SLIP (programming language)

Last updated

SLIP is a list processing computer programming language, invented by Joseph Weizenbaum in the 1960s. The name SLIP stands for Symmetric LIst Processor. It was first implemented as an extension to the Fortran programming language, and later embedded into MAD and ALGOL. [1] The best known program written in the language is ELIZA, an early natural language processing computer program created by Weizenbaum [2] at the MIT Artificial Intelligence Laboratory. [3]

Contents

General overview

In a nutshell, SLIP consisted of a set of FORTRAN "accessor" functions which operated on circular doubly linked lists with fixed-size data fields. The "accessor" functions had direct and indirect addressing variants.

List representation

The list representation had four types of cell: a reader, a header, a sublist indicator, and a payload cell. The header included a reference count field for garbage collection purposes. The sublist indicator allowed it to be able to represent nested lists, such as (A, B, C, (1, 2, 3), D, E, F) where (1, 2, 3) is a sublist indicated by a cell in the '*' position in the list (A, B, C, *, D, E, F). The reader was essentially a state history stack—a good example of a memento pattern—where each cell pointed to the header of the list being read, the current position within the list being read, and the level or depth of the history stack.

Related Research Articles

<span class="mw-page-title-main">Computer program</span> Instructions to be executed by a computer

A computer program is a sequence or set of instructions in a programming language for a computer to execute. It is one component of software, which also includes documentation and other intangible components.

<span class="mw-page-title-main">ELIZA</span> Early natural language processing computer program

ELIZA is an early natural language processing computer program developed from 1964 to 1967 at MIT by Joseph Weizenbaum. Created to explore communication between humans and machines, ELIZA simulated conversation by using a pattern matching and substitution methodology that gave users an illusion of understanding on the part of the program, but had no representation that could be considered really understanding what was being said by either party. Whereas the ELIZA program itself was written (originally) in MAD-SLIP, the pattern matching directives that contained most of its language capability were provided in separate "scripts", represented in a lisp-like representation. The most famous script, DOCTOR, simulated a psychotherapist of the Rogerian school, and used rules, dictated in the script, to respond with non-directional questions to user inputs. As such, ELIZA was one of the first chatterbots and one of the first programs capable of attempting the Turing test.

In computer science, the ELIZA effect is the tendency to project human traits — such as experience, semantic comprehension or empathy — into computer programs that have a textual interface. The effect is a category mistake that arises when the program's symbolic computations are described through terms such as "think", "know" or "understand."

<span class="mw-page-title-main">Fortran</span> General-purpose programming language

Fortran is a third generation, compiled, imperative programming language that is especially suited to numeric computation and scientific computing.

<span class="mw-page-title-main">Joseph Weizenbaum</span> German American computer scientist (1923–2008)

Joseph Weizenbaum was a German American computer scientist and a professor at MIT. The Weizenbaum Award and Weizenbaum Institute are named after him.

<span class="mw-page-title-main">Lisp (programming language)</span> Programming language family

Lisp is a family of programming languages with a long history and a distinctive, fully parenthesized prefix notation. Originally specified in 1960, Lisp is the third-oldest high-level programming language still in common use, after Fortran and COBOL. Lisp has changed since its early days, and many dialects have existed over its history. Today, the best-known general-purpose Lisp dialects are Common Lisp, Scheme, Racket, and Clojure.

<span class="mw-page-title-main">Spreadsheet</span> Computer application for organization, analysis, and storage of data in tabular form

A spreadsheet is a computer application for computation, organization, analysis and storage of data in tabular form. Spreadsheets were developed as computerized analogs of paper accounting worksheets. The program operates on data entered in cells of a table. Each cell may contain either numeric or text data, or the results of formulas that automatically calculate and display a value based on the contents of other cells. The term spreadsheet may also refer to one such electronic document.

<span class="mw-page-title-main">IBM 1620</span> Small IBM scientific computer released in 1959

The IBM 1620 was announced by IBM on October 21, 1959, and marketed as an inexpensive scientific computer. After a total production of about two thousand machines, it was withdrawn on November 19, 1970. Modified versions of the 1620 were used as the CPU of the IBM 1710 and IBM 1720 Industrial Process Control Systems.

