Re: [Fxruby-users] Message Identifiers, Types, etc again.

[Hugh S. S. E. E. <hg...@dm...>]

On Fri, 13 Jun 2003, Sander Jansen wrote:

> On Friday 13 June 2003 07:44 am, Hugh Sasse Staff Elec Eng wrote:
> > Just when I thought I was no longer confused about this:
> >
> > On Thu, 12 Jun 2003, Hugh Sasse Staff Elec Eng wrote:
> > > OK, reading this in conjunction with paragraphs 3 and 4 of
> > >
> > > http://www.fox-toolkit.org/messages.html
> > >
> > > it seems that message_id is actually the sender of the message, and
> > > message type is actually the message itself (not counting associated
> > > data).  I would have called the message itself the message_id,
> >
> > Well, it is not as simple as that.  The FXRuby API docs for
> > FXShutter, FXShutterItem, FXScrollbar and FXList at least refer to
> > Message Identifiers which are constants, and are not names of the
> > originating objects.  So should these be called Message Types for
> > consitency with other FOX docs, or what?
> >
> >         Hugh
>
> a message consists of a type and a id. Sometimes called the selector.

Yes, and from the above URL the id is the sender of the message, and
the type is the individual message without data.
>
> In C++ we have the following macros to get the type and id from a selector:
>
> FXSELTYPE(selector)
> FXSELID(selector)
>
> In constructors of widgets, you normally have to input a target and selector.
> In that case, the selector is only the ID. Its still named this way because
> of historically reasons.  Also "getSelector" would give you back the ID.

But then the id is the widget that sent the message. My point is
that
http://www.fxruby.org/doc/api/classes/Fox/FXScrollbar.html
and the similar pages refer to Message Identifiers, and then list
Message types.
<quote>
Message identifiers
ID_TIMEWHEEL:   x
ID_AUTOINC_LINE:        x
</quote>

I currently believe that these cannot be called identifiers because
the identifier is a widget, which is not a constant. A message type
is a constant.

So, either I am right about this, and the api docs need fixing, or I
am wrong about this, and http://www.fox-toolkit.org/messages.html
needs fixing because  it says:
<quote>
 The approach taken by FOX is a Target/Message System. Each Widget
 sends its message to a certain object called the target. As there
 may be multiple Widgets sending messages to one specific target, a
 message id is used to tell them apart.

 Moreover, a single Widget may be able to send several kinds of
 messages; this problem is solved by typing the messages by a
 message type. Using the message type and message id, the source and
 type of a GUI event or action can be uniquely identified.
</quote>

Or, is there in fact a third way to understand this, and reconcile
both these documents?
>
> 	Sander
>
        Hugh