Sean-Bradley

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Sean-Bradley

class IProtoType(metaclass=ABCMeta):
  
    """interface with clone method"""
    @abstractstaticmethod
    def clone():

        """The clone, deep or shallow, is up to how you 
        want implement the details in your concrete class?"""
        

Sean-Bradley

class IUndoRedo(metaclass=ABCMeta):
    """The Undo Redo interface"""
    @abstractstaticmethod
    def history():
        """the history of the states"""

    @abstractstaticmethod
    def undo():
        """for undoing the hsitory of the states"""

Sean-Bradley

def execute(self, command_name, *args):
        """Execute a pre defined command and log in history"""
        if command_name in self._commands.keys():
            self._history_position += 1
            self._commands[command_name].execute(args)
            if len(self._history) == self._history_position:
                # This is a new event in hisory
                self._history.append((time.time(), command_name, args))
            else:
                # This occurs if there was one of more UNDOs and then a new

Sean-Bradley

@property
def history(self):
        """Return all records in the History list"""
        return self._history

def undo(self):
        """Undo a command if there is a command that can be undone.
        Update the history psoition so that further UNDOs or REDOs
        point to the correct index"""
        if self._history_position > 0:

Sean-Bradley

class Slider(IUndoRedo):
    """The Invoker Class"""

    def __init__(self):
        self._commands = {}
        self._history = [(0.0, "OFF", ())]  # A default setting of OFF
        self._history_position = 0  # The position that is used for UNDO/REDO
 
 ...
 

Sean-Bradley

if __name__ == "__main__":
    # The Client is the main python app

    # The Light is the Reciever
    LIGHT = Light()

    # Create Commands
    SWITCH_ON = SwitchOnCommand(LIGHT)
    SWITCH_OFF = SwitchOffCommand(LIGHT)

Sean-Bradley

class Light:
    """The Reciever"""

    def turn_on(self):
        print("Light turned ON")

    def turn_off(self):
        print("Light turned OFF")

Sean-Bradley

class Switch:

    """The Invoker Class"""

    def __init__(self):
        self._commands = {}
        self._history = []

Sean-Bradley

class ICommand(metaclass=ABCMeta):
    """The command interface, which all commands will implement"""

    @abstractstaticmethod
    def execute():
        """The required execute method which all command obejcts will use"""


class SwitchOnCommand(ICommand):
    """A Command object, which implemets the ICommand interface"""