#!/usr/bin/perl
use strict;
use warnings;
use Carp qw(confess);
use Data::Dumper;
my @lines = <DATA>;
for (@lines) { $_ =~ s/^\s+//; chomp; }
close DATA;

sub match_block {
    my $first = shift @lines;
    $first =~ m/BEGIN\s+(\S+)/ or confess "Invalid data format in line <<$first>>, expected a BEGIN";
    my $block_name = $1;
    my @contents;
    while (@lines && $lines[0] !~ m/^END/){
        if ($lines[0] =~ m/^BEGIN/){
            push @contents, match_block(); # recurse here
        } else {
            my $current = shift @lines;
            push @contents, ['LINE', split(m/\s+/, $current, 2)];
        }
    }
    if (@lines){
        my $terminator = shift @lines;
        if ($terminator !~ m/^END\s*\Q$block_name\E/){
            die "Syntax error: expected 'END $block_name', got '$terminator'";
        }
    }

    return ['BLOCK', $block_name, @contents];
}
print Dumper match_block();


__DATA__
   BEGIN DSRECORD
      Identifier "ROOT"
      DateModified "1899-12-30"
      TimeModified "00.00.01"
      OLEType "CJobDefn"
      Readonly "0"
      Name "AP_CDBS_Vendor_Summary"
      Description "Collates all of the data for the customer master migration."
      NextID "194"
      Container "V0"
      FullDescription "The first part of the routine gathers data from the ABAP which extracts the necessary data from the SAP tables KNA1 and KNB1 (NB the key s of the link between KNA1 and KNB1 will form the basis of all the ABAP queries )."
      JobVersion "50.0.0"
      ControlAfterSubr "0"
      Parameters "CParameters"
      BEGIN DSSUBRECORD
         Name "ROOT"
         Prompt "/home/migration/Dev root "
         Default "/home/migration/Dev"
         ParamType "0"
         ParamLength "0"
         ParamScale "0"
      END DSSUBRECORD
      BEGIN DSSUBRECORD
         Name "SITE"
         Prompt "Business Unit, ie WHUB"
         Default "CDBS"
         ParamType "0"
         ParamLength "0"
         ParamScale "0"
      END DSSUBRECORD
      BEGIN DSSUBRECORD
         Name "AOW"
         Prompt "Area of Work ie AP"
         Default "AP"
         ParamType "0"
         ParamLength "0"
         ParamScale "0"
      END DSSUBRECORD
      BEGIN DSSUBRECORD
         Name "DMR"
         Prompt "DMR/Spec ie Vendors"
         Default "Vendors"
         ParamType "0"
         ParamLength "0"
         ParamScale "0"
      END DSSUBRECORD
      MetaBag "CMetaProperty"
      BEGIN DSSUBRECORD
         Owner "APT"
         Name "AdvancedRuntimeOptions"
         Value "#DSProjectARTOptions#"
      END DSSUBRECORD
      NULLIndicatorPosition "0"
      IsTemplate "0"
      NLSLocale ",,,,"
      JobType "0"
      Category "1.FSS\\2.AP\\6.CDBS\\1.Vendors\\3.Reports"
      CenturyBreakYear "30"
   END DSRECORD