1.0 2007/04/02 Fixed Greg's bug, see below, but failed to give him credit.
1.1 2007/04/02 Check return code from eval() in HP.pm. Fixed this bug reported by Greg O'Neil.
Can't locate object method "MainWindow" via package "Tk::Calculator::RPN::HP_21" at /usr/lib/perl5/site_perl/5.8.8/Tk/Calculator/RPN/HP.pm line 163.
at /usr/lib/perl5/site_perl/5.8.8/i586-linux-thread-multi/Tk/Widget.pm line 203
Amazingly, this was all because Tk::LCD and Tk::SlideSwitch were not installed.
1.2 2007/04/02 Display version for tkhpcalc -h, else same as above, CPAN hassles.