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PASC

Pascal

(After the French mathematician Blaise Pascal (1623-1662)) A programming language designed by Niklaus Wirth around 1970. Pascal was designed for simplicity and for teaching programming, in reaction to the complexity of ALGOL 68. It emphasises structured programming constructs, data structures and strong typing. Innovations included enumeration types, subranges, sets, variant records, and the case statement. Pascal has been extremely influential in programming language design and has a great number of variants and descendants.

ANSI/IEEE770X3.97-1993 is very similar to ISO Pascal but does not include conformant arrays.

ISO 7185-1983(E). Level 0 and Level 1. Changes from Jensen & Wirth's Pascal include name equivalence; names must be bound before they are used; loop index must be local to the procedure; formal procedure parameters must include their arguments; conformant array schemas.

An ALGOL-descended language designed by Niklaus Wirth on the CDC 6600 around 1967--68 as an instructional tool for elementary programming. This language, designed primarily to keep students from shooting themselves in the foot and thus extremely restrictive from a general-purpose-programming point of view, was later promoted as a general-purpose tool and, in fact, became the ancestor of a large family of languages including Modula-2 and Ada (see also bondage-and-discipline language). The hackish point of view on Pascal was probably best summed up by a devastating (and, in its deadpan way, screamingly funny) 1981 paper by Brian Kernighan (of K&R fame) entitled "Why Pascal is Not My Favourite Programming Language", which was turned down by the technical journals but circulated widely via photocopies. It was eventually published in "Comparing and Assessing Programming Languages", edited by Alan Feuer and Narain Gehani (Prentice-Hall, 1984). Part of his discussion is worth repeating here, because its criticisms are still apposite to Pascal itself after ten years of improvement and could also stand as an indictment of many other bondage-and-discipline languages. At the end of a summary of the case against Pascal, Kernighan wrote:

9. There is no escape

This last point is perhaps the most important. The language is inadequate but circumscribed, because there is no way to escape its limitations. There are no casts to disable the type-checking when necessary. There is no way to replace the defective run-time environment with a sensible one, unless one controls the compiler that defines the "standard procedures". The language is closed.

People who use Pascal for serious programming fall into a fatal trap. Because the language is impotent, it must be extended. But each group extends Pascal in its own direction, to make it look like whatever language they really want. Extensions for separate compilation, Fortran-like COMMON, string data types, internal static variables, initialisation, octal numbers, bit operators, etc., all add to the utility of the language for one group but destroy its portability to others.

I feel that it is a mistake to use Pascal for anything much beyond its original target. In its pure form, Pascal is a toy language, suitable for teaching but not for real programming.

Pascal has since been almost entirely displaced (by C) from the niches it had acquired in serious applications and systems programming, but retains some popularity as a hobbyist language in the MS-DOS and Macintosh worlds.

Pascal-

Pascal subset used in Brinch Hansen on Pascal Compilers, P. Brinch Hansen, P-H 1985.

[Jargon File]

Pascal-80

A successor of Platon. Developed at RC International for systems programming. Later it was renamed Real-Time Pascal. "PASCAL80 Report", J. Staunstrup, RC Intl, Denmark Jan 1980.

Pascal+CSP

"Pascal+CSP, Merging Pascal and CSP in a Parallel Processing Oriented Language", J. Adamo, Proc 3rd Intl Conf Distrib Comp Sys, IEEE 1982, pp.542-547.

Pascal-F

Pascal extended to include fixed-point arithmetic. E. Nelson, "Pascal-F: Programming Language for Real-Time Automotive Control", IEEE ElectroTechnol. Rev. (USA), 2:39, 1968.

Pascal-FC

A Pascal derived from Pascal-S which provides several types of concurrency: semaphores, monitors, both occam/CSP-style and Ada-style rendezvous.

["The Teaching Language Pascal-FC", G.L. Davies et al, Computer J 33(2):147-154 (Apr 1990)].

Last updated: 1994-11-02

Pascal/L

A SIMD parallel extension of Pascal.

["Implementation of an Array and Vector Processing Language", C. Fernstrom, Intl Conf Parallel Proc, IEEE, pp.113-127 (1982)].

Last updated: 1994-11-02

Pascal-Linda

Ian Flockhart, U Edinburgh, 1991. Under development.

Pascal-m

["Pascal-m: A Language for Loosely Coupled Distributed Systems", S. Abramsky et al in Distributed Computing Systems, Y. Paker et al eds, Academic Press 1986, pp. 163-189].

Last updated: 1994-11-02

Pascal-P

<language>

The variant of Pascal used by the UCSD p-system environment. Pascal-P has extended string and array operations, random-access files and separate compilation. It uses P-code intermediate code and is available from Pecan.

Last updated: 1994-11-02

Pascal P4

compiler and interpreter

Version ? 1

compiler, assembler/interpreter, documentation

Urs Ammann, Kesav Nori, Christian Jacobi

ftp://ftp.cwi.nl/pascal/.

A compiler for Pascal written in Pascal, producing an intermediate code, with an assembler and interpreter for the code.

reference: Pascal Implementation, by Steven Pemberton and Martin Daniels, published by Ellis Horwood, Chichester, UK (an imprint of Prentice Hall), ISBN: 0-13-653-0311. Also available in Japanese.

E-mail: <[email protected]>.

