Le 12 mai 2014 12:12, "Stephen" <sbun...@smartsonsite.com> a écrit : > > Hi Tobias, thanks for the reply, things got busy and I'm just getting > back to the keyboard. > > It was how things were being done in the (broken) GAMBASDOC example > confused me. > In one area the programmer is using the Add method of a string object > array, but this line > > $cPos[Key] = $aKey.Count > > caused me to pause. > > My thought at the time of reading it went something like this: > > "What being done here? There's been no use of the Add method! How can > you reference > something that doesn't yet exist and why is no error being thrown for > doing so"?
A collection automatically add an non existant entry ... Or just assign the new value... If the value is null then the entry is deleted. > > Now I think that the Add method of the collection is being implicitly > called using older > non OOP array assignment syntax. > > IMHO enforcing the explicit use of the object's Add method > > $cPos.Add($aKey.Count, Key) > > might take more keystrokes, but it definitely better communicates what > is being manipulated (an object vs an array) and what is being done > (Adding). > > > On 05/08/2014 09:28 AM, Tobias Boege wrote: > > On Thu, 08 May 2014, Stephen wrote: > >> Looking at the thread "New syntax for using variables arguments in a > >> function call" I realized that I needed to really brush up on my > >> somewhat marginal understanding of the evolving (a good thing) GAMBAS > >> and OOP. Not fully understanding "SUPER" (I've never used it but can see > >> a use for it) I trotted off to Google and the GAMBAS documentation, > >> where much reading was done, and (as usual) more questions raised. > > If you write a class and inherit from another class, you can override > > methods and properties in your inheriting class. However, sometimes the > > inherited class does a pretty good job already and you don't want to > > reinvent the wheel for doing something. That's when Super comes into play > > because Super knows where the method and property implementations of the > > inherited class (the super class) are. So you can still call methods of > > the super class in your subclass that you have actually just overridden. > > > > In the example below, you want to skim data in ListBox' Add() method but > > you don't want to implement the actual addition of a new element so you > > resort to the original ListBox' Add() implementation - which is available > > as Super.Add() and knows how to do the thing. > > > >> Studying the "SUPER" example at http://gambasdoc.org/hemp/lang/super, > >> I wondered at the purpose of a collection that seems not to be used but > >> once and some syntax in it's use in the example, which didn't make any > >> sense to my old brain. Below is a snippet from the example (where $cPos > >> is a collection, $aKey an Array of String Objects (I think) and Key a > >> string object; > >> > >> $cPos.Clear > >> $cPos[Key] = $aKey.Count > >> $aKey.Add(Key) > >> > >> OK, the first line clears the collection, got it, and the last line > >> adds the contents of "String" to $aKey, got that.... but what does the > >> second line do? It looks like it is adding the count of elements in > >> $aKey to the collection $cPos... but in OOP I would use a method call > >> i.e. $cPos.Add(Key,Key). Oh, and in trying to implement the example > >> GAMBAS (3.5.3) complained that "ListBox.Add is incorrectly overridden". > >> > > $cPos[Key] = $aKey.Count followed by $aKey.Add(Key) will store the *index* > > of Key in the $aKey array in the $cPos collection, indexed by the *value* of > > the key. (Think about it.) > > > > That means if the user gives you a Key, you can look up the index of that > > key in the $aKey array using $cPos[Key], i.e. the statement > > > > $aKey[$cPos[Key]] > > > > will always return Key (or raise an error, but see below for that). This > > also explains why the Collection is named $cPos. > > > > Not sure what that implies or what we can do with it and how $cPos.Clear() > > fits into the picture because it already deletes that additional information > > we collected... > > > > Either I don't get it or the example is just broken (I'd prefer the second > > option, of course :-)). > > > > Regards, > > Tobi > > > > > -- > Kindest Regards > Stephen A. Bungay, Prop. > Smarts On Site > > > ------------------------------------------------------------------------------ > "Accelerate Dev Cycles with Automated Cross-Browser Testing - For FREE > Instantly run your Selenium tests across 300+ browser/OS combos. > Get unparalleled scalability from the best Selenium testing platform available > Simple to use. Nothing to install. Get started now for free." > http://p.sf.net/sfu/SauceLabs > _______________________________________________ > Gambas-user mailing list > Gambas-user@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/gambas-user ------------------------------------------------------------------------------ "Accelerate Dev Cycles with Automated Cross-Browser Testing - For FREE Instantly run your Selenium tests across 300+ browser/OS combos. Get unparalleled scalability from the best Selenium testing platform available Simple to use. Nothing to install. Get started now for free." http://p.sf.net/sfu/SauceLabs _______________________________________________ Gambas-user mailing list Gambas-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/gambas-user
