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Stropping (syntax)
In computer language design, stropping is a method of explicitly marking letter sequences as having a special property, such as being a keyword, or a certain type of variable or storage location, and thus inhabiting a different namespace from ordinary names ("identifiers"), in order to avoid clashes. Stropping is not used in most modern languages – instead, keywords are reserved words and cannot be used as identifiers. Stropping allows the same letter sequence to be used both as a keyword and as an identifier, and simplifies parsing in that case – for example allowing a variable named if without clashing with the keyword if. Stropping is primarily associated with ALGOL and related languages in the 1960s. Though it finds some modern use, it is easily confused with other similar techniques that are superficially similar. History The method of stropping and the term "stropping" arose in the development of ALGOL in the 1960s, where it was used to represent typographical dis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Language
A computer language is a formal language used to communicate with a computer. Types of computer languages include: * Software construction#Construction languages, Construction language – all forms of communication by which a human can Computer programming, specify an executable problem solution to a computer ** Command language – a language used to control the tasks of the computer itself, such as starting programs ** Configuration file#Configuration languages, Configuration language – a language used to write configuration files ** Programming language – a formal language designed to communicate instructions to a machine, particularly a computer ***Scripting language – a type of programming language which typically is interpreted at runtime rather than being compiled ** Query language – a language used to make Information retrieval, queries in databases and information systems ** Transformation language – designed to transform some input te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atlas Autocode
Atlas Autocode (AA)Original scans)) is a programming language developed around 1963 at the University of Manchester. A variant of the language ALGOL, it was developed by Tony Brooker and Derrick Morris for the Atlas computer. The initial AA and AB compilers were written by Jeff Rohl and Tony Brooker using the Brooker-Morris Compiler-compiler, with a later hand-coded non-CC implementation (ABC) by Jeff Rohl. The word '' Autocode'' was basically an early term for ''programming language''. Different autocodes could vary greatly. Features AA was a block structured language that featured explicitly typed variables, subroutines, and functions. It omitted some ALGOL features such as '' passing parameters by name'', which in ALGOL 60 means passing the memory address of a short subroutine (a ''thunk'') to recalculate a parameter each time it is mentioned. The AA compiler could generate range-checking for array accesses, and allowed an array to have dimensions that were determined at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
4DOS
4DOS is a command-line interpreter by JP Software, designed to replace the default command interpreter COMMAND.COM in MS-DOS and Windows. It was written by Rex C. Conn and Tom Rawson and first released in 1989. Compared to the default, it has a large number of enhancements. 4OS2 and 4NT are similar products that replace cmd.exe in OS/2 and Windows NT respectively. Overview 4DOS is most often used as a command-line replacement for the following operating systems: * command-line: MS-DOS, IBM PC DOS, DR-DOS. * graphical: Windows 95 to Windows 98, Windows 98SE. Since Windows NT and Windows 2000 includes both COMMAND.COM and cmd.exe, 4DOS and 4NT and derivatives can both be installed. Earlier versions of 4OS2 can be run under Windows NT, and OS/2 can run the two DOS and Windows NT shells, all three can be used on Windows NT-type machines and OS/2 multiple boot machines. Among the many commands, statements and functions in 4DOS and lacking in DOS/Windows 95–98 COMMAND.COM ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Batch File
A batch file is a Scripting language, script file in DOS, OS/2 and Microsoft Windows. It consists of a series of Command (computing), commands to be executed by the command-line interpreter, stored in a plain text file. A batch file may contain any command the interpreter accepts interactively and use constructs that enable conditional branching and looping within the batch file, such as If statement, IF, Foreach loop, FOR, and GOTO label (computer science), labels. The term "batch" is from batch processing, meaning "non-interactive execution", though a batch file might not process a ''batch'' of multiple data. Similar to Job Control Language (JCL), DIGITAL Command Language, DCL and other systems on mainframe and minicomputer systems, batch files were added to ease the work required for certain regular tasks by allowing the user to set up a script to automate them. When a batch file is run, the Shell (computing), shell program (usually COMMAND.COM or cmd.exe) reads the file and ex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Six-bit Character Code
