Re^2: Pronoun Programming

[plobsing]

You could of course tie your hash to return values that allow for something similar.

You would have to choose something other than delete $val to keep it simple, but $val->delete is almost as good. Unfortunately, this falls down on assignment. I can't think of any good way to do it ($val->set($newval) is probably as good as it gets).

Also, you'd have to do some nasty business about garbage collection. You wouldn't want to keep an entire hash around just because you still have one element of the hash.

[BrowserUk]

I think a hash element reference would have to be a pointer to an HE struct. That contains pointers to both the key and it's value. The thing that is missing is some way to get back to the hash it is a part of, as they form a single linked list going in the wrong direction.

There are several ways I would like to extend Perl's hashes, had I the skills and patience. This is one. Another would be to add timestamps to keys, that gets set when keys are created. That would allow for time ordered hashes which could be useful. And the same field could be used to order keys according to any arbitrary sorting order, which would be more space and time efficient than current tied hash+array hybrid solutions.

But, as almost every attempt I've made at messing with Perl's internals has resulted in random, inexplicable crashes which my attempts to resolve have fallen on deaf ears and stoney ground, it's not something I am likely to get around to any time soon.

[plobsing]

I tried implementing this out of curiousity. HE* DO have a pointer back to the original hash, but there's no guaranteeing that the hash is there any more.

Thats why I tried using weakened references in stead. I would have used set/get magic if I was more comfortable with them, I never got those to work out for me before. Here's the begginings of the module (untested):
Read more... (1338 Bytes)

[BrowserUk]

There are several ordered hash implementations on cpan already that use tie and arrays to achieve their goal: Tie::Hash::Sorted, Tie::Hash::Array, Tie::Hash::Rank, Tie::Hash::Index, Tie::SortHash, Tie::LLHash etc.

I'm intrigued by your assertion that HE* have a link back to the hash. Nothing shows up on the PerlGuts Illustrated diagram?