To achieve all this, the application must deal not only with plain text strings, but also with control characters and escape sequenceswhich allow to move cursor to an arbitrary position, to clear portions of the screen, change colors and display special characters, and also respond to function keys.
Context-free grammars are those grammars in which the left-hand side of each production rule consists of only a single nonterminal symbol. Unix systems typically buffer the input text until the Enter key is pressed, so the application receives a ready string of text.
Even more advanced interactivity is provided with full-screen applications. A text editor occupies the full area of display, displays one or more text documents, and allows the user to edit the documents. Consider a grammar defined by two rules. In the classic formalization of generative grammars first proposed by Noam Chomsky in the s,   a grammar G consists of the following components: This type of program is often abbreviated "TTY" and may also be referred to as a command-line interface.
In this context dumb terminals are sometimes dubbed glass Teletypes, for they essentially have the same limited functionality as does a mechanical Teletype.
The fundamental type of application running on a text terminal is a command line interpreter or shellwhich prompts for commands from the user and executes each command after a press of Enter. The modern term for graphical terminal is " thin client ".
The user can enter input into multiple fields in a form on the screen defined to the terminal by the receiving systemmoving the cursor around the screen using keys such as.
In fact, the language defined by a grammar is precisely the set of terminal strings that can be so derived. A formal language defined or generated by a particular grammar is the set of strings that can be produced by the grammar and that consist only of terminal symbols.
Those that can are called context-free languages. The lines are continuously formed, but since the speed of electronics is limited, the number of concurrent lines that can be displayed at one time is limited.
A formal grammar includes a start symbol, a designated member of the set of nonterminals from which all the strings in the language may be derived by successive applications of the production rules.
This is very helpful for various interactive command line interpreters. This restriction is non-trivial; not all languages can be generated by context-free grammars. Terminal symbols[ edit ] Terminal symbols are literal symbols which may appear in the outputs of the production rules of a formal grammar and which cannot be changed using the rules of the grammar.
Smart or intelligent terminals are those that also have the ability to process escape sequences, in particular the VT52VT or ANSI escape sequences. For an application, the simplest way to use a terminal is to simply write and read text strings to and from it sequentially. Practically all modern graphic displays are raster-mode, descended from the picture scanning techniques used for televisionin which the visual elements are a rectangular array of pixels.
In the past, before the widespread use of local area networking and broadband internet access, many computers would use a serial access program to communicate with other computers via telephone line or serial device. Context-free languages are the theoretical basis for the syntax of most programming languages.
This includes Unix shells and some interactive programming environments. In this mode, the application need not know much about the terminal. Modern graphic terminals allow display of images in color, and of text in varying sizes, colors, and fonts type faces.Terminal is a program that allows the user to use the computer without him having to deal directly with it.
It is in a sense a protective shell that prevents the user. Terminal definition, situated at or forming the end or extremity of something: a terminal feature of a vista.
See more. mi-centre.com Computer Science A device, often equipped with a keyboard and a video display, by which one can read, enter, or manipulate information in a computer system. The word "terminal" comes from early computer systems that were used to send commands to other computers. Terminals often consist of just a keyboard and monitor, with a.
Computer terminal synonyms, Computer terminal pronunciation, Computer terminal translation, English dictionary definition of Computer terminal. adj. 1. Of, at, relating to, or forming a limit, boundary, extremity, or end: the terminal moraine of a glacier.
Jun 18, · A computer terminal is an electronic or electromechanical hardware device that is used for entering data into, and displaying data from, a computer or a computing system.
see definition of computer science noun the study of computers Relevance ranks synonyms and suggests the best matches based on how closely a synonym’s sense matches the sense you selected.Download