Re^3: Tkx and clear a textbox content

I'll reply to both of your posts^[1,2] here. There's a certain amount of overlap in the information: this will keep it all in one place.

"I am still trying to grasp 'use strict'."

Without knowing what aspect of that you're having problems grasping, it's somewhat difficult to give direct help. I'd suggest reading perlintro; follow the links therein for more detailed information; then, if you're still having difficulties, ask a specific question or, at least, tell us what the problem area is (maybe post that as separate question unless its specifically Tkx-related).

"My code has a hard time running; ..."

Sorry, that's unclear. Slow to start? Unresponsive? Something else?

"... due to my scope with functions and global/private."

I mentioned "scope" in both^[3,4] of my earlier replies. I've addressed this more fully below.

"I will be honest, I am not sure what is the correct way to program with the TCL/TK format as you point out. I am only using the Example from the TKDoc link http://www.tkdocs.com/tutorial/firstexample.html"

[Aside: Please provide actual links, rather than the URL as text. This allows you to test it when previewing; and it's easier for us to just follow a link instead of having to the select text, copy it, paste into address bar, ... See "What shortcuts can I use for linking to other information?" if you don't know how to do this.]

If you look at http://www.tkdocs.com/tutorial/firstexample.html, just below the sample code, you'll see the heading, A Note on Coding Style. The text that follows, includes:

"... a very direct coding style, rather than wrapping up most of our code in procedures, modules, objects, classes and so on."

So, in essence, it's showing you how to use Tcl/Tk code; it's not showing you the best way to write that code in Perl.

The following is a working and tested example, based loosely on your original code, showing how you could write it using lexical variables in minimal scope. There are no variables with global scope. The code consists of discrete subroutines that perform separate functions: &build_gui knows nothing about $entries; &write_entries knows nothing about $mw; the variables modified by &clear_entries are passed to that subroutine in its argument list; and so on.

#!/usr/bin/env perl -l

use strict;
use warnings;

use Tkx;

{
    my $mw = Tkx::widget->new(".");
    build_gui($mw);
}

Tkx::MainLoop();

sub build_gui {
    my ($mw) = @_;

    configure_gui($mw);
    my $frame = build_framework($mw);
    populate_framework($frame);

    return;
}

sub configure_gui {
    my ($mw) = @_;

    $mw->g_wm_title('Entry Example');
    $mw->g_wm_minsize(300, 200);

    return;
}

sub build_framework {
    my ($mw) = @_;

    my $frame = $mw->new_ttk__frame(-padding => '10 10 10 10');

    $frame->g_grid(-column => 0, -row => 0, -sticky => 'nsew');
    $mw->g_grid_columnconfigure(0, -weight => 1);
    $mw->g_grid_rowconfigure(0, -weight => 1);

    return $frame;
}

sub populate_framework {
    my ($frame) = @_;

    my ($string, $number);
    my $textvars = [ \($string, $number) ];

    my $string_label = $frame->new_ttk__label(-text => 'String:');
    $string_label->g_grid(-row => 0, -column => 0, -sticky => 'w');
    my $string_entry = $frame->new_ttk__entry(-textvariable => \$strin
+g);
    $string_entry->g_grid(-row => 0, -column => 1, -sticky => 'ew');

    my $number_label = $frame->new_ttk__label(-text => 'Number:');
    $number_label->g_grid(-row => 1, -column => 0, -sticky => 'w');
    my $number_entry = $frame->new_ttk__entry(-textvariable => \$numbe
+r);
    $number_entry->g_grid(-row => 1, -column => 1, -sticky => 'ew');

    my $write_button = $frame->new_ttk__button(-text => 'Write',
        -command => [\&write_entries, $textvars]
    );
    $write_button->g_grid(-row => 2, -column => 0, -sticky => 'ew');

    my $clear_button = $frame->new_ttk__button(-text => 'Clear',
        -command => [\&clear_entries, $textvars]
    );
    $clear_button->g_grid(-row => 2, -column => 1, -sticky => 'ew');

    $_->g_grid_configure(-padx => 5, -pady => 5) for $frame->_kids;

    return;
}

sub write_entries {
    my ($entries) = @_;

    print join ',', map { $$_ } @$entries;

    return;
}

sub clear_entries {
    my ($entries) = @_;

    $$_ = '' for @$entries;

    return;
}
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There shouldn't be anything in that code that you can't reference from the Tkx or Tkx::Tutorial documentation. I haven't attempted to show "Subclassing Tkx::widget": if you're currently having difficulties grasping strict, that may be a bit beyond your skills at the present; I would, however, encourage you to work towards it. I have used "Widget handles" throughout, which was something I discussed in an earlier response.

"... however, I do have the "Introducing Perl/TK" book coming soon via mail."

I own two Perl/Tk books: "Learning Perl/Tk" and "Mastering Perl/Tk" (both are now rather old — published in 1999 and 2002, respectively). I'm unfamiliar with "Introducing Perl/TK"; a link would have been useful.

"Yet, I am totally lost as to use Tk or Tkx - the syntax does appear to be different. What method do you recommend?"

I like Perl/Tk for a number of reasons, not least of which is the fact that I've been using it for about two decades and am very familiar with it. I've started to use Tkx recently mainly for cosmetic reasons: it just displays better on certain platforms.

Yes, the syntax is different. I'm currently using Tkx for a private project and, by following the suggestions in "Subclassing Tkx::widget", I now have almost identical syntax. Even if it wasn't private, the main module for performing that subclassing, currently stands at 2,305 lines, so not really something I would post here; I am, however, happy to help with specific issues.

— Ken

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