I called it a trick because it exploits undefined behaviour in the language. perl 5.10, 5.12 or some future version may or may not preserve the same behaviour, so it seems to me bad practice to promulgate it's use.
As I'm sure you know, perldoc perlsyn states:
NOTE: The behaviour of a "my" statement modified with a statement modi‐
fier conditional or loop construct (e.g. "my $x if ...") is undefined.
The value of the "my" variable may be "undef", any previously assigned
value, or possibly anything else. Don’t rely on it. Future versions
of perl might do something different from the version of perl you try
it out on. Here be dragons.
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Ah. I wasn't suggesting my $value if 0;, nor would that work to make the sub close over the outer $value. I was suggesting $value if 0;, to incorporate a reference to the outer $value into the sub, while avoiding the "Useless use of a variable in void context" warning you'd get from a bare $value;.
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[d/l]
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while (tight_loop) {
write_to_log("Some msg involving $somevar") if REALLY_HEAVY_DEBUG;
some_more_code();
}
if the constant evaluated to 0. I guess if $somevar was relevant to the debugging then it would be closed over anyway, but that is a bit too subtle.
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[d/l]
[select] |