Examples:: This example uses recursive factorial definition. Note that this example works in all given implementations of Pascal, but it produces slightly different results.
The Turbo Pascal Programming Language by Steven Park for CSC415Turbo Pascal is a robust. Turbo Pascal version 7.0 introduced the break statement. 3.x, 9x/Me, NT/2k, XP/Vista/7, 8/8.1, Alpha, Win64, Itanium, Unicode, Wine, OS/2, Konsole, DDE. Quell-Listings (16bit: Borland Pascal, 32bit: Visual C) sind dabei. Windows Netscape: fpatch -s'NETSCAPE2.0' -r'J' netscape.exe; Internet Explorer: fpatch -s'NETSCAPE2.0' -r'J' mshtml.dll; Unix Netscape: in der Datei.
In gpc everything works perfectly. And have arithmetic overflow for factorial of numbers greater than 12, but Free Pascal reports an error: 13!
= Runtime error 215 at $004013C7 $004013C7 $00401449 $004063E0 while Turbo Pascal doesn’t detect the error and simply prints wrong values: 13! = This example doesn’t work in and earlier due to absence of longint data type in these versions. In GNU Pascal this program works without any problems.
• • • • • / / • / • • • Pascal is an and, which designed in 1968–69 and published in 1970, as a small, efficient language intended to encourage good programming practices using and. It is named in honor of the French mathematician, philosopher and physicist. Pascal was developed on the pattern of the language.
Wirth had already developed several improvements to this language as part of the proposals, but these were not accepted and Pascal was developed separately and released in 1970. A derivative known as designed for was developed in 1985; this was used by and in the late 1980s and later developed into on the platform. Extensions to the Pascal concepts led to the Pascal-like languages and. Contents • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • History [ ] Earlier efforts [ ] Much of the history of design during the 1960s traces its history to the language. ALGOL was developed during the 1950s with the explicit goal to be able to clearly describe algorithms. It included a number of features for that remain common in languages to this day. Shortly after its introduction, in 1962 Wirth began working on his dissertation with Helmut Weber on the.
Euler was based on ALGOL's syntax and many concepts but was not a derivative. Its primary goal was to add dynamic lists and types, allowing it to be used in roles similar to the. The language was published in 1965. By this time, a number of problems in ALGOL had been identified, notably the lack of a standardized system. The group tasked with maintaining the language had begun the process to identify improvements, calling for submissions. Wirth and submitted a conservative set of modifications to add strings and clean up some of the syntax.
These were considered too minor to be worth using as the new standard ALGOL, so Wirth wrote a compiler for the language, which became known as. The ALGOL X efforts would go on to choose a dramatically more complex language,. The complexity of this language led to considerable difficulty producing high-performance compilers, and it was not widely used in the industry.
This left an opening for newer languages. Pascal [ ] Pascal was influenced by the ALGOL W efforts, with the explicit goals of producing a language that would be efficient both in the compiler and at run-time, allow for the development of well-structured programs, and to be useful for teaching students. A generation of students used Pascal as an introductory language in undergraduate courses. One of the early successes for language was the introduction of, a version that ran on a custom that could be ported to different platforms. A key platform was the, where it saw widespread use. This led to the use of Pascal becoming the primary high-level language used for development in the, and later, the.
Parts of the original were hand-translated into from the Pascal sources. The system by was written in, the original system, based on Pascal, while applications like, and Macromedia Captivate were written in Delphi (). Used Pascal as the systems programming language for its operating systems beginning in 1980. Variants of Pascal have also frequently been used for everything from research projects to and.
Newer Pascal compilers exist which are widely used. Object Pascal [ ] During work on the Lisa, began corresponding with Wirth on the idea of adding extensions to the language.
This led initially to, introduced in 1983. As the Lisa program faded and was replaced by the Mac, a further version known as was created. This was introduced on the Macintosh in 1985 as part of the, and became Apple's primary development language into the early 1990s. The Object Pascal extensions were later added to, and over the years became the system for. Delphi is still used for developing Windows applications, but also has the ability to cross-compile the same code to Mac, iOS and Android. Another cross-platform version called, with the IDE, is popular with Linux users since it also offers development.
CodeTyphon is a Lazarus distribution with more preinstalled packages and cross-compilers. Brief description [ ] Wirth's intention was to create an efficient language (regarding both compilation speed and generated code) based on, a recently popularized concept that he promoted in his book. Pascal has its roots in the language, but also introduced concepts and mechanisms which (on top of ALGOL's scalars and arrays) enabled programmers to define their own complex (structured) datatypes, and also made it easier to build dynamic and recursive data structures such as lists, trees and graphs. Important features included for this were records, enumerations, subranges, dynamically allocated variables with associated pointers, and sets. To make this possible and meaningful, Pascal has a on all objects, which means that one type of data cannot be converted or interpreted as another without explicit conversions. Similar mechanisms are standard in many programming languages today.
