Difference between revisions of "Character escape codes"
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− | Escape sequences use an escape character to change the meaning of the characters which follow it. In the | + | Escape sequences use an escape character to change the meaning of the characters which follow it. Escape sequences can be used for two purposes: |
+ | * to use non-printable characters in action strings | ||
+ | * quoting: ignore special meaning of a character in eventhandler parser. | ||
+ | |||
+ | The escape sequences are substituted when the eventhandler reads the action string. In the case of Data Protocol Commands ( @ $ ), the escape sequences are substituted ''before'' the messages are sent to the Data Protocol Router / Handler. | ||
+ | |||
+ | In the AlphaCom the chatracter backslash (\) is used as escape character. Escape sequences might be used in the [[EDO]] command to generate non-printable [http://en.wikipedia.org/wiki/ASCII ASCII] characters. | ||
Some frequently used escape sequences: | Some frequently used escape sequences: |
Revision as of 13:22, 21 October 2008
Escape sequences use an escape character to change the meaning of the characters which follow it. Escape sequences can be used for two purposes:
- to use non-printable characters in action strings
- quoting: ignore special meaning of a character in eventhandler parser.
The escape sequences are substituted when the eventhandler reads the action string. In the case of Data Protocol Commands ( @ $ ), the escape sequences are substituted before the messages are sent to the Data Protocol Router / Handler.
In the AlphaCom the chatracter backslash (\) is used as escape character. Escape sequences might be used in the EDO command to generate non-printable ASCII characters.
Some frequently used escape sequences:
\r = Carriage Return \n = Line Feed \t = Tab \xhh = hh is any ASCII value in HEX
Escape sequences:
Escape sequence | Result | Hex code | Description |
---|---|---|---|
\, | , | 2C | Comma |
\( | ( | 28 | Opening parenthese |
\) | ) | 29 | Closing parenthese |
\" | " | 22 | Double quote |
\; | ; | 3B | Semicolon |
\\ | \ | 5C | Backslash |
\% | % | 25 | Percent |
\t | TAB | 09 | ASCII TAB (Horisontal tab) |
\s | SP | 20 | Space |
\r | CR | 0D | Carriage return |
\n | LF | 0A | Line feed |
\a | BEL | 07 | Bell (Alert) |
\b | BS | 08 | Backspace |
\0 | NUL | 00 | ASCII NUL |
\l | 80 | Extended NUL ('\x80') | |
\! | Comment / ignore rest of string | ||
\xhh | 'hh' is the ASCII character code as 2 hex digits. Note that you must use 2 digits. | ||
\#hh | 'hh' is the ASCII character code as 2 hex digits. Note that you must use 2 digits. |
By using the escape sequence '\xhh' all sorts of ASCII characters can be generated.