Miranda (David Turner)

A Visual Studio Code extension with syntax highlighting and ESLint-style linting for the Miranda programming language, the pure functional language designed by David Turner.

Based on:

• ncihnegn/miranda — official implementation
• miralib/prelude — internal prelude
• garrett-may/miranda-documentation — language documentation

Features

Syntax Highlighting

• Comments ||
• Directives %include, %export, %bnf, etc.
• Reserved words: if, otherwise, where, abstype, with, type, div, mod
• Literals: True, False, numbers, strings, chars
• Operators: ::, ::=, ==, ++, --, <-, .., \/, ~, &, etc.
• List comprehensions [expr | var <- list; filter]
• Constructors (identifiers starting with an uppercase letter)

Linter (ESLint-style)

Configurable rules with severity off / warn / error:

Learn Miranda

Extension UI

The extension follows VS Code UX guidelines for sidebars, panels, walkthroughs, context menus, and the status bar.

Workflow: open Concepts in the sidebar → select a topic → read the explanation in Concept Guide → the matching example opens in the editor → check Lint Issues while editing.

Concepts sidebar

Twelve structured topics from David Turner's An Overview of Miranda. Each concept includes a summary, prose explanation, code sample, and linked example file.

Commands

All commands are available from the Command Palette (Cmd+Shift+P / Ctrl+Shift+P) under the Miranda: prefix.

Getting Started walkthrough

After installing the extension, open the Get Started with Miranda walkthrough from the VS Code Getting Started page (or run Help: Get Started). It guides you through:

1. Opening tutorial .m examples
2. Syntax highlighting features
3. Running the linter
4. Pattern matching and list comprehensions
5. Configuring lint rules
6. The full language guide

Walkthroughs follow the VS Code walkthrough guidelines with theme-aware SVG illustrations and actionable steps.

Context menus (guidelines) — grouped under a Miranda submenu, shown only when relevant:

Written tutorial

Step-by-step guide based on David Turner's An Overview of Miranda:

docs/walkthrough.md

Open any example in the extension dev host:

./scripts/dev.sh --example examples/01-basic-ideas.m

Installation

Local development

npm install
npm run compile

Then in VS Code: Run Extension (F5) or install the .vsix:

npx @vscode/vsce package
code --install-extension MirandaDavidTurner-0.1.0.vsix

Usage

Open Miranda .m files. Syntax highlighting is applied automatically and the linter runs on type or save.

• Command Palette: Miranda: Run Linter
• Sidebar: click the λ icon → Concepts or Examples
• Panel: Concept Guide for explanations, Lint Issues for diagnostics

Configuration

In VS Code settings.json:

{
  "miranda.lint.enable": true,
  "miranda.lint.run": "onTypeAndSave",
  "miranda.lint.maxLineLength": 80,
  "miranda.lint.indentSize": 1,
  "miranda.lint.rules.booleanLiteralCase": "error",
  "miranda.lint.rules.noUndefinedIdentifier": "warn"
}

You can also use .mirandarc.json in the project root as a configuration reference.

Testing

Unit test suite with Mocha + Chai (linter and provider) and vscode-tmgrammar-test (syntax highlighting):

npm test              # linter, config, diagnostics, provider, constants, examples, views
npm run test:grammar  # 6 tests: TextMate grammar
npm run test:all      # runs both suites (122 tests)

Quick development (install + test + open VS Code)

chmod +x scripts/dev.sh   # first time only
npm run dev               # install, test, open extension dev host
npm run guide             # open dev host with walkthrough (skip tests)

The scripts/dev.sh script:

1. Runs npm install
2. Runs npm run test:all (unless --skip-tests)
3. Opens VS Code or Cursor with --extensionDevelopmentPath and examples/fib.m

Useful options:

./scripts/dev.sh --example examples/quicksort.m
./scripts/dev.sh --walkthrough              # also open Getting Started walkthrough
./scripts/dev.sh --walkthrough --example examples/01-basic-ideas.m
./scripts/dev.sh --skip-tests               # compile and open only
./scripts/dev.sh --skip-launch              # install and test only
./scripts/dev.sh --install-vsix             # also package and install the .vsix

Coverage

Examples

The examples/ folder contains tutorial scripts adapted from Turner's overview, plus samples from the official repository. See docs/walkthrough.md for a guided tour.

References

• An Overview of Miranda — David Turner, University of Kent
• miranda.org.uk
• Operators and lexical notation

License

This extension code is free to use. Miranda is © Research Software Limited / David Turner.