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Pascal
<language> (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.
See also Kamin's interpreters, p2c.
["The Programming Language Pascal", N. Wirth, Acta Informatica
1:35-63, 1971].
["PASCAL User Manual and Report", K. Jensen & N. Wirth,
Springer 1975] made significant revisions to the language.
[BS 6192, "Specification for Computer Programming Language
Pascal", British Standards Institute 1982].
[Jargon File]
(1996-06-12)
Try this search on OneLook / Google
Nearby terms:
@-party « PARULEL « PASC « Pascal » Pascal- » Pascal-80 » Pascal+CSP
This article was derived from the Free Online Dictionary of Computers and is available under ther terms of the GNU Free Documentation License.
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