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Postings from July 2010
On Wed, Jul 28, 2010 at 15:40, Jan Dubois <jand@activestate.com> wrote: > On Wed, 28 Jul 2010, Zefram wrote: >> Jan Dubois wrote: >> >Well, you _could_ add a special case to the string comparison: >> >> That would be a mess. The better solution is for negative zero to >> stringify as "0". > > Indeed. > > <not-really-serious> > Or add a pragma to tree "-0" as false in boolean context: > > use feature "minus_zero_is_false"; > print "Yes" if "-0"; > > would then not print anything. > </not-really-serious> > > I'm more and more convinced that using a floating point number in > boolean context is simply something you should not be doing for > similar reasons that you generally are not comparing floating point > numbers for equality. > > Cheers, > -Jan > > Yeah, there are definitely problems with testing floats for truthiness: perl -MO=Deparse -e 'print "doesn't print" unless .1 * 4 - .1 * 3 - .1' perl -MO=Deparse -e 'print "prints" unless .1 - .1' I should probably mention that in the "Truth and Falsehood" section of perlsyn as well. -- Chas. Owens wonkden.net The most important skill a programmer can have is the ability to read.Thread Previous | Thread Next