Booleans in F# are represented by the bool type, which values can be either true or false.
F# supports three boolean operators: not (NOT), && (AND), and || (OR).
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:
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 the canFastAttack function that takes a boolean value that indicates if the knight is awake. This function returns true if a fast attack can be made based on the state of the knight. Otherwise, returns false:
let knightIsAwake = true
canFastAttack(knightIsAwake)
// => false
Implement the canSpy function that takes three boolean values, indicating if the knight, archer and the prisoner, respectively, are awake. The function returns true if the group can be spied upon, based on the state of the three characters. Otherwise, returns false:
let knightIsAwake = false
let archerIsAwake = true
let prisonerIsAwake = false
canSpy(knightIsAwake, archerIsAwake, prisonerIsAwake)
// => true
Implement the canSignalPrisoner function that takes two boolean values, indicating if the archer and the prisoner, respectively, are awake. The function returns true if the prisoner can be signalled, based on the state of the two characters. Otherwise, returns false:
let archerIsAwake = false
let prisonerIsAwake = true
canSignalPrisoner(archerIsAwake, prisonerIsAwake)
// => true
Implement the canFreePrisoner function 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 prisoner can be freed based on the state of the three characters and Annalyn's pet dog presence. Otherwise, it returns false:
let knightIsAwake = false
let archerIsAwake = true
let prisonerIsAwake = false
let petDogIsPresent = false
canFreePrisoner(knightIsAwake, archerIsAwake, prisonerIsAwake, petDogIsPresent)
// => false
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