Pascal (programming language): Difference between revisions

Revision as of 15:18, 9 November 2001

Revision as of 11:03, 25 November 2001

Line 1:

The '''Pascal''' [[programming language]] was developed by [[Niklaus Wirth]] as a simpletool languagefor to[[structured parse,programming]] aswhich itwould onlyat requiredthe asame singletime tokenbe ofsimple lookto ahead,process but which is an example offor a language that supports [[structured programmingcompiler]]. Wirth named the language in honor of [[Blaise Pascal]].

Early approaches (most notably the [[UCSD]] system) translated Pascal code into a machine-independent [[P-code]] representation. This intermediate code was then interpreted by a program specific to each architecture. As a consequence, only the small interpreter part had to be ported over to many architectures.

In the late [[1980s]] the Pascal community concentrated mainly on the [[IBM PC]] platform, driven in large parts by the inexpensive ''Turbo Pascal'' compiler by [[Borland]]. Many PC hobbyists in search for a structured replacement for [[BASIC programming language|BASIC]] used this product. ''Turbo Pascal'', being available only on one architecture, translated directly to [[Intel 8088]] [[machine language|machine code]], making it much faster than interpreted schemes.

During the [[1990s]] compilers that can be re-targeted to different hardware architectures became more prevalent. This allowed for Pascal translation to native machine code that is at the same time easily ported to new hardware.

The '''Pascal''' dialect at [[UCSD]] began as a hybrid language, aimed at being machine independent by having a common syntax interpreted into machine-dependent pseudocode which could then be executed by the final machine. As hardware became standardized on the IBM-Intel designs, the necessity for machine independence became less prominent. Although there are still Pascal interpreters available, there are compilers as well for many machines. These compilers frequently use today's large memories to accomplish both the first and second stage of processing.

----

In the PC community, an early inexpensive Pascal compiler was distributed by the [[Borland]] software company. This earned Pascal many hobbyist users during the 1980's.

Several Pascal compilers are available for the use of general public:

* [http://agnes.dida.physik.uni-essen.de/~gnu-pascal/about.html GNU Pascal Compiler] (GPC) is an additional front-end to the GNU Compiler Collection ([[GCC]]), and is written in C. Distributed freely under the GPL[[GNU General Public License]].

* [http://www.freepascal.org FreePascal] is written in Pascal (so that it compile itself), and is aimed at providing a convenient and powerful compiler, able both to compile legacy applications and to be the means of develop new ones. Also distributed freely under the GNU GPL.

* [http://community.borland.com Turbo Pascal] was the dominant Pascal compiler for PCs during the 80s and early 90s, popular both because of its powerful extensions and extremely low compilation times. Currently, older versions of Turbo Pascal (up to 5.5) are available for free download from Borland's site (registration required).

* [http://www.borland.com/kylix/ Kylix] is Borland's newest reiteration of the Pascal branch of their products. It is the descendant of [[Delphi programming language|Delphi]], with support for the [[Linux]] operating system and an improved object library. The compiler and the IDE are available now for non-commercial use. The compiler (but not the library or the IDE) is supposed to become [[Open Source]] software some time soon.