there is no way to create an abstract class in php4. in an abstract class definition subclasses are forced to implement those methods that have been declared abstract. or they are allowed to declare the method as abstract themselves and force their children to provide a concrete definition. the only way to achieve this in php4 is to have an essentially empty definition in a class and through external documentation or communication w/ other developers, indicate the function need be overridden to be usable. communicating externally, something that could be communicated inside the language itself is very delicate, one that would not do well in a scenario with a large number of developers. interfaces introduce the concept of design-by-contract. they are very powerful because they give code another avenue to be polymorphic. inheritance is often overused because people dont understand the power of composition and the benefit of interfaces to facilitate composition. for people coming to php4 from languages like java, or even .net; anything that implements proper access control mechanisms, abstract classes and interfaces; those people may be able to design systems w/ php4 that are properly structured. starting out w/ php4 and trying to learn oop will likely lead individuals into bad practices that they cannot foresee until years down the road, when their systems are growing at a slow rate and they have to figure out why or somebody who understands oop comes in and explains where the problems are. the most common mistake i encounter with oop php4 is accessing class member functions directly. this is a complete violation of encapsulation and php4 provides no way to enforce it. yes, php4 does provide some of the fundamental oop facilities and its all the community had for a while. the bottom line is the facilities it offers for oop are bare and i see no reason to try to understand its peculiarities and weaknesses when php5 is here and php6 is on the way. -nathan On 10/2/07, Tony Marston <tony@xxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > > ""Nathan Nobbe"" <quickshiftin@xxxxxxxxx> wrote in message > news:7dd2dc0b0709292018q6a5aa7d1w1c422628ca00ae7d@xxxxxxxxxxxxxxxxx > > although some people believe differently than i; i would argue > > trying to learn how to design w/ the classes that php4 provides > > is a waste of time. > > I disagree. PHP 4 gives you access to classes, encapsulation, inheriance > and > polymorphism. This is all you need for OO programming. All that extra crap > in PHP 5 is just window dressing. > > > most books you will find regarding object oriented > > design assume the language has the basic constructs. ppp mainly. > > also, there are other important facilities php4 lacks like abstract > > classes > > You can write abstact classses in PHP 4, it's just that you can't use the > word "abstract". Interfaces are totally irrelevant as any method can be > accessed directly through its function definition. > > > and interfaces, not to mention you have to explicitly assign objects by > > reference in php4. (if you dont want a copy created). > > unless you are bound to php4 by work or something > > i suggest you start working w/ php5. also, if your looking for some > > design > > techniques i recommend studying design patterns. > > Design patterns are overrated. For building transactions in CRUD > applications you need transaction patterns. > > -- > Tony Marston > http://www.tonymarston.net > http://www.radicore.org > > > the heads first book > > is a great starting point. > > actually if you want a solid reference thats free on the web look at > > phpPatterns <http://www.phppatterns.com/docs/start> > > the code is mostly php4 i believe. > > > > -nathan > > > > > > On 9/29/07, Jeff Cohan <jdcohan@xxxxxxxxxxxxx> wrote: > >> > >> Yes, I know how to Google, and I've been Googling... > >> > >> But I would appreciate advice about good beginner tutorials using > >> classes in PHP4 based on your actual experiences. I.e., have some of > >> you found tutorials that really unlocked the doors for you? > >> > >> Ideally, such tutorials would have somewhat realistic examples. (I > >> already know how to output "Hello, World" using a class, and I tend > >> to find examples like those unhelpful. Maybe it's just me.) > >> > >> My main challenge is modularizing yer basic BREAD/CRUD operations > >> with MySQL databases. > >> > >> I've made some strides in creating increasingly modular functions to > >> present browse lists, edit forms and add forms; to perform > >> field-level and form-level validations; and to perform inserts, > >> updates and deletes. My approach is to utilize multidimensional > >> arrays which define the column names, column labels (for forms), > >> form control types (input, select, checkbox, etc.) and other > >> attributes of the form controls. I've got a "library" of validation > >> routines with error messages that appear on the form under the > >> culprit form control. > >> > >> But I think taking the next step to use classes is going to make my > >> life much easier. > >> > >> TIA for any guidance you might be able to offer. > >> > >> Jeff > >> > >> -- > >> PHP General Mailing List (http://www.php.net/) > >> To unsubscribe, visit: http://www.php.net/unsub.php > >> > >> > > > > -- > PHP General Mailing List (http://www.php.net/) > To unsubscribe, visit: http://www.php.net/unsub.php > >
