1 :mod:`curses.ascii` --- Utilities for ASCII characters 2 ====================================================== 3 4 .. module:: curses.ascii 5 :synopsis: Constants and set-membership functions for ASCII characters. 6 7 .. moduleauthor:: Eric S. Raymond <esr (a] thyrsus.com> 8 .. sectionauthor:: Eric S. Raymond <esr (a] thyrsus.com> 9 10 -------------- 11 12 The :mod:`curses.ascii` module supplies name constants for ASCII characters and 13 functions to test membership in various ASCII character classes. The constants 14 supplied are names for control characters as follows: 15 16 +--------------+----------------------------------------------+ 17 | Name | Meaning | 18 +==============+==============================================+ 19 | :const:`NUL` | | 20 +--------------+----------------------------------------------+ 21 | :const:`SOH` | Start of heading, console interrupt | 22 +--------------+----------------------------------------------+ 23 | :const:`STX` | Start of text | 24 +--------------+----------------------------------------------+ 25 | :const:`ETX` | End of text | 26 +--------------+----------------------------------------------+ 27 | :const:`EOT` | End of transmission | 28 +--------------+----------------------------------------------+ 29 | :const:`ENQ` | Enquiry, goes with :const:`ACK` flow control | 30 +--------------+----------------------------------------------+ 31 | :const:`ACK` | Acknowledgement | 32 +--------------+----------------------------------------------+ 33 | :const:`BEL` | Bell | 34 +--------------+----------------------------------------------+ 35 | :const:`BS` | Backspace | 36 +--------------+----------------------------------------------+ 37 | :const:`TAB` | Tab | 38 +--------------+----------------------------------------------+ 39 | :const:`HT` | Alias for :const:`TAB`: "Horizontal tab" | 40 +--------------+----------------------------------------------+ 41 | :const:`LF` | Line feed | 42 +--------------+----------------------------------------------+ 43 | :const:`NL` | Alias for :const:`LF`: "New line" | 44 +--------------+----------------------------------------------+ 45 | :const:`VT` | Vertical tab | 46 +--------------+----------------------------------------------+ 47 | :const:`FF` | Form feed | 48 +--------------+----------------------------------------------+ 49 | :const:`CR` | Carriage return | 50 +--------------+----------------------------------------------+ 51 | :const:`SO` | Shift-out, begin alternate character set | 52 +--------------+----------------------------------------------+ 53 | :const:`SI` | Shift-in, resume default character set | 54 +--------------+----------------------------------------------+ 55 | :const:`DLE` | Data-link escape | 56 +--------------+----------------------------------------------+ 57 | :const:`DC1` | XON, for flow control | 58 +--------------+----------------------------------------------+ 59 | :const:`DC2` | Device control 2, block-mode flow control | 60 +--------------+----------------------------------------------+ 61 | :const:`DC3` | XOFF, for flow control | 62 +--------------+----------------------------------------------+ 63 | :const:`DC4` | Device control 4 | 64 +--------------+----------------------------------------------+ 65 | :const:`NAK` | Negative acknowledgement | 66 +--------------+----------------------------------------------+ 67 | :const:`SYN` | Synchronous idle | 68 +--------------+----------------------------------------------+ 69 | :const:`ETB` | End transmission block | 70 +--------------+----------------------------------------------+ 71 | :const:`CAN` | Cancel | 72 +--------------+----------------------------------------------+ 73 | :const:`EM` | End of medium | 74 +--------------+----------------------------------------------+ 75 | :const:`SUB` | Substitute | 76 +--------------+----------------------------------------------+ 77 | :const:`ESC` | Escape | 78 +--------------+----------------------------------------------+ 79 | :const:`FS` | File separator | 80 +--------------+----------------------------------------------+ 81 | :const:`GS` | Group separator | 82 +--------------+----------------------------------------------+ 83 | :const:`RS` | Record separator, block-mode terminator | 84 +--------------+----------------------------------------------+ 85 | :const:`US` | Unit separator | 86 +--------------+----------------------------------------------+ 87 | :const:`SP` | Space | 88 +--------------+----------------------------------------------+ 89 | :const:`DEL` | Delete | 90 +--------------+----------------------------------------------+ 91 92 Note that many of these have little practical significance in modern usage. The 93 mnemonics derive from teleprinter conventions that predate digital computers. 