I do not recommend this but you can possibly do it very simply. As noted it is already XMLish or even hashish. You can reformat it into a hash quite easily.....

String eval is dangerous but if you own the files and its your box.....

local $/;
my $data = <DATA>;
# unroll line continuations
$data =~ s/\\\n\s+//g;
# munge
$data =~ s/'/\\'/g;   # escape out quote char
$data =~ s/}/},/g;
$data =~ s/\s*{/' => {/g;
$data =~ s/\s*:\s*/' => '/g;
$data =~ s/\s*;/',/g;
$data =~ s/^(\s*)(?=\w)/$1'/mg;

print $data;
my $var = eval "{ $data }";
use Data::Dumper;
print Dumper $var;

__DATA__
library(ABC) {
   date : 04/10/04;
   revision : 1.5;
   conditions () {
      weather : o'bright ;
      temperature : 55 C;
      visible : heavy \
            fog;
   }
   location(work) : 1;
}
[download]

There is no doubt that ParseRecDescent could do a better job. But probably not in less lines.