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42-456: Kyoto Common Lisp ( KCL ) is an implementation of Common Lisp by Taichi Yuasa and Masami Hagiya , written in C to run under Unix -like operating systems. KCL is compiled to ANSI C . It conforms to Common Lisp as described in the 1984 first edition of Guy Steele 's book Common Lisp the Language and is available under a licence agreement. KCL was implemented from scratch, outside of

84-514: A compiler implementer at Tartan Laboratories . Then he joined the supercomputer company Thinking Machines , where he helped define and promote a parallel computing version of the Lisp programming language named *Lisp (Star Lisp) and a parallel version of the language C named C* . In 1994, Steele joined Sun Microsystems and was invited by Bill Joy to become a member of the Java team after

126-514: A hyperlinked HTML version, has been derived from the ANSI Common Lisp standard. The Common Lisp language was developed as a standardized and improved successor of Maclisp . By the early 1980s several groups were already at work on diverse successors to MacLisp: Lisp Machine Lisp (aka ZetaLisp), Spice Lisp , NIL and S-1 Lisp . Common Lisp sought to unify, standardise, and extend the features of these MacLisp dialects. Common Lisp

168-450: A 1988 paper by Richard P. Gabriel and Kent Pitman , which extensively compares the two approaches. Common Lisp supports the concept of multiple values , where any expression always has a single primary value , but it might also have any number of secondary values , which might be received and inspected by interested callers. This concept is distinct from returning a list value, as the secondary values are fully optional, and passed via

210-467: A binding is established at the start of the execution of some construct, such as a let block, and disappears when that construct finishes executing: its lifetime is tied to the dynamic activation and deactivation of a block. However, a dynamic binding is not just visible within that block; it is also visible to all functions invoked from that block. This type of visibility is known as indefinite scope. Bindings which exhibit dynamic extent (lifetime tied to

252-534: A collection of methods . The macro defmethod defines methods. Methods can specialize their parameters over CLOS standard classes , system classes , structure classes or individual objects. For many types, there are corresponding system classes . When a generic function is called, multiple-dispatch will determine the effective method to use. Generic Functions are also a first class data type . There are many more features to Generic Functions and Methods than described above. The namespace for function names

294-890: A dedicated side channel. This means that callers may remain entirely unaware of the secondary values being there if they have no need for them, and it makes it convenient to use the mechanism for communicating information that is sometimes useful, but not always necessary. For example, Multiple values are supported by a handful of standard forms, most common of which are the MULTIPLE-VALUE-BIND special form for accessing secondary values and VALUES for returning multiple values: Other data types in Common Lisp include: Like programs in many other programming languages, Common Lisp programs make use of names to refer to variables, functions, and many other kinds of entities. Named references are subject to scope. The association between

336-501: A facility not available in many languages. Common Lisp automatically coerces numeric values among these types as appropriate. The Common Lisp character type is not limited to ASCII characters. Most modern implementations allow Unicode characters. The symbol type is common to Lisp languages, but largely unknown outside them. A symbol is a unique, named data object with several parts: name, value, function, property list, and package. Of these, value cell and function cell are

378-455: A name and the entity which the name refers to is called a binding. Scope refers to the set of circumstances in which a name is determined to have a particular binding. The circumstances which determine scope in Common Lisp include: To understand what a symbol refers to, the Common Lisp programmer must know what kind of reference is being expressed, what kind of scope it uses if it is a variable reference (dynamic versus lexical scope), and also

420-458: A parody of the behavior of a series of PDP-10 TELNET implementations written by Mark Crispin ). Steele has served on accredited technical standards committees, including: Ecma International (formerly European Computer Manufacturers Association (ECMA)) TC39 (for the language ECMAScript , for which he was editor of the first edition), X3J11 (for C ), and X3J3 (for Fortran ) and is, as of 2019 , chairman of X3J13 (for Common Lisp ). He

462-537: A precise description of the language C , which Tartan Laboratories was trying to implement on a wide range of systems. Both authors participated in the American National Standards Institute (ANSI) C standardization process; several revisions of the book were issued to reflect the new standard. On 16 March 1984, Steele published Common Lisp the Language (Digital Press; ISBN   0-932376-41-X ; 465 pages). This first edition

