[Gambas-user] Safety for collections

[BB]

On 22/8/23 9:11 pm, Bruce Steers wrote:
>
>
> On Tue, 22 Aug 2023 at 12:19, BB <adamnt42 at gmail.com 
> <mailto:adamnt42 at gmail.com>> wrote:
>
>
>     On 22/8/23 8:38 pm, BB wrote:
>>
>>     There is probably a simple way to do this, damned if I can see how.
>>
>>     I have a collection of things (datObjects) that have a property
>>     (ObjectName::string) that in UML terms are Unique and ID. What I
>>     am trying to do is prevent the _replacement_ of an object in the
>>     collection if the ObjectName is already there. Better still, I'd
>>     like to warn the user when they enter the ObjectName that it
>>     already exists.
>>
>>     The input form has a TextBox for the ObjectName and a "save"
>>     button. The latter updates the collection, whose key is the
>>     ObjectName, either adding or amending the item in the collection.
>>     So I kind of need to do this:
>>
>>     1) Are they really trying to add a new item or update an existing
>>     one?
>>
>>     If adding then prevent them from overwriting one with the same
>>     ObjectName, otherwise if amending then only allow changes to the
>>     other data and not the ObjectName.
>>
>>     2) Then update the collection accordingly.
>>
>>     Is that clear? It isn't to me. Any input would really be appreciated.
>>
>>     b
>>
>>     p.s. I am trying to avoid having separate Add and Update buttons
>>     for reasons.
>>
>     I may have oversimplified. The basic gen is that there is a form
>     with a list of some type on the left and an "editor" panel on the
>     right. The user clicks on an item in the list and the data for
>     that item is loaded in the editor. Now the quick way for them to
>     add a new item is to click on a similar one, give it a new name
>     and change some of the other data as required, then click the save
>     button. BUT the new name they use may already exist. ... ...
>
>
> I may not be getting the jist as i only have simple code to suggest..
>
> If datObjects.Exist(sName) Then
>
>   Dim c As Integer = 2
>   While dat.Objects.Exist(sName & Str(c))
>     Inc c
>   Wend
>   sName = sName & Str(c)
> Endif
>
> That'll try Name2, Name3 etc till a free name is found.
>
> Respects
> BruceS
>
OK, you have given me a start. The real issue is that the structured 
naming convention was invented by a very clever person from a town in a 
European country that may-or-may-not end in "ermany" (or "eutschland" if 
you prefer). A name looks like this "ind_cl3_1x2_E0_03_09". Zounds egad! 
you may exclaim*. That "_03_" is an index (that indicates a color 
variant), so I can at least use your idea there. I think that I may have 
to denature that name into some sort of structure somehow, which is a 
damn problem as the so called structure seems to be an idea rather than 
a standard and there are many, lets say, "irregularities" in usage. 🙁

txs

b

* The "full" explanation of that name is "this is an industrial building 
in climate zone 3 that occupies 2 building blocks (1 wide by 2 long) 
that can or was only be built in or after "epoch" 0**, color variant 3 
and an 09 something (that is yet to be determined). You can see, I 
believe why users have some kind of difficulty in creating or copying 
new names.

** Australia is a wonderful place, there are only two epochs "before" 
and "after" a certain Captain Arthur Phillip 
<https://en.wikipedia.org/wiki/Arthur_Phillip> arrived. Actually there 
are really 3 but I wont go into that piece of political prehistory.

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