Other languages that influenced Pascal's development were 67 and Wirth's own. Pascal, like many programming languages of today (but unlike most languages in the C family), allows definitions to any level of depth, and also allows most kinds of definitions and declarations inside (procedures and functions). This enables a very simple and coherent syntax where a complete program is syntactically nearly identical to a single procedure or function (except for the heading, which has one of these three keywords). Implementations [ ] Early Pascal compilers [ ] The first Pascal was designed in for the family. Reports that a first attempt to implement it in in 1969 was unsuccessful due to Fortran's inadequacy to express complex data structures.
The second attempt was implemented in a C-like language (Scallop by Max Engeli) and then translated by hand (by R. Schild) to Pascal itself for boot-strapping. It was operational by mid-1970.
Many Pascal compilers since have been similarly, that is, the compiler is itself written in Pascal, and the compiler is usually capable of recompiling itself when new features are added to the language, or when the compiler is to be to a new environment. The compiler is one notable exception, being written in C. The first successful port of the CDC Pascal compiler to another mainframe was completed by Welsh and Quinn at the (QUB) in 1972. The target was the. This compiler, in turn, was the parent of the Pascal compiler for the Information Computer Systems (ICS) minicomputer. The Multum port was developed – with a view to using Pascal as a systems programming language – by Findlay, Cupples, Cavouras and Davis, working at the Department of Computing Science in. It is thought that Multum Pascal, which was completed in the summer of 1973, may have been the first 16-bit implementation.
A completely new compiler was completed by Welsh et al. At QUB in 1977.
It offered a source-language diagnostic feature (incorporating profiling, tracing and type-aware formatted postmortem dumps) that was implemented by Findlay and Watt at Glasgow University. This implementation was ported in 1980 to the series by a team based at and Glasgow University. The Standard Pascal Model Implementation was also based on this compiler, having been adapted, by Welsh and Hay at in 1984, to check rigorously for conformity to the BSI 6192/ISO 7185 Standard and to generate code for a portable abstract machine. The first Pascal written in North America was constructed at the under for the and generated native machine code. The Pascal-P system [ ] To propagate the language rapidly, a compiler 'porting kit' was created in Zurich that included a compiler that generated code for a 'virtual' stack machine, i.e., code that lends itself to reasonably efficient interpretation, along with an interpreter for that code – the Pascal-P system. Windows File Protection Wfp Patcher Switzerland on this page. The P-system compilers were termed Pascal-P1,, Pascal-P3, and Pascal-P4. Pascal-P1 was the first version, and Pascal-P4 was the last to come from Zurich.
The version termed Pascal-P1 was coined after the fact for the many different sources for Pascal-P that existed. The compiler was redesigned to enhance portability, and issued as. This code was later enhanced to become Pascal-P3, with an intermediate code with, and Pascal-P4, which was not backward compatible.
The Pascal-P4 compiler/interpreter can still be run and compiled on systems compatible with original Pascal. However, it only accepts a subset of the Pascal language. Pascal-P5, created outside the Zurich group, accepts the full Pascal language and includes ISO 7185 compatibility. Branched off, where utilized it to create the. The UCSD p-System was one of three operating systems available at the launch of the original. UCSD Pascal used an intermediate code based on byte values, and thus was one of the earliest 'byte code compilers'. Pascal-P1 through Pascal-P4 was not, but rather based on the CDC 6600 60 bit word length.
A compiler based on the Pascal-P4 compiler, which created native binaries, was released for the by the; it was called the 'AAEC Pascal Compiler' after the abbreviation of the name of the Commission. In the early 1980s, Pascal was developed, also for the IBM.
Into the 1990s, Pascal was still running on terminals at to teach computer programming. Object Pascal and Turbo Pascal [ ] Apple Computer created its own Lisa Pascal for the Lisa Workshop in 1982, and ported the compiler to the Apple Macintosh and in 1985. In 1985, in consultation with Niklaus Wirth, defined Object Pascal and these extensions were incorporated in both the Lisa Pascal and Mac Pascal compilers. In the 1980s, wrote the Blue Label Pascal compiler for the -2.
A reimplementation of this compiler for the was marketed under the names Compas Pascal and PolyPascal before it was acquired by and renamed Turbo Pascal. Became hugely popular, thanks to an aggressive pricing strategy, having one of the first full-screen, and very fast turnaround time (just seconds to compile, link, and run). It was written and highly optimized entirely in, making it and faster than much of the competition. In 1986, Anders ported Turbo Pascal to the Macintosh and incorporated Apple's Object Pascal extensions into Turbo Pascal.