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504-444: A single community standard Lisp dialect. Much of the initial language design was done via electronic mail. In 1982, Guy L. Steele Jr. gave the first overview of Common Lisp at the 1982 ACM Symposium on LISP and functional programming. The first language documentation was published in 1984 as Common Lisp the Language (known as CLtL1), first edition. A second edition (known as CLtL2), published in 1990, incorporated many changes to

546-526: A specific type of members, as in a vector of bits. Usually, only a few types are supported. Many implementations can optimize array functions when the array used is type-specialized. Two type-specialized array types are standard: a string is a vector of characters, while a bit-vector is a vector of bits . Hash tables store associations between data objects. Any object may be used as key or value. Hash tables are automatically resized as needed. Packages are collections of symbols, used chiefly to separate

588-632: A team of researchers at Sun developing a new language named Fortress , a high-performance language designed to obsolete Fortran . Steele participated in the development of the Verse programming language designed by Epic Games . In 1982, Steele edited The Hacker's Dictionary (Harper & Row, 1983; ISBN   0-06-091082-8 ), which was a print version of the Jargon File . Steele and Samuel P. Harbison wrote C: A Reference Manual , ( Prentice-Hall , 1984; ISBN   0-13-110016-5 ), to provide

630-560: Is a modern western square dancer and caller from Mainstream up through C3A, a member of Tech Squares , and a member of Callerlab . Under the pseudonym Great Quux , which was an old student nickname at the Boston Latin School and MIT, he has published light verse and "Crunchly" cartoons; a few of the latter appeared in The New Hacker's Dictionary . He has also used his initials (GLS). In 1998, Steele solved

672-399: Is a data structure with two slots, called its car and cdr . A list is a linked chain of conses or the empty list. Each cons's car refers to a member of the list (possibly another list). Each cons's cdr refers to the next cons—except for the last cons in a list, whose cdr refers to the nil value. Conses can also easily be used to implement trees and other complex data structures; though it

714-575: Is not an implementation, but rather a language specification . Several implementations of the Common Lisp standard are available, including free and open-source software and proprietary products. Common Lisp is a general-purpose, multi-paradigm programming language . It supports a combination of procedural , functional , and object-oriented programming paradigms. As a dynamic programming language , it facilitates evolutionary and incremental software development , with iterative compilation into efficient run-time programs. This incremental development

756-479: Is often done interactively without interrupting the running application. It also supports optional type annotation and casting, which can be added as necessary at the later profiling and optimization stages, to permit the compiler to generate more efficient code. For instance, fixnum can hold an unboxed integer in a range supported by the hardware and implementation, permitting more efficient arithmetic than on big integers or arbitrary precision types. Similarly,

798-443: Is separate from the namespace for data variables. This is a key difference between Common Lisp and Scheme . For Common Lisp, operators that define names in the function namespace include defun , flet , labels , defmethod and defgeneric . To pass a function by name as an argument to another function, one must use the function special operator, commonly abbreviated as #' . The first sort example above refers to

840-495: Is some conceptual overlap with structures. Objects created of classes are called Instances . A special case is Generic Functions. Generic Functions are both functions and instances. Common Lisp supports first-class functions . For instance, it is possible to write functions that take other functions as arguments or return functions as well. This makes it possible to describe very general operations. The Common Lisp library relies heavily on such higher-order functions. For example,

882-436: Is the name of a function, then the arguments a1, a2, ..., an are evaluated in left-to-right order, and the function is found and invoked with those values supplied as parameters. The macro defun defines functions where a function definition gives the name of the function, the names of any arguments, and a function body: Function definitions may include compiler directives , known as declarations , which provide hints to

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924-487: Is useful to provide anonymous functions as arguments. Local functions can be defined with flet and labels . There are several other operators related to the definition and manipulation of functions. For instance, a function may be compiled with the compile operator. (Some Lisp systems run functions using an interpreter by default unless instructed to compile; others compile every function). The macro defgeneric defines generic functions . Generic functions are

966-447: Is usually advised to use structure or class instances instead. It is also possible to create circular data structures with conses. Common Lisp supports multidimensional arrays , and can dynamically resize adjustable arrays if required. Multidimensional arrays can be used for matrix mathematics. A vector is a one-dimensional array. Arrays can carry any type as members (even mixed types in the same array) or can be specialized to contain

