Basic example using flex and bison

A quick example to get yourself started with flex and bison. If you want to start creating a quick parser out of the box, it may take too long to get a basic setup working. This repo is meant to get you started.

graph TD;
    A[parser.y]--bison--> B[parser.tab.h];
    A--bison--> C[parser.tab.c];
    B--lex--> D[tokenizer.c];
    E[tokenizer.l]--lex--> D;
    C--cc--> F[parser]
    B--cc--> F
    D--cc--> F

Loading

This graph shows the build flow to create the parser executable (see Makefile)

About flex and bison

Flex and bison are tools for generating lexical analyzers (scanners) and parsers respectively, for use in development of compilers and interpreters. They are the GNU alternatives for lex and yacc.

Mac OSX

brew install flex bison

Linux

sudo apt install flex bison

Build and execute

$ make
bison -d parser.y
flex -o tokenizer.c tokenizer.l
cc parser.tab.c tokenizer.c -o parser -O2 -lc -ll
$ ./parser 
heat off target temperature 62 heat on
        Heat turned off
        Temperature set to 62 Fahrenheit
        Heat turned on

Reference links

• Flex project page
• Flex wiki
• Bison project
• Bison wiki