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. Escape sequences can be used for two purposes: | 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 | + | * to use non-printable characters in action strings, e.g. in [[EDO]] and [[MPP]] commands |
* quoting: ignore special meaning of a character in eventhandler parser. | * 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. | 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 character backslash (\) is used as escape character | + | In the AlphaCom the character backslash (\) is used as escape character. |
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Escape sequences: | Escape sequences: | ||
Revision as of 14:27, 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, e.g. in EDO and MPP commands
- 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 character backslash (\) is used as escape character.
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.