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Lisp (historically LISP, an abbreviation of "list processing") is a family of programming languages with a long history and a distinctive, fully parenthesized prefix notation. [3] Originally specified in the late 1950s, it is the second-oldest high-level programming language still in common use, after Fortran.
In Lisp, lists are implemented on top of cons pairs. More specifically, any list structure in Lisp is either: An empty list (), which is a special object usually called nil. A cons cell whose car is the first element of the list and whose cdr is a list containing the rest of the elements.
Common Lisp is sometimes termed a Lisp-2 and Scheme a Lisp-1, referring to CL's use of separate namespaces for functions and variables. (In fact, CL has many namespaces, such as those for go tags, block names, and loop keywords). There is a long-standing controversy between CL and Scheme advocates over the tradeoffs involved in multiple namespaces.
Lisp was originally implemented on the IBM 704 computer, in the late 1950s.. The popular explanation that CAR and CDR stand for "Contents of the Address Register" and "Contents of the Decrement Register" [1] does not quite match the IBM 704 architecture; the IBM 704 does not have a programmer-accessible address register and the three address modification registers are called "index registers ...
Lisp (historically LISP, an abbreviation of "list processing") is a family of programming languages with a long history and a distinctive, fully parenthesized prefix notation. [3] Originally specified in the late 1950s, it is the second-oldest high-level programming language still in common use, after Fortran .
In the early development of Lisp, association lists were used to resolve references to free variables in procedures. [ 5 ] [ 6 ] In this application, it is convenient to augment association lists with an additional operation, that reverses the addition of a key–value pair without scanning the list for other copies of the same key.
In the Lisp family of languages, list appending is provided by the append procedure. Many of the special cases of linked list operations can be eliminated by including a dummy element at the front of the list.
In the usual parenthesized syntax of Lisp, an S-expression is classically defined [1] as an atom of the form x, or; an expression of the form (x. y) where x and y are S-expressions. This definition reflects LISP's representation of a list as a series of "cells", each one an ordered pair. In plain lists, y points to the next cell (if any), thus ...