BYU CS classes

Learn the basics of Elixir.

Install Elixir on your own machine. Use Erlang OTP version 19 (or more recent versions).

Create a module named Elixir_Intro that contains the following functions:

• fib/1
• area/2
• sqrList/1
• calcTotals/1
• map/2
• quickSortServer/0

You do not need to validate function input.

def fib(n) do ...

fib will return the n'th Fibonacci number where fib(1) = 1, fib(2) = 1, and fib(n) = fib(n-1) + fib(n-2).

def area(shape, shape_info) do ....

Area takes either :rectangle, :square, :circle, or :triangle and the shape info, and returns its area. Note for rectangle the shape Info will be a tuple {length, height}, triangle's shape_info will be a tuple {base, height}, and circle and square will each get a single scalar (radius and side length, respectively). Use pattern matching. Also note that pi is called via :math.pi .

def sqrList(nums) do ....

Returns a new list in which each item of nums has been squared.

def calcTotals(inventory) do ...

Takes an inventory list of tuples of the form {item, quantity, price} and returns a list of the form {item, total_price}. (Treat the list item by item: no need to consider the possibility of multiple tuples with the same “item” name.)

def map(function, vals) do ...

Map takes a function and a list vals and applies that function to each item in the list. Note that when using higher order functions in Elixir, you use &Module.functionName/arity to pass it, and functionName.(…) to call it. Thus,to test it, the call should look like this map(&Module.functionName/arity, list). For this lab, you can assume the arity of the function being passed in is 1.

def quickSortServer() do ...

quickSortServer will start a simple server that will receive a list and sort it and send it to the caller. It should sort via a modified version of quickSort as discussed in class. quickSort will choose the pivot randomly, and you will need to implement the new pivot functionality. The module random function :random.uniform(N) will be useful for this, as well as :lists.nth(N, List)

Remember that starting a new process would look like pid = spawn &Elixir_Intro.quickSortServer/0

To test your quickSortServer(), it might be helpful to set up a simple client module like this:

defmodule Client do
    def callServer(pid,nums) do
        send(pid, {nums, self()})
	listen
    end
 
    def listen do
        receive do
	    {sorted, pid} -> sorted
	end
    end
end