Freemarker

Freemarker Extension for Zed

License: MIT Version

Full-featured syntax highlighting and language support for Apache Freemarker Template Language (FTL) files in Zed editor, powered by a custom tree-sitter grammar.

Table of Contents

• Features
• Installation
• Usage
• Syntax Examples
• Development
• Roadmap
• Contributing
• Credits
• License

Features

• Full Syntax Highlighting: Complete tree-sitter-based parser for accurate FTL syntax highlighting
• Comment Support: Both angle bracket (<#-- -->) and square bracket ([#-- --]) comment styles
• Smart Bracket Matching: Automatic closing and matching for all bracket types
• HTML Integration: Seamless HTML syntax highlighting within templates
• Freemarker Directives: Full support for:
  • Control structures (if, else, elseif, switch)
  • Loops (list, foreach)
  • Variable assignment and interpolation
  • Macros and functions
  • Built-in functions
  • Include and import statements
• Lightweight: Minimal overhead, fast parsing
• Standards Compliant: Follows Apache Freemarker 2.3+ syntax specification

Installation

From Zed Extensions Gallery (Recommended)

1. Open Zed editor
2. Press Cmd+Shift+X (macOS) or Ctrl+Shift+X (Linux/Windows) to open Extensions
3. Search for "Freemarker"
4. Click Install

Manual Installation (Development)

For local development or testing unreleased versions:

# Clone the repository into your Zed extensions directory
git clone https://github.com/debba/zed-freemarker ~/.config/zed/extensions/freemarker

# Restart Zed or reload extensions

Verify Installation

1. Open a .ftl file in Zed
2. Check the language indicator in the bottom-right corner
3. You should see "Freemarker" as the active language

Usage

Once installed, the extension automatically activates for files with the .ftl extension. The editor will provide:

• Syntax highlighting for Freemarker directives and expressions
• Comment toggling with Cmd+/ (macOS) or Ctrl+/ (Linux/Windows)
• Automatic bracket pairing and closing
• HTML syntax within templates

Syntax Examples

Basic Variable Interpolation

<#-- Variable assignment -->
<#assign userName = "John Doe">
<#assign userAge = 25>

<h1>Welcome ${userName}!</h1>
<p>Age: ${userAge}</p>

Conditional Statements

<#if userAge >= 18>
    <p>You are an adult.</p>
<#elseif userAge >= 13>
    <p>You are a teenager.</p>
<#else>
    <p>You are a child.</p>
</#if>

List Iteration

<#assign fruits = ["Apple", "Banana", "Cherry", "Date"]>

<h2>Fruit List:</h2>
<ul>
    <#list fruits as fruit>
        <li>${fruit}</li>
    </#list>
</ul>

Hash/Map Operations

<#assign user = {
    "name": "Jane Smith",
    "email": "jane@example.com",
    "role": "Administrator"
}>

<h2>User Information:</h2>
<dl>
    <dt>Name:</dt>
    <dd>${user.name}</dd>
    <dt>Email:</dt>
    <dd>${user.email}</dd>
</dl>

Built-in Functions

<p>Name in uppercase: ${user.name?upper_case}</p>
<p>Name length: ${user.name?length}</p>
<p>First fruit: ${fruits?first}</p>
<p>Capitalized: ${userName?cap_first}</p>

Null Handling

<#-- Check if variable exists -->
<#if optionalValue??>
    <p>Value: ${optionalValue}</p>
<#else>
    <p>Value is not set</p>
</#if>

<#-- Default value -->
<p>${pageTitle!"Default Title"}</p>

Macros

<#-- Macro definition -->
<#macro greet person>
    <p>Hello, ${person}! Nice to meet you.</p>
</#macro>

<#-- Macro usage -->
<@greet person="Alice" />
<@greet person="Bob" />

Alternative Square Bracket Syntax

[#assign name = "John Doe"]
<h1>Hello ${name}!</h1>

[#if user??]
    <p>Welcome, ${user.name}!</p>
[#else]
    <p>Please log in.</p>
[/#if]

[#list products as product]
    <li>${product.name} - ${product.price}</li>
[/#list]

Include and Import

<#-- Include another template -->
<#include "header.ftl">

<#-- Import macros from another file -->
<#import "lib/utils.ftl" as utils>
<@utils.formatDate date=.now />

Development

Prerequisites

• Rust (for building tree-sitter grammar)
• Node.js (for tree-sitter CLI)
• Tree-sitter CLI

Building from Source

# Clone the repository
git clone https://github.com/debba/zed-freemarker.git
cd zed-freemarker

# Build the tree-sitter grammar
cd grammars/freemarker
npm install
npm run build

# Return to root and install in Zed
cd ../..
cp -r . ~/.config/zed/extensions/freemarker

Testing the Grammar

cd grammars/freemarker

# Run tree-sitter tests
tree-sitter test

# Open the playground for interactive testing
tree-sitter playground

Project Structure

zed-freemarker/
├── extension.toml              # Extension metadata
├── languages/
│   └── freemarker/
│       └── config.toml         # Language configuration
├── grammars/
│   └── freemarker/             # Tree-sitter grammar
│       ├── src/
│       │   ├── grammar.json
│       │   └── node-types.json
│       ├── bindings/
│       ├── Cargo.toml
│       └── package.json
├── example.ftl                 # Example template file
└── README.md

Roadmap

• Language Server Protocol (LSP) support for:
  • Code completion
  • Go to definition
  • Find references
  • Hover documentation
• Snippet library for common Freemarker patterns
• Auto-formatting support
• Template validation and error checking
• Integration with Freemarker documentation
• Support for custom directives
• Theme customization for better highlighting

Contributing

Contributions are welcome and appreciated! Here's how you can help:

Reporting Issues

If you find a bug or have a feature request:

1. Check if the issue already exists in GitHub Issues
2. If not, create a new issue with:
   • Clear description of the problem or feature
   • Steps to reproduce (for bugs)
   • Example code that demonstrates the issue
   • Your Zed version and operating system

Pull Requests

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Make your changes
4. Test thoroughly with various .ftl files
5. Commit your changes (git commit -m 'Add amazing feature')
6. Push to the branch (git push origin feature/amazing-feature)
7. Open a Pull Request with a clear description of your changes

Development Guidelines

• Follow existing code style and conventions
• Add tests for new features when applicable
• Update documentation for user-facing changes
• Keep commits focused and atomic
• Write clear commit messages

Credits

• Inspired by the VS Code vs-freemarker extension
• Built with Tree-sitter
• Developed for Zed editor
• Apache Freemarker project

License

This project is licensed under the MIT License - see the LICENSE file for details.

Copyright (c) 2026 Andrea Debernardi

Support

• Issues: GitHub Issues
• Repository: GitHub
• Tree-sitter Grammar: tree-sitter-freemarker
• Freemarker Documentation: Official Docs

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Made with care for the Zed community