Perl provides three logical operators: &&, ||, and !, and they have the same meaning as in C.
Wiki Markup and}}, {{or}}, and {{not}}. They have the same meanings as {{&&}}, {{||}}, and {{\!}}. They have much lower binding precedence, which makes them useful for control flow \[ [Wall 2011|AA. Bibliography#Manpages]\]. They are called the late-precedence logical operators, whereas {{&&}}, {{||}}, and {{!}} are called the early-precedence logical operators.
It is possible to mix the early-precedence logical operators with the late-precedence logical operators, but this mixture of precedence often leads to confusing, counterintuitive behavior. Therefore, every Perl expression should use either the early-precedence operators or the late-precedence ones, never both.
Wiki Markup not}} and {{and}} entirely and using {{or}} only in control-flow operations, as a failure mode:
| Code Block | ||
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| ||
print $filehandle $data or croak("Can't write to file: $!");
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...
Tool | Diagnostic |
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Perl::Critic | ValuesAndExpressions::ProhibitMixedBooleanOperators |
Bibliography
Wiki Markup
[Conway 2005] pg. 70
[Wall 2011] perlop
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