Editing GNU Bison (section)

===A GPL-compatible license is not required===
The code generated by Bison includes significant amounts of code from the Bison project itself. The Bison package is distributed under the terms of the [[GNU General Public License]] (GPL) but an exception has been added so that the GPL does not apply to output.<ref>[https://www.gnu.org/software/bison/manual/html_node/Conditions.html Bison Manual: Conditions for Using Bison]</ref><ref>[http://git.savannah.gnu.org/cgit/bison.git/tree/src/parse-gram.c A source code file, parse-gram.c, which includes the exception]</ref>

Earlier releases of Bison stipulated that parts of its output were also licensed under the GPL, due to the inclusion of the yyparse() function from the original source code in the output.