'Fill frame with Checkbuttons bound to SearchEngine booleanvars.'

def create_option_buttons(self):

    f = self.make_frame('Options')
    btn = Checkbutton(f, anchor='w', variable=self.engine.revar, text='Regular    expression')
    btn.pack(side='left', fill='both')
    if self.engine.isre():
        btn.select()
    btn = Checkbutton(f, anchor='w', variable=self.engine.casevar, text='Match    case')
    btn.pack(side='left', fill='both')
    if self.engine.iscase():
        btn.select()
    btn = Checkbutton(f, anchor='w', variable=self.engine.wordvar, text='Whole    word')
    btn.pack(side='left', fill='both')
    if self.engine.isword():
        btn.select()
    if self.needwrapbutton:
        btn = Checkbutton(f, anchor='w', variable=self.engine.wrapvar, text='Wrap    around')
        btn.pack(side='left', fill='both')
        if self.engine.iswrap():
            btn.select()
