sysml2-mode

An Emacs major mode for editing SysML v2 and KerML textual notation files.

Provides syntax highlighting, indentation, completion, navigation, diagram generation, native simulation, FMI/FMU integration, co-simulation orchestration, and LSP support.

Follows the book's house style: quoted unrestricted names (package <DSPA> 'Drone System Product Architecture') and <ID> requirement short names (requirement <REQ23> observeArea) are first-class in highlighting, navigation, imenu, and model extraction.

Requires: Emacs 29.1+ | Platforms: Linux, macOS, Windows

Documentation

Document	Description
Tutorial	Step-by-step guide to building a complete SysML v2 model (drone system example covering all 20 SysML v2 concepts)
SysML v2 Syntax Reference	Language syntax reference and best practices for SysML v2 textual notation
FMI Integration Guide	Complete workflow for SysML v2 + Modelica/FMI co-simulation (8-step process from model to results)
Literate SysML Guide	Org-babel literate programming: tangle, noweb, inline validation, simulation, and diagrams
Changelog	Release history and version notes
Book Review Findings	Systematic review of the toolchain against the SysML v2 Book (Weilkiens 2026-05) — the working backlog

Table of Contents

• Installation
• First-Run Health Check
• Menu Bar and Transient Pickers
• Features
• Diagram Generation
• Model Scaffolding
• Model Inspection
• FMI/FMU Integration
• Co-Simulation
• Native Simulation
• CLI Analysis
• Formatting
• Systems Modeling API
• LSP Support
• Evil-Mode Integration
• Keybinding Reference
• Customization
• Module Architecture
• Testing
• License

Installation

From source

git clone https://github.com/jackhale98/sysml2-mode.git

Add to your init file:

(add-to-list 'load-path "/path/to/sysml2-mode")
(require 'sysml2-mode)
;; .sysml and .kerml files auto-activate — no auto-mode-alist needed

use-package

(use-package sysml2-mode
  :load-path "/path/to/sysml2-mode")

straight.el / elpaca

(use-package sysml2-mode
  :straight (:host github :repo "jackhale98/sysml2-mode"
             :files ("*.el" "snippets")))

Doom Emacs

Add to ~/.config/doom/packages.el:

(package! sysml2-mode
  :recipe (:host github :repo "jackhale98/sysml2-mode"
           :files ("*.el" "snippets")))

Add to ~/.config/doom/config.el:

(use-package! sysml2-mode
  :mode "\\.sysml\\'")

sysml2-mode.el already requires sysml2-evil (SPC m keybindings) and sysml2-ts (tree-sitter) internally — no :config block needed.

Then run doom sync.

First-Run Health Check

After installing, run M-x sysml2-doctor to probe every external tool the mode can leverage — sysml CLI, tree-sitter grammar, LSP server, D2, PlantUML, GraphViz, Pandoc, and the resolved SysML stdlib path. The doctor buffer shows one line per check with [ok], [warn] (optional, not installed), or [FAIL] (required, missing) plus an install hint. Re-run it any time something stops working to quickly separate "the mode is broken" from "I haven't installed that tool yet."

Menu Bar and Transient Pickers

Every major feature is exposed on a SysML2 menu-bar item (no external dependencies) for mouse-driven discovery, and three keyboard-driven transient pickers replace minibuffer-prompt sub-menus:

Picker	Binding	Covers
Diagrams	C-c C-d RET	tree, IBD, state, action, requirement, use case, package, view, preview, export, open in playground
Scaffold	C-c m RET	model skeleton, package, part def, port def, requirement, state, action, calc, enum, use case
CLI / Refactor	C-c C-t RET	check, list, show, trace, deps, coverage, doc, analyze (incl. uncertainty cases), rollup, view (model-defined reports), allocation, diff, rename, add, remove

Vanilla-Emacs users with which-key installed also see prefix labels ("diagram", "scaffold", "cli-analyze", …) when they hold a C-c prefix.

Features

Syntax Highlighting

Three font-lock levels with 216 keywords across 9 categories:

• Level 1: Keywords only (multi-word matched before single-word)
• Level 2: + definition names, usage names, type references
• Level 3 (default): + visibility, modifiers, literals, operators, short names (<R1>), metadata (#Annotation), numeric literals, qualified name prefixes (Package::)

package Vehicle {
    part def Engine :> PowerSource {
        attribute displacement : Real;
        port fuelIn : FuelPort;
    }
}

Indentation

Automatic indentation with sysml2-indent-offset (default 4):

• Brace/bracket/paren alignment
• Continuation line handling inside blocks
• Comment and string awareness
• Electric indent on {, }, ;, newline

Completion

Context-aware completion-at-point with annotation hints:

