RE: Infrastructural complexity.

[Thomas Lord]

On Sun, 2009-07-19 at 16:54 -0700, Drew Adams wrote:

> > Menu bars are an example of a virtual input/output device.
> > Scrollbars are examples of virtual input/output devices.
> > So are mode lines.   A little hierarchical command menu
> > could be the same sort of thing.
> 
> So, I would think, is the minibuffer. (I'm just following your examples. I
> didn't see any definition of virtual i/o device, so I might be mistaken.)

I guess you could say, the way I'm using the phrase,
that the minibuffer area - and each Emacs window - are
virtual i/o devices.  Minibuffer buffers and regular 
buffers are not virtual i/o devices but they are parameters
to some virtual i/o devices (e.g., the parameter of what 
buffer should be displayed in a window or the minibuffer
area).

The minibuffer area, each window, the menu bar, etc.
are all features of the display and I/O system that 
exist to show constantly-updated views on some object
and to translate system input events into various kinds
of command loop input events (e.g., a mouse action into 
a MENU event).

It (the concept of a virtual i/o device) is just supposed
to be a handy way of thinking about the core architecture
of Emacs.  If the concept fails to work that way for you,
don't get hung up on it - I'm sure there are other good ways
of thinking about the same architectural details.

-t