OpenAPSSwift

A standalone Swift Package extraction of the oref0 algorithm port from nightscout/Trio, branch feat/dev-oref-swift. Carved out so a host project can call oref's determineBasal (and friends) without depending on the full Trio application.

This is the source used by loopkitdev/LoopEval as a second DosingEngine for closed-loop counterfactual evaluation.

What's in the box

Sources/OpenAPSSwift/ — the library
OpenAPSSwift.swift — public façade: makeProfile, meal,
autosense, iob, determineBasal
JSONBridge.swift — JSON-in/JSON-out boundary
OrefFunctionResult.swift — typed result wrapper
Helpers/ — JSON, rounding, formatters, Decimal/Date
bridges, logging shim
Engine subdirs — Autosens, DetermineBasal, Forecasts,
Iob, Meal, Models, Profile, Utils,
TrioModels
Sources/OpenAPSSwiftSmoke/ — executable smoke target (sanity-check
that the package builds and the public
API is reachable)

74 Swift source files. All public entry points are JSON-in / JSON-out so the package can be linked against any host without dragging in Trio's app-level types.

Usage

import OpenAPSSwift
letdeterminationJSON=tryOpenAPSSwift.determineBasal(
iobInputs: iobJSON,
meal: mealJSON,
profile: profileJSON,
glucose: glucoseJSON,
currentTemp: tempJSON,
autosens: autosensJSON,
pumpHistory: pumpHistoryJSON,
preferences: prefsJSON
)

See Sources/OpenAPSSwiftSmoke/main.swift for a worked example, and the OpenAPSAdapter in LoopEval (Sources/EvalCore/Engine/OpenAPSAdapter.swift) for a full host integration that translates simulator state into the JSON shapes above and back.

Building

swift build
swift build -c release
swift run OpenAPSSwiftSmoke # builds + runs the smoke executable

Requires Swift 6.0 toolchain (declared in Package.swift). Tested on macOS 13+ and iOS 15+.

Licensing

AGPL-3.0 (see LICENSE). Trio is licensed AGPL-3.0; because this extraction is a derived work, the same license applies. If you link this into a network-served application, the AGPL-3.0 obligations apply to your service.

Provenance

Extracted in June 2026 from nightscout/Trio commit on the feat/dev-oref-swift branch. Original source paths were Trio/Sources/APS/OpenAPSSwift/ plus the model + helper files it transitively referenced from Trio/Sources/{Models,Helpers}/.

No algorithm changes from the upstream Trio extraction — this package is a packaging change only. Bug fixes and behavior changes that show up here should be considered for upstreaming to Trio.

Related projects

• nightscout/Trio — the source project, full app + algorithm.
• openaps/oref0 — the original JavaScript algorithm that Trio's Swift port mirrors.
• loopkitdev/LoopEval — the primary host for this package; provides Loop-vs-OAPS closed-loop counterfactual evaluation.