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SysML v2 · KerML 1.1 · written in Go

Author, check and run systems models from one toolchain.

OpenSysML parses and validates SysML v2 and KerML 1.1, serves an editor over the Language Server Protocol, executes actions, state machines and constraints, and exports models as RDF — with a Python client for the same runtime.

Install Read the guide Source How it compares

Apache-2.0 · Linux, macOS and Windows binaries 

sysml> part def Wheel { attribute diameter = 16.0; }
✓ part def Wheel

sysml> %instantiate Wheel
✓ Created instance of Wheel
  ID: 1

sysml> calc add { in x; in y; x + y }
✓ calc add

sysml> %calc add 10 20
✓ add(10, 20)
  = 30

Refereed against the OMG pilot implementation

Not self-assessed — measured against the reference implementation.

OpenSysML is run beside a pinned build of the OMG pilot implementation over the same models, and the two are compared wherever they can be: the diagnostics each reports, the diagnostics the reference's own test suites declare, how names resolve, and whether an invalid model is turned away. Each comparison has a committed baseline that anyone can reproduce, and the results are kept in the records rather than restated here.

Diagnostic differential Both implementations validate the same models and their diagnostics are compared file by file, in both directions. Declared diagnostics The errors the reference's own test suites declare, checked against what we report on the same source. Name resolution The scopes the reference's test suites assert, matched against the ones we resolve. Rejection Invalid models the reference turns away, checked to be turned away here too, by default and not only when asked strictly.

What this is not: the comparison is of what two implementations report on the same files, not an official conformance suite, and no certification or percentage of the specification is claimed. The reference evaluates expressions but executes neither actions nor state machines, so behavior is beyond what it can referee. Read how each comparison is measured and what it currently reports, or which rules are faithful, approximate or missing.

What it does

Parse and validate

A hand-written parser for the full surface syntax, name resolution, and validation split into tiers so a model is checked as strictly as you ask.

Edit anywhere

sysml-lsp speaks the Language Server Protocol — completion, diagnostics, hovers and navigation in VS Code or any LSP client.

Explore in a REPL

An interactive session that keeps your model: instantiate parts, inspect feature values, and step through behavior at a breakpoint.

Execute behavior

Actions, state machines, calculations and constraints really run, with a step budget so a model can never spin forever.

Interoperate

Round-trip models through RDF/Turtle and query them with OSLC query text, so a model is data other tools can read.

Automate from your language

Go, Python, Node/TypeScript, Java and Rust clients drive the same execution runtime — in process, or over the sysml-grpc service.

Install

# macOS
brew install Open-MBEE/tap/opensysml

# with a Go toolchain
go install github.com/Open-MBEE/OpenSysML/cmd/sysml@latest

Linux and Windows archives are on the releases page; the install page covers every route, checksums, and macOS Gatekeeper.

Compliance, stated plainly

Every construct is recorded as faithful, approximate or not implemented. No conformance certification is claimed.

Defects, declared

Where the published reference material is itself defective, the correction is declared and the corpus left as published.

Known gaps

The roadmap lists what is missing, in the order it should be picked up.

OpenSysML documentation

Using OpenSysML

The guide — a handbook, presented in reading order: install, your first model, the command line, the REPL, checks, behavior, saving and RDF, editors, from your own program, troubleshooting.

Runnable models are provided in examples/, together with a catalog describing what each one demonstrates.

Document generation manual — generating documents from models with native document queries: concepts, getting started, a query cookbook, document authoring, outputs (Markdown and PDF), interfaces, a complete worked example and limitations and troubleshooting.

Reference

  • CLI — every flag of sysml, the modes, and the exit status
  • REPL commands — every % command and its arguments
  • LSP extensions — the custom render requests sysml-lsp serves a diagram client
  • Environment variables — the bounds a single run may consume, and paths
  • Client libraries — the Go, Python, Node, Java and Rust surfaces, and how to choose between them
  • Go packages — client/opensysml and the packages behind it, type by type
  • Python API — opensysml, its generated typed classes and latency
  • Service transports — what sysml-grpc serves on a single port, and the behavior of an absent capability
  • RDF mapping — the triples a model becomes, the constructs that are not mapped, and why the mapping is experimental
  • Grammar — grammar production → parser implementation

Internals

Project status

  • Spec compliance — faithful, approximate or not implemented
  • Training examples — the OMG corpus, 100/100 clean
  • Pilot corpora gate — OpenSysML diagnostics on the three pinned OMG pilot corpora, ratcheted in CI
  • Pilot differential — OpenSysML diagnostics compared against the OMG pilot implementation
  • Grammar coverage — the OMG grammar productions the project's inputs exercise
  • Roadmap — the known gaps, in the order they should be addressed
  • Releasing — the pre-tag gate, tagging, artifacts and Homebrew
  • macOS distribution — Gatekeeper and the signing decision
  • Demo — a scripted walkthrough of the full surface

Contribution guidance, including where a new page belongs, is in CONTRIBUTING.md.