While I was looking at regex to reverse string, I thought about re-inventing the reverse function with regex only. So I wrote routine: 
sub rev ($) {
    $_ = shift;
    s/^(.)(.*)$/swap($2)."$1"/e if (length>1);
#    print "in swap: $_\n";
    return $_;
}

[download]
This does not work. For instance, if I feed asdfghjkl;', I get back ';;lkjhgfds. It appears to me $1 and $2 are overwritten at each level of recusion, although these should be localized. Am I missing something here?

Update: I meant to type: 

sub rev ($) {
    $_ = shift;
    s/^(.)(.*)$/rev($2)."$1"/e if (length>1);
#    print "in rev: $_\n";
    return $_;
}

[download]

Update at author's req. - dvergin 2003-08-31

In reply to Recursion and scoping of $1, $2 and friends by asarih

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