Alex and Happy
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Alex and Happy

Lexers and Parsers in Haskell

About the Book

This is a book-in-progress about building lexers and parsers in Haskell for beginning to intermediate Haskell programmers. Please send your feedback to

About the Author

Jyotirmoy Bhattacharya
Jyotirmoy Bhattacharya

Jyotirmoy Bhattacharya teaches Economics at Bharat Ratna Dr. B.R. Ambedkar University, New Delhi. He has been programming since he was 13. Visit his blog to follow his explorations in economics, mathematics and programming.

Table of Contents

  • Preface
    • Cover image
  • 1. Introduction
    • 1.1 Lexers and parsers
    • 1.2 Alex and Happy
  • 2. A Basic Lexer
    • 2.1 Structure of an Alex file
  • 3. Monadic Parsers and Lexers
    • 3.1 The Lexer
    • 3.2 The Abstract Syntax Tree Type
    • 3.3 The Parser
    • 3.4 The Driver
  • 4. Significant Whitespace
    • 4.1 Imports
    • 4.2 Alex rules
    • 4.3 Datatypes and utility functions
    • 4.4 Lexer actions
    • 4.5 Driver
  • 5. Parsing comments and strings: Startcodes
    • 5.1 Token definitions
    • 5.2 The state
    • 5.3 The Lexer Actions
    • 5.4 String lexing actions
    • 5.5 Comment lexing actions
    • 5.6 The driver

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