| MG Mud User | 88f1247 | 2016-06-24 23:31:02 +0200 | [diff] [blame^] | 1 | CONCEPT |
| 2 | character escape codes |
| 3 | |
| 4 | DESCRIPTION |
| 5 | Character escape codes are used to represent some common |
| 6 | special characters that would be awkward or impossible to |
| 7 | enter in the source program directly. The escape characters |
| 8 | come in two varieties: 'character escapes', which can be |
| 9 | used to represent some particular formatting and special |
| 10 | characters, and 'numeric escapes', which allow a character to |
| 11 | be specified by its numeric encoding. |
| 12 | |
| 13 | Escapes begin always with a backslash '\'. If the following |
| 14 | characters could not be treated as a valid escape the backslash |
| 15 | is merely ignored. |
| 16 | |
| 17 | The following character escapes are available in LPC (the code |
| 18 | may differ from platform to platform): |
| 19 | |
| 20 | \a Code 007 Bell |
| 21 | \b Code 008 Backspace |
| 22 | \e Code 027 Escape |
| 23 | \f Code 012 Formfeed |
| 24 | \n Code 010 Newline |
| 25 | \r Code 013 Carriage-Return |
| 26 | \t Code 009 Tabulator |
| 27 | \\ Code 092 Backslash itself |
| 28 | \' Code 039 Single quote |
| 29 | \" Code 034 Double quote |
| 30 | |
| 31 | The single quote may appear without preceding backslash in character |
| 32 | constants, and the double quote may appear without a backslash in |
| 33 | string constants. |
| 34 | |
| 35 | The numeric escapes could be used to express a character directly |
| 36 | by its code in binary, octal, decimal or hexadecimal notation. |
| 37 | |
| 38 | \0b Beginning of binary notation |
| 39 | \0o Beginning of octal notation |
| 40 | \0x Beginning of hexadecimal notation |
| 41 | \x Beginning of hexadecimal notation |
| 42 | |
| 43 | A backslash followed by a digit ([0-9]) which does not map to one |
| 44 | of the above starts an escape in decimal notation. |
| 45 | |
| 46 | A numeric escape terminates when N digits have been used up or |
| 47 | when the first character that is not a valid digit in that |
| 48 | notation is encountered. N is 2 for hexadeximals, 3 for |
| 49 | decimals and octals and 8 for binarys. |
| 50 | |
| 51 | If the specified code is greater than 255 a warning is issued and |
| 52 | the value modulo 256 is used. |
| 53 | |
| 54 | EXAMPLES |
| 55 | Put a newline at the end of user output |
| 56 | "You enter.\n" |
| 57 | |
| 58 | Alert the user |
| 59 | "Beeep.\a Wake up\n" |
| 60 | |
| 61 | Put a double quote in a string |
| 62 | "You say \"hello\"\n" |
| 63 | |
| 64 | Write the line from above |
| 65 | "\"You say \\\"hello\\\"\\n\"" |
| 66 | |
| 67 | Put a single quote in a string |
| 68 | "You say 'hello'\n" |
| 69 | |
| 70 | Some forms to write "abcde" |
| 71 | "abcde" |
| 72 | "ab\99de" (with c's code being 99) |
| 73 | "ab\099de" |
| 74 | "ab\x63de" (99 = 0x63) |
| 75 | "ab\0x63de" |
| 76 | |
| 77 | The following string consists of two characters |
| 78 | "\0111" (\011 and 1) |
| 79 | |
| 80 | The following string consists of three characters |
| 81 | "\0o090" (\000 and 9 and 0) |