Re^3: Parsing and extracting data from files.

Well, after some reading, I ended up attempting RecDescent (only because it ended up 1st on my list), and have started as follows:

#!/usr/bin/perl

use vars qw(%VARIABLE);
use Data::Dumper;
use Parse::RecDescent;
$::RD_ERRORS = 1;
$::RD_HINT = 1;
$::RD_WARN = 1;
$::RD_TRACE = 1;

my %album = (
  Title => 'The Collected Works of Mozart',
  Performer => 'The Royal Symphonic Orchestra',
  Barcode => '1234567890123',
);
my %hash1 = (
  Title => 'Disk 1',
  Type  => 'Audio',
  Foo   => 'bar',
);
my %hash2 = (
  Title => 'Disk 2',
  Type  => 'Audio',
  Foo   => 'FooBar',
);
my %hash3 = (
  Title => 'Chopsticks',
  Performer => 'Pascal Roge',
  ISRC => 'AABBB1122222',
);        # Example data for illustration purposes.

$album{'Disc'}[0]=\%hash1;        # Example data, stored as Disc[0].
$album{'Disc'}[1]=\%hash2;        # Example data, stored as Disc[1].
$album{'Disc'}[1]{'Track'}[0]=\%hash3;    # Disc 2 Track 1

#=========== Start of actual parsing code ============================
+========

my $file = '/home/Media/Music/tmp/01.toc';

{
  local $/;
  undef $/;
  
  open my $grammarfh, '<', 'TOC.bnf' or die "Arghh! Cannot open gramma
+r.\n";
  $grammar = <$grammarfh>;

  open my $fh, '<', $file or die "Arghh! Cannot open file.\n";
  $text = <$fh> ;
}

my $parser = new Parse::RecDescent($grammar) || die "Bad Grammar!\n";
my $cd = $parser->contents($text);

push @{$album{'Disc'}}, $cd;            # Not quite right! Check.. Cop
+y data, not store a reference.

print Dumper(\%album);
print Dumper(\%VARIABLE);        # Perhaps we should store the parsed 
+info in here?

print Dumper($cd);

sub subroutine {
  shift; print "Entered Subroutine\n";
  my ($foo, $bar) = @_;
  return $foo;
[download]

It has been drafted specifically to load the grammar from an external file. It allows me to edit thta just a little easier, but also allows me to reuse the same code por parsing a CUE file later. However, it is the grammar that is proving frustrating. This is what I have so far...

#===============================================#
# RecDescent grammar to parse a CD TOC file.    #
#===============================================#

{
  # Nothing here yet.
}

# Grammar:
contents:    line(s?)        # <skip: qr/[^\S\n]/>
line:            text { }
                | Parameter {$return = $item{'Parameter'};}
                | word foo { $main::VARIABLE{$item{'word'}}=$item{'foo
+'} } # not quite sure how this will be useful...
                | text
                | word {
                  $return = $item{'word'};
                }
                | BlankLine 
#                | Comment
                | <error>
                
# Next line not quite right. Consider using $VARIABLE
Parameter:    word qstring { $return = { $item{'word'} => $item{'qstri
+ng'} }; }

# CD_TEXT is *always* followed by a <CR>, then LANGUAGE_MAP or LANGUAG
+E.
# Should I be considering recursion here?
text:            /CD_TEXT {/ { return main::subroutine(@item) }
setting:        /LANGUAGE_MAP \d/ { print "Map\n"; }
                | /LANGUAGE \d/ { print "Lang\n"; }
                
# Tokens:
BlankLine:    <skip: q{}> /^\s+$/m
Comment:        <skip: qr{\s* (/[*] .*? [*]/ \s*)*}x>
word:         /\w+/
msf:            /\d\d:\d\d:\d\d/
newline:        /\n/
number:         /\d+/


qstring:        '"'/[^"]+/'"' { $return = $item[2]; }
#qstring:        <perl_quotelike>         # See http://www.perlmonks.o
+rg/?node_id=485933
#                    { my ($marker, $quote, $text) = @{$item[0]}[0..2]
+; }


foo:            /\d+.\d+.\d+/            # This will match both 14:43:
+00 and 38935137
[download]

Apologies - it is quite awful at the moment, but I am too tired and confused to start tidying it up... If you have the time, I could do with a pointer or two. I have a feeling that I should be calling recursively to parse the CD_TEXT, but I am afraid I don't know RecDescent well enough.

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