Too Hash Happy?

SmokeyB has asked for the wisdom of the Perl Monks concerning the following question:

Is there such as thing as being hash happy? By that I mean can you have too many hashes of hashes of hashes.. and so on, or is there a better way to do it? For example, here's how I have criteria setup for my program:

my %MasterType = (
   'TEXT'   => {
      'function'        => \&run_default,
      'command'         => 'SIIA',
      'linkedHeaders'   => {
         'r#'    => 'INO',
         'rf'    => 'IS1',
         'rt'    => 'ITE',
      },
   },
);
[download]

and from that I call the following function accordingly:

&{%MasterType->{'TEXT'}->{'function'}}(
   %MasterType->{'TEXT'}->{'command'},
   %MasterType->{'TEXT'}->{'linkedHeaders'}
);
[download]

I'm just curious to know if I'm on the right track of things.

Comment on Too Hash Happy? Select or Download Code

Replies are listed 'Best First'.
Re: Too Hash Happy? by bart (Canon) on May 01, 2003 at 19:38 UTC
Sure you can do it that way, but you really ought to be using `$MasterType{'TEXT'}` instead of `%MasterType->{'TEXT'}`. You appear to be using the same hash entry, containing a record, over and over again. It might not be a bad idea to use an alias to that hash entry, or, since it's a reference, make a copy. A copy of a reference points to the same thing as the original reference, so you still have read/write access to its contents. So: using an alias, you can do: `for my $r ($masterType{'TEXT'}) { $r->{'function'}->($r->{'command'}, $r->{'linkedHeaders'}); }` [download] or, using a copy: `my $r = $masterType{'TEXT'}; $r->{'function'}->($r->{'command'}, $r->{'linkedHeaders'});` [download] Note that I use the `$subref->(PARAMS)` syntax to do the sub call, instead of `&{$subref}(PARAMS)`. It does the same thing, but I just like it better. It's less cluttered. p.s. For cases like this, I see nothing wrong with extremely short names for the variables. $r stands for "current record", for me, anyway.	[reply] [d/l] [select]
Re: Too Hash Happy? by diotalevi (Canon) on May 01, 2003 at 19:31 UTC
No, that's perfectly fine. I'd clean up the syntax and only dereference TEXT once. Also, you're misusing the '%' sigil. It changes depending on what you get back out - $ for scalars, @ for slices. `my $type = $MasterType{TEXT}; $type->{function}( $type->{command}, $type->{linkedHeaders} );` [download] Added: Mr. Muskrat and bart noticed that I used $type and $text but really I should have said only $type. So I fixed it.	[reply] [d/l]
Re: Re: Too Hash Happy? by SmokeyB (Scribe) on May 01, 2003 at 20:03 UTC
Thanks alot! That really clears things up for me! And it's good to know I'm on the right track. Cheers!	[reply]
Re: Too Hash Happy? by gjb (Vicar) on May 01, 2003 at 19:29 UTC
You might consider introducing classes such as `MaterType` and (since I guess there's more than only text) `TextType`. The way you structure your data suggests you're thinking of it as objects, so why not go all the way? Just my 2 cents, -gjb-	[reply] [d/l] [select]
Re: Too Hash Happy? by hardburn (Abbot) on May 02, 2003 at 14:19 UTC
Since Perl's data structures are just references to references to references to . . . you can have as many levels as your brain can keep track of. ---- I wanted to explore how Perl's closures can be manipulated, and ended up creating an object system by accident. -- Schemer Note: All code is untested, unless otherwise stated	[reply]