It is easy to see that $string =~ /#(.*?)$/ could be processed as reverse $string =~ /^(.*?)#/ and it would then produce very different and perhaps more intuitive results.

Those aren't identical. 

$string = "abc#def#ghi";

($x) = $string =~ /#(.*?)$/;
print "$x\n";

($x) = reverse($string) =~ /^(.*?)#/;
$x = reverse $x;
print "$x\n";

----
def#ghi
ghi

[download]
You're still thinking of $ as a starting point versus simply being a zero-width assertion. /#([^#]*)$/ is the one that reverses to /^(.*?)#/. The original regex /#(.*?)$/ is more clearly written as /#(.*)$/. Because you don't have any non-zero-width assertions between the .*? and the $, the non-greedy modifier doesn't actually change any behavior. The reverse of the original is /^(.*)#/ - explicitly greedy.
My criteria for good software:
  1. Does it work?
  2. Can someone else come in, make a change, and be reasonably certain no bugs were introduced?

In reply to Re^2: The "anchor" misnomer in regexes by dragonchild
in thread The "anchor" misnomer in regexes by japhy

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