Pascal (programming language)

Pascal is an <a href="/facts/Imperative_programming/6b5dUnE1">imperative</a> and <a href="/facts/Procedural_programming/7r5xz7kx">procedural</a> <a href="/facts/Programming_language/cWTYbgWa">programming language</a>, designed by <a href="/facts/Niklaus_Wirth/krsLUB11">Niklaus Wirth</a> as a small, efficient language intended to encourage good programming practices using <a href="/facts/Structured_programming/zA8b8dP1">structured programming</a> and <a href="/facts/Data_structure/yNsNvL1I">data structuring</a>. It is named after French mathematician, philosopher and physicist <a href="/facts/Blaise_Pascal/Huy5LenL">Blaise Pascal</a>.
Pascal was developed on the pattern of the <a href="/facts/ALGOL_60/QnpxUYQm">ALGOL 60</a> language. Wirth was involved in the process to improve the language as part of the <a href="/facts/ALGOL_X/u31Ev9tQ">ALGOL X</a> efforts and proposed a version named <a href="/facts/ALGOL_W/xcgYM80d">ALGOL W</a>. This was not accepted, and the ALGOL X process bogged down. In 1968, Wirth decided to abandon the ALGOL X process and further improve ALGOL W, releasing this as Pascal in 1970.
On top of ALGOL's <a href="/facts/Variable_(computer_science)/VoCKtwml">scalars</a> and <a href="/facts/Array_(data_type)/gHJJ3XPw">arrays</a>, Pascal enables defining complex datatypes and building dynamic and recursive data structures such as <a href="/facts/List_(abstract_data_type)/9tzhAH6M">lists</a>, <a href="/facts/Tree_(data_structure)/RcXz9noF">trees</a> and <a href="/facts/Graph_(abstract_data_type)/b8qcddXa">graphs</a>. Pascal has <a href="/facts/Strong_and_weak_typing/WYexudnr">strong typing</a> on all objects, which means that one type of data cannot be converted to or interpreted as another without explicit conversions. Unlike C (and also unlike most other languages in the <a href="/facts/C-family/Pn4W8RB3">C-family</a>), Pascal allows <a href="/facts/Nested_procedure/Rw2xzMLP">nested procedure</a> definitions to any level of depth, and also allows most kinds of definitions and declarations inside <a href="/facts/Subroutines/9vFJrg0A">subroutines</a> (procedures and functions). A program is thus syntactically similar to a single procedure or function. This is similar to the block structure of ALGOL 60, but restricted from arbitrary block statements to just procedures and functions.
Pascal became very successful in the 1970s, notably on the burgeoning <a href="/facts/Minicomputer/g8hvpQxe">minicomputer</a> market. <a href="/facts/Compiler/WNfCDFJe">Compilers</a> were also available for many <a href="/facts/Microcomputer/ETW22UTv">microcomputers</a> as the field emerged in the late 1970s. It was widely used as a teaching language in <a href="/facts/University/skaJt2Io">university</a>-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 <a href="/facts/C_(programming_language)/Ky2No763">C programming language</a> during the late 1980s and early 1990s as <a href="/facts/UNIX/0pNL2seI">UNIX</a>-based systems became popular, and especially with the release of <a href="/facts/C%252B%252B/Et0F2qn9">C++</a>.
A derivative named <a href="/facts/Object_Pascal/cuGkuISv">Object Pascal</a> designed for <a href="/facts/Object-oriented_programming/TxNMEcao">object-oriented programming</a> was developed in 1985. This was used by <a href="/facts/Apple_Inc./oTJYta3k">Apple Computer</a> (for the <a href="/facts/Apple_Lisa/PJpJhNRK">Lisa</a> and <a href="/facts/Mac_(computer)/8GhnXTK0">Macintosh</a> machines) and <a href="/facts/Borland/crI5pTzW">Borland</a> in the late 1980s and later developed into <a href="/facts/Delphi_(software)/mAqCJnqm">Delphi</a> on the <a href="/facts/Microsoft_Windows/bwhAhuSL">Microsoft Windows</a> platform. Extensions to the Pascal concepts led to the languages <a href="/facts/Modula-2/DFyUTdAq">Modula-2</a> and <a href="/facts/Oberon_(programming_language)/YHFyy3UU">Oberon</a>, both developed by Wirth.

Pascal (programming language) open-in-new

Pascal (programming language)