BASIC developers were upgrading to Pascal in search of a structured programming replacement. The Object Pascal extensions were less radical than the C++ extensions because of this, Object Pascal is frequently simply referred to as Pascal, while C++ is rarely referred to as C.ĭuring the late 1980s with Turbo Pascal’s aggressive pricing leading the way, Pascal greatly increased in popularity on both the Apple and PC platforms. Both started as a structured procedural language and then, through a number of extensions, gained Object Oriented Programming concepts. The evolution of Pascal to Object Pascal is similar to the evolution of C to C++. Also at this time, Microsoft implemented their short-lived Pascal compilers. In 1986, Anders Hejlsberg also integrated Object Pascal features into Turbo Pascal. Features of Object Pascal were integrated into Mac Pascal and Lisa Pascal. This new language was called Object Pascal. In 1985, Apple consulted with Niklaus Wirth and took influence from SmallTalk to add Object Oriented extensions to Pascal. During compilation, all the units are compiled into a single binary or object file. Units also allowed for a greater degree of code reuse. The other advantage of units was the concept of namespaces - they allowed duplicate identifiers to exist in two different units since the unit name provided a way to differentiate the identifiers. Units allowed source code to be divided between multiple source files that referenced each other. ![]() Prior to the introduction of units, all source code was in a single source file. This included the introduction of unit files, which made Pascal a modular language. The 1980s saw a lot of evolution and growth for Turbo Pascal. Blue Label Pascal was purchased by Borland, renamed Turbo Pascal, and ported to CP/M, IBM PC and the Macintosh. In the early 1980s, Anders Hejlsberg wrote the Blue Label Pascal compiler for the Nascom-2. UCSD Pascal remained the dominant Pascal on most platforms until the rise of Turbo Pascal. In the early 1980s it was ported to Apple II and Apple III computers, providing a structured alternative to the default BASIC interpreters. This architecture was a key influence on Java, its byte code and virtual machine. In 1978, UCSD Pascal was introduced, which offered Strings and Units and introduced p-Code and the p-System virtual machine. Throughout the 1970s, Pascal was ported to a variety of different mainframe systems, including the PDP-11, ICL 1900 and IBM System/370. The first Pascal compiler was designed in Zürich for the CDC 6000 series mainframe computer family. Those students went on to design and influence other modern languages, taking what they learned from Pascal with them. Because of Pascal’s efficiency, clean design and emphasis on structure, many schools adopted it as the de facto language for generations of students learning programming. In 1970, when Pascal was originally published, the concept of structured programming had just recently become popular. ![]() ALGOL also uses the := operator to differentiate setting a value instead of comparing values (which just uses the = operator). ![]() This inspiration is evident in its use of English keywords (Begin, End, Procedure, etc.) and some of the primitive data types (real, integer, array, etc.). When designing Pascal, Wirth took inspiration from ALGOL (specifically ALGOL-60 and his own ALGOL-W), as well as Simula 67. It was named in honor of French mathematician and philosopher Blaise Pascal. Niklaus Wirth started designing Pascal in 1968, publishing it in 1970. Pascal favors the use of English language keywords to create a language that is as easy for a human to read as for a computer. This means that all variables have a specific type (integer, string, etc.), and the compiler enforces that the type is respected and only converted through explicit conversions. Pascal is characterized as being strongly typed and type safe. It was also specifically designed to be a small and efficient language that quickly produces efficiently generated code. The Pascal programming language was designed to promote good programming practices and properly structured programming and data structures.
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