##############################################################################
# a customization with an extra row of buttons for common operations;
# a more useful customization: adds buttons for more operations (sqrt, 
# 1/x, etc.) by subclassing to extend the original class, not embedding;
# new buttons show up before frame attached to bottom be calcgui class; 
##############################################################################

from Tkinter import *
from calculator import CalcGui, getCalcArgs
from PP2E.Dbase.TableBrowser.guitools import *

class CalcGuiPlus(CalcGui): 
    def makeWidgets(self, *args):
        label(self, TOP, 'PyCalc Plus - Subclass')
        apply(CalcGui.makeWidgets, (self,) + args)
        frm = frame(self, BOTTOM)
        extras = [('sqrt', 'sqrt(%s)'),
                  ('x^2 ', '(%s)**2'),  
                  ('x^3 ', '(%s)**3'),
                  ('1/x ', '1.0/(%s)')]
        for (lab, expr) in extras:
            button(frm, LEFT, lab, (lambda m=self.onExtra, e=expr: m(e)) )
        button(frm, LEFT, ' pi ', self.onPi)
    def onExtra(self, expr):
        try:
            self.text.set(self.eval.runstring(expr % self.text.get()))
        except:
            self.text.set('ERROR')
    def onPi(self):
        self.text.set(self.eval.runstring('pi'))

if __name__ == '__main__': 
    apply(CalcGuiPlus, (), getCalcArgs()).mainloop()     # passes -bg, -fg on