- Text editor
A text editor is a type of program used for editing plain
Text editors are often provided with
operating systems or software development packages, and can be used to change configuration files and programming language source code.
Plain text files vs. word processor files
There are important differences between plain text files created by a text editor, and
documentfiles created by word processors such as Microsoft Word, WordPerfect, or OpenOffice.org. Briefly:
*A plain text file is represented and edited by showing all the characters as they are present in the file. The only characters usable for 'mark-up' are the
control characters of the used character set; in practice this is newline, tab and formfeed. The most commonly used character set is ASCII, especially recently, as plain text files are more used for programming and configuration and less frequently used for documentation than in the past.
*Documents created by a word processor generally contain fileformat-specific "
control characters" beyond what is defined in the character set. These enable functions like bold, italic, fonts, columns, tables, etc. These and other common page formatting symbols were once associated only with desktop publishingbut are now commonplace in the simplest word processor.
*Word processors can usually edit a plain text file and save in the plain text file format. However one must take care to tell the program that this is what is wanted. This is especially important in cases such as source code, HTML, and configuration and control files. Otherwise the file will contain those "special characters" unique to the word processor's file format and will not be handled correctly by the utility the files were intended for.
Before text editors existed, computer text was punched into
Hollerith cards with keypunchmachines. The text was carried as a physical box of these thin cardboard cards, and read into a card-reader.
The first text editors were line editors oriented on
typewriterstyle terminals and they did not provide a window or screen-oriented display. They usually had very short commands (to minimize typing) that reproduced the current line. Among them were a command to print a selected section(s) of the file on the typewriter (or printer) in case of necessity. An "edit cursor", an imaginary insertion point, could be moved by special commands that operated with line numbers of specific text strings (context). Later, the context strings were extended to regular expressions. To see the changes, the file needed to be printed on the printer. These "line-based text editors" were considered revolutionary improvements over keypunch machines. In case typewriter-based terminals were not available, they were adapted to keypunch equipment. In this case the user needed to punch the commands into the separate deck of cards and feed them into the computer in order to edit the file.
computer terminals with video screens became available, screen-based text editors became common. One of the earliest "full screen" editors was O26 - which was written for the operator console of the CDC 6000 seriesmachines in 1967. Another early full screen editor is vi. Written in the 1970s, vi is still a standard editor for Unixand Linuxoperating systems. The productivity of editing using full-screen editors (compared to the line-based editors) motivated many of the early purchases of video terminals.
Types of text editors
Some text editors are small and simple, while others offer a broad and complex range of functionality. For example,
Unixand Unix-like operating systems have the vieditor (or a variant), but many also include the Emacseditor. Microsoft Windowssystems come with the very simple Notepad, though many people—especially programmers—prefer to use one of many other with more features. Under Apple Macintosh's classic Mac OSthere was the native SimpleText, which was replaced by TextEdit. Some editors, such as WordStar, have dual operating modes allowing them to be either a text editor or a word processor.
Text editors geared for professional computer users place no limit on the size of the file being opened. In particular, they start quickly even when editing large files, and are capable of editing files that are too large to fit the computer's main memory. Simpler text editors often just read files into an array in RAM. On larger files this is a slow process, and very large files often do not fit.
The ability to read and write very large files is needed by many professional computer users. For example, system administrators may need to read long log files. Programmers may need to change large
source codefiles, or examine unusually large texts, such as an entire dictionary placed in a single file.
Some text editors include specialized computer languages to customize the editor (programmable editors). For example, Emacs can be customized by programming in Lisp. These usually permit the editor to simulate the keystroke combinations and features of other editors, so that users do not have to learn the native command combinations.
Another important group of programmable editors use
REXXas their scripting language. These editors permit entering both commands and REXX statements directly in the command line at the bottom of the screen (can be hidden and activated by a keystroke). These editors are usually referred to as "orthodox editors", and most representatives of this class are derivatives of Xedit, IBM's editor for VM/CMS. Among them are THE, Kedit, SlickEdit, X2, Uni-edit, UltraEdit, and Sedit. Some vi derivatives such as Vim also support folding as well as macro languages, and have a command line at the bottom for entering commands. They can be considered another branch of the family of orthodox editors.
Many text editors for software developers include source code
syntax highlightingand automatic completion to make programs easier to read and write. Programming editors often permit one to select the name of a subprogram or variable, and then jump to its definition and back. Often an auxiliary utility like ctagsis used to locate the definitions.
Some editors include special features and extra functions, for instance,
Source code editors are text editors with additional functionality to facilitate the production of source code. These often feature user-programmable syntax highlighting, and coding tools or keyboard macros similar to an HTML editor (see below).