Context	Candidates
Line start	Definition, usage, structural, and behavioral keywords
After import	Standard library packages (58), *
After : (type position)	Buffer definitions, standard library
After :> (specialization)	Buffer definitions, standard library
After :>> (redefinition)	Buffer definitions
After connect / to	Part and port names
After satisfy/verify ... by	Buffer definitions and usages
After in/out/inout	Usage keywords
After #	Metadata
Inside a definition body	Usage keywords and members

Navigation

• Imenu (C-c C-n o): Hierarchical index organized by definition category (40 categories, SysML v2 + KerML)
• which-function-mode: Shows enclosing definition/package in mode line
• beginning/end-of-defun: C-M-a / C-M-e navigate between definitions
• Find references (M-?): All references to the symbol at point
• Outline side panel (C-c C-n t): Tree view in a left side window

Snippets

49 yasnippet templates for common patterns (requires yasnippet):

Key	Expansion
pkg	package Name { ... }
pd	part def Name { ... }
p	part name : Type;
ad	action def Name { ... }
sd	state def Name { ... }
ptd	port def Name { ... }
rd	requirement def Name { ... }
cd	connection def Name { ... }
imp	import Package::*;
doc	doc /* ... */
sat	satisfy requirement ... by ...;

...and more (at, atd, s, a, pt, cn, cnd, ucd, vd, vpd, c, pdb, imps).

Flymake Diagnostics

Three layers of diagnostics, from zero-dependency to deep cross-file analysis:

In-process checks (no external tools):

1. Unmatched delimiters — detects mismatched {}, [], ()
2. Unknown definition keywords — catches typos like prat def
3. Missing semicolons — warns on single-line usages without trailing ;
4. Unsatisfied requirements — requirement defs with no satisfy statement
5. Unverified requirements — requirement defs with no verify statement
6. Unused definitions — definitions never referenced elsewhere in the buffer
7. Invalid library references — validates ISQ, SI, and ScalarValues qualified names

Tree-sitter checks (when grammar installed):

8. Syntax errors — ERROR nodes from the incremental parser
9. Missing nodes — expected tokens the parser couldn't find

CLI checks (when sysml CLI installed, async):

10. Unresolved types (W004) — type references that don't resolve across files
11. Unresolved targets (W005) — reference targets that don't resolve
12. Port type mismatches (W006) — connected ports with incompatible types
13. Empty constraints (W007) — constraint defs with body but no expression
14. Missing returns (W008) — calc defs with body but no return
15. Port direction mismatches (W009) — in/out incompatibility
16. Import cycles (W010) — recursive import chains
17. Multiplicity violations (W011) — bounds violations
18. Missing documentation (W012) — public top-level defs without doc /* ... */
19. Naming conventions (W013) — definitions not in PascalCase, usages not in camelCase
20. Orphaned requirements (W014) — requirement defs that are never satisfied, verified, or specialized
21. Self-specialization (W015) — part def X :> X infinite-recursion typos
22. Unbound ports (W016) — port usages declared inside a part but never connected
23. Value-constraint violations (W017) — model-declared assert constraints evaluated against concrete values (e.g. an @Fmea severity of 12 fails FmeaRating's 1–10 range)

Project Detection

Automatic project root detection (ascending search):

1. .sysml-project file (highest priority)
2. sysml.library/ directory
3. .git directory

Standard library path is auto-resolved from project root or a custom path.

Tree-Sitter Support

When the sysml tree-sitter grammar is installed, sysml2-mode automatically remaps to sysml2-ts-mode for:

• Font-lock — node-type-aware highlighting (8 features across 3 levels)
• Indentation — 50 parent-type-based indent rules covering all body types, control flow, fork/join/merge/decide, metadata, and multi-line expressions
• Formatting — C-c C-= = re-indents the buffer using tree-sitter rules (no external tool needed)
• Imenu — 28 definition categories from parse tree
• Which-function — accurate enclosing definition via treesit-parent-until
• Completion — context-aware CAPF using parse tree queries
• Flymake — tree-sitter ERROR node reporting
• Goto-definition / Rename — parse-tree-based search
• Structural movement (Emacs 30+) — treesit-thing-settings for forward-sexp, forward-sentence, forward-list driven by AST node types
• Outline (Emacs 30+) — treesit-outline-predicate recognises every definition node as an outline heading

Canonical tree-sitter query files for downstream editors (Helix, Neovim, Zed) live in tree-sitter-sysml/queries/: highlights.scm, indents.scm, folds.scm, locals.scm, tags.scm.

