15.3 Lex and Yacc

You might encounter Lex and Yacc in the course of compiling programs that read configuration files or commands. These tools are building blocks for programming languages.

• Lex is a tokenizer that transforms text into numbered tags with labels. The GNU/Linux version is named flex. You may need a -ll or -lfl linker flag in conjunction with Lex.
• Yacc is a parser that attempts to read tokens according to a grammar. The GNU parser is bison; to get Yacc compatibility, run bison -y. You may need the -ly linker flag.