There is a difference in operator precedence between $cell || next and $cell or next, so they're not quite the same. While they're effectively identical in this case, even the minor modification of adding an assignment results in $x = $cell || next and $x = $cell or next behaving differently.

The efficiency explanation you've heard is accurate when dealing with extremely-close-to-the-metal languages and non-optimizing compilers, since testing whether a memory location already holds the value 0 is one of the fastest tests you can do at the machine level. But optimizing compilers are smart enough to figure out for themselves that if (not $cell) ... is equivalent to $cell || ... while still allowing you to write it the more readable way, and Perl is so far from the metal that these kinds of concerns are completely inapplicable anyhow.

In reply to Re^3: next unless condition by dsheroh
in thread next unless condition by hankcoder

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