This change has two implications:
1) tree_render() will now be called precisely once for input which consists of
multiple commands (like "focus left; focus right"). Also, the caller of
parse_command() has to call it. This makes us able to fix tickets such as
ticket #608 (where multiple tree_render() calls are noticable).
2) The output of a command is now a JSON array of return values of the
individual subcommands. In the case of "focus left; focus right", this is:
[{"success":true}, {"success":true}]
While this is incompatible with what i3 returned before, the return value of
commands was undocumented and therefore not subject to our API stability.
Some of them are useless nowadays, others very unlikely to be a problem.
Those which might still be interesting somewhen in the future are just
commented out.
An example to set all XTerms floating:
for_window [class="XTerm"] mode floating
To make all urxvts use a 1-pixel border:
for_window [class="urxvt"] border 1pixel
A less useful, but rather funny example:
for_window [title="x200: ~/work"] mode floating
The commands are not completely arbitrary. The commands above were tested,
others may need some fixing. Internally, windows are compared against your
criteria (class, title, …) when they are initially managed and whenever one of
the relevant values change. Then, the specified command is run *once* (per
window). It gets prefixed with a criteria to make it match only the specific
window that triggered it. So, if you configure "mode floating", i3 runs
something like '[id="8393923"] mode floating'.