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Postings from October 2003
>>>>> "Roy" == Roy Johnson <rjohnson22@ercot.com> writes: Roy> defined() should evaluate its arguments in a context [I'm using this Roy> term generically] wherein only undef is false. The normal usage of Roy> defined() is unchanged: if you give it an undef value, it returns false, Roy> otherwise, it returns true. However, if you give it a complex Boolean Roy> argument, all of the logical operators recognize undef as false, and Roy> everything else as true, and logical operators yield undef instead of Roy> normal-perl-false. Roy> Examples: Roy> defined($v = a() || b()) ## equivalent to $v = a() // b(); Roy> defined($v ||= a()) ## equivalent to $v //= a(); Roy> defined($v = \( $a && $b && $c && 'full')) How far down would it reach? Is it merely lexical, or is it dynamic? That is, if I call a subroutine within that "change false to mean only undef" scope, does the subroutine inherit the modified falseness? I don't like creating new "action at a distance" settings. -- Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095 <merlyn@stonehenge.com> <URL:http://www.stonehenge.com/merlyn/> Perl/Unix/security consulting, Technical writing, Comedy, etc. etc. See PerlTraining.Stonehenge.com for onsite and open-enrollment Perl training!Thread Previous | Thread Next