Pairs and Lists in The Racket Guide introduces pairs and lists. A pair combines exactly two values. The first value is accessed with the car procedure, and the second value is accessed with the cdr procedure. … A list is recursively defined: it is either the constant null, or it is a pair whose second value is a list.
Hereof, what do CAR and CDR stand for?
In computer programming, CAR ( car ) /kɑːr/ ( listen) and CDR ( cdr ) (/ˈkʌdər/ ( listen) or /ˈkʊdər/ ( listen)) are primitive operations on cons cells (or “non-atomic S-expressions”) introduced in the Lisp programming language.
- There are pros and cons to this, to be sure, but overall, this has increased our empathy. …
- We finally decided the pros out weighted the cons and I should make the call. …
- The commander-in-chief weighed the pros and cons and he decided against a combination of war on such lines.
One may also ask, what is a stream in racket?
A stream is a kind of sequence that supports functional iteration via stream-first and stream-rest. … The bindings documented in this section are provided by the racket/stream and racket libraries, but not racket/base.
What does cdr do?
The CDR of a list is the rest of the list, that is, the cdr function returns the part of the list that follows the first item. … Like car , cdr does not remove any elements from the list—it just returns a report of what the second and subsequent elements are. Incidentally, in the example, the list of flowers is quoted.
What does let do in racket?
Local Binding: let, let*, letrec, … in The Racket Reference also documents let. A let form binds a set of identifiers, each to the result of some expression, for use in the let body: (let ([id expr] …)
What does car stand for in racket?
car == return the first element in a pair. > cdr == return the second element in a pair. > >
What is pair in Scheme?
Pairs are used to combine two Scheme objects into one compound object. Hence the name: A pair stores a pair of objects. The data type pair is extremely important in Scheme, just like in any other Lisp dialect. … Because lists are so important in Scheme, they are described in a section of their own (see Lists).
What is Lisp full form?
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 cons short for?
CONS
| Acronym | Definition |
|---|---|
| CONS | Construction Technology (course) |
| CONS | Contracting Squadron |
| CONS | Connection Oriented Network Service |
| CONS | Connection-Oriented Network Services |
What are the cons?
The pros and cons of something are its advantages and disadvantages, which you consider carefully so that you can make a sensible decision. They sat for hours debating the pros and cons of setting up their own firm. Motherhood has both its pros and cons. See full dictionary entry for pro.
What does cons do in Lisp?
cons constructs memory objects which hold two values or pointers to values. These objects are referred to as (cons) cells, conses, non-atomic s-expressions (“NATSes”), or (cons) pairs. In Lisp jargon, the expression “to cons x onto y” means to construct a new object with (cons x y) .