use warnings;
use strict;
use 5.010; # required for Regexp::Grammars

my $parser = do {
  use Regexp::Grammars;
  qr{
    <[Block]>*
    <rule: Block>       <BlockName=Word> \{ <[BlockItem]>* \}
        (?{ $MATCH = { $MATCH{BlockName} => $MATCH{BlockItem} } })
    <rule: BlockItem>   (?: <Block> | <KeyValue> )
        (?{ $MATCH = $MATCH{KeyValue} || $MATCH{Block} })
    <rule: KeyValue>    <Key=Word> (?: <Value=Word>
      | \[ <[Value=Word]>* % \s+ \] ) \;
        (?{ $MATCH = { $MATCH{Key} => $MATCH{Value} } })
    <token: Word>       [\w-]+
  } };

my $input = do { open my $fh, '<', '1112435.txt' or die $!;
  local $/; <$fh> };

$input =~ $parser
  or die "Failed to parse input";

use Data::Dump 'pp';
say pp $/{Block};