# J David Eisenberg

• About: Signed up to make a comment.
• Commented on A follow up on three-value logic in Perl
Maybe I'm not thinking this through carefully enough, but, since undef coerces to zero, couldn't the original problem be solved with: if ( \$employee->salary > 0 && \$employee->salary < \$threshold ) Also, is unknown analogous to NaN (not a number)?...
• Commented on Perl tutorials suck (and cause serious damage)
I wrote some material for a Perl course that I teach; http://evc-cit.info/cit042 (see the "Additional Readings" section, which uses my material and some perldoc material). Anyone who wishes to use my material may feel free to do so....
Recent Actions from J David Eisenberg

• StommePoes commented on Perl tutorials suck (and cause serious damage)

Meta keywords are almost entirely useless. Because, as so many other things, they were ruined by spammers.

Yahoo bots do look at it, but they don't count as anything towards perceived relevancy.

• barricas commented on Perl tutorials suck (and cause serious damage)

Have the 'known good' tutorials link each other, or perhaps have learn.perl.org link them and perhaps provide a 'certified good tutorials' image link. Automate this as much as possible.

• Ovid commented on A follow up on three-value logic in Perl

J David Eisenberg: that looks tempting and it might be right for some code. However testing for \$employee->salary being greater than zero skips a use case: what if an employee's salary is legitimately at zero and they should have the increase?

Or we could skip the "salary" idea altogether and talk about any situation whereby something might need adjustment and undef gets coerced to zero when, in fact, it might not actually mean that. If a distinction is needed between undef and zero and it's not made, code can easily make bad assumptions.

• Buddy Burden commented on A follow up on three-value logic in Perl

The problem with ditching the stringification is that it could make debugging problematic.

I'm interested to see where this goes.

• Ovid commented on A follow up on three-value logic in Perl

Try the "fatal" option. Stringification is ditched, but it gives you a nice stack trace so you can (hopefully) figure out how you got there.

Responses to Comments from J David Eisenberg