Prev: Tk : trying to manage a labelframe
Next: adding jpeg to mp3 file
From: mark anthony on 21 Feb 2010 19:50
On Jan 15, 4:54 am, shags72 <je...(a)mtco.com> wrote:
> On Jan 14, 5:12 am, mark anthony <koyam...(a)gmail.com> wrote:
>
>
>
>
>
> > On Jan 13, 3:37 pm, shags72 <je...(a)mtco.com> wrote:
>
> > > > However, it is not needed as lappend (and append) are documented and defined
> > > > to create the variable if it does not exists.  Thus you could just do:
> > > Yes I should be checking listvar, my typing mistake.
>
> > Avoid info commands if you do not need them, esp if you loop. They are
> > damn expensive.
>
> > If you know it fails you only once or not that often, constructs like:
>
> > if {[::catch {
> >    something_that_might_fail}]} then {
>
> >    it_failed_so_init_it
>
> > }
>
> > are better.
>
> > In your example you use globals.
>
> > So instead of info exists checks all over the place, initialize them.
>
> > cleaner and cheaper.
>
> > koyama
>
> What does the :: do for you in front of the catch? I have seen it used
> for establishing what I consider global but have
> something to do with namespace.

sorry for the late reply just in case ppl stumble upon this, here is
my answer.

yes, you are right. its namespaces. i am used to put it in front
because i tend to like to use names, that buildin commands have, in my
namespaces.

so for the sake of less headache i use :: everywhere when i refer to
the real thing (as you said its the global command for that name).

things like

::car::open $door
::db::set $key $value
::queue::append $guy

just look better to the eye, imho.

usually i don't use it here on the newsgroup but sometimes it turns up
in my snippets and is doing confusion. sorry about that.

koyama
 | 
Pages: 1
Prev: Tk : trying to manage a labelframe
Next: adding jpeg to mp3 file