate
pip install -e ".[dev]"      # add the optional lxml backend with: ".[dev,lxml]"
pytest                       # run the conformance suite
ruff check . && mypy         # lint + type-check

License

Eclipse Public License 2.0 (EPL-2.0) — same as Eclipse EMF.