Install the grammar:

(add-to-list 'treesit-language-source-alist
             '(sysml "https://github.com/jackhale98/tree-sitter-sysml"
                     nil "src"))
M-x treesit-install-language-grammar RET sysml

Diagram Generation

Generate diagrams from SysML v2 models with a dual-backend architecture. Seven diagram types:

Binding	Command	Diagram
C-c C-d t	sysml2-diagram-tree	Parts Tree (BDD)
C-c C-d i	sysml2-diagram-ibd	Interconnection (IBD)
C-c C-d s	sysml2-diagram-state-machine	State Machine
C-c C-d a	sysml2-diagram-action-flow	Action Flow
C-c C-d r	sysml2-diagram-requirement	Requirement Tree
C-c C-d u	sysml2-diagram-use-case	Use Case
C-c C-d k	sysml2-diagram-package	Package
C-c C-d p	sysml2-diagram-preview	Auto-detect at point
C-c C-d b	sysml2-diagram-preview-buffer	Whole-buffer diagram
C-c C-d v	sysml2-diagram-view	Generate from view def filter
C-c C-d e	sysml2-diagram-export	Export to file
C-c C-d o	sysml2-diagram-open-plantuml	View diagram source
C-c C-d w	sysml2-diagram-open-in-playground	Open in D2 web playground

Scoped diagrams (IBD, state machine, action flow) auto-detect the enclosing definition or prompt for a scope name. Diagram export (C-c C-d e) prompts for diagram type, scope, and output file.

Diagrams are automatically scaled to fit the preview window.

UML-style compartments: Block diagrams (BDD/tree) show ports, attributes, and parts in separate compartments. State machine nodes show entry/do/exit actions. IBD parts show attributes from their type definitions.

Transition labels: State machine transitions display the full trigger [guard] / effect label.

Control flow nodes: Action flow diagrams render fork/join as bars and decide/merge as diamonds.

View-filtered diagrams (C-c C-d v) parse view def declarations with render clauses, filter @SysML::... metatype filters, expose clauses (for automatic scope resolution), and :> inheritance to determine the diagram type automatically.

Native Backend (default)

The native backend (sysml2-diagram-backend = native) uses two rendering engines:

• D2 for all seven diagram types: tree/BDD, requirements, IBD, state machine, action flow, use case, and package
• Direct SVG (zero-dependency fallback) for tree and requirement diagrams when D2 is not installed

When D2 is not installed locally, graph diagrams automatically fall back to opening in the D2 Playground in your browser — no local installation required. Changes in the playground do NOT update the SysML model; this is a one-way, read-only visualization.

You can also open any D2-backed diagram in the playground explicitly with C-c C-d w / SPC m d w.

;; Install D2 for local rendering (optional):
;; https://d2lang.com/tour/install

;; Customize D2 settings:
(setq sysml2-d2-executable-path "/path/to/d2")  ; nil = search exec-path
(setq sysml2-d2-theme 0)                         ; theme number
(setq sysml2-d2-layout-engine 'elk)              ; nil (dagre), elk, or tala

PlantUML Backend (legacy)

Set sysml2-diagram-backend to plantuml to use PlantUML for all diagram types:

(setq sysml2-diagram-backend 'plantuml)

;; Direct executable (default)
(setq sysml2-plantuml-exec-mode 'executable)

;; Java JAR
(setq sysml2-plantuml-exec-mode 'jar)
(setq sysml2-plantuml-jar-path "/path/to/plantuml.jar")

;; Remote server
(setq sysml2-plantuml-exec-mode 'server)
(setq sysml2-plantuml-server-url "https://www.plantuml.com/plantuml")

Org-Babel Integration

Execute SysML blocks in org-mode:

#+BEGIN_SRC sysml :cmd diagram :diagram-type tree :file vehicle.svg
package Vehicle {
    part def Engine { }
    part def Body { }
}
#+END_SRC

Model Scaffolding

Interactive commands to bootstrap common SysML v2 model structures. Each command prompts for names, types, and optional elements, then inserts well-formed SysML v2 code at point.

Binding	Command	Scaffolds
C-c m m	sysml2-scaffold	Menu of all scaffolding commands
C-c m M	sysml2-scaffold-model	Whole-model skeleton (package + parts + requirements)
C-c m p	sysml2-scaffold-package	Package with optional imports
C-c m d	sysml2-scaffold-part-def	Part def with attributes, ports, specialization
C-c m o	sysml2-scaffold-port-def	Port def with directional items
C-c m r	sysml2-scaffold-requirement-def	Requirement def with doc, subject, constraint
C-c m s	sysml2-scaffold-state-def	State def with states and auto-generated transitions
C-c m a	sysml2-scaffold-action-def	Action def with sub-actions and successions
C-c m e	sysml2-scaffold-enum-def	Enum def with literals
C-c m u	sysml2-scaffold-use-case-def	Use case def with subject, actors, includes
C-c m c	sysml2-scaffold-calc-def	Calc def with in params and return value

Model Inspection

Interactive reporting and analysis commands for model understanding and ISO 13485 traceability.

