Re: What does

It means I've confused yet another generation of budding Perl programmers with a microoptimization that I called for back in the Perl 3 alpha days, and probably can be safely ignored now.

There are very few pieces of Perl that are uniquely mine. This is one of them. Sorry. :)

-- Randal L. Schwartz, Perl hacker

Comment on Re: What does _ mean?

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Re^2: What does _ mean? by holli (Abbot) on Feb 04, 2009 at 16:24 UTC
So how much more expensive is `-e($file) && -f(_)` than `-e($file) && -f($file)`? holli When you're up to your ass in alligators, it's difficult to remember that your original purpose was to drain the swamp.	[reply] [d/l] [select]
Re^3: What does _ mean? by massa (Hermit) on Feb 04, 2009 at 22:59 UTC
Four characters. Six, if you also rip out the parentheses. :-) Seriously, it's not just about saving one system call or half a dozen source code chars (altough I am all in favour of both) -- `-d $filename && -x _ && -k _ && -u _` is simpler, cleaner, and more expressive than the alternative IMHO. BTW, I happen to like even more the perl6ish `$filename ~~ :d & :x & :k & :u`. []s, HTH, Massa (κς,πμ,πλ)	[reply] [d/l] [select]
Re^4: What does _ mean? by ikegami (Patriarch) on Feb 04, 2009 at 23:21 UTC
In Perl 5.10, you can do `-d -x -u $filename` [download]	[reply] [d/l]
Re^3: What does _ mean? by tirwhan (Abbot) on Feb 04, 2009 at 17:05 UTC
`strace -tt -f -e '$file="filename";-e($file) && -f($file)'` (as well as the alternative) says it's exactly one stat system call more expensive, unsurprisingly. Which on the system I tested it on was something like 0.0001 seconds but that will obviously vary. All dogma is stupid.	[reply] [d/l]