ECL Language Tools

IDE support for SNOMED CT Expression Constraint Language (ECL) 2.2 — parsing, validation, completion, formatting, refactoring, and terminology integration across 7 editors, the browser, and Slack.

Screenshots

Syntax Highlighting	Error Diagnostics

Autocompletion	Hover Information

Dark Theme

What is ECL?

Expression Constraint Language (ECL) is the standard query language for SNOMED CT, the world's most comprehensive clinical terminology. ECL expressions define sets of clinical concepts — for use in value sets, clinical decision support, analytics, and data validation. See the ECL Specification.

Packages

Package	Description	Install
@aehrc/ecl-core	Zero-dependency core library (parser, formatter, validation, completion, refactoring, terminology, knowledge)	npm install @aehrc/ecl-core
@aehrc/ecl-lsp-server	LSP server for IDE integration	npm install -g @aehrc/ecl-lsp-server
@aehrc/ecl-editor-core	Headless Monaco Editor integration	npm install @aehrc/ecl-editor-core
@aehrc/ecl-editor-react	React component	npm install @aehrc/ecl-editor-react
@aehrc/ecl-editor	Web Component (<ecl-editor>)	npm install @aehrc/ecl-editor
@aehrc/ecl-slack-bot	Slack bot for validating, formatting, and evaluating ECL expressions	Docker

IDE Clients

Editor	Type	Link
VSCode	Extension (VSIX)	clients/vscode
IntelliJ IDEA	Plugin (Kotlin/Gradle)	clients/intellij
Eclipse	Plugin (LSP4E/TM4E)	clients/eclipse
Neovim	LSP config	clients/neovim
Sublime Text	LSP config	clients/sublime
Emacs	eglot/lsp-mode config	clients/emacs
Claude Code	Plugin	clients/claude-code

Features

Feature	Description
Diagnostics	Syntax errors, inactive/unknown concept warnings, semantic validation
Completion	Context-aware operators, keywords, filter values, SNOMED CT concept search, 18 snippets
Hover	Operator documentation, concept information (FSN, PT, active status)
Formatting	Document and range formatting with 9 configurable options
Code Actions	8 refactoring actions (strip/add display terms, simplify, parentheses, history supplement, description filter)
Code Lens	"Evaluate" lens with inline concept count
Semantic Tokens	Token-level highlighting
SNOMED CT Edition	Status bar selector for edition/version switching
FHIR Integration	Concept lookup, ECL evaluation, concept search via FHIR terminology server

Full ECL 2.2 coverage: constraint operators, logical operators, refinements, dotted expressions, member of, concrete values, filters, history supplements, nested expressions, and comments.

Quick Start

git clone https://github.com/aehrc/ecl-lsp.git && cd ecl-lsp
npm install          # Installs all workspace dependencies
npm run compile      # Compiles all packages
npm test             # Runs 1653+ tests

Then open the project in VSCode and press F5 to launch with the ECL extension, or install @aehrc/ecl-lsp-server globally and configure your preferred editor (see IDE Clients).

Project Structure

ecl-lsp/
├── grammar/                  ANTLR4 ECL grammar (official IHTSDO)
├── shared/syntaxes/          TextMate grammar (shared across clients)
├── packages/
│   ├── ecl-core/             Core library (parser, formatter, completion, refactoring, semantic, terminology, knowledge)
│   ├── ecl-lsp-server/       LSP server
│   ├── ecl-editor-core/      Monaco Editor integration
│   ├── ecl-editor-react/     React component
│   ├── ecl-editor/           Web Component
│   └── ecl-slack-bot/        Slack bot
├── clients/
│   ├── vscode/               VSCode extension
│   ├── intellij/             IntelliJ IDEA plugin
│   ├── eclipse/              Eclipse IDE plugin
│   ├── claude-code/          Claude Code plugin
│   ├── neovim/               Neovim config guide
│   ├── sublime/              Sublime Text config guide
│   └── emacs/                Emacs config guide
└── examples/                 Example ECL files

Configuration

All LSP settings are under the ecl.* namespace. See the @aehrc/ecl-lsp-server README for the full configuration reference.

Contributing

See CONTRIBUTING.md for setup, testing, and development workflow.

Security

See SECURITY.md for reporting vulnerabilities.

Resources

• SNOMED CT ECL Specification
• ECL Grammar (IHTSDO)
• Language Server Protocol
• FHIR Terminology Services

License

Copyright 2026 Commonwealth Scientific and Industrial Research Organisation (CSIRO) ABN 41 687 119 230

Licensed under the Apache License, Version 2.0 — see LICENSE.