1008-402: The sort function takes a relational operator as an argument and key function as an optional keyword argument. This can be used not only to sort any type of data, but also to sort data structures according to a key. The evaluation model for functions is very simple. When the evaluator encounters a form (f a1 a2...) then it presumes that the symbol named f is one of the following: If f

1050-772: The activation and deactivation of a block) and indefinite scope (visible to all functions which are called from that block) are said to have dynamic scope. Common Lisp has support for dynamically scoped variables, which are also called special variables. Certain other kinds of bindings are necessarily dynamically scoped also, such as restarts and catch tags. Function bindings cannot be dynamically scoped using flet (which only provides lexically scoped function bindings), but function objects (a first-level object in Common Lisp) can be assigned to dynamically scoped variables, bound using let in dynamic scope, then called using funcall or APPLY . Guy L. Steele Jr. Steele

1092-698: The argument to the nearest integer, with halfway cases rounded to the even integer. The functions truncate , floor , and ceiling round towards zero, down, or up respectively. All these functions return the discarded fractional part as a secondary value. For example, (floor -2.5) yields −3, 0.5; (ceiling -2.5) yields −2, −0.5; (round 2.5) yields 2, 0.5; and (round 3.5) yields 4, −0.5. Sequence types in Common Lisp include lists, vectors, bit-vectors, and strings. There are many operations that can work on any sequence type. As in almost all other Lisp dialects, lists in Common Lisp are composed of conses , sometimes called cons cells or pairs . A cons

1134-504: The compiler about optimization settings or the data types of arguments. They may also include documentation strings (docstrings), which the Lisp system may use to provide interactive documentation: Anonymous functions ( function literals ) are defined using lambda expressions, e.g. (lambda (x) (* x x)) for a function that squares its argument. Lisp programming style frequently uses higher-order functions for which it

1176-710: The compiler can be told on a per-module or per-function basis which type of safety level is wanted, using optimize declarations. Common Lisp includes CLOS , an object system that supports multimethods and method combinations. It is often implemented with a Metaobject Protocol. Common Lisp is extensible through standard features such as Lisp macros (code transformations) and reader macros (input parsers for characters). Common Lisp provides partial backwards compatibility with Maclisp and John McCarthy's original Lisp . This allows older Lisp software to be ported to Common Lisp. Work on Common Lisp started in 1981 after an initiative by ARPA manager Bob Engelmore to develop

1218-455: The function named by the symbol > in the function namespace, with the code #'> . Conversely, to call a function passed in such a way, one would use the funcall operator on the argument. Scheme's evaluation model is simpler: there is only one namespace, and all positions in the form are evaluated (in any order) – not just the arguments. Code written in one dialect is therefore sometimes confusing to programmers more experienced in

1260-492: The language had been designed, since he had a track record of writing good specifications for extant languages. He was named a Sun Fellow in 2003. Steele joined Oracle in 2010 when Oracle acquired Sun Microsystems . While at MIT, Steele published more than two dozen papers with Gerald Jay Sussman on the subject of the language Lisp and its implementation (the Lambda Papers ). One of their most notable contributions

1302-566: The language, made during the ANSI Common Lisp standardization process: extended LOOP syntax, the Common Lisp Object System, the Condition System for error handling, an interface to the pretty printer and much more. But CLtL2 does not describe the final ANSI Common Lisp standard and thus is not a documentation of ANSI Common Lisp. The final ANSI Common Lisp standard then was published in 1994. Since then no update to

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1344-599: The most important. Symbols in Lisp are often used similarly to identifiers in other languages: to hold the value of a variable; however there are many other uses. Normally, when a symbol is evaluated, its value is returned. Some symbols evaluate to themselves, for example, all symbols in the keyword package are self-evaluating. Boolean values in Common Lisp are represented by the self-evaluating symbols T and NIL. Common Lisp has namespaces for symbols, called 'packages'. A number of functions are available for rounding scalar numeric values in various ways. The function round rounds

