Also, the n$ "format parameter index" attribute of the sprintf format specifier can free you from the capture variable lockstep of $1 .. $n: 

c:\@Work\Perl\monks>perl -wMstrict -le
"my $template = 'all the %3$s %1$s %2$s';
 my $extract  = 'all at sea in ships';
 ;;
 if ($extract =~ m{ \A all \s+ (\w+) \s+ (\w+) \s+ in \s+ (\w+) \z }xm
+s) {
   my $string = sprintf $template,
     $1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13;
   print qq{>$string<};
   }
"
>all the ships at sea<

[download]
Both safe and flexible.

Give a man a fish:  <%-{-{-{-<

In reply to Re^2: Extracting regex from string by AnomalousMonk
in thread Extracting regex from string by mleshin

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