What does cons do in Scheme?

In Scheme, car , cdr , and cons are the most important functions. The cons function is used to construct pairs and pairs are used to construct the lists. The car and cdr are used to access data and return accordingly first and second element from a pair.

What is nil and cons?

It is constructed from two building blocks: Nil: The empty list. Cons: A cell containing an element also known as head; and a pointer to the rest of the list also known as tail. The term cons comes form functional programming language ‘lisp’. In Scala, there is a double colon operator :: called cons operator.

What is the purpose of Lisp?

LISP, an acronym for list processing, is a programming language that was designed for easy manipulation of data strings. Developed in 1959 by John McCarthy, it is a commonly used language for artificial intelligence (AI) programming. It is one of the oldest programming languages still in relatively wide use.

What is the difference between Scheme and Lisp?

Scheme is a dialect of Lisp that stresses conceptual elegance and simplicity. Scheme is much smaller than Common Lisp; the specification is about 50 pages, compared to Common Lisp’s 1300 page draft standard. (See question [4-10] for details on standards for Common Lisp.)

What is a cons cell in Lisp?

A cons cell is a data object that represents an ordered pair. That is, it has two slots, and each slot holds, or refers to, some Lisp object. One slot is known as the CAR, and the other is known as the CDR. (These names are traditional; see Cons Cell Type.)

What is the difference between cons and list?

A cons is a record structure containing two components called the car and the cdr. Conses are used primarily to represent lists. A list is recursively defined to be either the empty list or a cons whose cdr component is a list. For each element of the list there is a cons.