Hey... that is an awsome link. (Even if I shared it here in the past... my point is not that this is a repeat... it is that this is a worth reading article! It is to PHP... but my thought is most of us will be able to easily translate it to CFCs and Coldfusion.)
John Farrar ----- Original Message ----- From: "Doug Keen" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Tuesday, December 02, 2003 10:02 AM Subject: Re: [CFCDev] recursive functions > You may want to check out this article: > http://www.sitepoint.com/article.php/1105 > > It's a really good explanation of using a "modified preorder tree > traversal" algorithm for storing and navigating trees (which may make > your "pruning" problem much easier!) The article is specifically in the > context of storing trees/hierarchical structures in a relational > database, but the translation of these database structures into CFCs > should be relatively straightforward. > > A fair warning... it definitely took me a couple times reading through > the article to really grasp what the author was talking about! Though > there are definitely some tradeoffs to consider with the modified > preorder tree traversal algorithm, it seems like a pretty solid solution > for many different situations and is something to consider. > > -Doug (CFCDev Newbie) > > > Nando wrote: > > >>Do a walk of the tree, maintaining a list of nodeIDs (pageID or something) > >>that grows and shrinks as you walk. > >> > >> > > > >Ummm ... sounds like i SHOULD know what this means but i don't. Not familar > >with the term 'walk' in programming speak. How does the list grow and shrink > > > >When you find your node (the current > > > > > >>page), abort the walk. The start a new walk that will actually generate > >>your pruned tree, and use that list that you build (which will contain the > >>path to the target node) to determine what branches you need to > >>process and > >>which branches you can skip. > >> > >> > > > >I probably don't understand this, again, because of the 'walk' term. Do you > >have a few minutes to explain a little more sometime? > > > >[In the back of the class with arm raised ...] > > > >Nando > > > >You'll probably want to prepend a > > > > > >>NULL to the > >>front, so that the 'parent' of the topmost node is represented in > >>your list. > >>Typically, you want to display the children of all the nodes in the list, > >>but nothing else. > >> > >>You can use a loop for both walks, and I'd definitely recommend it for the > >>first walk, as a loop is a lot easier to break (CFBREAK) than a recursive > >>function. > >> > >>Cheers, > >>barneyb > >> > >> > >> > >>>-----Original Message----- > >>>From: [EMAIL PROTECTED] > >>>[mailto:[EMAIL PROTECTED] On Behalf Of Nando > >>>Sent: Monday, December 01, 2003 3:25 PM > >>>To: [EMAIL PROTECTED] > >>>Subject: RE: [CFCDev] recursive functions > >>> > >>>I'm caching the results of a few recursive function in an > >>>object that create > >>>a tree structure of the site nav and a linked breadcrumb > >>>trail for each page > >>>in the site. So the performance hit is only taken once in a > >>>great while. I > >>>DO have to agree with Sean that the code is much more > >>>elegant, and the depth > >>>of the tree is unlimited, something i didn't see how to do > >>>with loops, (but > >>>might now if i really thought about it.) > >>> > >>>The next challenge is how to "prune" the siteMap tree to > >>>display only the > >>>navigation tree needed for a particular page - hopefully > >>>that's easy, but i > >>>haven't looked into it yet. > >>> > >>> > >>> > >>>>-----Original Message----- > >>>>From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > >>>>Behalf Of Sean A Corfield > >>>>Sent: Monday, December 01, 2003 11:40 PM > >>>>To: [EMAIL PROTECTED] > >>>>Subject: Re: [CFCDev] recursive functions > >>>> > >>>> > >>>>On Dec 1, 2003, at 1:47 PM, Patrick Branley wrote: > >>>> > >>>> > >>>>>This is a very good point. Anything that can be done with > >>>>> > >>>>> > >>>recursion > >>> > >>> > >>>>>can also > >>>>>be done using a loop. > >>>>> > >>>>> > >>>>Sometimes implementing an algorithm with a loop makes for horrendous > >>>>code whereas recursive code can be elegant and simple - consider > >>>>algorithms for processing tree-structured data! > >>>> > >>>> > >>>> > >>>>>Does anybody know if there is a performance increase ? I > >>>>> > >>>>> > >>>would assume > >>> > >>> > >>>>>there > >>>>>isnt. > >>>>> > >>>>> > >>>>It depends. Recursion relies on function calls which can be > >>>> > >>>> > >>>expensive > >>> > >>> > >>>>(creating a stack frame, pushing variables etc). If the algorithm is > >>>>sufficiently complex, the extra work you have to do to > >>>> > >>>> > >>>manage 'context' > >>> > >>> > >>>>for a loop may exceed the function call overhead. > >>>> > >>>>Sean A Corfield -- http://www.corfield.org/blog/ > >>>> > >>>>"If you're not annoying somebody, you're not really alive." > >>>>-- Margaret Atwood > >>>> > >>>>---------------------------------------------------------- > >>>>You are subscribed to cfcdev. To unsubscribe, send an email > >>>>to [EMAIL PROTECTED] with the word 'unsubscribe cfcdev' > >>>>in the message of the email. > >>>> > >>>>CFCDev is run by CFCZone (www.cfczone.org) and supported > >>>>by Mindtool, Corporation (www.mindtool.com). > >>>> > >>>>An archive of the CFCDev list is available at > >>>>www.mail-archive.com/[EMAIL PROTECTED] > >>>> > >>>> > >>>---------------------------------------------------------- > >>>You are subscribed to cfcdev. To unsubscribe, send an email > >>>to [EMAIL PROTECTED] with the word 'unsubscribe cfcdev' > >>>in the message of the email. > >>> > >>>CFCDev is run by CFCZone (www.cfczone.org) and supported > >>>by Mindtool, Corporation (www.mindtool.com). > >>> > >>>An archive of the CFCDev list is available at > >>>www.mail-archive.com/[EMAIL PROTECTED] > >>> > >>> > >>> > >>---------------------------------------------------------- > >>You are subscribed to cfcdev. To unsubscribe, send an email > >>to [EMAIL PROTECTED] with the word 'unsubscribe cfcdev' > >>in the message of the email. > >> > >>CFCDev is run by CFCZone (www.cfczone.org) and supported > >>by Mindtool, Corporation (www.mindtool.com). > >> > >>An archive of the CFCDev list is available at > >>www.mail-archive.com/[EMAIL PROTECTED] > >> > >> > > > > > >---------------------------------------------------------- > >You are subscribed to cfcdev. 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