Natural-language understanding (NLU) or natural-language interpretation (NLI) is a subset of natural-language processing in artificial intelligence that deals with machine reading comprehension. Natural-language understanding is considered an AI-hard problem.

In computer science, imperative programming is a programming paradigm of software that uses statements that change a program's state. In much the same way that the imperative mood in natural languages expresses commands, an imperative program consists of commands for the computer to perform. Imperative programming focuses on describing how a program operates step by step, rather than on high-level descriptions of its expected results.

In computer programming, standard streams are preconnected input and output communication channels between a computer program and its environment when it begins execution. The three input/output (I/O) connections are called standard input (stdin), standard output (stdout) and standard error (stderr). Originally I/O happened via a physically connected system console, but standard streams abstract this. When a command is executed via an interactive shell, the streams are typically connected to the text terminal on which the shell is running, but can be changed with redirection or a pipeline. More generally, a child process inherits the standard streams of its parent process.

In computer programming, a global variable is a variable with global scope, meaning that it is visible throughout the program, unless shadowed. The set of all global variables is known as the global environment or global state. In compiled languages, global variables are generally static variables, whose extent (lifetime) is the entire runtime of the program, though in interpreted languages, global variables are generally dynamically allocated when declared, since they are not known ahead of time.

The Burroughs Large Systems Group produced a family of large 48-bit mainframes using stack machine instruction sets with dense syllables. The first machine in the family was the B5000 in 1961, which was optimized for compiling ALGOL 60 programs extremely well, using single-pass compilers. The B5000 evolved into the B5500 and the B5700. Subsequent major redesigns include the B6500/B6700 line and its successors, as well as the separate B8500 line.

<span class="mw-page-title-main">IBM 1130</span> 16-bit IBM minicomputer introduced in 1965

The IBM 1130 Computing System, introduced in 1965, was IBM's least expensive computer at that time. A binary 16-bit machine, it was marketed to price-sensitive, computing-intensive technical markets, like education and engineering, succeeding the decimal IBM 1620 in that market segment. Typical installations included a 1 megabyte disk drive that stored the operating system, compilers and object programs, with program source generated and maintained on punched cards. Fortran was the most common programming language used, but several others, including APL, were available.

In computer programming, a return statement causes execution to leave the current subroutine and resume at the point in the code immediately after the instruction which called the subroutine, known as its return address. The return address is saved by the calling routine, today usually on the process's call stack or in a register. Return statements in many programming languages allow a function to specify a return value to be passed back to the code that called the function.

<i>Computer Power and Human Reason</i> 1976 book by Joseph Weizenbaum

Computer Power and Human Reason: From Judgment to Calculation (1976) by Joseph Weizenbaum displays the author's ambivalence towards computer technology and lays out the case that while artificial intelligence may be possible, we should never allow computers to make important decisions because computers will always lack human qualities such as compassion and wisdom.

<span class="mw-page-title-main">Computer programming in the punched card era</span> History of computer programming using punch cards

From the invention of computer programming languages up to the mid-1970s, most computer programmers created, edited and stored their programs line by line on punch cards.

In computer programming, a variable-length array (VLA), also called variable-sized or runtime-sized, is an array data structure whose length is determined at run time . In C, the VLA is said to have a variably modified type that depends on a value.

In computer programming, a function, subprogram, procedure, method, routine, subroutine, or callable unit is a sequence of instructions that has a well-defined behavior and can be invoked by other software to exhibit that behavior.

References

  1. Computer Programming Languages – S
  2. "Alan Turing at 100". Harvard Gazette. 13 September 2012. Retrieved 2016-02-22.
  3. Weizenbaum, Joseph (1976). Computer Power and Human Reason: From Judgment to Calculation. New York: W.H. Freeman and Company. pp.  2, 3, 6, 182, 189. ISBN   0-7167-0464-1.