Compiler Design & Systems Software Lab

Lex/Flex and Yacc/Bison Programs

Building and Running Lex Programs

lex filenamehere.l
gcc lex.yy.c -ll # use -lfl for flex

./a.out <command line args>

A two step compilation is not convenient if you are using the terminal. Here is a trick to compile in one step:

# Setup:
echo "lex \$1 && gcc lex.yy.c -ll" > lexy.sh
alias lexy="sh lexy.sh"

# Usage:
lexy my_lex_program.l
./a.out <command line args>

lex filenamehere.l
yacc -d filenamehere.y
gcc lex.yy.c y.tab.c -ll # use -lfl for flex

./a.out <command line args>

Here is a trick to compile in one step:

# Setup:
# copy yax.sh to current directory
alias yax="sh lexy.sh"

# Usage:
yax filenamehere.l filenamehere.y
./a.out <command line args>

I would recommend that you put the shell scripts in a fixed location and add the aliases to your .bashrc or .bash_aliases.