Binding	Command	Description
C-c C-i s	sysml2-report-summary	Model statistics (definitions, usages, relationships, coverage)
C-c C-i t	sysml2-report-traceability	Sortable traceability matrix (IDs, satisfy, verify, derive, refine)
C-c C-i a	sysml2-impact-analysis	Upstream/downstream dependency analysis at point
C-c C-i m	sysml2-report-export-markdown	Export model report as Markdown (13 sections)
C-c C-i e	sysml2-report-export	Export via Pandoc (PDF/HTML/DOCX)

Impact analysis (C-c C-i a) shows all relationships for the definition at point:

• Upstream: supertypes, parent compositions, connections from, flows from, satisfies, verifies, derived from, refines
• Downstream: subtypes, child compositions, connections to, flows to, satisfied by, verified by, derived to, refined by, sub-requirements, port type usages

Markdown report sections: Model Summary, Part Decomposition (BOM), Interface Table, Connection Matrix, Requirements Specification, Traceability Matrix, Allocation Matrix, State Machines, Action Flows, Calculations, Analysis Cases, Constraint Definitions, Enumerations.

FMI/FMU Integration

FMI 3.0 support for model exchange and co-simulation workflows. See the FMI Integration Guide for a complete walkthrough from SysML model to co-simulation.

FMU Inspector

Inspect .fmu files by parsing modelDescription.xml:

Binding	Command	Description
C-c C-s i	sysml2-fmi-inspect-fmu	Open FMU inspector (variables, structure, metadata)

Interface Extraction

Extract FMI-compatible interface contracts from SysML port definitions:

Binding	Command	Description
C-c C-s e	sysml2-fmi-extract-interfaces	Extract ports as FMI variables

Handles:

• Port conjugation (~) with automatic direction flipping
• SysML-to-FMI type mapping (Real -> Float64, Integer -> Int32, Boolean -> Boolean)
• User-extensible type mapping via sysml2-fmi-type-mapping-alist

Modelica Stub Generation

Generate partial Modelica models from SysML part definitions:

Binding	Command	Description
C-c C-s m	sysml2-fmi-generate-modelica	Generate .mo file from part def
C-c C-s M	sysml2-fmi-generate-all-modelica	Generate .mo files for all parts in current file
C-c C-s F	sysml2-fmi-batch-generate-modelica	Generate .mo files for all parts across multiple SysML files

partial model Engine
  "Generated from SysML v2 part def Engine"
  Modelica.Blocks.Interfaces.RealInput fuelFlow "From port fuelIn";
  Modelica.Blocks.Interfaces.RealOutput torque "From port driveOut";
  parameter Real displacement "From SysML attribute";
equation
  // Equations to be filled by model developer
end Engine;

Interface Validation

Compare FMU modelDescription.xml against SysML port definitions:

Binding	Command	Description
C-c C-s v	sysml2-fmi-validate-interfaces	Show match/mismatch/missing report
C-c C-s V	sysml2-fmi-validate-all	Validate all FMUs against SysML

FMU Compilation

Compile Modelica models to FMUs via OpenModelica:

Binding	Command	Description
C-c C-s b	sysml2-fmi-compile-fmu	Compile single .mo to FMU
C-c C-s B	sysml2-fmi-compile-all-fmus	Compile all .mo files to FMUs

FMI Dashboard

Binding	Command	Description
C-c C-s d	sysml2-fmi-dashboard	Status overview (stubs, FMUs, validation)

Co-Simulation

Orchestrate co-simulation runs with FMPy or OMSimulator. See the FMI Integration Guide for a complete end-to-end walkthrough.

SSP Generation

Generate SSP (System Structure and Parameterization) packages from SysML connections:

Binding	Command	Description
C-c C-s g	sysml2-cosim-generate-ssp	Generate SSP from connections

Simulation Execution

Binding	Command	Description
C-c C-s r	sysml2-cosim-run	Run simulation (async)

Supports FMPy and OMSimulator via sysml2-cosim-tool.

Results Visualization

Binding	Command	Description
C-c C-s p	sysml2-cosim-results	Display CSV results in tabulated buffer

Optional gnuplot integration for time-series plots.

Requirement Verification

Binding	Command	Description
C-c C-s c	sysml2-cosim-verify-requirements	Check simulation results against requirements

Parses simple constraints from requirement doc comments (signal <= bound) and checks simulation data. Complex constraints are flagged as MANUAL.

End-to-End Pipeline

Binding	Command	Description
C-c C-s P	sysml2-cosim-pipeline	Full pipeline: generate all stubs, compile FMUs, package SSP, run simulation

Native Simulation

Built-in SysML v2 behavioral simulation powered by the sysml CLI. Evaluate constraints, run calculations, simulate state machines, and execute action flows directly from Emacs.

