use strict;
use warnings;
use HOP::Lexer 'string_lexer';
use Data::Dumper;
my $document = join '', <DATA>;

my @keywords = (
    'PRODUCT:',
    'SUBJECT:',
    'SUBMITTED BY:',
    'SUBMITTED DATE:',
    'IR #:',
    'DOCUMENT ID:',
    'PLATFORM:',
    'OPERATING SYSTEM:',
    'OS VERSION:',
    'PRODUCT VERSION:'
);

my @input_tokens = (
    [ 'KEYWORD', qr/(?i:@{[join '|', map {$_} @keywords]})/ ],
    [ 'TEXT', qr/(.*)/, \&text ],
);

my $lexer = string_lexer( $document, @input_tokens );

while ( defined( my $token = $lexer->() ) ) {
    my ( $label, $value ) = @$token;
    print $label, "  =>  ", $value, "\n";

    #print Dumper($token);

}

sub text {
    my ( $label, $value ) = @_;
    for ($value) {
        s/^\s+//;
        s/\s+$//;
    }

    return [ $label, $value ];
}

__DATA__
PRODUCT:      NX_Nastran
SUBJECT: How can I multiply the displacement vector by a matrix?

SUBMITTED BY: TOM ZHANG                 SUBMITTED DATE:   02/07/2006
IR #:         5395926                   DOCUMENT ID:      001-5395926
PLATFORM:     INTEL                     OPERATING SYSTEM: WINDOW
OS VERSION:   XP32_SP2                  PRODUCT VERSION:  V4.0

===============================================================================

HARDWARE
--------
Family	    : NX_NASTRAN
Application : NASTRAN
Function    : DMAP
Subfunction : ALL
Release     : V4.0

Platform    : INTEL
OS	    : WINDOW
OS Version  : XP32_SP2

SYMPTOM
-------
This article discusses writing a DMAP that performs multiplication of the 
displacement vector by a matrix. SOL 101 is used. The article discusses 
these concerns:

1. what data block is the displacement vector?
2. how to handle multiple subcases?
3. which print module to use

SOLUTION
--------
Answer:
1. The displacement vector is UG. It is generated in subDMAP SEDISP (you can 
use DIAG 14 to print the whole thing in the f06 file and search for SEDISP).
You can put your alter in any place in SEDISP after it is created. A suggested 
entry point is after line 587. You can use something like ALTER 'CALL SESUM' 
this is better than "ALTER 587' because the latter would break if the subDMAP 
SEDISP changed.

REFERENCES
----------------

===============================================================================

-- End of document --