Mike, Just this week Josh Adams gave a really good presentation on scopes. Have a watch of this I am sure it will answer many of your questions.
https://admin.na3.acrobat.com/_a204547676/p74013218/ Paul. On 07/02/2009, at 10:12 PM, Mike Soultanian wrote: > > Brian Kotek wrote: >> - All function-local variables must be declared with the "var" >> keyword > > Yeah, I've read extensively that it's very important to do this with > every variable declared inside a function. Btw, does this also mean > that query names need to be var-scoped as well? i.e. > > <cfset var GetParks = 1> > > <cfquery name="GetParks" datasource="dsn"> > SELECT name FROM table > </cfquery> > > >> - The VARIABLES scope within a CFC represents private data > > That I understand. > > >> - The VARIABLES scope should be used instead of the THIS scope >> for object >> properties to enforce encapsulation > > Yeah, I noticed that the book uses the "this" scope. I also noticed > that the book outputs data from CFCs which I've read is a nono in > regards to best practices. I'm assuming the correct method to > retrieve > the data stored in the properties is by calling the class' methods, > correct? > > >> - An init() method is the de-facto constructor method > > Correct me if I'm wrong, but based on my initial reading of CFCs on > the > web, it seems like there are three ways of setting up constructor > data: > putting any cf tags or functions in the constructor area, putting a > <cfset init()> statement in the constructor area that calls the init() > method, or calling the init() method during the object instantiation. > Is there a preferred method? > > Maybe I'm not understanding the goal of the init() method and to whom > that data is supposed to be made available. Is it for the purpose of > providing data to the newly created object or is it to initialize data > for the other methods in the class.. or both? If anyone has any pages > describing constructors and their uses (even if it's in another > language), that would be helpful. > > >> - We can now call super.[method] to invoke methods on a >> superclass. > > seems simple enough. Don't have any near-future plans to call super > methods just yet until I get my head wrapped around this :) > > >> If you can keep those rules in your head as you read (which I >> realize may be >> difficult), the majority of the concepts are still valid >> (composition, >> polymorphism, etc,). > > I think knowing about the "this" scope best practices is helpful. Was > the variables and var scope not available at the time > > >> (Yes, I know the variables scope behaves like protected, not >> private. Yes, I >> know some people prefer keeping properties in the THIS scope. I >> kept the >> list simple because it's already going to be hard enough for him >> to keep >> track of it and there's no need to dive into minutiae at this point.) > > I like the idea of keeping the properties local to the CFC > otherwise you > break the benefits of encapsulation (or at least, I see it as a > benefit). > > What's the difference between private and protected? > > thanks! > Mike > > > > >> >> Regards, >> >> Brian >> >> >> On Sat, Feb 7, 2009 at 8:06 PM, Mike Soultanian >> <msoul...@csulb.edu> wrote: >> >>> Hey Everyone, >>> I just purchased Discovering CFCs by Hal Helms and I already know >>> that >>> the book is somewhat out of date (Hal told me so). However, what I >>> really wanted was an introduction to OO and CFCs and this seemed >>> like a >>> descent starting point. >>> >>> I am starting to get further into the book (on page 50 right now) >>> and >>> I'm starting to see more CFC code. What I wanted to find out is >>> what >>> stuff is out of date, if it's possible to generalize. Are there any >>> sites out there that outline the changes since MX? Any suggestions >>> would be much appreciated! >>> >>> Thanks, >>> Mike >>> >>> >> >> >> > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~| Adobe® ColdFusion® 8 software 8 is the most important and dramatic release to date Get the Free Trial http://ad.doubleclick.net/clk;207172674;29440083;f Archive: http://www.houseoffusion.com/groups/cf-talk/message.cfm/messageid:319029 Subscription: http://www.houseoffusion.com/groups/cf-talk/subscribe.cfm Unsubscribe: http://www.houseoffusion.com/cf_lists/unsubscribe.cfm?user=89.70.4