A six-bit character code is a character encoding designed for use on computers with word lengths a multiple of 6. Six bits can only encode 64 distinct characters, so these codes generally include only the upper-case letters, the numerals, some punctuation characters, and sometimes control characters. The IBM 7 track, 7-track Magnetic tape data storage, magnetic tape format was developed to store data in such codes, along with an additional parity bit. Types of six-bit codes An early six-bit binary code was used for Braille, the reading system for the blind that was developed in the 1820s. The earliest computers dealt with numeric data only, and made no provision for character data. Six-bit BCD, with several variants, was used by IBM on early computers such as the IBM 702 in 1953 and the IBM 704 in 1954. Six-bit encodings were replaced by the 8-bit EBCDIC code starting in 1964, when System/360 standardized on 8-bit bytes. There are some variants of this type of code (see #BCD-varia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Binary Codes
This is a list of some binary codes that are (or have been) used to represent text as a sequence of binary digits "0" and "1". Fixed-width binary codes use a set number of bits to represent each character in the text, while in variable-width binary codes, the number of bits may vary from character to character. Five-bit binary codes Several different five-bit codes were used for early punched tape systems. Five bits per character only allows for 32 different characters, so many of the five-bit codes used two sets of characters per value referred to as FIGS (figures) and LTRS (letters), and reserved two characters to switch between these sets. This effectively allowed the use of 60 characters. Standard five-bit standard codes are: * International Telegraph Alphabet No. 1 (ITA1) – Also commonly referred to as Baudot code * International Telegraph Alphabet No. 2 (ITA2) – Also commonly referred to as Murray code * American Teletypewriter code (USTTY) – A variant of ITA2 use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lightweight Markup Language
A lightweight markup language (LML), also termed a simple or humane markup language, is a markup language with simple, unobtrusive syntax. It is designed to be easy to write using any generic text editor and easy to read in its raw form. Lightweight markup languages are used in applications where it may be necessary to read the raw document as well as the final rendered output. For instance, a person downloading a software library might prefer to read the documentation in a text editor rather than a web browser. Another application for such languages is to provide for data entry in web-based publishing, such as blogs and wikis, where the input interface is a simple text box. The server software then converts the input into a common document markup language like HTML. History Lightweight markup languages were originally used on text-only displays which could not display characters in italics or bold, so informal methods to convey this information had to be developed. This ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Edinburgh IMP
Edinburgh IMP is a development of Atlas Autocode, initially developed around 1966-1969 at the University of Edinburgh, Scotland. It is a general-purpose programming language which was used heavily for systems programming. Expressively, IMP is highly similar to ALGOL and includes all the ALGOL-style block structure, reserved words (keywords), and data types such as arrays, and records. It adds to ALGOL-style languages a string type (an array of characters, although these have a predeclared size) and built-in operators for string manipulation and character handling. One significant difference from ALGOL is that IMP does not support parameters passed by name, although it does support parameters passed by reference. IMP provides significant control over the storage mapping of data, plus commands for addressing within parts of words. Most IMP compilers offer compiler-generated runtime checks and a stack trace (backtrace) facility by default, even in production code. IMP allows ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ALGOL 68RS
ALGOL 68RS is the second ALGOL 68 compiler written by I. F. Currie and J. D. Morrison, at the Royal Signals and Radar Establishment (RSRE). Unlike the earlier ALGOL 68-R, it was designed to be portable, and implemented the language of the Revised Report. Versions of ALGOL 68RS were written for the ICL 2900 Series, Multics, and VAX running VMS. Subsequently, parts of this compiler were released into the public domain, as a translator from ALGOL 68 to C, as part of the public release of the hardware description language ELLA, also by the RSRE. History Although the ALGOL 68-R compiler, written by I.F. Currie, J.D. Morrison, and S.G. Bond, was a great success, it suffered from two major problems: it had been written for the nearly obsolete ICL 1900 computer, and it implemented an out-of-date version of the language as it was released before the Revised Report on ALGOL 68 was available. RSRE needed a newer compiler for various internal projects, so the team of Currie and Morris ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
English Electric KDF9
KDF9 was an early British 48-bit computer designed and built by English Electric (which in 1968 was merged into International Computers Limited (ICL)). The first machine came into service in 1964 and the last of 29 machines was decommissioned in 1980 at the National Physical Laboratory. The KDF9 was designed for, and used almost entirely in, the mathematical and scientific processing fields in 1967, nine were in use in UK universities and technical colleges. The KDF8, developed in parallel, was aimed at commercial processing workloads. The KDF9 was an early example of a machine that directly supported multiprogramming, using offsets into its core memory to separate the programs into distinct virtual address spaces. Several operating systems were developed for the platform, including some that provided fully interactive use through PDP-8 machines acting as smart terminal servers. A number of compilers were available, notably both checkout and globally optimizing compilers for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |