"filtered view" upon lists?

[Steve Holden]

Wildemar Wildenburger wrote:
> Steve Holden wrote:
> 
>>> I think SQL views are the direct analog.
>>>
>> I don't think they are. If you add a non-conforming row to a SQL view 
>> it doesn't appear int he view. If you modify a row in an updateable 
>> view so it no longer confirms with the view's conditions it disappears 
>> from the view.
> 
> Me and my wording again: I typed 'direct analog' but meant 'somewhat 
> analog'.
> 
>> Also you don't say whether changes to l are supposed to be reflected 
>> in f in the same way that changes to f are reflected in l.
> 
> Right. Yes, the synchronicity (a word?) is meant to be in both directions.
> 
>> It might be better if you were to explain your use case: what is this 
>> beast supposed to be for?
> 
> I have a database of interconnected objects. Each object has a list 
> tuples; these tuples hold references to other objects and details about 
> the type of connection.
> The 'views' I am imagining are sub-lists of this one list, based on the 
> connection types. Order is important here, that's why I'm not using sets.
> BTW: I have gone the way of nested lists before and found it too rigid 
> and complicated to use.
> 
> 
>>> A bit clearer now?
>>>
>> Hardly at all. Frankly it doesn't seem as though you really know what 
>> the specifications are yourself, so you can hardly expect us to divine 
>> them by use of our psychic powers. Besides which, psychic powers cost 
>> extra ;-)
> 
> Right again. I'm not sure what I want yet as I'm still exploring ideas. 
> If something /like/ the above had existed (which by now I'm gathering is 
> not the case) I'd just adapted my ideas to the specs given.
> 
> 
>> So give us that use case so we get a bit more insight into why you 
>> even see the need for such a thing and how you want it ti behave. Or 
>> is all this just theoretical?
> 
> No no, its very much real. Just not as fleshed out as it might be --- 
> I'm sort of an explorative coder; I usually don't know how something is 
> going to work until it works.
> 
That's all very well, but you might want to Google for "YAGNI". You 
still haven't given us mcuh of a clue about the real need.

> Thx for the effort :)Happy to (tray to) help.

regards
  Steve

-- 
Steve Holden       +44 150 684 7255  +1 800 494 3119
Holden Web LLC/Ltd          http://www.holdenweb.com
Skype: holdenweb       http://holdenweb.blogspot.com
Recent Ramblings     http://del.icio.us/steve.holden