def create(self, args):
"""
Create the skewer that will hold the food.
:param args: a string containing the size to create
:return: None
"""
try:
# make sure the size is valid
if len(args) == 0 or int(args[0]) < 1:
raise SkewerException("Skewer size must be greater than 0")
size = int(args[0])
# force close a pre-existing skewer
if self.skewer != None:
self.skewer.close()
self.skewer = Skewer(size)
print("Skewer created.")
except SkewerException as e:
print(e)
self.skewer = None
except Exception as e:
sys.stderr.write(e)
self.usage()
return
class Kebab:
"""
Class: Kebab
Description: This class contains the main loop for the program. It
filters the command line input and then calls a Skewer instance
to deal with the appropriate action.
"""
__slots__ = "skewer",
def __init__(self):
"""Create a Kebab instance."""
# initially there is no skewer until one is created by command.
self.skewer = None
def usage(self):
"""
Displays the valid commands and their usage.
:return: None
"""
print("Kebab commands:")
print("add item - adds an item to the skewer")
print(
"calories - get the total number of calories of items on the skewer"
)
print("create N - creates a skewer to hold N items")
print("destroy - destroys the current skewer")
print("display - displays all the items on the skewer, in order")
print("eat - eat the front item on the skewer")
print("foods - display the food items that can be added to the skewer")
print("front - the front item on the skewer")
print("has item - is an item on the skewer?")
print("quit - exit the program")
print(
"status - the capacity and current number of items on the skewer")
print("vegan - does the skewer have any meat?")
def create(self, args):
"""
Create the skewer that will hold the food.
:param args: a string containing the size to create
:return: None
"""
try:
# make sure the size is valid
if len(args) == 0 or int(args[0]) < 1:
raise SkewerException("Skewer size must be greater than 0")
size = int(args[0])
# force close a pre-existing skewer
if self.skewer != None:
self.skewer.close()
self.skewer = Skewer(size)
print("Skewer created.")
except SkewerException as e:
print(e)
self.skewer = None
except Exception as e:
sys.stderr.write(e)
self.usage()
return
def add(self, args):
"""
Add a specified item to the skewer.
:param args: the name of the item to add
:return: None
"""
if len(args) < 1:
self.usage()
return
name = args[0]
# check that the name is in the list of valid foods
if name not in FOODS:
print("Skewer can only hold these kinds of food: ", FOODS)
return
try:
self.skewer.add(name)
print(name, "successfully added to the skewer.")
except SkewerException as e:
print(e)
def calories(self, args):
"""
Returs the total number of calories on the skewer
:param args: ignored
:return: None
"""
print("The skewer has ", int(self.skewer.calories()), " calories.")
def eat(self, args):
"""
Eat the front item on the skewer.
:param args: ignored
:return: None
"""
try:
name = self.skewer.front()
self.skewer.remove()
print("Ate", name, ". Yum!")
except SkewerException as e:
print(e)
def has(self, args):
"""
Checks if the skewer holds a certain item.
:param args: the name of the item to search for
:return: None
"""
if len(args) < 1:
self.usage()
return
name = args[0]
if self.skewer.has(name):
print(name, "does exist on the Skewer.")
else:
print(name, "doesn't exist on the Skewer.")
def status(self, args):
"""
Displays the number of items on the skewer and its capacity.
:param args: ignored
:return: None
"""
print(str(self.skewer.size()), "out of", self.skewer.capacity(),
"items on the skewer.")
def front(self, args):
"""
Displays the name of the front item on the skewer.
:param args: ignored
:return: None
"""
try:
print(self.skewer.front(), "is on the front of the skewer.")
except SkewerException as e:
print(e)
def display(self, args):
"""
Displays the items on the skewer by name.
:param args: ignored
:return: None
"""
print("The skewer contains: ", self.skewer)
def vegan(self, args):
"""
Displays whether all items on the skewer are vegetarian or not.
:param args: ignored
:return: None
"""
if self.skewer.is_vegan():
print("The skewer is vegan friendly.")
else:
print("The skewer contains meat.")
def foods(self, args):
"""
Display the valid food items that can be added to the skewer
:param args: ignored
:return: None
"""
print(FOODS)
def destroy(self, args):
"""
Destroys the skewer if one was previously created.
:param args: ignored
:return: None
"""
if self.skewer:
self.skewer.close()
self.skewer = None
def quit(self, args):
"""
Exit the program
:param args: ignored
:return: None
"""
if self.skewer:
self.skewer.close()
print("Goodbye!")
sys.exit(0)
def main_loop(self):
"""
Runs the main command loop by prompting for input and responding.
:return: None
"""
# Each valid command is stored in a dictionary as string by key.
# The corresponding method to call is stored as the value.
CMDS = {
"add": self.add,
"calories": self.calories,
"create": self.create,
"destroy": self.destroy,
"eat": self.eat,
"foods": self.foods,
"has": self.has,
"status": self.status,
"front": self.front,
"display": self.display,
"vegan": self.vegan,
"quit": self.quit
}
# the command line prompt
PROMPT = "> "
# the command loop runs until the user enters the quit command
while sys.stdin:
line = input(PROMPT).split()
cmd = line[0]
if cmd in CMDS:
# if the skewer does not exist, the only valid commands
# are to create it, list the food items, or quit
if not self.skewer and cmd != "create" and cmd != "foods" and cmd != "quit":
print("Skewer has not been created yet.")
else:
# strip off the command and pass the remaining line
# arguments to the appropriate method
CMDS[cmd](line[1:])
else:
self.usage()