Lexical Analyzer
토큰으로 잘개 쪼개는 부분을 어휘 분석기
스캐너를 생성하는 도구인 LEX
FLEX Tutorial
FLEX (Fast LEXical analyzer generator) is a tool for generating scanners. In stead of writing a scanner from scratch, you only need to identify the vocabulary of a certain language (e.g. Simple), write a specification of patterns using regular expressions (e.g. DIGIT [0-9]), and FLEX will construct a scanner for you.
http://alumni.cs.ucr.edu/~lgao/teaching/flex.html

Flex - a scanner generator
Vern Paxson Copyright (C) 1990 The Regents of the University of California. All rights reserved. This code is derived from software contributed to Berkeley by Vern Paxson. The United States Government has rights in this work pursuant to contract no. DE-AC03-76SF00098 between the United States Department of Energy and the University of California.
https://ftp.gnu.org/old-gnu/Manuals/flex-2.5.4/html_mono/flex.html
flex & bison
Chapter 1. Introducing Flex and Bison The earliest compilers back in the 1950s used utterly ad hoc techniques to analyze the syntax of the source code of programs they were compiling. During the 1960s, the field got a lot of academic attention, and by the early 1970s, syntax analysis was a well-understood field.
https://www.oreilly.com/library/view/flex-bison/9780596805418/ch01.html

Seonglae Cho