From: amnesiacx <louis@...>
Date: 2004-01-09T19:51:39+09:00
Subject: Call method from a TK object

Please can someone tell my why the code that follows works when the
"tick" and "zero" methods are nested inside "gui" , but when I move
the "tick" and "zero" methods out of gui - into a top level class
methods, the calls to tick from within the $stop object gets a "local
method not found" error? (You need TK libs to run)

# This script generates a counter with start and stop buttons.

class StopWatch 

	@@seconds=0
	@@hundredths=0
	@@stopped=TRUE
   	 $heading = "Ticker"

#------------------------------------------------------------------------------
    public
	
		def initialize(head)
			$heading = head
			gui $heading
			root = Tk.root
			root.bind "Control-c", proc{root.destroy}
			root.bind "Control-q", proc{root.destroy}
			Tk.root.focus
			Tk.mainloop
		end
	
#------------------------------------------------------------------------------
private
	
		def gui(head)
		
			require "tk"
	
			$title = TkLabel.new {
	  			text head 
	  			relief 'raised'
	  			width 20
	  			font 'courier'
	  			pack('side'=>'top', 'fill'=>'both')
			}
	
			$label = TkLabel.new {
	  			text '0.00' 
	  			relief 'raised'
	  			width 10
	  			font 'verdana'
	  			pack('side'=>'bottom', 'fill'=>'both')
			}
	
			$start = TkButton.new {
	  			text 'Start'
	  			command proc {
	    			$stop.text "Stop"
	    			if @@stopped
	      				@@stopped = FALSE
	      				tick
	    			end
	  			}

pack('side'=>'left','fill'=>'both','expand'=>'yes')
			}
	
			$stop = TkButton.new {	
	  			text 'Stop'
	  			command proc{
	    			text "Zero"
	    			if @@stopped then
						zero
	        			text 'Stop'
	    			end
	    			@@stopped = TRUE
	  			}

pack('side'=>'right','fill'=>'both','expand'=>'yes')
			}

	# the following two methods do not work when NOT nested inside
the gui method as they are now
            # starts the timer
            def tick
                if @@stopped then return end
	  		        Tk.after 50, proc{tick}
	  		        @@hundredths+=5
	  		        if @@hundredths >= 100
	    		        @@hundredths=0
	    		        @@seconds+=1
	  		    end
	  		    $label.text format("%d.%02d", @@seconds,
@@hundredths)
		    end
		
            # resets timer to zero
            def zero
		        @@seconds=0
		        @@hundredths=0
		        $label.text format("%d.%02d", @@seconds,
@@hundredths)
            end

		end
		   	
end

#------------------------------------------------------------------------------
# run app
StopWatch.new("BIT Ruby Stop Watch!")