Perl's comma operator , performs several duties. The most widely known duty is to serve as a list separator. List separators are called fat commas [Conway 05].:
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my @list = (2, 3, 5, 7); |
Outside of list context, the comma can also be used to combine multiple expressions into one statement. Each expression is evaluated, and its result is discarded. The last expression's result is returned as the result of the comma operator. Comma operators are called thin commas [Conway 052005]. This behavior was adopted from C.
The potential for confusing thin commas with fat commas in list context is large enough to forbid use of thin commas. Commas shall must be used only to separate items in list context.
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| [Conway 2005] | "Thin Commas," p. 68 |
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| [CPAN] | Elliot Shank, Perl-Critic-1.116 ValuesAndExpressions::ProhibitCommaSeparatedStatements |
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