[Gambas-user] My confusion Re: New Syntax, SUPER && !comprehension(mine) Re.: SUPER example at gambasdoc

[Fabien Bodard]

yes and that's why you need to use good naming for your variables !!


Dim cX as New Collection

Dim aX as New Integer[]


You now all classes can use that syntax too :

MyClass[0]=toto

If the special procedure _put(index as integer) is declared. The []
are not specific to the arrays or collections.





2014-05-12 18:31 GMT+02:00 Stephen <sbungay at ...3301...>:
>   Hi Fabien!
>
>
>> Le 12 mai 2014 12:12, "Stephen"<sbungay at ...3301...>  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.
>>
> Yes, it is a convenient way of adding, editing, or deleting items from a
> collection,
> but I personally will never use it. Why? Because IMHO it introduces
> inconsistencies in the language. The short form of adding, updating, or
> deleting items to/from a collection exactly mimics the syntax of assigning
> a value to an array element, but they can not actually be used the same way;
>
> ' This throws an error
> DIM X AS NEW Integer[]
> X[0] = 1
>
>
> ' This doesn't
> DIM X AS NEW Collection
> X[0] = 1
>
> Even GambasDoc lead me astray as it says a collection is a "class" that
> "acts like a read
> <http://gambasdoc.org/help/comp/gb/collection/_get?view> / write
> <http://gambasdoc.org/help/comp/gb/collection/_put?view> array.", but it
> doesn't does it? The second example above doesn't work with an array
> unless the element has been Added
> first, which IMHO is as it should be.
>
>>> 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
>>>
>>>
>>>
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>
>
> --
> 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."
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-- 
Fabien Bodard