[jawsscripts] Re: How to null a global object array
- From: John Martyn <johnrobertmartyn@xxxxxxxxx>
- To: jawsscripts@xxxxxxxxxxxxx
- Date: Sat, 26 Apr 2014 05:36:38 -0600
I actually discovered that just recreating the array wipes it out. the
null didn't work unless you stepped it out.
Thanks,
John
On 4/22/2014 8:28 PM, Doug Lee wrote:
> I use it for convenience sometimes, with both arrays and collections.
> The following code is approximate and not tested:
>
> var collection c c = new collection
> var variantArray a a = new VariantArray(10)
> c.a = a
> a[1] = "Hello"
> a[2] = "goodbye"
> ; now c.a[1] and c.a[2] are set also.
>
> I say convenience, but also efficiency at run time: The compiler does
> not allow assignment to things like c.a[1], so copying the entire
> array would effectively force you to construct a duplicate in order to
> put an array into a collection.
>
> On Tue, Apr 22, 2014 at 09:21:43PM -0500, Jim Snowbarger wrote:
> Right, But, I was questioning the need to ever do that.
> Why have two copies of identical data, such that modifying one copy also
> results in the other copy being modified. What purpose might that serve?
>
> ----- Original Message -----
> From: "Doug Lee" <doug.lee@xxxxxxxxxxxxxxxx>
> To: <jawsscripts@xxxxxxxxxxxxx>
> Sent: Tuesday, April 22, 2014 9:03 PM
> Subject: [jawsscripts] Re: How to null a global object array
>
>
> It's done this way for efficiency reasons, as explained in FS
> documentation: "assigning one array to another will result in two
> variables referring to the same array. This is to avoid the very
> expensive process of copying arrays."
>
> On Tue, Apr 22, 2014 at 08:52:04PM -0500, Jim Snowbarger wrote:
> That is a strange arrangement, where arrays are pointers to data.
> For arrays x and y, set x equal to y.
> And, you would think you now have two copies of data which you could modify
> independently.
> But, if you change the value of x[1] you would find that
> y[1] has also changed.
> So, what would be the purpose of ever assigning one array to another?
>
>
>
>
>
> ----- Original Message -----
> From: "Geoff Chapman" <gch@xxxxxxxxxxxxxxxx>
> To: <jawsscripts@xxxxxxxxxxxxx>
> Sent: Tuesday, April 22, 2014 9:40 AM
> Subject: [jawsscripts] Re: How to null a global object array
>
>
> yeah man what a total champion our Doug is with all his hard-earned
> oft-practised shared knowledge eh?
> Thanks doug just so much from up here for all you know/give out so
> helpfully.
> total Gold!
>
> ----- Original Message -----
> From: "John Martyn" <johnrobertmartyn@xxxxxxxxx>
> To: <jawsscripts@xxxxxxxxxxxxx>
> Sent: Wednesday, April 23, 2014 12:25 AM
> Subject: [jawsscripts] Re: How to null a global object array
>
>
>> Thank you Doug. I got things working now. I'll post the tree walker
>> function soon.
>> John
>> On 4/20/2014 9:28 AM, Doug Lee wrote:
>>> If you assign anything to a global, its previous value reference is
>>> cleared; so if nothing else refers to the previous contents, they go
>>> away. An example: Assume we have globals gA and gB, and your TW
>>> treeWalker object. Then:
>>>
>>> let gA = new variantArray(50)
>>> let gB = gA
>>> ; gB now refers to the same array as gA, with all this implies...
>>> gA[1] = TW.currentElement
>>> gA[2] = IEGetCurrentDocument()
>>> gA[3] = "Hi there, I'm not an object."
>>> ; ... code to fill other elements of gA.
>>> ; gB[1] also equals TW.currentElement now, etc.
>>> TW.gotoFirstChild() ; Assume this succeeds (returns True)
>>> ; TW.currentElement is now changed, but gA[1] is still its original
>>> value.
>>> ; gB[1] is also still the original currentElement value.
>>> gA = null()
>>> ; gA no longer refers to the array, but gB still does.
>>> ; gB[1] is still an object.
>>> var object el = gB[1]
>>> ; el is now the original value of TW.currentElement
>>> gB = null()
>>> ; The last reference to the array is gone,
>>> ; so the array and all its elements go away.
>>> ; But since we saved the original value of TW.currentElement in el,
>>> ; it's still there as we would expect.
>>> el = null()
>>> ; Last reference to the original currentElement value is gone now.
>>>
>>> On Sun, Apr 20, 2014 at 09:15:06AM -0600, John Martyn wrote:
>>> Do you have to assign null to every element in the array in a for
>>> statement? Or would just assigning null work like for example
>>> myArray[1,1] = ?Null
>>> or
>>> let c = ArrayLength(my array)
>>> for i=1 to c
>>> myArray[i,1] = Null
>>> endFor
>>> Thanks,
>>> John
>>> On 4/20/2014 7:45 AM, Soronel Haetir wrote:
>>>> wouldn't assigning Null() do the trick?
>>>>
>>>> --
>>>>
>>>> Globals
>>>> object glbArray
>>>>
>>>> void
>>>> Function AutoFinishEvent()
>>>> glbArray = Null()
>>>> EndFunction
>>>>
>>>> On 4/19/14, John Martyn <johnrobertmartyn@xxxxxxxxx> wrote:
>>>>> I've done functions and scripts with temporary arrays, but never a
>>>>> global array. How do you clear the the array to null?
>>>>> I am creating an object walker and I need to store the objects in the
>>>>> array. When I'm done, I'll post the functions for tabbing and shift
>>>>> tabbing.
>>>>> Thanks,
>>>>> John
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