2025-11-20 Basics Quiz

1. Define a new data type Plant that can hold either (Thistle) or (Dandelion with an Int field called num and a String field called flavor).

2. A field contains a list of Plant. Each Thistle subtracts 0.50 from the value of the field. Dandelions add 1.25 times the num of each.

    landValue :: [Plant] -> Double
   

   1. Write a recursive version.
   2. Write a version that uses list comprehension.

3. In springtime, thistles double in number and dandelions triple. Write a recursive function to make a new list:

    spring :: [Plant] -> [Plant]
   
    d = Dandelion 4 "bitter"
    check_spring = [
      spring [Thistle] == [Thistle, Thistle]
      ,spring [d] == [d,d,d]]
   

4. (Refers to work from 2021 AoC 4.) True if any row (inner list) has all negative numbers.

    hwin :: [Int] -> Bool
    check_hwin = [
      hwin [[1,3,2],[-4,-5,-6]] == True
      ,hwin [[-1,1,-1]] == False
    ]
   

5. Get feedback on question 4 and write it another way. Recursion, list comprehension, higher order function.