The only reason the normalized designation is a field is purely a syntactic one: it makes it (admittedly slightly!) easier to print within a string: print qq{$standart->{des} ($standart->{norm_des})\n}; looks nicer than print qq{$standart->{des} (} . normalized( $standart->{des}) . qq{)\n};. Otherwise it would be really easy to use a Memoize-ed function to compute it on the fly.

And (before you jump on this one ;--) yes, if I used objects I could use the printf version which looks ok: printf( "%s (%s)\n", $standard->des, $standard->norm_des);

I guess it's purely a matter of personal preference here, but I usually leave OO out of smallish scripts, and comment my data structures.