use strict;
use warnings;

while( my $line = <DATA> ) {
  chomp $line;
  my( $a, $b, $c, $d )
    = split /(?(?=^[^|]*\|)(?{die "Pipe [|] detected in input."})|)[,\t]/,
      $line;
  print "[($a)($b)($c)($d)]\n";
}


__DATA__
ABC,DEF,GHI,JKL
ABC|DEF|GHI|JKL

##</code><code>##

[(ABC)(DEF)(GHI)(JKL)]
Pipe [|] detected in input. at (re_eval 1) line 1, <DATA> line 2.