$A += ('(A)' =~ m(\(A\)))[0] == ('(A)' =~ m((A)))[0];
$A += ('(A)' =~ m|\(A\)|)[0] == ('(A)' =~ m|(A)|)[0];

##</code><code>##

DB<1> $a = qr((a));     print "'$a'  "; print '(a)' =~ m|$a|
'(?-xism:(a))'  a
DB<2> $a = qr(\(a\));   print "'$a'  "; print '(a)' =~ m|$a|
'(?-xism:(a))'  a
DB<3> $a = qr(\\(a\\)); print "'$a'  "; print '(a)' =~ m|$a|
'(?-xism:\\(a\\))'  
DB<4> $a = qr|\(a\)|;   print "'$a'  "; print '(a)' =~ m|$a|
'(?-xism:\(a\))'  1