Requires: sysml on exec-path (install from sysml-cli releases)

Simulation Commands

Binding	Command	Description
C-c C-x s	sysml2-simulate	Open simulation dispatch menu
C-c C-x l	sysml2-simulate-list	List all simulatable constructs in the current file
C-c C-x e	sysml2-simulate-eval	Evaluate a constraint or calculation (with parameter completion)
C-c C-x m	sysml2-simulate-state-machine	Simulate a state machine (with trigger signal completion)
C-c C-x a	sysml2-simulate-action-flow	Execute an action flow

All simulation commands offer model-aware completion: construct names, trigger signals for state machines, and parameter names for constraints and calculations are extracted from the model and presented as candidates.

Listing Constructs

C-c C-x l scans the current file and lists all simulatable constructs with their parameters:

=== Simulatable Constructs: model.sysml ===

Constraints:
  SpeedLimit (speed: Real)

Calculations:
  KineticEnergy (mass: Real, velocity: Real) -> Real

State Machines:
  TrafficLight [entry: red, states: red, yellow, green, transitions: 3]

Actions:
  ProcessOrder (7 steps)

Evaluating Constraints and Calculations

C-c C-x e prompts for a constraint/calculation name (with completion) and variable bindings, then displays the result:

=== Eval: SpeedLimit ===

constraint SpeedLimit: satisfied

Variable bindings use name=value format, comma-separated (e.g., speed=100,mass=1500).

State Machine Simulation

C-c C-x m prompts for the state machine name, events to inject, variable bindings for guards, and maximum steps. The simulation trace shows each state transition:

=== State Machine: TrafficLight ===

State Machine: TrafficLight
Initial state: red

  Step 0: red -- [next]--> green
  Step 1: green -- [next]--> yellow
  Step 2: yellow -- [next]--> red

Status: deadlocked (3 steps, current: red)

Action Flow Execution

C-c C-x a executes an action flow and traces each step, including fork/join parallelism, conditionals, assignments, and loops:

=== Action Flow: ProcessOrder ===

Action: ProcessOrder

  Step 0: [perform] perform validate
  Step 1: [perform] perform checkInventory
  Step 2: [perform] perform ship
  Step 3: [perform] perform notifyCustomer

Status: completed (4 steps)

Simulation Capabilities

The simulation engine supports:

• Constraints: Boolean expression evaluation with comparison, logical, and arithmetic operators
• Calculations: Expression evaluation with parameterized inputs and built-in functions (abs, sqrt, min, max, etc.)
• State machines: Entry state, signal triggers, guard conditions, entry/exit actions, effects, deadlock detection. Supports state def, exhibit state, and nested state regions (e.g. parallel orthogonal states)
• Action flows: Sequential execution, fork/join, if/else, while loops, assign, send actions

Customization

Variable	Default	Description
sysml2-cli-executable	"sysml"	Path to the sysml CLI binary
sysml2-simulate-max-steps	100	Default maximum simulation steps

Multi-File Import Resolution

When models span multiple files with import statements, use -I to include additional files for resolution:

sysml simulate list model.sysml -I lib/
sysml check model.sysml -I shared-library/

CLI Analysis

When the sysml CLI is installed, additional analysis and refactoring commands are available for cross-file validation, project-level queries, and code transformation. Refactoring commands always show a JSON-driven preview and prompt for confirmation before touching disk.

Binding	Command	Description
C-c C-t l	sysml2-cli-lint	Alias for sysml2-cli-check (the CLI's lint command was removed)
C-c C-t c	sysml2-cli-check	Comprehensive checks + project integrity
C-c C-t s	sysml2-cli-list	List model elements (with kind filter)
C-c C-t w	sysml2-cli-show	Show element details
C-c C-t t	sysml2-cli-trace	Requirements traceability matrix
C-c C-t a	sysml2-cli-stats	Model statistics (renders the ModelStats view)
C-c C-t d	sysml2-cli-deps	Forward/reverse dependency analysis
C-c C-t v	sysml2-cli-coverage	Model completeness and quality score
C-c C-t f	sysml2-cli-find	Search names via sysml list -n (prefix arg: --doc text search)
C-c C-t g	sysml2-cli-doc	Generate Markdown documentation
C-c C-t n	sysml2-cli-analyze	List analysis cases (sysml list -k analyses)
C-c C-t r	sysml2-cli-rollup	Attribute rollup (mass/cost/power/…)
C-c C-t i	sysml2-cli-interfaces	Render the PortTable view (C-u: unconnected ports via check/W016)
C-c C-t o	sysml2-cli-allocation	Logical-to-physical allocation matrix
C-c C-t D	sysml2-cli-diff	Semantic diff between two SysML files
C-c C-t R	sysml2-cli-rename	Refactor: rename element (C-u for project-wide)
C-c C-t A	sysml2-cli-add	Refactor: add an element from a template
C-c C-t K	sysml2-cli-remove	Refactor: remove an element
C-c C-t V	sysml2-cli-view	Render a model-defined view (empty name lists views)
C-c C-t u	sysml2-cli-analyze-run	Run an analysis case (prefix arg: choose uncertainty method)

All commands automatically forward -I PROJECT-ROOT and --stdlib-path to the CLI when a project root is detected, so cross-file resolution Just Works without per-buffer configuration.