Last updated: 1993-07-05

Pascal Plus

<language>

Pascal with extensions for object-oriented multiprogramming by Jim Welsh and D. Bustard of Queens University, Belfast, UK. Pascal Plus uses an "envelope" construct for both packages and classes.

["Pascal Plus - Another Language for Modular Multiprogramming", J. Welsh et al, Soft Prac & Exp 9:947 (1979)].

["Sequential Program Structures", J. Welsh et al, P-H 1984, ISBN 0-13806828-3].

Last updated: 1997-12-09

Pascal/R

Pascal with relational database constructs added. The first successful integrated database language.

["Pascal/R Report", J.W. Schmidt et al, U Hamburg, Fachbereich Informatik, Report 66, Jan 1980].

Last updated: 1994-10-19

Pascal-S

Simplified Pascal. June, 1975. A strict subset of Pascal, omits scalar types, subranges, sets, files, pointers, packed structures, 'with' and 'goto. Source for a complete Pascal-S compiler is in "Pascal-S: A Subset and Its Implementation", N. Wirth in Pascal - The Language and Its Implementation, by D.W. Barron, Wiley 1979.

ftp://csseq.cs.tamu.edu/mcguire/pascal-s.

Pascal-SC

ESPRIT DIAMOND Project. An extension of Pascal for numerical analysis, with controlled rounding, overloading, dynamic arrays and modules. "PASCAL-SC, A Computer Language for Scientific Computation", G. Bohlender et al, Academic Press 1987.

pasos2

version: Alpha

parts: Compiler, run-time library

author: Willem Jan Withagen <[email protected]>

how to get: ftp://ftp.eb.ele.tue.nl/pub/src/pascal/pasos2*.

A PASCAL/i386 compiler which generates code for OS/2 and DOS. It uses EMX as DOS extender and GNU/GAS, MASM or TASM as assembler.

1993-12-17

Pasqual

["Pasqual: A Proposed Generalization of Pascal", R.D. Tennent, TR75-32, Queen's U, Canada, 1975].

PASRO

<robotics>

PAScal for RObots.

["PASRO - Pascal for Robots", C. Blume et al, Springer 1985].

Last updated: 1999-07-19

PASSIM

A simulation language based on Pascal.

["PASSIM: A Discrete-Event Simulation Package for Pascal", D.H Uyeno et al, Simulation 35(6):183-190 (Dec 1980)].

passive matrix display

<hardware>

A type of liquid crystal display which relies on persistence to maintain the state of each display element (pixel) between refresh scans. The resolution of such displays is limited by the ratio between the time to set a pixel and the time it takes to fade.

Contrast active matrix display.

Last updated: 1995-12-09

passphrase

<operating system>

A string of words and characters that you type in to authenticate yourself. Passphrases differ from passwords only in length. Passwords are usually short - six to ten characters. Passphrases are usually much longer - up to 100 characters or more.

Modern passphrases were invented by Sigmund N. Porter in 1982.

Their greater length makes passphrases more secure.

Phil Zimmermann's popular encryption program PGP, for example, requires you to make up a passphrase that you then must enter whenever you sign or decrypt messages.

http://world.std.com/~reinhold/diceware.page.html.

Last updated: 1996-12-21

passw0rd

<security>

A common default password, often given out by system administrtors to new users, the hope being that they will change it immediately.

Last updated: 2011-11-22

password

<security>

An arbitrary string of characters chosen by a user or system administrator and used to authenticate the user when he attempts to log on, in order to prevent unauthorised access to his account.

A favourite activity among unimaginative computer nerds and crackers is writing programs which attempt to discover passwords by using lists of commonly chosen passwords such as people's names (spelled forward or backward). It is recommended that to defeat such methods passwords use a mixture of upper and lower case letters or digits and avoid proper names and real words. If you have trouble remembering random strings of characters, make up an acronym like "ihGr8trmP" ("I have great trouble remembering my password").

Last updated: 1994-10-27

Password Authentication Protocol

<networking>

(PAP) An authentication scheme used by PPP servers to validate the identity of the originator of the connection.

PAP applies a two-way handshaking procedure. After the link is established the originator sends an id-password pair to the server. If authentication succeeds the server sends back an acknowledgement; otherwise it either terminates the connection or gives the originator another chance.

PAP is not a strong authentication method. Passwords are sent over the circuit "in the clear" and there is no protection against playback or repeated "trial and error" attacks. The originator is in total control of the frequency and timing of the attempts. Therefore, any server that can use a stronger authentication method, such as CHAP, will offer to negotiate that method prior to PAP. The use of PAP is appropriate, however, if a plaintext password must be available to simulate a login at a remote host.

PAP is defined in RFC 1334.

Last updated: 1996-03-23

paste

copy and paste

pastie

/pay'stee/ An adhesive label designed to be attached to a key on a keyboard to indicate some non-standard character which can be accessed through that key. Pasties are likely to be used in APL environments, where almost every key is associated with a special character. A pastie on the R key, for example, might remind the user that it is used to generate the rho character. The term properly refers to nipple-concealing devices formerly worn by strippers in concession to indecent-exposure laws; compare tits on a keyboard.

[Jargon File]

Nearby terms:

partitioned data set ♦ PARTS ♦ PARULEL ♦ PASC ♦ Pascal ♦ Pascal- ♦ Pascal-80

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