Oak COBOL Parser

High-performance incremental COBOL parser for the oak ecosystem with flexible configuration, optimized for legacy system analysis and mainframe development.

🎯 Overview

Oak COBOL is a robust parser for COBOL, designed to handle complete COBOL syntax including legacy and modern features. Built on the solid foundation of oak-core, it provides both high-level convenience and detailed AST generation for legacy system analysis and mainframe development.

✨ Features

• Complete COBOL Syntax: Supports all COBOL features including legacy specifications
• Full AST Generation: Generates comprehensive Abstract Syntax Trees
• Lexer Support: Built-in tokenization with proper span information
• Error Recovery: Graceful handling of syntax errors with detailed diagnostics

🚀 Quick Start

Basic example:

use oak_cobol::{Parser, CobolLanguage, SourceText};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let parser = Parser::new();
    let source = SourceText::new(r#"
       IDENTIFICATION DIVISION.
       PROGRAM-ID. HELLO-WORLD.
       
       ENVIRONMENT DIVISION.
       CONFIGURATION SECTION.
       
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01 WS-MESSAGE PIC X(20) VALUE 'Hello, World!'.
       
       PROCEDURE DIVISION.
       MAIN-PROCEDURE.
           DISPLAY WS-MESSAGE
           STOP RUN.
    "#);
    
    let result = parser.parse(&source);
    println!("Parsed COBOL program successfully.");
    Ok(())
}

📋 Parsing Examples

Program Parsing

use oak_cobol::{Parser, CobolLanguage, SourceText};

let parser = Parser::new();
let source = SourceText::new(r#"
IDENTIFICATION DIVISION.
PROGRAM-ID. CALCULATOR.

DATA DIVISION.
WORKING-STORAGE SECTION.
01 NUM1 PIC 9(3) VALUE 10.
01 NUM2 PIC 9(3) VALUE 20.
01 RESULT PIC 9(4).

PROCEDURE DIVISION.
MAIN-PROCEDURE.
    COMPUTE RESULT = NUM1 + NUM2
    DISPLAY 'Result: ' RESULT
    STOP RUN.
    "#);

let result = parser.parse(&source);
println!("Parsed COBOL program successfully.");

Data Division Parsing

use oak_cobol::{Parser, CobolLanguage, SourceText};

let parser = Parser::new();
let source = SourceText::new(r#"
DATA DIVISION.
WORKING-STORAGE SECTION.
01 CUSTOMER-RECORD.
    05 CUSTOMER-ID PIC 9(5).
    05 CUSTOMER-NAME PIC X(30).
    05 CUSTOMER-BALANCE PIC 9(7)V99.
    "#);

let result = parser.parse(&source);
println!("Parsed COBOL data division successfully.");

🔧 Advanced Features

Token-Level Parsing

use oak_cobol::{Parser, CobolLanguage, SourceText};

let parser = Parser::new();
let source = SourceText::new("IDENTIFICATION DIVISION.");
let result = parser.parse(&source);
// Token information is available in the parse result

Error Handling

use oak_cobol::{Parser, CobolLanguage, SourceText};

let parser = Parser::new();
let source = SourceText::new(r#"
IDENTIFICATION DIVISION
PROGRAM-ID. INVALID
DATA DIVISION
PROCEDURE DIVISION
    DISPLAY 'Missing periods'
    STOP RUN
    "#);

let result = parser.parse(&source);
if let Err(e) = result.result {
    println!("Parse error: {:?}", e);
}

🏗️ AST Structure

The parser generates a comprehensive AST with the following main structures:

• Program: Root container for COBOL programs
• IdentificationDivision: Program identification information
• EnvironmentDivision: Environment and configuration settings
• DataDivision: Data definitions and working storage
• ProcedureDivision: Program logic and procedures
• Statement: Various COBOL statement types
• Expression: Arithmetic and conditional expressions

📊 Performance

• Streaming: Parse large COBOL files without loading entirely into memory
• Incremental: Re-parse only changed sections
• Memory Efficient: Smart AST node allocation
• Fast Recovery: Quick error recovery for better IDE integration

🔗 Integration

Oak COBOL integrates seamlessly with:

• Legacy System Analysis: Analyze and understand legacy COBOL codebases
• Mainframe Development: Build tools for mainframe development environments
• Migration Tools: Convert COBOL code to modern languages
• IDE Support: Language server protocol compatibility for COBOL
• Documentation Tools: Extract documentation from COBOL source code

📚 Examples

Check out the examples directory for comprehensive examples:

• Complete COBOL program parsing
• Data division analysis
• Procedure division extraction
• Integration with development workflows

🤝 Contributing

Contributions are welcome!

Please feel free to submit pull requests at the project repository or open issues.