A transient picker is available at C-c C-t RET for keyboard browsing.

Formatting

Re-indent the buffer or region using the tree-sitter indentation engine (no external tools needed):

Binding	Command	Description
C-c C-= =	sysml2-format-buffer	Re-indent entire buffer
C-c C-= r	sysml2-format-region	Re-indent selected region

Enable sysml2-format-on-save-mode to auto-format before every save.

For a CI-style "would the canonical formatter change anything?" gate that does NOT modify the buffer, run M-x sysml2-format-check-via-cli (uses sysml fmt --check -f json), or set the defcustom sysml2-format-check-on-save to t to warn automatically on every save.

Systems Modeling API

REST client for the Systems Modeling API v1.0:

Binding	Command	Description
C-c C-a l	sysml2-api-list-projects	List remote projects
C-c C-a q	sysml2-api-query	Execute query against project

(setq sysml2-api-base-url "http://localhost:9000")
(setq sysml2-api-project-id "my-project-id")

LSP Support

Integrates with both eglot (built into Emacs 29+) and lsp-mode. Provides cross-file go-to-definition, find-references, completion, hover, inlay hints, semantic tokens, code actions, type hierarchy, code lenses, document links, and diagnostics from the language server.

The default server is sysml-lsp (Rust, from the same workspace as the CLI) which advertises 17 capabilities including codeLens (satisfy/verify/usage counts above each definition) and documentLink (clickable imports and super-types). Three additional servers are recognised:

sysml-lsp (default, recommended)

(setq sysml2-lsp-server 'sysml-lsp)   ;; default

Built from https://github.com/jackhale98/sysml-cli (same workspace as the sysml CLI). Install with cargo install --path crates/sysml-lsp. Advertises 17 capabilities including codeLens (satisfy/verify/usage counts above each definition) and documentLink (clickable imports and super-types).

SysIDE (Sensmetry)

SysIDE is an open-source LSP server for SysML v2. Note: this project was archived in Oct 2025 but remains functional.

(setq sysml2-lsp-server 'syside)
(setq sysml2-lsp-server-path "/path/to/syside-lsp")

Eclipse SysON

SysON is Eclipse's actively maintained SysML v2 tooling with LSP support.

(setq sysml2-lsp-server 'syson
      sysml2-lsp-server-path "/path/to/syson-language-server.jar")

(The syson backend runs the jar with java -jar, so both variables are required.)

With eglot (recommended, built into Emacs 29+):

(use-package sysml2-mode
  :hook (sysml2-mode . eglot-ensure))

SysML v2 Pilot Implementation

The official OMG pilot is an Eclipse/Xtext-based implementation that can run as a Java LSP server.

(setq sysml2-lsp-server 'pilot)
(setq sysml2-lsp-server-path "/path/to/sysml2-pilot.jar")

Disabling LSP

(setq sysml2-lsp-server 'none)

Evil-Mode Integration

Optional keybindings for evil-mode users via general.el (SPC m prefix, Doom/Spacemacs style):

Prefix	Category
SPC m n	Navigation (outline, goto-definition)
SPC m r	Rename symbol
SPC m o	Outline panel
SPC m c	Connections (connect, flow, bind, verify, subject, etc.)
SPC m d	Diagram (tree, IBD, state, playground, etc.)
SPC m m	Model scaffolding
SPC m a	API
SPC m l	LSP
SPC m s	Simulation / FMI
SPC m x	Native simulation
SPC m =	Format (buffer, region)
SPC m t	CLI analysis (lint, trace, deps, coverage)
SPC m i	Inspect / Report
SPC m f	Code folding

Plus gd for goto-definition in normal state. Neither evil nor general.el is a hard dependency.

