Re: get_maximized

On Sep 6, 2006, at 9:54 AM, Sergei Steshenko wrote:

--- Emmanuele Bassi <ebassi gmail com> wrote:

      if ($event->changed_mask & [ 'maximized', ]) {

Isn't "&" in

$event->changed_mask & [ 'maximized', ]

bitwise AND ?

In this context, no. Read about it in the "This is now that" section of the Glib manpage: Glib.html#This_Is_Now_That

The API was designed this way to allow you to use C-ish syntax if that's what you're used to, or more meaningful syntax if you prefer. The implementations of the operators have the necessary magic to ensure that you get what you mean with various ways to ask for it.

Quoting the manpage:
Flags have some additional magic abilities in the form of overloaded operators:

  + or |   union of two flagsets ("add")
  -        difference of two flagsets ("sub", "remove")
  * or &   intersection of two bitsets ("and")
  / or ^   symmetric difference ("xor", you will rarely need this)
>= contains-operator ("is the left set a superset of the right set?")
  ==       equality
In addition, flags in boolean context indicate whether they are empty or not, which allows you to write common operations naturally:

  $widget->set_events ($widget->get_events - "motion_notify_mask");
  $widget->set_events ($widget->get_events - ["motion_notify_mask",

  # shift pressed (both work, it's a matter of taste)
  if ($event->state >= "shift-mask") { ...
  if ($event->state * "shift-mask") { ...

  # either shift OR control pressed?
  if ($event->state * ["shift-mask", "control-mask"]) { ...

  # both shift AND control be pressed?
  if ($event->state >= ["shift-mask", "control-mask"]) { ...
In general, + and - work as expected to add or remove flags. To test whether any bits are set in a mask, you use $mask * ..., and to test whether all bits are set in a mask, you use $mask >= ....

When dereferenced as an array @$flags or $flags->[...], you can access the flag values directly as strings (but you are not allowed to modify the array), and when stringified "$flags" a flags value will output a human-readable version of its contents.

Meg: Brian! Chris picked his nose and keeps trying to touch me with his finger! Chris: What good is mining nose gold if I can't share it with the townspeople?
   -- Family Guy

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