#+title: Lexical Analysis in Racket
#+roam_key: http://matt.might.net/articles/lexers-in-racket/
- source :: [[http://matt.might.net/articles/lexers-in-racket/][Lexical analysis in Racket]]
- tags :: [[file:../20210516173327-lexical_analysis.org][lexical analysis]]

* Notes
[[file:../20210307165050-racket.org][Racket]] has a library for making [[file:../20210516173347-lexer.org][lexers]] easily: =parser-tools/lexer=.

#+begin_src racket
#lang racket/base
(require parser-tools/lexer)

(define ab-lexer 
 (lexer 
   [#\a  (display "You matched a.\n")]
   [#\b  (display "You matched b.\n")]))
#+end_src

This will create a lexer that matches input character by character until,
finally, returning ='eof=.

The rest of this article contains a number of useful examples.