Enumeration Exercises
module Tutorial.DataTypes.Exercises1
The solutions to these exercises can be found in src/Solutions/DataTypes.idr.
Exercise 1
Use pattern matching to implement your own versions of boolean operators (&&) and (||), calling them and and or respectively.
tip
One way to go about this is to enumerate all four possible combinations of two boolean values and give the result for each. However, there is a shorter, more clever way, requiring only two pattern matches for each of the two functions.
Exercise 2
Define your own data type representing different units of time (seconds, minutes, hours, days, weeks), and implement the following functions for converting between time spans with different units.
tip
Use integer division (div) when going from seconds to some larger unit like hours).
data UnitOfTime = Second -- add additional values
-- calculate the number of seconds from a
-- number of steps in the given unit of time
total
toSeconds : UnitOfTime -> Integer -> Integer
-- Given a number of seconds, calculate the
-- number of steps in the given unit of time
total
fromSeconds : UnitOfTime -> Integer -> Integer
-- convert the number of steps in a given unit of time
-- to the number of steps in another unit of time.
-- use `fromSeconds` and `toSeconds` in your implementation
total
convert : UnitOfTime -> Integer -> UnitOfTime -> Integer
Exercise 3
Define a data type for representing a subset of the chemical elements: Hydrogen (H), Carbon (C), Nitrogen (N), Oxygen (O), and Fluorine (F).
Declare and implement function atomicMass, which for each element returns its atomic mass in dalton:
Hydrogen : 1.008
Carbon : 12.011
Nitrogen : 14.007
Oxygen : 15.999
Fluorine : 18.9984