Folding editors. This subclass includes so-called "orthodox editors" that are derivatives of Xedit. The specialized version of folding is usually called outlining (see below).
*IDEs (integrated development environments) are designed to manage and streamline larger programming projects. They are usually only used for programming as they contain many features unnecessary for simple text editing.
World Wide Webprogrammers are offered a variety of text editors dedicated to the task of web development. These create the plain text files that deliver web pages. HTML editors include: Dreamweaver, E (text editor), Frontpage, HotDog, Homesite, Nvu, Tidy, GoLive, and BBedit. Many offer the option of viewing a work in progress on a built-in web browser.
Outliners. Folding (see above) can generally be considered a generalized form of outlining.
Typical features of text editors
The process of searching for a word or string in a text file and optionally replacing the search string with a replacement string. Different methods are employed, Global(ly) Search And Replace, Conditional Search and Replace, Unconditional Search and Replace.
Cut, copy, and paste
Most text editors provide methods to duplicate and move text within the file, or between files.
Text editors often provide basic formatting features like
line wrap, auto-indentation, bullet listformatting, comment formatting, and so on.
As with word processors, text editors will provide a way to undo and redo the last edit. Often—especially with older text editors—there is only one level of edit history remembered and successively issuing the undo command will only "toggle" the last change. Modern or more complex editors usually provide a multiple level history such that issuing the undo command repeatedly will revert the document to successively older edits. A separate redo command will cycle the edits "forward" toward the most recent changes. The number of changes remembered depends upon the editor and is often configurable by the user.
Reading or merging the contents of another text file into the file currently being edited. Some text editors provide a way to insert the output of a command issued to the operating system's shell.
Some advanced text editors allow you to send all or sections of the file being edited to another utility and read the result back into the file in place of the lines being "filtered". This, for example, is useful for sorting a series of lines alphabetically or numerically, doing mathematical computations, and so on.
List of text editors
Comparison of text editors
File viewer- does not change file, faster for very large files
Hex editor- used for editing binary files
* [http://TextEditors.org The text editor wiki]
* [http://sourceforge.net/softwaremap/trove_list.php?form_cat=63 Text Editors at sourceforge.net]
* [http://www.softpanorama.org/Editors/index.shtml Orthodox Editors as a Special Class of Advanced Editors] Discusses Xedit and its clones with an emphasis of folding capabilities and programmability.
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См. также в других словарях:
text editor — noun 1. an editor who prepares text for publication • Syn: ↑copy editor, ↑copyreader • Derivationally related forms: ↑copyread (for: ↑copyreader) • Hypernyms: ↑ … Useful english dictionary
text editor — UK / US noun [countable] Word forms text editor : singular text editor plural text editors computing a computer program that allows you to create and edit written documents … English dictionary
Text-Editor — tekstų redaktorius statusas T sritis automatika atitikmenys: angl. text editor vok. Text Editor, m rus. редактор текста, m; текстовый редактор, m pranc. éditeur de texte, m … Automatikos terminų žodynas
text editor — tekstų redaktorius statusas T sritis automatika atitikmenys: angl. text editor vok. Text Editor, m rus. редактор текста, m; текстовый редактор, m pranc. éditeur de texte, m … Automatikos terminų žodynas
text editor — rašyklė statusas T sritis informatika apibrėžtis Programa, skirta tekstiniams dokumentams rengti. Rašyklių pavyzdžiai: „MS Word“, „Tekstų doroklis“ („Word Pad“). Dar vartojama tekstų redaktorius. atitikmenys: angl. composer; editor; text editor;… … Enciklopedinis kompiuterijos žodynas
text editor — text editing, adj. Computers. a program for editing stored documents, performing such functions as adding, deleting, or moving text. [1970 75] * * * … Universalium
text editor — text′ ed itor n. cmp a computer program for writing and modifying documents or program code on screen, usu. having little or no formatting ability • Etymology: 1970–75 text′ ed it•ing, adj … From formal English to slang
Text-Editor — Texteditor Ein Texteditor (lat. editor „Herausgeber“, „Erzeuger“) ist ein Computerprogramm zum Bearbeiten von Texten. Der Editor lädt die zu bearbeitende Textdatei und zeigt ihren Inhalt auf dem Bildschirm an. Durch diverse Aktionen können die… … Deutsch Wikipedia
text editor — noun A program which allows a user to edit the contents of a text file, usually in an interactive way with immediate visual feedback. Compare word processor … Wiktionary
text editor — program which enables users to edit text files without design preferences or control characters … English contemporary dictionary