w4_1.1_lambdas_as_values.md

LAMBDA-EXPRESSIONS AS VALUES (20 points possible)

In this exercise, we will define functions as values, also called lambda expressions, using the keyword function to do a pattern-matching on their argument. As a result, you are not allowed to use match ... with in your code.

1. Define a function last_element: 'a list -> 'a that returns the last element of a list. Your function may return (invalid_arg "last_element") when the list is empty.

2. Write a function is_sorted: 'a list -> bool that takes a list l as argument, and that checks that the list is sorted in increasing order according to the polymorphic comparison operator <.

YOUR OCAML ENVIRONMENT

let rec last_element = function _ ->
  "Replace this string with your implementation." ;;

let rec is_sorted = function _ ->
  "Replace this string with your implementation." ;;