In this exercise, you'll be implementing the quest logic for a new RPG game a friend is developing. The game's main character is Annalyn, a brave girl with a fierce and loyal pet dog. Unfortunately, disaster strikes, as her best friend was kidnapped while searching for berries in the forest. Annalyn will try to find and free her best friend, optionally taking her dog with her on this quest.
After some time spent following her best friend's trail, she finds the camp in which her best friend is imprisoned. It turns out there are two kidnappers: a mighty knight and a cunning archer.
Having found the kidnappers, Annalyn considers which of the following actions she can engage in:
- Fast attack: a fast attack can be made if the knight is sleeping, as it takes time for him to get his armor on, so he will be vulnerable.
- Spy: the group can be spied upon if at least one of them is awake. Otherwise, spying is a waste of time.
- Signal prisoner: the prisoner can be signalled using bird sounds if the prisoner is awake and the archer is sleeping, as archers are trained in bird signaling so they could intercept the message.
- Free prisoner: if the prisoner is awake and the other two characters are sleeping, a sneaky entry into the camp can free the prisoner. This won't work if the prisoner is sleeping, as the prisoner will be startled by the sudden appearance of her friend and the knight and archer will be awoken. The prisoner can also be freed if the archer is sleeping and Annalyn has her pet dog with her, as the knight will be scared by the dog and will withdraw, and the archer can't equip his bow fast enough to prevent the prisoner from being freed.
You have four tasks: to implement the logic for determining if the above actions are available based on the state of the three characters found in the forest and whether Annalyn's pet dog is present or not.
Implement a function named canExecuteFastAttack
that takes a boolean value which indicates if the knight is awake. This function returns true
if the 'Fast Attack' action is available based on the state of the character. Otherwise, returns false
:
knightIsAwake :: Boolean
knightIsAwake = true
canExecuteFastAttack knightIsAwake
-- => false
Implement a function named canSpy
that takes three boolean values, indicating if the knight, archer and the prisoner, respectively, are awake. The function returns true
if the 'Spy' action is available based on the state of the characters. Otherwise, returns false
:
knightIsAwake :: Boolean
knightIsAwake = true
archerIsAwake :: Boolean
archerIsAwake = true
prisonerIsAwake :: Boolean
prisonerIsAwake = true
canSpy knightIsAwake archerIsAwake prisonerIsAwake
-- => true
Implement a function named canSignalPrisoner
that takes two boolean values, indicating if the archer and the prisoner, respectively, are awake. The function returns true
if the 'Signal Prisoner' action is available based on the state of the characters. Otherwise, returns false
:
archerIsAwake :: Boolean
archerIsAwake = false
prisonerIsAwake :: Boolean
prisonerIsAwake = true
canSignalPrisoner archerIsAwake prisonerIsAwake -- => true
Implement a function named canFreePrisoner
that takes four boolean values. The first three parameters indicate if the knight, archer and the prisoner, respectively, are awake. The last parameter indicates if Annalyn's pet dog is present. The function returns true
if the 'Free Prisoner' action is available based on the state of the characters and Annalyn's pet dog presence. Otherwise, it returns false
:
knightIsAwake :: Boolean
knightIsAwake = true
archerIsAwake :: Boolean
archerIsAwake = false
prisonerIsAwake :: Boolean
prisonerIsAwake = true
petDogIsPresent :: Boolean
petDogIsPresent = true
canFreePrisoner knightIsAwake archerIsAwake prisonerIsAwake petDogIsPresent
-- => false