I want to reuse Properties' Arbitrary instance (as well as the T and
NonNegative types) in an upcoming set of SwapWorkspaces QC props.
`module Main where import Main` doesn't work too well. :)
If this patch is accepted, the darcs 'test' pref should be modified to
"-itests tests/Main.hs".
First, if float is called with window which is on a hidden workspace,
then the window will remain on that hidden workspace.
Now the focus should change more as expected:
float w = (view current) . (shiftWin ws w)
where
current is the current screen/workspace
shiftWin ws w is: - view the workspace w is on
- set focus on w
- shift ws
- set focus back to window it was on that workspace
unless w was focused
shiftWin was add to StackSet.hs
This change also removes the barely used 'size' field, and replaces
it with a tagMember predicate. The idea is to move towards the ability
to make the workspace tag be a String, which by default might be "1".."9",
but could also be customized to be something meaningful to the user.
The use of arrow keys for swapLeft/Right clash with firefox's back
button. Use the more intuitive mod-shift-jk for this. (It's a movement
operation, after all).
This clashes with IncMaster, so we use mod+comma and mod+period for
these (i.e. the keys mod < and mod > , to move windows to and from the
master area).
While we're here, replace the use of the terms 'left' and 'right' for
navigation, in comments and identifiers, with 'up' and 'down' instead.
Hence mod-j == focusDown. Far more intuitive for people (dons) who live
in fullscreen mode and have vim movement wired into their central
nervous system.
Principle of least VI surprise: movement down or up means using j and k.
ws used by noDuplicates is actually a list of list of elements which
will pretty rarely raise any flags even if the StackSet actually does
contain duplicates. This patch concatenates ws to ensure the quickcheck
property tests accurately.
In order to give a better account of how focus and master interact, and
how each operation affects focus, we reimplement the StackSet type as a
two level nested 'Zipper'. To quote Oleg:
A Zipper is essentially an `updateable' and yet pure functional
cursor into a data structure. Zipper is also a delimited
continuation reified as a data structure.
That is, we use the Zipper as a cursor which encodes the window which is
in focus. Thus our data structure tracks focus correctly by
construction! We then get simple, obvious semantics for e.g. insert, in
terms of how it affects focus/master. Our transient-messes-with-focus
bug evaporates. 'swap' becomes trivial.
By moving focus directly into the stackset, we can toss some QC
properties about focus handling: it is simply impossible now for focus
to go wrong. As a benefit, we get a dozen new QC properties for free,
governing how master and focus operate.
The encoding of focus in the data type also simplifies the focus
handling in Operations: several operations affecting focus are now
simply wrappers over StackSet.
For the full story, please read the StackSet module, and the QC
properties.
Finally, we save ~40 lines with the simplified logic in Operations.hs
For more info, see the blog post on the implementation,
http://cgi.cse.unsw.edu.au/~dons/blog/2007/05/17#xmonad_part1b_zipper
When focus was separated from the stack order on each workspace, we
forgot to update the Arbitrary instance to set random focus. As spotted
by David R, this then invalidates 4 of our QC properties. In particular,
the property involving where focus goes after a random transient
(annoying behaviour) appeared to be correct, but wasn't, due to
inadequate coverage.
This patch sets focus to a random window on each workspace. As a result,
we now catch the focus/raise/delete issue people have been complaining
about.
Lesson: make sure your QuickCheck generators are doing what you think
they are.