Keybinding Reference

Binding	Command
Navigation
M-.	sysml2-goto-definition
M-?	sysml2-find-references
C-c C-r	sysml2-rename-symbol
C-c C-n o	imenu
C-c C-n t	sysml2-outline-toggle
Connections
C-c C-c c	sysml2-connect
C-c C-c f	sysml2-insert-flow
C-c C-c b	sysml2-insert-binding
C-c C-c i	sysml2-insert-interface
C-c C-c a	sysml2-insert-allocation
C-c C-c s	sysml2-insert-satisfy
C-c C-c v	sysml2-insert-verify
C-c C-c u	sysml2-insert-subject
Diagram
C-c C-d t	sysml2-diagram-tree
C-c C-d i	sysml2-diagram-ibd
C-c C-d s	sysml2-diagram-state-machine
C-c C-d a	sysml2-diagram-action-flow
C-c C-d r	sysml2-diagram-requirement
C-c C-d u	sysml2-diagram-use-case
C-c C-d k	sysml2-diagram-package
C-c C-d p	sysml2-diagram-preview
C-c C-d v	sysml2-diagram-view
C-c C-d e	sysml2-diagram-export
C-c C-d o	sysml2-diagram-open-plantuml
C-c C-d w	sysml2-diagram-open-in-playground
Scaffolding
C-c m m	sysml2-scaffold
C-c m p	sysml2-scaffold-package
C-c m d	sysml2-scaffold-part-def
C-c m o	sysml2-scaffold-port-def
C-c m r	sysml2-scaffold-requirement-def
C-c m s	sysml2-scaffold-state-def
C-c m a	sysml2-scaffold-action-def
C-c m e	sysml2-scaffold-enum-def
C-c m u	sysml2-scaffold-use-case-def
C-c m c	sysml2-scaffold-calc-def
LSP
C-c C-l s	sysml2-lsp-ensure
C-c C-l r	sysml2-lsp-restart
API
C-c C-a l	sysml2-api-list-projects
C-c C-a q	sysml2-api-query
Simulation / FMI
C-c C-s i	sysml2-fmi-inspect-fmu
C-c C-s e	sysml2-fmi-extract-interfaces
C-c C-s m	sysml2-fmi-generate-modelica
C-c C-s M	sysml2-fmi-generate-all-modelica
C-c C-s F	sysml2-fmi-batch-generate-modelica
C-c C-s b	sysml2-fmi-compile-fmu
C-c C-s B	sysml2-fmi-compile-all-fmus
C-c C-s v	sysml2-fmi-validate-interfaces
C-c C-s V	sysml2-fmi-validate-all
C-c C-s d	sysml2-fmi-dashboard
C-c C-s g	sysml2-cosim-generate-ssp
C-c C-s r	sysml2-cosim-run
C-c C-s p	sysml2-cosim-results
C-c C-s c	sysml2-cosim-verify-requirements
C-c C-s P	sysml2-cosim-pipeline
Native Simulation
C-c C-x s	sysml2-simulate
C-c C-x l	sysml2-simulate-list
C-c C-x e	sysml2-simulate-eval
C-c C-x m	sysml2-simulate-state-machine
C-c C-x a	sysml2-simulate-action-flow
Format
C-c C-= =	sysml2-format-buffer
C-c C-= r	sysml2-format-region
CLI Analysis
C-c C-t l	sysml2-cli-lint
C-c C-t c	sysml2-cli-check
C-c C-t s	sysml2-cli-list
C-c C-t w	sysml2-cli-show
C-c C-t t	sysml2-cli-trace
C-c C-t a	sysml2-cli-stats
C-c C-t d	sysml2-cli-deps
C-c C-t v	sysml2-cli-coverage
C-c C-t f	sysml2-cli-find
C-c C-t g	sysml2-cli-doc
C-c C-t n	sysml2-cli-analyze
C-c C-t r	sysml2-cli-rollup
C-c C-t i	sysml2-cli-interfaces
C-c C-t o	sysml2-cli-allocation
C-c C-t D	sysml2-cli-diff
C-c C-t R	sysml2-cli-rename
C-c C-t A	sysml2-cli-add
C-c C-t K	sysml2-cli-remove
C-c C-t V	sysml2-cli-view
C-c C-t u	sysml2-cli-analyze-run
C-c C-t RET	sysml2-transient-analyze (picker)
REPL
C-c C-x r	sysml2-repl (comint inferior sysml repl)
Health Check
M-x sysml2-doctor	Probe sysml CLI, grammar, LSP, D2, PlantUML, Pandoc
Inspect / Report
C-c C-i s	sysml2-report-summary
C-c C-i t	sysml2-report-traceability
C-c C-i a	sysml2-impact-analysis
C-c C-i m	sysml2-report-export-markdown
C-c C-i e	sysml2-report-export
Code Folding
C-c C-f t	hs-toggle-hiding
C-c C-f h	hs-hide-block
C-c C-f s	hs-show-block
C-c C-f H	hs-hide-all
C-c C-f S	hs-show-all
C-c C-f l	hs-hide-level

Customization

All customization variables are in the sysml2 group. M-x customize-group RET sysml2 RET to browse.

