universal-chain-ontology (UCO)

The standalone Link / Chain homoiconic composition primitives — the chain substrate that a lot of systems reimplement. Pure stdlib, zero dependencies.

from uco import Link, Chain, LinkResult, LinkStatus

class Inc(Link):
    async def execute(self, context=None, **_):
        ctx = dict(context or {}); ctx["n"] = ctx.get("n", 0) + 1
        return LinkResult(status=LinkStatus.SUCCESS, context=ctx)

# a Chain IS a Link (homoiconic) — so Chains nest like any other Link
import asyncio
out = asyncio.run(Chain("two", [Inc(), Inc()]).execute({"n": 0}))
assert out.context["n"] == 2

What's here

Why standalone

The same Link/Chain abstraction was living inside SDNA and getting copy-pasted into other projects. UCO is that abstraction extracted once. Downstreams import uco; sdna.chain_ontology re-exports it, so existing from sdna.chain_ontology import Link, Chain, … keeps working unchanged and the class identity is shared (one Link everywhere).

MIT.