expression. I<STRING> is interpolated the same way as I<PATTERN>
in C<m/PATTERN/>. If "'" is used as the delimiter, no interpolation
is done. Returns a Perl value which may be used instead of the
-corresponding C</STRING/imosx> expression.
+corresponding C</STRING/imosx> expression. The returned value is a
+normalized version of the original pattern. It magically differs from
+a string containing the same characters: ref(qr/x/) returns "Regexp",
+even though dereferencing the result returns undef.
For example,
$rex = qr/my.STRING/is;
+ print $rex; # prints (?si-xm:my.STRING)
s/$rex/foo/;
is equivalent to