[tcltk-perl] Re: scalar($w->getOpenFile)

[Gisle A. <gi...@Ac...>]

"Jeff Hobbs" <je...@Ac...> writes:

> > Gisle Aas <gi...@Ac...> writes:
> > 
> > > To me it wrong if:
> > >     $tcl->Eval("set var {a b c}");
> > > returns something different to perl than
> > >     $tcl->Eval("set var [list a b c]");
> > > if these two expressions have exactly the same semantics in Tcl.
> > > 
> > > I would suggest that we always return the string in scalar context and 
> > > always list in list context.  If the value is not a valid list, then 
> > > we croak in list context.
> 
> The thing is that there is a difference, it's just very, very
> subtle.  The problem is that the subtle distinctions are very
> important.

So tell me what breaks if we do it like this.

> > If you try the following program:
> > 
> >     #!/usr/bin/perl -w
> >     
> >     use Tcl::Tk qw(:perlTk);
> >     
> >     my $mw = MainWindow->new;
> >     my $label = $mw->Label(-text => "Hello")->pack;
> >     if (my $file = $mw->getOpenFile) {
> >         $label->configure(-text => "File [$file]");
> >         $mw->after(5000, sub { $mw->destroy });
> >     }
> >     
> >     MainLoop;
> > 
> > and then hit "Cancel" to the dialog that pops up, then we 
> > fill in the field with something like "File 
> > [ARRAY(0x8141ad8)]".  Apparently tk_getOpenFile returns a 
> > list instead of string, but this is not documented.  Since 
> 
> This is just a bad example.  The fact that it returns anything
> on unix is wrong wrong wrong (and possibly a bug to look into).
> On Windows, the expected "" is returned and thus you never
> enter into that loop.
> 
> Looking into the Tk code ... I'm suspecting bug, as I see that
> the variable returned is specifically set to "" (empty string,
> not empty list) when cancel is hit.

So why was it returning a reference to an empty array then?  Some bug
in the Tcl.pm interface code?

> The important thing in getOpenFile is in making sure whatever
> changes you do correctly handle files with spaces and multiple
> files (in case you pass -multiple 1 to the dialog).

If you call $mw->getOpenFile in list context it should all work.  And
if you provide -multiple 1 you probably know that you must do that.

--Gisle