sub splitAB
{
  my $STRING = shift;
  my $PATTERN = shift;
  # when debugging "print is your friend"
  
  print "pattern in sub splitAB= $PATTERN\n"; #####
  print "string in sub splitAB = $STRING\n"; #####
  my @OUTPUT = split(/\Q$PATTERN\E/, $STRING, 2); #####
  $a = $b = '';
  if (@OUTPUT > 0) { $a = $OUTPUT[0]; }
  if (@OUTPUT > 1) { $b = $OUTPUT[1]; }
}

sub decodeURLstr
{
  my $S = shift;
  return unescape( join(' ', split('\+', $S) ) ); #####
}

##</code><code>##

pattern in sub splitAB= ?
string in sub splitAB = file:///c:/html/testing.html?P1=123&P2=%28%28BLAH+BLAH+BLAH%29%29
pattern in sub splitAB= #
string in sub splitAB = P1=123&P2=%28%28BLAH+BLAH+BLAH%29%29

R: P1
R: 123
R: P2
R: ((BLAH BLAH BLAH))
Process completed successfully

##</code><code>##

my @OUTPUT = split(/\Q$PATTERN\E/, $STRING, 2); #####
  $a = $b = '';
  if (@OUTPUT > 0) { $a = $OUTPUT[0]; }
  if (@OUTPUT > 1) { $b = $OUTPUT[1]; }

##</code><code>##

($a, $b) = split(/\Q$PATTERN\E/, $STRING, 2); #####
  $a //= '';  #null string if undefined
  $b //= '';  #null string if undefined