The goal is to catch cases where the return value exists, but is
forgotten. There was a large enough number of them to turn this
into a real check. Initially, I just wanted to implement it to fix
the problems, then delete the code. But since this is so common, I
think it is worth the annoyance.
Right now, all rules are additive, they are squashed into one big
array of properties. This is normally fine, but sometime you want
explicit rules for some objects, but also default rules if nothing
matches.
While this can be expressed in the current system by overriding
*all* properties, this require more effort than having "special"
and "fallback" rules.
Nobody wants to set this parameter. It is necessary because the old
API allowed `awful.rules` to be used with random for random matching.
This stopped "really" working between the 3.4 and 3.5 release because
the code started to accumulate "corner case" fixes aligned with the
client properties. v4.0 added more ordering and v4.3 added external
sources. After this, it is unusable with external objects, but
`gears.matcher` handle this use case very well.
In a perfect world we would have pure expression matching, but
that's problematic with all the "metaness" of the code. For now,
this adds an imperfect way to match the minimum and maximum of
number properties.
It will be used by the screen rules for the DPI and size properties.
This is hardcoded in `awful.rules`, but cannot be shared due to the
priority corner cases. Given in the long run any "standard" priority
should use the topological sort API, better not try to share *that*
code.
It is now possible to add and remove rules. This is superior to how
`awful.rules` originally handled rules because modules can now
assume adding and removing rules works.
The reason for the methods rather than `table.insert` is partially
because future commits will add signals. In turn, this will allow
`gears.matcher` to be extended by module using it using the extra
"introspection" made possible by the signals.
Emmanuel Lepage Vallee
actionless
Uli Schlachter