Pascal
Pascal is an imperative and procedural programming language, designed by Niklaus Wirth as a small, efficient language intended to encourage good programming practices using structured programming and data structuring. It is named after French mathematician, philosopher and physicist Blaise Pascal.
Pascal became very successful in the 1970s, notably on the burgeoning minicomputer market. Compilers were also available for many microcomputers as the field emerged in the late 1970s. It was widely used as a teaching language in university-level programming courses in the 1980s, and also used in production settings for writing commercial software during the same period. It was displaced by the C programming language during the late 1980s and early 1990s as UNIX-based systems became popular, and especially with the release of C++.
UCSD Pascal formed the basis of many systems, including Apple Pascal. Borland Pascal was not based on the UCSD codebase, but arrived during the popular period of UCSD and matched many of its features. This started the line that ended with Delphi Pascal and the compatible Open Source compiler FPC/Lazarus.
A derivative named Object Pascal designed for object-oriented programming was developed in 1985. This was used by Apple Computer (for the Lisa and Macintosh machines) and Borland in the late 1980s and later developed into Delphi on the Microsoft Windows platform. Extensions to the Pascal concepts led to the languages Modula-2 and Oberon, both developed by Wirth.
Turbo Pascal became hugely popular, thanks to an aggressive pricing strategy, having one of the first full-screen IDEs, and very fast turnaround time (just seconds to compile, link, and run). It was written and highly optimized entirely in assembly language, making it smaller and faster than much of the competition.
My exposure to Pascal was in college where we had Apple Pascal. I started using it professionally on CP/M with Turbo Pascal and then under a Unix distributed multi-processor system to build a medical billing support system for one of the local hospitals. Later I would use it again as Delphi to write Windows Utilities to support the management of media and speech recognition grammars for some educational software development.
Sample Code
The Pascal Hello World program is aso a looped version of the Hello World program. We will be using Turbo Pascal for CP/M for this.
G>type hello.pas
program hello;
var no : integer;
begin
ClrScr;
for no := 1 to 10 do
writeln('Hello World from Turbo Pascal Line ', no);
end.
G>turbo
G>hello
Hello World from Turbo Pascal Line 1
Hello World from Turbo Pascal Line 2
Hello World from Turbo Pascal Line 3
Hello World from Turbo Pascal Line 4
Hello World from Turbo Pascal Line 5
Hello World from Turbo Pascal Line 6
Hello World from Turbo Pascal Line 7
Hello World from Turbo Pascal Line 8
Hello World from Turbo Pascal Line 9
Hello World from Turbo Pascal Line 10
G>
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