sorting technique

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

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Re: sorting technique by chb (Deacon) on Feb 18, 2005 at 09:55 UTC
`$a` and `$b` are indeed special variables in a sort-block. See `perldoc -f sort` and `perldoc perlvar`.	[reply] [d/l] [select]
Re^2: sorting technique by Anonymous Monk on Feb 18, 2005 at 10:04 UTC
Thanks a lot.	[reply]
Re: sorting technique by gopalr (Priest) on Feb 18, 2005 at 10:07 UTC
Hi, `$c` and `$d` are not special package variables in `sort` function. The `sort` function takes an optional code block, which lets you replace the default alphabetic comparison subroutine with your own. This comparison function is called each time sort has to compare two values. The values to compare are loaded into the special package variables `$a` and `$b`.	[reply] [d/l] [select]
Re: sorting technique by samy_kumar (Scribe) on Feb 18, 2005 at 11:57 UTC
Have alook at this link for more info.	[reply]
Re: sorting technique by Anonymous Monk on Feb 21, 2005 at 12:01 UTC
Yes, $a and $b are special, as mentioned. Think about it, suppose sort would not use special variables, and you could pick any variable you wanted. How would sort than distinguish between: `sort {$a <=> $b}` [download] and `sort {$b <=> $a}` [download] Or what if you have something like: `sort {$a < $c ? $b <=> $d : $a <=> $e}` [download] then what?	[reply] [d/l] [select]
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