Coba Programming Language

Coba is a modern programming language that provides a contemporary way to write COBOL. It features clean, readable syntax inspired by JavaScript/TypeScript while maintaining full interoperability with COBOL through bidirectional compilation.

Overview

Coba bridges the gap between modern programming practices and legacy COBOL systems by providing:

• Modern Syntax: Clean, readable code inspired by JavaScript/TypeScript
• Bidirectional Compilation: Convert seamlessly between Coba and COBOL
• Type Safety: Strong type system with inference
• COBOL Compatibility: Generate valid, idiomatic COBOL code

Features

Language Features

• Modern type system (decimal, text, etc.)
• Structured control flow (if/elif/else, loops)
• Procedure definitions with parameters
• Lexical scoping with proper variable management
• Reserved word handling and name mangling

Compiler Features

• Coba → COBOL: Compile modern Coba code to COBOL
• COBOL → Coba: Decompile existing COBOL to readable Coba
• Recursion Detection: Build call graphs and detect recursive patterns
• GO TO Elimination: Convert spaghetti code to structured control flow
• Type Inference: Reverse-engineer types from PICTURE clauses
• Column Rule Handling: Proper COBOL positional syntax support

Architecture

The project is organized as a Rust workspace with the following crates:

• coba-lexer: Tokenization for both Coba and COBOL
• coba-parser: Parsing to Abstract Syntax Tree
• coba-ast: AST node definitions
• coba-semantic: Type checking and semantic analysis
• coba-codegen: Code generation (Coba ↔ COBOL)
• coba-cli: Command-line interface

Example

dec(9,2) totalPrice = 0.00
text(50) customerName = "John Doe"

function calculateTotal(dec(9,2) price, dec(5,0) quantity) {
    set totalPrice = price * quantity
}

Compiles to valid COBOL with proper PICTURE clauses, PROCEDURE DIVISION structure, and column formatting.

Edge Cases

Coba handles various COBOL edge cases gracefully:

• Numeric Precision: Documents maximum values, runtime overflow errors
• Text Truncation: Truncates to declared length (COBOL behavior)
• Division by Zero: Compiles successfully, runtime error in COBOL
• Empty Procedures: Valid syntax, generates empty COBOL paragraphs
• Reserved Words: Automatic escaping/mangling of COBOL keywords
• Deep Nesting: Supports arbitrary nesting levels (tested to 20+)

Development

Building

cargo build

Running

# Compile Coba to COBOL
cargo run --bin coba-cli compile input.coba output.cob

# Decompile COBOL to Coba
cargo run --bin coba-cli decompile input.cob output.coba

Testing

cargo test

Project Status

🚧 In Active Development 🚧

This project is currently in early development. Core features are being implemented.

License

MIT

Contributing

Contributions are welcome! Please see our contributing guidelines for more information.