Well, this isn't code being written for any purpose other than to experiment with some algorithms and data structures. The fact that it is in Perlis just for fun. That said, I believe that there is a good use case for linked lists when you want to strictly control memory allocation.Last I heard, Perl arrays grew in large chunks (I forget the details) whereas with a LL the memory allocated by perl will growmore slowly. This is from a talk I heard back in 2009 at YAPC (http://www.slideshare.net/lembark/perly-linked-lists) so some of these advantagesmay no longer be applicable. I'd be interested in knowing of this was the case. As to your question, well, I have no strong reason (again, just playing around here). My thinking is along the lines of that I would rather have a "book" have "pages"than just have "pages". Perhaps too subtle a point that isn't worth trying to capturing. Anyway, my analogy isn't exact since my "book" is really just a reference to the title page. :)
> Date: Sat, 1 Nov 2014 22:44:50 -0700 > Subject: Re: [Boston.pm] object composition (has-a) with built-in OO system > From: [email protected] > To: [email protected] > CC: [email protected] > > Just so that you know, it is very hard to find a use case for linked > lists in Perl where a native array is not a better option. That said, > why draw a distinction between a node in a linked list and a linked > list? I would just have one class, that is a reference to a node. > (That itself might have children.) The one exception is if you wanted > a doubly linked linked list, and wanted to avoid having a memory leak. > > For inheritance, usually you just set up @ISA in some way. Either by > explicit assignment, or with 'use parent'. (The modern replacement > for 'use base'. Though I don't know why that needed replacing...) > > On Sat, Nov 1, 2014 at 10:36 PM, Adam Russell <[email protected]> wrote: > > I was experimenting with some code, jogging my memory of linked lists. > > > > The approach I took was to define a package LinkedListNode and then a > > package LinkedList. > > My idea is that my LinkedList package is a wrapper around the head node > > which would also define > > some useful methods such as print_list(), remove_node(), and so forth. > > > > I did this by having the constructor for LinkedList create and bless() > > the head node. > > But then I ran into a problem having this object call LinkedListNode > > methods. This was solved > > by making LinkedList a subclass of LinkedListNode with the line > > unshift @ISA, 'LinkedListNode'; > > > > Ok, so I am doing what seems to me to be "composition" in OO speak. That > > was my design intention anyway. > > The only way I've found that it works is to use a parent class > > relationship. Does Perl have some > > other way of doing this, using the built in OO system? > > I've read > > http://search.cpan.org/~rjbs/perl-5.18.4/pod/perlootut.pod#Composition > > and it seems that the answer is "No, what I've done is the way to do > > it." but I thought I'd ask in case > > I'm just not getting something? > > > > I only want to use the Perl built in OO system. I am aware Moose (and > > others) have facilities for this. > > > > My code is at http://pastebin.com/8fnxY0Xy if you'd like to take a look. > > Any other questions or comments on this code would be appreciated as > > well. I've been brushing up on a few things > > and am open to comments. > > > > Thanks! > > Adam > > > > _______________________________________________ > > Boston-pm mailing list > > [email protected] > > http://mail.pm.org/mailman/listinfo/boston-pm _______________________________________________ Boston-pm mailing list [email protected] http://mail.pm.org/mailman/listinfo/boston-pm
