Pascal

'''Pascal''' is an imperative computer programming language, developed in 1970 by Niklaus Wirth as a language particularly suitable for structured programming. A derivative known as Object Pascal was designed for object-oriented programming. Pascal can be used very easily in conjunction with fundamental discrete mathematics as sets are built into the language.

There are actually several varieties of Pascal. The most important ones are:

Standard Pascal (ISO 7185) is the original Pascal standard. However, there are many features missing from that language version, which has led to a wide variety of nonstandard extensions. On the other hand, there are features of Standard Pascal which are seldom implemented by Pascal compilers. A compiler which implements all features of Standard Pascal is GNU Pascal.
Extended Pascal (ISO 10206) is a later Pascal standard which adds a lot to the original Pascal standard. However, compilers implementing Extended Pascal are even more rare than those implementing Standard Pascal. GNU Pascal implements most of Extended Pascal as well.
Turbo Pascal was a very successful Pascal implementation for DOS and 16 bit Windows (the latest version was sold under the name "Borland Pascal 7.0") and became the de-facto standard for Pascal on DOS. Even today many Pascal compilers provide compatibility to Turbo Pascal.
Object Pascal is the Pascal dialect used in Delphi, Borland's successor product to Turbo/Borland Pascal. It extends Pascal with a new object model (in addition to the object model introduced in Turbo Pascal 5.5). This language is also implemented by Free Pascal and Lazarus.

Grammar