94 95 The module supplies the following functions, patterned on those in the standard 96 C library: 97 98 99 .. function:: isalnum(c) 100 101 Checks for an ASCII alphanumeric character; it is equivalent to ``isalpha(c) or 102 isdigit(c)``. 103 104 105 .. function:: isalpha(c) 106 107 Checks for an ASCII alphabetic character; it is equivalent to ``isupper(c) or 108 islower(c)``. 109 110 111 .. function:: isascii(c) 112 113 Checks for a character value that fits in the 7-bit ASCII set. 114 115 116 .. function:: isblank(c) 117 118 Checks for an ASCII whitespace character; space or horizontal tab. 119 120 121 .. function:: iscntrl(c) 122 123 Checks for an ASCII control character (in the range 0x00 to 0x1f or 0x7f). 124 125 126 .. function:: isdigit(c) 127 128 Checks for an ASCII decimal digit, ``'0'`` through ``'9'``. This is equivalent 129 to ``c in string.digits``. 130 131 132 .. function:: isgraph(c) 133 134 Checks for ASCII any printable character except space. 135 136 137 .. function:: islower(c) 138 139 Checks for an ASCII lower-case character. 140 141 142 .. function:: isprint(c) 143 144 Checks for any ASCII printable character including space. 145 146 147 .. function:: ispunct(c) 148 149 Checks for any printable ASCII character which is not a space or an alphanumeric 150 character. 151 152 153 .. function:: isspace(c) 154 155 Checks for ASCII white-space characters; space, line feed, carriage return, form 156 feed, horizontal tab, vertical tab. 157 158 159 .. function:: isupper(c) 160 161 Checks for an ASCII uppercase letter. 162 163 164 .. function:: isxdigit(c) 165 166 Checks for an ASCII hexadecimal digit. This is equivalent to ``c in 167 string.hexdigits``. 168 169 170 .. function:: isctrl(c) 171 172 Checks for an ASCII control character (ordinal values 0 to 31). 173 174 175 .. function:: ismeta(c) 176 177 Checks for a non-ASCII character (ordinal values 0x80 and above). 178 179 These functions accept either integers or single-character strings; when the argument is a 180 string, it is first converted using the built-in function :func:`ord`. 181 182 Note that all these functions check ordinal bit values derived from the 183 character of the string you pass in; they do not actually know anything about 184 the host machine's character encoding. 185 186 The following two functions take either a single-character string or integer 187 byte value; they return a value of the same type. 188 189 190 .. function:: ascii(c) 191 192 Return the ASCII value corresponding to the low 7 bits of *c*. 193 194 195 .. function:: ctrl(c) 196 197 Return the control character corresponding to the given character (the character 198 bit value is bitwise-anded with 0x1f). 199 200 201 .. function:: alt(c) 202 203 Return the 8-bit character corresponding to the given ASCII character (the 204 character bit value is bitwise-ored with 0x80). 205 206 The following function takes either a single-character string or integer value; 207 it returns a string. 208 209 210 .. index:: 211 single: ^ (caret); in curses module 212 single: ! (exclamation); in curses module 213 214 .. function:: unctrl(c) 215 216 Return a string representation of the ASCII character *c*. If *c* is printable, 217 this string is the character itself. If the character is a control character 218 (0x00--0x1f) the string consists of a caret (``'^'``) followed by the 219 corresponding uppercase letter. If the character is an ASCII delete (0x7f) the 220 string is ``'^?'``. If the character has its meta bit (0x80) set, the meta bit 221 is stripped, the preceding rules applied, and ``'!'`` prepended to the result. 222 223 224 .. data:: controlnames 225 226 A 33-element string array that contains the ASCII mnemonics for the thirty-two 227 ASCII control characters from 0 (NUL) to 0x1f (US), in order, plus the mnemonic 228 ``SP`` for the space character. 229 230
