litle calculette, with Ruiby, without list!

calculator.rb

require  'ruiby'

class App  < Ruiby_gtk
  
  ####################### last result is '_' alias
  def _()
     @lastValue || 0
  end  
  
  ######### context evaluation formula : the context is the first call of b()
  def b
	  @bind_ || @bind_=binding
  end  

  def calc(formule)
	 txt=formule.chomp.strip
	 value=(eval(txt,b) )
	 o=@lastValue
	 @lastValue=value
	 txt=txt.gsub(/_/,"("+o.to_s+")")
	 append_result(txt,value.to_s)
  rescue
	 error("#{$!}\n     #{$!.backtrace().join("\n    ")}")
  end
  def append_result(txt,value)
	 append_to(@body) { 
	    clickable(:selection) { flow { 
			sloti(label(txt +  (value ? (" ==> " + value.to_s) : "" ))) } 
		}
	 }
	 @vb.scroll_to_bottom()
  end
  def selection(wi) 
	t=wi.children[0].children[0].text.split(/\s+==>\s+/)[0]
	@edit.text=t
  end
  def component()
    @lastValue=0
    @excel=[]
	@body=1
    stack do
		flowi do
			sloti(label("Formule : "))
			@edit=slot(entry("",50) { 
			   calc(@edit.text=$1) if @edit.text =~ /(.*)[= ]+$/
			})
			sloti(button("Go") { calc(@edit.text) })
		end
		@vb =vbox_scrolled(200,300) { stack { @body=stacki{} } }
		sloti(button("Clear") {  clear_append_to(@body) {} ; @excel=[] })
    end
  end
end
Ruiby.start { App.new("Calculate",200,100) }