cpp-hub: C++ Project Template Hub (AI-Generated Demo)

⚠️ STABILITY NOTICE: CONCEPTUAL REFERENCE

This repository is currently under active construction and is considered highly volatile. It is intended strictly as a conceptual reference point "a demonstration of what a C++ project template hub could have been" rather than a stable utility.

Please be advised that this is not a production-ready tool. Users should anticipate incomplete functionality and frequent breaking changes.

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Overview

cpp-hub is a small C++20 CLI designed to significantly reduce the "Day Zero" friction associated with starting new C++ projects. It acts as a project generator that leverages remote templates.

Core Functionality

1. Discovery: Finds available project templates through a local registry (a Git repository containing an index.json).
2. Caching: Clones template repositories into a local cache (~/.cpp-hub/cache).
3. Generation: Creates new projects by applying simple {{variable}} substitutions within template file contents and paths.
4. Hooks: Optionally runs template-defined post-generation hooks (e.g., git init, git add .).

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Features

Registry-Backed Discovery

• The Registry is a Git repository (default URL is hard-coded in config.cpp).
• The local clone lives under: ~/.cpp-hub/registry.
• Templates are cataloged in an index.json file (including id, name, url, tags, build system, etc.).
• cpp-hub update executes a git pull on the local registry clone.

Template Cache

• Template repositories are cloned under: ~/.cpp-hub/cache/<template-id>.
• Templates are reused on subsequent runs, eliminating the need to re-clone every time.

Template Manifests

Each template repository must contain a hub-manifest.json at its root. This manifest defines the template's behavior:

• Basic metadata: schema_version, id, name, version, description.
• variables: Defines inputs requested from the user, supporting:
  • string (with optional validation_regex and error_message).
  • select (with predefined options and a default).
  • boolean (y/n, yes/no, true/false, case-insensitive).
• hooks.post_gen: A list of shell commands to optionally run after the project is generated.

Simple Templating

Variable substitution ({{variable_name}}) is applied to:

• File contents
• Relative paths / filenames

This mechanism applies to all regular files under the template root, excluding:

• The .git directory.
• The hub-manifest.json file.

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Commands

Command	Description
cpp-hub new <template-id> [--defaults]	Generates a new project from a registered template.
cpp-hub new --git <url> [--branch <name>] [--defaults]	Generates a new project directly from a Git URL.
cpp-hub search <query>	Searches the registry for templates matching the query.
cpp-hub list [--tag <tag>]	Lists all available templates (optionally filtered by tag).
cpp-hub update	Updates the local template registry via git pull.
cpp-hub validate <path>	Validates the hub-manifest.json within a template path.
cpp-hub version	Displays the cpp-hub version information.

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Requirements

Toolchain

• Language: C++20 (or newer)
• Build system: CMake $\geq$ 3.16

Dependencies

• nlohmann::json (available via package managers or vcpkg, etc.)

Runtime Tools

• git must be available on your PATH (used internally via std::system).

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Building

Assuming nlohmann_json is installed on your system so that find_package(nlohmann_json CONFIG REQUIRED) works:

# Configure the build system
cmake -S . -B build

# Build the project executable
cmake --build build