Rpg Explainer

RPG Explainer

A CLI tool that parses IBM ILE RPG (RPGLE) programs using Tree-sitter and generates human-readable architecture reports with Mermaid diagrams using Claude LLM.

Features

• Tree-sitter parsing: Uses a custom RPG grammar to parse both free-form and fixed-form RPGLE code (RPG III/IV)
• Mixed format support: Automatically detects **FREE directive and handles mixed-format files
• Static analysis: Extracts procedures, subroutines, file definitions, data structures, and call graphs
• LLM-powered explanations: Uses Claude via LangChain to generate detailed program explanations
• Mermaid diagrams: Generates flowcharts, sequence diagrams, ER diagrams, and state diagrams for visualization
• Dependency detection: Identifies internal and external calls, file usage, and resource dependencies

Example Output

The tool generates comprehensive analysis reports including:

• Executive summary
• Program architecture with flowcharts
• File dependencies with ER diagrams
• Processing flow with sequence diagrams
• Business logic analysis
• Modernization recommendations

See [examples.md](examples.md) for complete analysis examples.

Installation

Prerequisites

• Python 3.10+
• Node.js (for building the Tree-sitter grammar)
• An Anthropic API key

Setup

1. Clone the repository:

   git clone https://github.com/YOUR_USERNAME/rpg-explainer.git
   cd rpg-explainer

2. Build the Tree-sitter RPG grammar:

   cd tree-sitter-rpg
   npm install
   npx tree-sitter generate
   cd ..
   python build_rpg_language.py

3. Install the Python package:

   pip install -e .

4. Set your Anthropic API key:

   export ANTHROPIC_API_KEY=your-api-key-here

Usage

Analyze one or more RPG source files:

rpg-explain path/to/program.rpgle

Analyze multiple files:

rpg-explain src/module1.rpgle src/module2.rpgle

Save the report to a file:

rpg-