These extensions were then added back into the PC version of Turbo Pascal for version 5.5. At the same time also implemented the Object Pascal compiler. Turbo Pascal 5.5 had a large influence on the Pascal community, which began concentrating mainly on the IBM PC in the late 1980s.
Many PC hobbyists in search of a structured replacement for BASIC used this product. It also began to be adopted by professional developers. Around the same time a number of concepts were imported from to let Pascal programmers use the C-based of directly. These extensions included null-terminated,,, an address-of operator and unsafe. Turbo Pascal, and other derivatives with or module concepts are. However, it does not provide a nested module concept or qualified import and export of specific symbols. Other variants [ ] is a variant that added non-numeric labels, a return statement and expressions as names of types.
The universities of Wisconsin-Madison,, and developed the Pascal-SC and Pascal-XSC ( ) compilers, aimed at programming numerical computations. TMT Pascal the first -compatible compiler for 32-bit protected mode, and operating systems. Also the TMT Pascal language was the first one which allowed function and. Development for Pascal-SC started in 1978 supporting ISO 7185 Pascal level 0, but level 2 support was added at a later stage. Pascal-SC originally targeted the processor, but was later rewritten for DOS () and.
Pascal-XSC has at various times been ported to Unix (Linux,,, ) and Microsoft/IBM (DOS with, OS/2, ) operating systems. It operates by generating intermediate C source code which is then compiled to a native executable.
Some of the Pascal-SC language extensions have been adopted. Pascal Sol was designed around 1983 by a French team to implement a Unix-like systems named Sol.
It was standard Pascal level-1 (with parametrized array bounds) but the definition allowed alternative keywords and predefined identifiers in French and the language included a few extensions to ease system programming (e.g. An equivalent to lseek). The Sol team later on moved to the project to design a distributed operating system. Was an implementation of the Pascal programming language using DOS, but was moved rapidly to running on the Z80. It was moved to the machine types in 1994, and exists today as Windows/XP and Linux implementations.
In 2008, the system was brought up to a new level and the resulting language termed 'Pascaline' (after ). It includes objects, namespace controls,, along with many other extensions, and generally features the same functionality and type protection as. It is the only such implementation that is also compatible with the original Pascal implementation, which is standardized as ISO 7185.
Is ignored in Pascal source. Here is an example of the source code in use for a very simple. Type a = array [ 1.
10 ] of integer; b = record x: integer; y: char end; c = file of a; File type [ ] As shown in the example above, Pascal are sequences of components. Every file has a buffer variable which is denoted by f^. The procedures get (for reading) and put (for writing) move the buffer variable to the next element. Read is introduced such that read(f, x) is the same as x:= f^; get(f). Write is introduced such that write(f, x) is the same as f^:= x; put(f); The type text is predefined as file of char. While the buffer variable could be used for inspecting the next character to be used (check for a digit before reading an integer), this leads to serious problems with interactive programs in early implementations, but was solved later with the 'lazy I/O' concept. In Jensen & Wirth Pascal, strings are represented as packed arrays of chars; they therefore have fixed length and are usually space-padded.
Pointer types [ ] Pascal supports the use of. New ( NodePtr ). With NodePtr ^ do begin a:= 10; b:= 'A'; c:= NIL end. Inside of the scope of the with statement, a and b refer to the subfields of the record pointer NodePtr and not to the record Node or the pointer type pNode., and can be created by including a pointer type field (c) in the record (see also ). Unlike many languages that feature pointers, Pascal only allows pointers to reference dynamically created variables that are anonymous, and does not allow them to reference standard static or local variables. Pointers also must have an associated type, and a pointer to one type is not compatible with a pointer to another type (e.g.
A pointer to a char is not compatible with a pointer to an integer). This helps eliminate the type security issues inherent with other pointer implementations, particularly those used for.
It also removes some risks caused by, but the ability to dynamically deallocate referenced space by using the dispose function (which has the same effect as the free library function found in ) means that the risk of dangling pointers has not been entirely eliminated as it has in languages such as Java and C#, which provide (but which do not entirely eliminate the related problem of ). Some of these restrictions can be lifted in newer dialects. Control structures [ ] Pascal is a language, meaning that the flow of control is structured into standard, usually without ' commands.
From Dev-Pascal is a full-featured integrated development environment (IDE) that enables you to create Windows-, DLL-, or console-based Pascal programs using the Free Pascal compiler. Features include a Pascal compiler for Win32 (Free Pascal), a debugger (GDB or Insight), customizable syntax highlighting, a powerful multiwindow editor with many options, the ability to work in source file or project mode, a setup creator, a project manager, a compiler, a linker and resource results, the ability to insert Pascal codes and statements automatically, two different icon sets for menus and toolbars in Dev-Pascal, a tool manager, and templates for creating your own project types, and more. It also contains support for Insight Debugger. Version 1.9.2 may include unspecified updates, enhancements, or bug fixes.