# Python-to-Ruby Transpiler (py2rb)

A source-to-source transpiler that converts Python syntax into Ruby code. Built using **Flex** for lexical analysis and **Bison** for LALR(1) parsing, this project implements a full compilation pipeline from tokenization to code generation.

## Technical Architecture

The transpiler is architected into three distinct phases:

1.  **Lexical Analysis (`Flex`):** Handles Python-specific challenges like indentation-based scoping using a custom `indent_stack`. It supports complex literals including f-strings, triple-quoted strings, and various numeric bases (hex, binary).
2.  **LALR Parsing (`Bison`):** Implements a formal grammar for a significant subset of Python, including class definitions, function nesting, and control flow. It constructs a strongly-typed Abstract Syntax Tree (AST) using C++17 smart pointers.
3.  **Code Generation:** A recursive AST visitor (via the `RubyGenerator`) that maps Python semantics to Ruby equivalents. This includes specialized mapping for Python dunder methods (e.g., `__init__` → `initialize`, `__str__` → `to_s`) and boolean literals.



## Key Features

* **Semantic Mapping:** Automatically converts Python-specific constructs (like `self`) into Ruby syntax.
* **Indentation-to-Block Conversion:** Correctly translates Python's significant whitespace into Ruby's `end`-delimited blocks.
* **Comprehensive Test Suite:** Includes test cases covering lexing, parsing, and end-to-end Ruby generation.
* **AST Auditing:** Built-in support for AST and token stream dumping for debugging and verification.

## Build and Usage

### Prerequisites
* `g++` 
* `flex`
* `bison` 

### Build
```bash
make
```

### Usage
```bash
# Transpile a file and output to stdout
./build/py2rb --file input.py

# Run the automated test suite
make test
```

Implementation Details & Shortcomings

For a list of current language subset limitations (e.g., tuple-to-list conversion, specific string processing logic), see shortcomings.md.