Editing Escape character (section)

==Definition==
An escape character may not have its own meaning, so all escape sequences are of two or more characters.

Escape characters are part of the [[formal syntax|syntax]] for many programming languages, data formats, and communication protocols. For a given [[alphabet (computer science)|alphabet]] an escape character's purpose is to start character sequences (so named [[escape sequence]]s), which have to be interpreted differently from the same characters occurring without the prefixed escape character.

The functions of escape sequences include:

* To encode a syntactic entity, such as device commands or special data, which cannot be directly represented by the alphabet.
* To represent characters, referred to as ''character quoting'', which cannot be typed in the current context, or would have an undesired interpretation. In this case, an escape sequence is a [[digraph (computing)|digraph]] consisting of an escape character itself and a "quoted" character.

===Control character===
Generally, an escape character is not a particular case of (device) [[control character]]s, nor vice versa. If we define control characters as non-[[graphic character|graphic]], or as having a special meaning for an output device (e.g. [[computer printer|printer]] or [[text terminal]]) then any escape character for this device is a control one. But escape characters used in programming (such as the [[backslash]], "\") are graphic, hence are not control characters. Conversely most (but not all) of the [[ASCII]] "control characters" have some control function in isolation, therefore they are not escape characters.

In many programming languages, an escape character also forms some escape sequences which are referred to as control characters. For example, [[Line break (computing)|line break]] has an escape sequence of {{code|\n}}.