On Thu, Apr 19, 2007 at 07:10:36PM -0600, Jason Creighton wrote:
On Wed, Apr 18, 2007 at 09:27:03PM -0700, David Roundy wrote:
On Wed, Apr 18, 2007 at 07:06:11PM -0600, Jason Creighton wrote:
If I'm reading this correctly, I don't think that will work. "full" doesn't display the first window in the tiling order, it displays the focused window. So Rectangle -> [Window] -> [(Window, Rectangle)] is not sufficient to support all the cases we have now: The layout function has to somehow know which window is focus. To that end, I think the layout function type is going to have to be something like
I can assure you that full does work (I just double-checked), although I couldn't really explain why--except experimentally. (By which I mean that it displays the focussed window, and no other.) Perhaps the focussed window is always displayed on top of the other windows when they overlap?
Oh, right. "refresh" raises the focused window. So it works, but by accident.
Maybe that's not a fair way of putting it. As xmonad is currently written, the focused window has to be raised because we don't move the other windows out of the way. So while it seems kludgey to me, it will work, as you have noted. But it also seems distasteful to not be able to, for example, check all the normal properties (non-overlapping windows among them, I believe) with QC. So my opinion is that it would be better to pass in the focused window, as you propose below.
I agree. It'll be cleaner to pass in the focussed window. It's also helpful for certain sorts of layouts I can imagine, where the focussed window is treated specially (e.g. if I had a keybinding to make the focussed window a bit wider).
In that scenario, I'm not quite sure where you'd want to parameterize your user-defined message type. Indeed, I'm not quite sure what to do about that in the first place. If the whole X monad takes this type, doesn't that mean that you made up a totally new type, you couldn't mix and match your layout functions with the builtin ones?
In the scenario I'm imagining, layout functions would define a class describing the messages they accept, and the Config file would define a data type that is an instance of all those classes. Thus we can have any combination of layouts, which can each accept any number of messages. The Config file needs to "know" the details of the messages in order to set up key bindings anyhow.
In practice, there probably won't be very many such classes, since most layouts will accept similar commands.
Hmm. What advantage does using classes have over just having a data type with multiple constructors, and have layout functions ignore messages (ie, constructors) they don't know about?
The advantage is that new layouts can be developed that desire new sorts of messages without modifying all the other layouts. You could also acheive this by having a standardized name for the message datatype and adding an additional config file that is imported into Operations, but that seems kludgey. Or if ghc supported mutually recursive modules, that could also make it work. But the class approach seems cleanest to me--I don't like the mutually recursive approach, as it means that a change in Config could cause Operations to fail to compile, which doesn't seem like a friendly interface for people who just want to change their key bindings. -- David Roundy http://www.darcs.net