Re: A suggestion for Tcl 9

Helmut Giese <hgiese@ratiosoft.com> wrote:

Hello out there,
currently Tk accepts only  _gobal_ variables for widgets which set a
value. I always wondered why it doesn't also accept a fully namespaced
variable, too.

Unless something has changed in 9, Tk has always accepted fully
qualified namespaced variables for Tk widget variables.

I.e.:

    $ rlwrap wish
    % namespace eval ns {
    variable someVar ""
    }
    % puts $::ns::someVar

    % ttk::radiobutton .r1 -text R1 -value R1 -variable ::ns::someVar
    .r1
    % ttk::radiobutton .r2 -text R2 -value R2 -variable ::ns::someVar
    .r2
    % pack .r1 .r2 -side top
    % puts $::ns::someVar

    % # clicks upon r1
    % puts $::ns::someVar
    R1
    % # clicks upon r2
    % puts $::ns::someVar
    R2
    %

The thing is, they do have to be 'fully qualified' (which is something
that is easy to forget).

In Tcl 8 a syntax like
        -var ::ns::someVar
is not illegal: it just doesn't have any effect

As I show above, it does.  But, for a radio button, you do need to give
each widget a -value or the widget never sets anything into the
variable.