Re: gparamspecs.c param_double_validate() doesn't support NaN/Inf?

[Owen Taylor <otaylor redhat com>]

On Sat, 2009-01-10 at 14:30 +0200, Andrew W. Nosenko wrote:
> On Sat, Jan 10, 2009 at 2:06 PM, Brian J. Tarricone <bjt23 cornell edu> wrote:
> > On Sat, 10 Jan 2009 13:42:31 +0200 Andrew W. Nosenko wrote:
> >
> >> First at all, could you provide any real-world example, where min/max
> >> restriction on GParamSpec could be usefull?  The reason is simple:
> >> when validation fails, the application has no way to know about it
> >> and, therefore, to do anything usefull.  There just no interface for
> >> such things, like "validation-fails-callback".  As consequence, any
> >> validation should be done at the application level, before bringing
> >> GObject/GParamSpec/GValue/etc machinery into game.  Hence, I hard to
> >> imagine any usefull example of using restrcted GParamSpecs...
> >
> > Then you really just aren't imagining hard enough.  If you look at the
> > gdk/gtk sources, there are quite a few GObject properties that use
> > GParamSpecDouble that restricts the min/max value a property can have.
> > For example, think of a progress bar that uses a double to indicate
> > the percent full: 0.0 is 0%, 1.0 is 100%.  Any value outside that
> > range is invalid.
> 
> I know about that.  But how it usefull?  What you can to do with it?
> Yes, for progressbar it resulted just for some different rendering
> that has nothing but visual effect.  You could to don't use restricted
> paramespec but just silently CLAMP(), for example, without any harm.
> Even if you do not do any validation, the result would be the same:
> just a visual effects, possible ugly, but have nothing with the core
> functionality.

One of the main reasons for the presence of limits in the paramspec
is to allow proper presentation in user interface builders.

- Owen