That wasn't sarcasm. I meant that if you mean to flatten a multi-level key into a string you find out the maximum length of each key component (or truncate and pad) and join them together in the proper order after padding. I include both a Lotus Domino @Formula and some perl code because I find both to be really, really typical. The Lotus Domino code is a bit simpler because the sorting is actually occuring just outside of this snippet in a View so all you see here is the serialization of a single record's keys.

REM { Sorting by three values for Lotus Domino (in a single view colum
+n). }
MaxLength := 255;

@Implode( @Transform(
    A : B : C;
    "key";
    @If(
        @Length( key ) > 255;
        @Left( key; MaxLength );
        key + @Repeat( @Char( 0 ); MaxLength - @Length( key ) ) )
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# Sorting a three level hash in perl
my $a_len = max( map length(),
                 keys %h );
my $b_len = max( map length(),
                 map keys %$_,
                 values %h );
my $c_len = max( map length(),
                 map keys %$_,
                 map values %$_,
                 values %h );
my $fmt = "a$a_len a$b_len a$c_len";

# Assumes \0 is not present in any keys
my @sorted_keys =
    ( map [ unpack( "a$a_len a$b_len a$c_len ",
                    $_ ) ],
      sort
      map( {
          my $a = $_;
          map( {
              my $b = $_;
              map( { pack( "a$a_len a$b_len a$c_len",
                           $a,      $b      $_ ) }
                   keys %{ $h{ $a }{ $b } } )
              } keys %{ $h{ $a } } )
          } keys %h );
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