Y 034309201607258   1        #Y means header
Q     02751VACANT / CLOSE    #comment
G   ....            # inner head
...
...
...                          
T RCRC   0810010
T RDRD   0810010
A 22OP
A 13O 
A 12O 
P 3472CHSK00010014 #P means inner trailer
Z 034309201607258  #Z means trailer


##</code><code>##

use Parse::RecDescent;
  use IO::All;

  my $text = io("xxx.DAT")->slurp;
  # Create and compile the source file
  $parser1 = Parse::RecDescent->new(q(
    startrule : HeadRule /.+/ms TrailerRule 

    HeadRule : /^Y.+$/m
    TrailerRule: /^Z.+$/m
  ));

  $parser2 = Parse::RecDescent->new(q(
    startrule : HeadRule 

    HeadRule : /^Y.+^Z.+$/ms

  ));


# Test it
  print "Valid data\n" if $parser1->startrule($text); #no!
  print "Valid data\n" if $parser2->startrule($text); #yes