[WJG] (02/08/2016) Now that the OO package has been integrated into the Tcl core module I thought it about time to take a look at creating [Gnocl] megawidgets using this method. This task proved much easier and quicker to implement than widget overloading and with no loss of flexibility. Here's the basic megawidget template which I now stash away in my ./config/geany/filedefs folder.


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#{fileheader}

#---------------
# Boilerplate object builder package for Gnocl derived megawidgets.
# Based upon approach used in Gnocl source code.
#---------------
# USAGE: Substitute keywords "_prj_" and "_widget_" for unique project and object type identifier.
#---------------

#!/bin/sh
# the next line restarts using tclsh \
exec tclsh "$0" "$@"

package require Gnocl

#---------------
# lists of valid widget options, commands and components
#---------------
#
oo::class create _prj_:_widget_ {
        
        constructor {} {
                # declare variables to store data, settings and widget ids
                my variable container
                my variable but1
                my variable but2
                my variable parts
                
                my variable data
                
                set data "How Now Brown Cow"
                
                # create and assemble megawidget parts                
                set container [gnocl::vBox]
                set but1 [gnocl::button -text HIDIHI -icon %#Help]
                set but2 [gnocl::button -text HODIHO -icon %#Stop]
                $container add $but1
                $container add $but2

                # retain a list of parts
                set parts [list container but1 but2]
                }
                
        destructor {
                my variable container
                $container delete
                }

        method getId {} {
                my variable container
                return $container
                }

        method class {} {
                return _widget_
                }

        #---------------
        
        # generic controller, directly access all elements of widget control
        method cmd { args } {
                my variable parts
                foreach var $parts { my variable $var }
                eval [set [lindex $args 0]] [lindex $args 1] [lrange $args 2 end]
                }
        
        
                
        method configure { args } {
                my variable parts
                foreach var $parts { my variable $var }        
                eval [set [lindex $args 0]] configure [lrange $args 1 end]
                }
                
        method cget { args } {
                my variable parts
                foreach var $parts { my variable $var }
                eval [set [lindex $args 0]] cget [lrange $args 1 end]
                }


        # set or retrieve megawidget internal data
        method getData {} {
                my variable data
                return $data
                }

        method setData {val} {
                my variable data
                set data $val
                }
        
        # object operations, or specfic methods
        method tooltips { tt1 tt2 } {
                my variable parts
                foreach var $parts { my variable $var }
                
                $but1 configure -tooltip $tt1
                $but2 configure -tooltip $tt2                
                }

        # manipulate internal data
        method tocaps {} {
                my variable data
                set data [string toupper $data]
                }

}

#===============
# DEMO
#===============
proc demo {} {
        
        set b1 [_prj_:_widget_ new]
        
        puts [$b1 class]
        
        gnocl::window -child [$b1 getId] -title A -setSize 0.125 -x 200 
        $b1 configure but1 -onClicked { puts "HI %d" }  -data PING
        $b1 configure but2 -onClicked { puts "HO %d" }  -data PONG
        
        puts [$b1 cget but1 -data]
        
        $b1 tooltips "HI DI HI" "HO DI HO"

        puts [$b1 getData]

        $b1 tocaps

        puts [$b1 getData]


        set b2 [_prj_:_widget_ new]
        gnocl::window -child [$b2 getId] -title B -setSize 0.125 -x 400 

        $b2 destroy
        catch { $b2 configure but2 -onClicked { puts "HO %d" }  -data PONG } {}
        
}

demo

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