Editing Text editor (section)

==Types of text editors==
[[File:Colorsyntax.png|thumbnail|right|Emacs, a text editor popular among programmers, running on [[Microsoft Windows]]]]
[[File:Gedit 3.32 screenshot.png|thumb|[[gedit]] is a text editor shipped with [[GNOME]]]]
Some text editors are small and simple, while others offer broad and complex functions. For example, [[Unix]] and Unix-like operating systems have the [[pico (text editor)|pico]] editor (or a variant), but many also include the [[Vi (text editor)|vi]] and Emacs editors. [[Microsoft Windows]] systems come with the simple [[Notepad (Windows)|Notepad]], though many people&mdash;especially programmers&mdash;prefer other [[:Category:Windows text editors|editors]] with more features. Under [[Apple Macintosh]]'s [[classic Mac OS]] there was the native [[TeachText]] later replaced by [[SimpleText]] in 1994, which was replaced in [[Mac OS X]] by [[TextEdit]], which combines features of a text editor with those typical of a word processor such as rulers, margins and multiple font selection. These features are not available simultaneously, but must be switched by user command, or through the program automatically determining the [[file type]]. 

Most word processors can read and write files in plain text format, allowing them to open files saved from text editors. Saving these files from a word processor, however, requires ensuring the file is written in [[plain text]] format, and that any [[text encoding]] or [[Byte Order Mark|BOM]] settings will not obscure the file for its intended use. Non-[[WYSIWYG]] word processors, such as [[WordStar]], are more easily pressed into service as text editors, and in fact were commonly used as such during the 1980s. The default [[file format]] of these word processors often resembles a markup language, with the basic format being plain text and visual formatting achieved using non-printing [[control characters]] or [[escape sequence]]s. Later word processors like [[Microsoft Word]] store their files in a [[binary format]] and are almost never used to edit plain text files.<ref>{{cite web |url= http://www.cprogramming.com/texteditors.html |title=Text Editors for Programmeres - Programming Tools |quote=If you open a .doc file in a text editor, you will notice that most of the file is formatting codes.  Text editors, however, do not add formatting codes, which makes it easier to compile your code.}}</ref>

Some text editors can [[Memory-mapped file|edit unusually large files]] such as [[logfile|log files]] or an entire [[database]] placed in a single file. Simpler text editors may just read files into the computer's main [[Random access memory|memory]]. With larger files, this may be a slow process, and the entire file may not fit.  Some text editors do not let the user start editing until this read-in is complete. Editing performance also often suffers in nonspecialized editors, with the editor taking seconds or even minutes to respond to keystrokes or navigation commands. Specialized editors have optimizations such as only storing the visible portion of large files in memory, improving editing performance.

Some editors are programmable, meaning, e.g., they can be customized for specific uses. With a programmable editor it is easy to automate repetitive tasks or, add new functionality or even implement a new application within the framework of the editor.  One common motive for customizing is to make a text editor use the commands of another text editor with which the user is more familiar, or to duplicate missing functionality the user has come to depend on. Software developers often use editor customizations tailored to the programming language or development environment they are working in. The programmability of some text editors is limited to enhancing the core editing functionality of the program, but [[Emacs]] can be extended far beyond editing text files&mdash;for web browsing, reading email, online chat, managing files or playing games and is often thought of as a Lisp execution environment with a [[Text User Interface]]. Emacs can even be programmed to emulate [[Vi (text editor)|Vi]], its rival in the traditional [[editor wars]] of [[Unix philosophy|Unix culture]].<ref>{{Cite web|url=https://juanjoalvarez.net/posts/2014/vim-emacsevil-chaotic-migration-guide/|title=Vim to Emacs' Evil chaotic migration guide|website=juanjoalvarez.net|date=19 September 2014 }}</ref><ref>{{cite web |url= https://gitorious.org/evil/pages/Home%7ctitle=Evil |title= Gitorious |access-date= 27 May 2015 |archive-date= 28 May 2015 |archive-url= https://web.archive.org/web/20150528010711/https://gitorious.org/evil/pages/Home%7ctitle=Evil |url-status= dead }}</ref>

An important group of programmable editors uses [[REXX]]{{efn|Originally macros were written in assembler, [[CLIST]] ([[Time Sharing Option|TSO]]), [[EXEC|CMS EXEC]] ([[VM (operating system)|VM]]), [[EXEC2]] (VM/SE) or [[PL/I]], but most users dropped CLIST, EXEC and EXEC2 once REXX was available.}} as a scripting language. These "orthodox editors" contain a "command line" into which commands and macros can be typed and text lines into which line commands{{efn|A line command is a command typed into the sequence number entry area associated with a specific line of text and whose scope is limited to that line, or, in the case of a block command, associated with the block of lines between the beginning and ending line commands. An example of the latter would be typing the command '''ucc''' (block upper case) into the entry areas of two lines; this has the same effect as typing '''uc''' (upper case) into the entry area of each line in the range.}} and macros can be typed. Most such editors are derivatives of [[ISPF|ISPF/PDF]] [[ISPF#ISPF Editor|EDIT]] or of [[XEDIT]], IBM's flagship editor for [[VM (operating system)|VM/SP]] through [[z/VM]]. Among them are [[The Hessling Editor|THE]], [[XEDIT#PC and Unix adaptations|KEDIT]], X2, Uni-edit, and [[XEDIT#PC and Unix adaptations|SEDIT]].

A text editor written or customized for a specific use can determine what the user is editing and assist the user, often by [[autocomplete|completing]] programming terms and showing [[tooltip]]s with relevant documentation.  Many text editors for software developers include source code [[syntax highlighting]] and automatic [[indent style|indentation]] to make programs easier to read and write.  Programming editors often let the user select the name of an [[include file]], [[function (programming)|function]] or [[variable (programming)|variable]], then jump to its definition. Some also allow for easy navigation back to the original section of code by storing the initial cursor location or by displaying the requested definition in a [[popup window]] or temporary buffer. Some editors implement this ability themselves, but often an auxiliary utility like [[ctags]] is used to locate the definitions.