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For example, the Lisp expression (cons 1 2) constructs a cell holding 1 in its left half (the so-called car field) and 2 in its right half (the cdr field). In Lisp notation, the value (cons 1 2) looks like: (1 . 2) Note the dot between 1 and 2; this indicates that the S-expression is a "dotted pair" (a so-called "cons pair"), rather than a "list."
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 ...
AutoLISP is a small, dynamically scoped, dynamically typed Lisp language dialect with garbage collection, immutable list structure, and settable symbols, lacking in such regular Lisp features as macro system, records definition facilities, arrays, functions with variable number of arguments or let bindings.
Many programming languages such as Lisp and Scheme have singly linked lists built in. In many functional languages, these lists are constructed from nodes, each called a cons or cons cell. The cons has two fields: the car, a reference to the data for that node, and the cdr, a reference to the next node. Although cons cells can be used to build ...
Lisp originally had very few control structures, but many more were added during the language's evolution. (Lisp's original conditional operator, cond, is the precursor to later if-then-else structures.) Programmers in the Scheme dialect often express loops using tail recursion. Scheme's commonality in academic computer science has led some ...
Following Lisp, other high-level programming languages which feature linked lists as primitive data structures have adopted an append. To append lists, as an operator, Haskell uses ++, OCaml uses @. Other languages use the + or ++ symbols to nondestructively concatenate a string, list, or array.
Common Lisp: General Yes Yes Yes Yes Yes Yes Extensible syntax, Array-oriented, syntactic macros, multiple dispatch, concurrent Yes 1994, ANSI COMAL 80 Education Yes No No Yes No No No Crystal: General purpose Yes Yes [21] Yes Yes Yes [22] No Concurrent [23] No Curry: Application No No Yes No Yes No lazy evaluation, non-determinism
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.