1386-852: The original The Java Language Specification with James Gosling and Bill Joy . Steele received the ACM Grace Murray Hopper Award in 1988. He was named a Founding AAAI Fellow in 1990, an ACM Fellow in 1994, a member of the National Academy of Engineering of the United States of America in 2001 and a Fellow of the American Academy of Arts and Sciences in 2002. He received the Dr. Dobb's Excellence in Programming Award in 2005. Steele

1428-579: The other. For instance, many Common Lisp programmers like to use descriptive variable names such as list or string which could cause problems in Scheme, as they would locally shadow function names. Whether a separate namespace for functions is an advantage is a source of contention in the Lisp community. It is usually referred to as the Lisp-1 vs. Lisp-2 debate . Lisp-1 refers to Scheme's model and Lisp-2 refers to Common Lisp's model. These names were coined in

1470-522: The parts of a program into namespaces . A package may export some symbols, marking them as part of a public interface. Packages can use other packages. Structures , similar in use to C structs and Pascal records, represent arbitrary complex data structures with any number and type of fields (called slots ). Structures allow single-inheritance. Classes are similar to structures, but offer more dynamic features and multiple-inheritance. (See CLOS ). Classes have been added late to Common Lisp and there

1512-474: The run-time situation: in what environment is the reference resolved, where was the binding introduced into the environment, et cetera. Some environments in Lisp are globally pervasive. For instance, if a new type is defined, it is known everywhere thereafter. References to that type look it up in this global environment. One type of environment in Common Lisp is the dynamic environment. Bindings established in this environment have dynamic extent, which means that

1554-583: The standard committee, solely on the basis of the specification. It was one of the first Common Lisp implementations ever, and exposed a number of holes and mistakes in the specification that had gone unnoticed. This programming-tool -related article is a stub . You can help Misplaced Pages by expanding it . Common Lisp Common Lisp ( CL ) is a dialect of the Lisp programming language , published in American National Standards Institute (ANSI) standard document ANSI INCITS 226-1994 (S2018) (formerly X3.226-1994 (R1999) ). The Common Lisp HyperSpec ,

1596-685: The standard has been published. Various extensions and improvements to Common Lisp (examples are Unicode, Concurrency, CLOS-based IO) have been provided by implementations and libraries . Common Lisp is a dialect of Lisp. It uses S-expressions to denote both code and data structure. Function calls, macro forms and special forms are written as lists, with the name of the operator first, as in these examples: Common Lisp has many data types . Number types include integers , ratios , floating-point numbers , and complex numbers . Common Lisp uses bignums to represent numerical values of arbitrary size and precision. The ratio type represents fractions exactly,

1638-878: Was also a member of the Institute of Electrical and Electronics Engineers (IEEE) working group that produced the IEEE Standard for the language Scheme, IEEE Std 1178-1990. He represented Sun Microsystems in the High Performance Fortran Forum, which produced the High Performance Fortran specification in May, 1993. In addition to specifications of the language Java, Steele's work at Sun Microsystems has included research in parallel algorithms, implementation strategies, and architecture and software support. In 2005, Steele began leading

1680-475: Was born in Missouri and graduated from the Boston Latin School in 1972. He received a Bachelor of Arts (BA) in applied mathematics from Harvard University (1975) and a Master's degree (MS) and Doctor of Philosophy (PhD) from Massachusetts Institute of Technology (MIT) in computer science (1977, 1980). He then worked as an assistant professor of computer science at Carnegie Mellon University and

1722-552: Was the design of the language Scheme . Steele also designed the original command set of Emacs and was the first to port TeX (from WAITS to ITS ). He has published papers on other subjects, including compilers, parallel processing, and constraint languages. One song he composed has been published in the official journal of the Association for Computing Machinery Communications of the ACM (CACM) ("The Telnet Song", April 1984,

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1764-506: Was the original specification of Common Lisp (CLtL1) and served as the basis for the ANSI standard. Steele released a greatly expanded second edition in 1990, (1029 pages) which documented a near-final version of the ANSI standard. Steele, along with Charles H. Koelbel, David B. Loveman, Robert S. Schreiber, and Mary E. Zosel wrote The High Performance Fortran Handbook (MIT Press, 1994; ISBN   0-262-11185-3 ). Steele also coauthored

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