ggen Documentation

Language-agnostic generator for reproducible code projections.

ggen turns one ontology into CLI subcommands, APIs, schema files, and docs for any target language.

🧭 Purpose

Developers repeat the same scaffolding logic across stacks. ggen removes the language barrier.

You describe the intent (command, type, or system capability) once as a graph or RDF-like metadata block. ggen projects that intent into any target framework or language.

🚀 Quick Start

Using marketplace gpacks (recommended)

# Search for CLI subcommand templates
ggen search rust cli

# Install a high-quality gpack
ggen add io.ggen.rust.cli-subcommand

# Generate using the installed gpack
ggen gen io.ggen.rust.cli-subcommand:rust.tmpl cmd=hello description="Print a greeting"

Using local templates

ggen gen cli subcommand --vars cmd=hello summary="Print a greeting"

🏪 Marketplace

The ggen marketplace provides a curated ecosystem of reusable code generation packs (gpacks) served via GitHub Pages with automated validation and deployment.

Registry API: registry/index.json

Discover gpacks

# Search for templates by language and type
ggen search rust cli
ggen search python api
ggen search typescript react

# Browse popular categories
ggen categories

# Get detailed information about a specific gpack
ggen show io.ggen.rust.cli-subcommand

Install and use

# Install the latest version
ggen add io.ggen.rust.cli-subcommand

# Install specific version
ggen add io.ggen.rust.cli-subcommand@0.1.0

# List installed gpacks
ggen packs

# Update to latest versions
ggen update

# Use installed gpack templates
ggen gen io.ggen.rust.cli-subcommand:rust.tmpl cmd=users

📚 Documentation Sections

Getting Started

Get started quickly with installation, basic usage, and template development.

Core Concepts

Understand the fundamental ideas behind ggen: templates, RDF integration, projections, and determinism.

Reference

Complete CLI reference, troubleshooting guides, and technical details.

Advanced

Deep dive into mathematical foundations, developer experience features, and gpack development.

Examples

Real-world usage examples and tutorials.

🔧 Installation

Homebrew

brew tap seanchatmangpt/tap
brew install ggen

Cargo

cargo install ggen

🔁 Determinism

ggen computes a manifest hash over:

graph data + shape + frontmatter + template + seed

The same graph + seed = byte-identical results.

📦 Extend

Create local templates

Add your own generator:

mkdir -p templates/api/endpoint
cp templates/cli/subcommand/rust.tmpl templates/api/endpoint/rust.tmpl

Edit frontmatter and target path. ggen will detect and render automatically.

Publish gpacks to marketplace

Share your templates with the community:

# Initialize new gpack
ggen pack init

# Lint and test your gpack
ggen pack lint
ggen pack test

# Publish to registry
ggen pack publish

🔒 License

ggen — one intent, many projections. Code is just a projection of knowledge.

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ggen Documentation