Key variables:

Variable	Default	Description
sysml2-indent-offset	4	Spaces per indentation level
sysml2-diagram-backend	'native	Backend: native (SVG + D2) or plantuml
sysml2-d2-executable-path	nil	Path to D2 binary (nil = search exec-path)
sysml2-d2-theme	nil	D2 theme number (nil = default)
sysml2-d2-layout-engine	nil	D2 layout: nil (dagre), elk, or tala
sysml2-lsp-server	'sysml-lsp	LSP server (sysml-lsp, pilot, syside, syson, none)
sysml2-format-check-on-save	nil	When non-nil, run sysml fmt --check -f json on save and report drift
sysml2-plantuml-exec-mode	'executable	PlantUML invocation mode
sysml2-diagram-output-format	"svg"	Diagram output format
sysml2-cli-executable	"sysml"	Path to sysml CLI binary
sysml2-cosim-tool	'fmpy	Co-simulation tool (fmpy, omsimulator)
sysml2-cosim-stop-time	10.0	Default simulation stop time
sysml2-fmi-type-mapping-alist	nil	User SysML-to-FMI type overrides

Additional customization (see M-x customize-group RET sysml2 RET for the full set of 39 options): indentation (sysml2-indent-tabs-mode), library discovery (sysml2-standard-library-path, sysml2-auto-detect-library), diagram presentation (sysml2-diagram-auto-preview, sysml2-diagram-page-size, sysml2-diagram-direction, sysml2-diagram-preview-window, sysml2-graphviz-dot-path, sysml2-plantuml-executable-path), FMI (sysml2-fmi-openmodelica-path, sysml2-fmi-fmpy-executable, sysml2-fmi-default-fmi-version, sysml2-fmi-modelica-output-dir), co-simulation (sysml2-cosim-omsimulator-path, sysml2-cosim-gnuplot-path, sysml2-cosim-step-size, sysml2-cosim-output-dir, sysml2-cosim-results-format), native simulation (sysml2-simulate-executable), and report export (sysml2-report-pandoc-executable).

Module Architecture

sysml2-vars.el          Customization variables, faces, shared state
sysml2-lang.el          Keyword lists, regexp constants (pure data)
sysml2-font-lock.el     Syntax highlighting rules
sysml2-indent.el        Indentation engine
sysml2-completion.el    Context-aware completion, scaffolding commands
sysml2-navigation.el    Imenu, which-function, defun movement
sysml2-snippets.el      Yasnippet template registration
sysml2-project.el       Project root detection, library resolution
sysml2-lsp.el           LSP client config (eglot + lsp-mode)
sysml2-flymake.el       In-buffer diagnostics (syntax + semantic)
sysml2-model.el         Shared model extraction (parts, ports, reqs, analyses, constraints, refinements)
sysml2-svg.el           Direct SVG generation (tree, requirement diagrams)
sysml2-d2.el            D2 language generation (IBD, state, action, etc.)
sysml2-plantuml.el      SysML-to-PlantUML transformation (legacy backend)
sysml2-diagram.el       Diagram dispatch, preview, export
ob-sysml.el             Org-babel: execute SysML blocks (diagrams + CLI commands)
sysml2-report.el        Model summary, traceability (IDs, derivations, refinements), analyses, constraints, allocations, Markdown/Pandoc export
sysml2-api.el           Systems Modeling API REST client
sysml2-fmi.el           FMU inspector, interface extraction, Modelica gen
sysml2-cosim.el         SSP generation, simulation, results, verification
sysml2-simulate.el      Native simulation via sysml CLI (constraints, state machines, actions)
sysml2-format.el        In-process formatting (tree-sitter indent-region)
sysml2-cli-commands.el  CLI analysis + refactor wrappers (check, list, show, trace, stats, deps, coverage, find, doc, analyze, rollup, interfaces, allocation, diff, rename, add, remove)
sysml2-doctor.el        Health check probe for CLI, grammar, LSP, D2, PlantUML, Pandoc, stdlib
sysml2-menu.el          Easy-menu bar + which-key prefix labels
sysml2-repl.el          comint-mode inferior `sysml repl' session
sysml2-transient.el     transient.el pickers for diagrams, scaffold, analyze
sysml2-outline.el       Outline side panel
sysml2-eldoc.el         Definition/documentation at point (ElDoc)
sysml2-evil.el          Optional evil-mode keybindings
sysml2-ts.el            Tree-sitter grammar integration (font-lock, indent, imenu, thing-settings, outline)
sysml2-mode.el          Entry point, syntax table, keymap, mode definition

Canonical tree-sitter query files (consumed by other editors) live in tree-sitter-sysml/queries/: highlights.scm, indents.scm, folds.scm, locals.scm, tags.scm.

Testing

365 ERT tests across 28 test files (make test).

make test

Test files cover the language layer, font-lock, indentation, completion, navigation, project detection, flymake (in-process and CLI codes), tree-sitter parsing/imenu/structural movement, outline, FMI, co-simulation, evil-mode wiring, REST API, org-babel, the menu bar + which-key registration, sysml2-doctor, autoload coverage, the canonical .scm query files, REPL prompt-regex detection, transient pickers, all CLI command wrappers (including rename / add / remove preview-then-apply flows), and sysml2-format-check-via-cli.

License

GPL-3.0-or-later