| On Tue, Feb 07, 2012 at 03:41:22PM -0500, Chris Siebenmann wrote:
| > My current version is:
| > AddToFunc ToWindow
| > + I Current ("XTerm|9term|Gnome-terminal", "$0") Break
| > + I Next ("XTerm|9term|Gnome-terminal", "$0") Iconify False
| > + I Next ("XTerm|9term|Gnome-terminal", "$0") Focus
| > + I Next ("XTerm|9term|Gnome-terminal", "$0") Raise
| > + I Next ("XTerm|9term|Gnome-terminal", "$0") WarpToWindow 80 5
|
| This is why it's better to do this:
|
| Style XTerm State 1
| Style 9term State 1
| Style Gnome-terminal State 1
|
| DestroyFunc ToWindow
| AddToFunc ToWindow
| + I Current (State 1, $0) Break
| + I Next (State 1, $0) SomeFunction
Oh that's clever. I hadn't even thought of using states that way,
and it makes everything much more modular (I don't have to hunt down
N places to add things to if I decide that rxvt is also a terminal).
Clearly I need to think more about ways to use States.
Thank you!
| > This works but seems unnecessarily repetitive (actually I'm suddenly
| > not convinced that it does nothing if the current window is a terminal
| > window called $0). So I thought I could rewrite it like this (with
| > comments about the logic):
| >
| > AddToFunc ToWindow
| > # do nothing if current window is called $0
| > + I Current ("XTerm|9term|Gnome-terminal", "$0") Break
| > + I Next ("XTerm|9term|Gnome-terminal", "$0") Focus
| > # if no window is called $0, this stops; otherwise Focus has
| > # made that window the current window.
| > + I TestRc (NoMatch) Break
| > # do the rest of the work
| > + I Iconify False
| > + I Raise
| > + I WarpToWindow 80 5
| >
| > However, this doesn't work if no such window actually exists; before
| > anything from the function seems to execute (even an 'Echo' statement
|
| Context is about how functions run, and the way you have it there, FVWM will
| need a window context to run in -- that is, a window to operate on. Your
| use of "$0" implies this to some extent, in that you have a name or
| something being passed in, but you don't say how.
|
| If FVWM doesn't have an operand window, then it will ask for one. This will
| depend on how you're trying to call this function. This is perhaps the most
| important piece of information you've failed to provide.
Sorry, my lack of clarity. This is being invoked (more or less) as
echo "Function ToWindow \"$win\"" | FvwmCommand -c
(and for testing I have been just doing the 'Function ...' inside a
FvwmConsole.)
| > Do I need to make all commands conditional in this function in order
| > to have things work right, by putting plain 'Current ' in front of the
| > last three lines? (A version with this change seems to do nothing if
| > there's no terminal window by that name, but I feel I'm just sort of
| > writing code by superstition instead of actual understanding at this
| > point.)
|
| No you don't. Consider this:
|
| AddToFunc ToWindow
| + I Current ("XTerm|9term|Gnome-terminal", "$0") Break
| + I Next ("XTerm|9term|Gnome-terminal", "$0") Focus
| + I TestRc (NoMatch) Break
| + I Iconify False
| + I Raise
| + I WarpToWindow 80 5
[...]
| It may well be that the window we're operating on is implied,
| in which case FVWM won't ask for a window -- and indeed, your
| implementation of ToWindow doesn't. FVWM processes the commands in
| order, top-to-bottom. It comes across "Current" and evaluates that in
| the context of the binding. Of course, there is nothing special about
| Current, Next, or TestRc, they can run inside a function just fine,
| and at this point assume no specific window -- but because you have
| this:
|
| + I Iconify False
|
| ... if FVWM processes this from your ToWindow function and there is no
| implied operand window for ToWindow to be running in, it will prompt
| for a window to run against, because it needs a window.
I guess my lack of understanding this: when I invoked ToWindow with
Function ToWindow "nosuchwindow"
I expected the 'Next' to fail and then the TestRc to succeed and abort
the function before FVWM reached 'Iconify False' and needed a window
to operate on. Instead nothing seems to be run at all before FVWM asks
for a window -- I can put an unconditional 'Echo' in as the first + I
in ToWindow, invoke 'Function ToWindow "nosuchwindow"', and if I then
clicked on the root window, no Echo output showed up at all. (If I did
select a window, things seemed to work as expected.)
| Once you have a window you're hooked on it though. So really, establishing
| a binding to one window can happen outside the function before invoking it,
| and that's precisely what I did with my original suggestion to you above:
|
| DestroyFunc ToWindow
| AddToFunc ToWindow
| + I Current (State 1, $0) Break
| + I Next (State 1, $0) SomeFunction
|
| DestroyFunc SomeFunction
| AddToFunc SomeFunction
| + I Iconify False
| + I Focus
| + I Raise
| + I WarpToWindow 80 5
|
| So can you not see now, why in SomeFunction I do not need to prefix the
| commands with Current, because they're all called in the matched window from
| ToWindow, coming from the Next command?
Yes, I think I understand. Calling 'Next ... SomeFunction' (or I assume
any successful conditional window selection command) sets the window
binding in effect for SomeFunction, and if Next cannot find such a
window it will not run SomeFunction at all. Do I have that right?
- cks
