use warnings;
use strict;
use v5.10;

sub add_incr_suffix
{
  state $suffix = 'A';
  return "prefix-TEXT-" . $suffix++;
}

print 'Test ' .
    ( add_incr_suffix =~ /^prefix-*/p ? ${^POSTMATCH} : '' ) . "," .
    ( add_incr_suffix =~ /^prefix-*/p ? ${^POSTMATCH} : '' ) . "," .
    ( add_incr_suffix =~ /^prefix-*/p ? ${^POSTMATCH} : '' ) . "\n";