SysML v2 Mode for Emacs

Major mode for editing SysML v2 (Systems Modeling Language) files with syntax highlighting and validation integration.

Features

• Syntax Highlighting: Keywords, types, operators, comments, and documentation blocks
• ElDoc Support: Inline documentation in minibuffer when cursor is on keywords or operators
• Quick Reference: C-c C-h displays a syntax guide with examples
• Context-Sensitive Help: C-c C-d opens web documentation for the keyword at point
• Validation: Integration with validate-sysml.sh for on-save validation (C-c C-v)
• Spell Checking: Intelligent spell checking that only checks strings and comments, not code
• Indentation: Automatic indentation based on block structure
• Comments: Support for // single-line and /* */ multi-line comments

Auto-mode Association

The mode automatically associates with .sysml files. To manually enable:

M-x sysml-mode

Configuration

Enable Validation on Save

(setq sysml-validate-on-save t)

Set Validator Script Path

By default, the mode auto-detects validate-sysml.sh in the project directory tree. To set explicitly:

(setq sysml-validator-script "/path/to/validate-sysml.sh")

Example Configuration

;; Load SysML mode
(load-file "sysml-mode.el")

;; Enable validation on save
(setq sysml-validate-on-save t)

;; Optional: Set custom tab width
(add-hook 'sysml-mode-hook
          (lambda ()
            (setq tab-width 4)
            (setq indent-tabs-mode t)))

Key Bindings

Key	Command	Description
C-c C-v	sysml-validate-buffer	Validate current file
C-c C-h	sysml-quick-reference	Show quick reference guide
C-c C-d	sysml-browse-doc-at-point	Open documentation for keyword

Syntax Highlighting

The mode provides color highlighting for:

Keywords

• Package: package, import, private, public, standard, library
• Definitions: def, part, attribute, ref, item, port, action, state, requirement, constraint
• Behavioral: exhibit, perform, then, first, accept, send, entry, exit, do
• Relationships: specializes, subsets, redefines, bind, connect, satisfy, verify

Operators

• :> (specialization)
• :>> (redefinition)
• :: (qualified names)

Types

• Built-in types: String, Boolean, Integer, Real, Natural, DataValue
• User-defined types in type position
• Qualified names: Package::SubPackage::Type

Literals

• Strings: "text"
• Numbers: 123, 3.14
• Booleans: true, false
• Multiplicity: [0..1], [0..*], [1]

Comments and Documentation

• Single-line: // comment
• Multi-line: /* comment */
• Documentation: doc /* documentation */

Documentation Features

ElDoc Mode (Inline Help)

ElDoc is enabled by default. Move your cursor over any keyword or operator to see a brief description in the minibuffer (echo area).

Examples:

• Cursor on :> shows: "specialization operator - inherit from supertype"
• Cursor on part def shows: "defines a structural component type (specializes Parts::Part)"
• Cursor on :>> shows: "redefinition operator - redefine inherited feature"

Quick Reference Guide

Press C-c C-h to open a comprehensive quick reference buffer showing:

• Operator syntax and examples
• Common code patterns
• Multiplicity notation
• Key bindings
• Links to authoritative documentation sources

The quick reference is designed as a cheat sheet for quick lookups without leaving Emacs.

Context-Sensitive Documentation

Press C-c C-d with cursor on any keyword to open the relevant section of the OMG SysML v2 specification in your web browser. This provides access to the authoritative documentation for detailed information.

Authoritative Sources

The mode links to these official documentation sources:

• OMG SysML v2 Specification: https://www.omg.org/spec/SysML/2.0/
• Normative Example Model: https://www.omg.org/cgi-bin/doc?ptc/25-04-31.sysml
• SysML v2 Release Repository: https://github.com/Systems-Modeling/SysML-v2-Release

Spell Checking

The mode provides intelligent spell checking that only checks strings and comments, not code identifiers or keywords.

Batch Spell Checking

Simply use the standard ispell-buffer command:

M-x ispell-buffer

The mode automatically remaps this to ispell-comments-and-strings, which checks only:

• String literals: "text to check"
• Single-line comments: // comment text
• Multi-line comments: /* comment text */
• Documentation blocks: doc /* documentation */

On-the-Fly Spell Checking (flyspell)

For real-time spell checking as you type:

(add-hook 'sysml-mode-hook 'flyspell-prog-mode)

The flyspell-prog-mode function is the standard Emacs way to enable spell checking in programming modes - it only checks comments and strings.

Validation Integration

When sysml-validate-on-save is enabled, the mode runs validate-sysml.sh after saving. Validation errors appear in the *compilation* buffer with GNU format:

filename:line:column: error: message

Click on errors to jump to the corresponding location.

Manual Validation

Run validation at any time with C-c C-v or:

M-x sysml-validate-buffer

Compatibility

• Emacs 24.3 or later
• Based on OMG SysML v2 specification (https://www.omg.org/spec/SysML/2.0/)
• Compatible with SysML v2 Pilot Implementation validator

Troubleshooting

Validation not working

1. Check that validate-sysml.sh is in your project directory
2. Verify the script is executable: chmod +x validate-sysml.sh
3. Set sysml-validator-script explicitly if auto-detection fails
4. Check the *Messages* buffer for error messages

Syntax highlighting issues

1. Reload the mode: M-x revert-buffer
2. Force font-lock refresh: M-x font-lock-fontify-buffer
3. Check that the file has .sysml extension

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