Method preloop

Lib/pdb.py:337–348

(self)

    # Called before loop, handles display expressions
    def preloop(self):
        displaying = self.displaying.get(self.curframe)
        if displaying:
            for expr, oldvalue in displaying.items():
                newvalue = self._getval_except(expr)
                # check for identity first; this prevents custom __eq__ to
                # be called at every loop, and also prevents instances whose
                # fields are changed to be displayed
                if newvalue is not oldvalue and newvalue != oldvalue:
                    displaying[expr] = newvalue
                    self.message('display %s: %r  [old: %r]' %
                                 (expr, newvalue, oldvalue))

    def interaction(self, frame, traceback):
        # Restore the previous signal handler at the Pdb prompt.