Output Languages

OpenLexer generates lexers and parsers in three target languages:

• C - Standard C99
• Java - Java 8+
• Python - Python 3.6+

Language Selection

Use the --lang option:

openlexer gen-lexer --lexer rules.l --lang c --output ./
openlexer gen-parser --parser grammar.y --lang java --output ./

Output Files

File Organization

Each language has specific file organization requirements and best practices:

• Java: Requires one public class per file; generated files are designed to work standalone or together
• C: Can be compiled separately or combined; use preprocessor flags to control test drivers
• Python: Generated files are importable modules

📖 See File Organization Guide for detailed instructions on organizing generated code.

Common Interface

All generated lexers provide:

• Token type constants
• A method to get the next token
• Access to the matched text

All generated parsers provide:

• A parse method that drives the parsing loop
• Semantic value stack management
• Error reporting hooks

Integration

The lexer and parser integrate through a common interface:

Input Text
    │
    ▼
┌─────────┐
│  Lexer  │ ──▶ Token Stream
└─────────┘
    │
    ▼
┌─────────┐
│ Parser  │ ──▶ Parse Result / AST
└─────────┘

Each language chapter describes the specific integration method.