I just released version 0.2.2 of PHP_LexerGenerator. This release fixes two bugs, one where / characters were erroneously being replaced by \ characters in regular expressions, and another where lexers with no %statename processing instruction were outputting "const 1=1;" which is invalid PHP.
Otherwise, the release is identical. I recommend upgrading because of the first bugfix - this could be a significant problem for many lexers.
more info is at http://pear.php.net/PHP_LexerGenerator