List processing: Be familiar with representing a list as a concatenation of a head and a tail. Know that the head is an element of a list and the tail is a list. Know that a list can be empty. Describe and apply the following operations: • return head of list • return tail of list • test for empty list • return length of list • construct an empty list • prepend an item to a list • append an item to a list. Have experience writing programs for the list operations mentioned above in a functional programming language or in a language with support for the functional paradigm. For example, in Haskell the list [4, 3, 5] can be written in the form head:tail where head is the first item in the list and tail is the remainder of the list. In the example, we have 4:[3, 5]. We call 4 the head of the list and [3, 5] the tail. [] is the empty list. 94

Quick explanation

List processing: Be familiar with representing a list as a concatenation of a head and a tail. Know that the head is an element of a list and the tail is a list. Know that a list can be empty. Describe and apply the following operations: • return head of list • return tail of list • test for empty list • return length of list • construct an empty list • prepend an item to a list • append an item to a list. Have experience writing programs for the list operations mentioned above in a functional programming language or in a language with support for the functional paradigm. For example, in Haskell the list [4, 3, 5] can be written in the form head:tail where head is the first item in the list and tail is the remainder of the list. In the example, we have 4:[3, 5]. We call 4 the head of the list and [3, 5] the tail. [] is the empty list. 94

• This point belongs to Lists in functional programming, especially List processing.
• You need to be able to list processing: Be familiar with representing a list as a concatenation of a head and a tail. Know that the head is an element of a list and the tail is a list. Know that a list can be empty. Describe and apply the following operations: • return head of list • return tail of list • test for empty list • return length of list • construct an empty list • prepend an item to a list • append an item to a list. Have experience writing programs for the list operations mentioned above in a functional programming language or in a language with support for the functional paradigm. For example, in Haskell the list [4, 3, 5] can be written in the form head:tail where head is the first item in the list and tail is the remainder of the list. In the example, we have 4:[3, 5]. We call 4 the head of the list and [3, 5] the tail. [] is the empty list. 94.
• Use the linked flashcards and practice questions to check recall, then practise applying the idea in an exam-style answer.