~cpp
from Tkinter import * 
import Pmw 

class SLabel(Frame): 
    def __init__(self, master, left1, right1): 
        Frame.__init__(self, master, bg='gray40') 
        self.pack(side=LEFT, expand=YES, fill=BOTH) 
        Label(self, text=left1, fg='steelblue1', 
              font=("arial", 6, "bold"), width=5, bg='gray40').pack(
              side = LEFT, expand=YES, fill=BOTH)
        
        Label(self, text=right1, fg='white', 
              font=("arial", 6, "bold"), width=1, bg='gray40').pack(
              side = RIGHT, expand=YES, fill=BOTH) 

class Key(Button): 
    def __init(self, master, font=('arial', 8, 'bold'), fg='white',
               width=5, borderwidth=5, **kw): 
        kw['font'] = font 
        kw['fg'] = fg 
        kw['width'] = width 
        kw['borderwidth'] = borderwidth 

        apply(Button.__init__, (self, master), kw) 

        self.pack(side=LEFT, expand=NO, fill=NONE) 

class Evaluator:
    def __init__(self):
        self.myNameSpace = {}
        self.runpython("from math import *")

    def runpython(self, code):
        try:
            return repr(eval(code, self.myNameSpace, self.myNameSpace))
        except SyntaxError:
            try :
                exec code  in self.myNameSpace, self.myNamespace
            except:
                return 'Error'


class Calculator(Frame):
    def __init__(self, parent = None):
        Frame.__init__(self, bg='gray40')
        self.pack(expand = YES, fill = BOTH)
        self.master.title('Tkinter Toolkit TT - 42')
        self.master.iconname('Tk-42')
        self.calc = Evaluator()
        self.buildCalculator()
        self.actionDict = { 'second' : self.doThis, 'mode': self.doThis,
                            'delete' : self.doThis, 'alpha' : self.doThis,
                            'stat' : self.doThis, 'math' : self.doThis,
                            'matrix': self.doThis, 'program' : self.doThis,
                            'vars' : self.doThis, 'clear' : self.clearall,
                            'sin' : self.doThis, 'cos' : self.doThis,
                            'tan' : self.doThis, 'up' : self.doThis,
                            'X1' : self.doThis, 'X2' : self.doThis,
                            'log' : self.doThis, 'ln' : self.doThis,
                            'store' : self.doThis, 'off' : self.turnoff,
                            'neg' : self.doThis, 'enter' : self.doEnter,
                            }

        self.current = ''

    def doThis(self, action):
        print '"%s" has not been implemented' % action

    def turnoff(self, *args):
        self.quit()

    def clearall(self, *args):
        self.current = ""
        self.display.component('text').delete(1.0, END)

    def doEnter(self, *args):
        self.display.insert(END, '\n')
        result = self.calc.runpython(self.current)
        if result :
            self.display.insert(END, '%s\n' % result, 'ans')
        self.current = ""

    def doKeypress(self, event):
        key = event.char
        if key != '\b':
            self.current = self.current + key
        else:
            self.current = self.currnet[:-1]

    def keyAction(self, key):
        self.display.insert(END, key)
        self.current = self.currnet + key

    def evalAction(self, action):
        try:
            self.actionDict[action](action)
        except:
            pass

    def buildCalculator(self):
        FUN = 1
        KEY = 0
        KC1 = 'gray30'
        KC2 = 'gray50'
        KC3 = 'steelblue1'
        KC4 = 'steelblue'

        keys = [
            [ ('2nd', '', '', KC3, FUN, 'second'),
              ('Mode', 'Quit', '', KC1, FUN, 'mode'),
              ('Del', 'Ins', '', KC1, FUN, 'delete'),
              ('Alpha', 'Lock', '', KC2, FUN, 'alpha'),
              ('Stat', 'List', 'A', KC1, FUN, 'stat')],
            [ ('Math', 'Test', 'B', KC1, FUN, 'math'),
              ('Mtrx', 'Angle', 'C', KC1, FUN, 'matrix'),
              ('Prgm', 'Draw', '', KC1, FUN, 'program'),
              ('Vars', 'YVars', '', KC1, FUN, 'vars'),
              ('Clr', '', '', KC1, FUN, 'clear')],
            [ ('X-1', 'Abs', 'D', KC1, FUN, 'X1'),
              ('Sin', 'Sin-1', 'E', KC1, FUN, 'sin'),
              ('Cos', 'Cos-1', 'F', KC1, FUN, 'cos'),
              ('Tan', 'Tan-1', 'G', KC1, FUN, 'tan'),
              ('^', 'PI', 'H', KC1, FUN, 'up')],
            [ ('X2', 'Root', 'I', KC1, FUN, 'X2'),
              (',', 'RE', 'J', KC1, FUN, ','),
              ('(', '{', 'K', KC1, FUN, '('),
              (')', '}', 'L', KC1, FUN, ')'),
              ('/', '', ',', KC4, FUN, '/')],
            [ ('Log', '10x', 'N', KC1, FUN, 'log'),
              ('7', 'Un-1', 'O', KC2, KEY, '7'),
              ('8', 'Vn-1', 'P', KC2, KEY, '8'),
              ('9', 'n', 'Q', KC2, KEY, '9'),
              ('X', '[', 'R', KC4, KEY, '*')],
            [ ('Ln', 'ex', 'S', KC1, FUN, 'ln'),
              ('4', 'L4', 'T', KC2, KEY, '4'),
              ('5', 'L5', 'U', KC2, KEY, '5'),
              ('6', 'L6', 'V', KC2, KEY, '6'),
              ('-', ']', 'W', KC4, KEY, '-')],
            [ ('STO', 'RCL', 'X', KC1, FUN, 'store'),
              ('1', 'L1', 'Y', KC2, KEY, '1'),
              ('2', 'L2', 'Z', KC2, KEY, '2'),
              ('3', 'L3', '', KC2, KEY, '3'),
              ('+', 'MEM', '"', KC4, KEY, '+')],
            [ ('Off', '', '', KC1, FUN, 'off'),
              ('0', '', '', KC2, KEY, '0'),
              ('.', '', '', KC2, KEY, '.'),
              ('(-)', 'ANS', '?', KC2, FUN, 'neg'),
              ('Enter', 'Enter', '', KC4, FUN, 'enter')]]
                
        self.display = Pmw.ScrolledText(self, hscrollmode = 'dynamic',
                                        vscrollmode = 'dynamic', hull_relief = 'sunken',
                                        hull_background='gray40', hull_borderwidth = 10,
                                        text_background='honeydew4', text_width = 16,
                                        text_foreground = 'black', text_height=6,
                                        text_padx = 10, text_pady=10, text_relief = 'groove',
                                        text_font = ('arial', 12, 'bold'))

        self.display.pack(side=TOP, expand = YES, fill=BOTH)

        self.display.tag_config('ans', foreground='white')
        self.display.component('text').bind('<Key>', self.doKeypress)
        self.display.component('text').bind('<Return>', self.doEnter)

        for row in keys:
            rowa = Frame(self, bg='gray40')
            rowb = Frame(self, bg='gray40')

            for p1, p2, p3, color, ktype, func in row:
                if ktype == FUN:
                    a = lambda s=self, a = func : s.evalAction(a)
                else:
                    a = lambda s=self, k = func : s.keyAction(k)
                SLabel(rowa, p2, p3)
                Key(rowb, text=p1, bg=color, command=a)

            rowa.pack(side=TOP, expand=YES, fill=BOTH)
            rowb.pack(side=TOP, expand=YES, fill=BOTH)

Calculator().mainloop()