Implicit initialization is EVIL!

Steven D'Aprano steve+comp.lang.python at pearwood.info
Fri Jul 8 03:25:14 CEST 2011


rantingrick wrote:

> On Jul 7, 12:34 am, Gregory Ewing <greg.ew... at canterbury.ac.nz> wrote:

>> The important thing is that it's okay for an app to stay
>> alive until its *last* top level window is closed.

I partially disagree with Greg on this. This is not the only model: on the
Apple Mac, or any system with a similar GUI design, the application can
survive having the last window closed. There are other application types
that don't need any window at all. So while it is common for closing the
last window to exit the application, it is not a necessary requirement.


 
>> There
>> doesn't have to be a special "main" window that kills the
>> whole app when you close it.
> 
> So you prefer to close a gazillion windows one by one? 

Nonsense. Greg says nothing of the sort.

Avoiding the anti-pattern "close a gazillion windows one by one" is why you
have an application-wide Quit or Exit command, as opposed to a Close
command which applies only to the current window.


> If so, why not 
> just code the GUI correctly from the start; by creating separate
> transactions? Thereby reducing the number of windows a user must
> juggle? FYI: You know the user complexity of a GUI increases
> exponentially by the number of windows present.

Don't assume that there is a one-to-one relationship between transactions
(documents?) and windows. The relationship is actually many-to-many:
windows can contain tabbed or notepad interfaces, or can be split into
multiple panes, or both. Panes and tabs can be split into independent
windows, or rejoined into one main window.

E.g. I can have six Firefox windows open, each one with many different
websites open in separate tabs. I have Close Tab, Close Window and Exit
Firefox commands.

In Konquorer, not only can I have multiple windows and multiple tabs, but I
can split each tab into two or more panes, and display two views of the
same document in the same tab, or two different documents in the one tab.
This is especially useful when using it as a file manager.

In older versions of Word (and possibly current, although I haven't tested
it) you can open files multiple times. Each time opens in a new window,
representing a new view of the one file. Edits in one window update all the
others. This can be useful for, e.g. making edits to page 3 while
simultaneously viewing page 303. An alternate UI for to split the one
window into two panes, and scroll them independently. So a single file may
have one or two panes, in one or more windows.

So, you can have multiple documents in multiple windows, and there is no 1:1
relationship between them.



-- 
Steven




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