Mercurial > hg > xemacs-beta
annotate man/lispref/strings.texi @ 5167:e374ea766cc1
clean up, rearrange allocation statistics code
-------------------- ChangeLog entries follow: --------------------
src/ChangeLog addition:
2010-03-21 Ben Wing <ben@xemacs.org>
* alloc.c:
* alloc.c (assert_proper_sizing):
* alloc.c (c_readonly):
* alloc.c (malloced_storage_size):
* alloc.c (fixed_type_block_overhead):
* alloc.c (lisp_object_storage_size):
* alloc.c (inc_lrecord_stats):
* alloc.c (dec_lrecord_stats):
* alloc.c (pluralize_word):
* alloc.c (object_memory_usage_stats):
* alloc.c (Fobject_memory_usage):
* alloc.c (compute_memusage_stats_length):
* alloc.c (disksave_object_finalization_1):
* alloc.c (Fgarbage_collect):
* mc-alloc.c:
* mc-alloc.c (mc_alloced_storage_size):
* mc-alloc.h:
No functionality change here. Collect the allocations-statistics
code that was scattered throughout alloc.c into one place. Add
remaining section headings so that all sections have headings
clearly identifying the start of the section and its purpose.
Expose mc_alloced_storage_size() even when not MEMORY_USAGE_STATS;
this fixes build problems and is related to the export of
lisp_object_storage_size() and malloced_storage_size() when
non-MEMORY_USAGE_STATS in the previous change set.
| author | Ben Wing <ben@xemacs.org> |
|---|---|
| date | Sun, 21 Mar 2010 04:41:49 -0500 |
| parents | 99f8ebc082d9 |
| children | 3889ef128488 |
| rev | line source |
|---|---|
| 428 | 1 @c -*-texinfo-*- |
| 2 @c This is part of the XEmacs Lisp Reference Manual. | |
| 444 | 3 @c Copyright (C) 1990, 1991, 1992, 1993, 1994 Free Software Foundation, Inc. |
| 428 | 4 @c See the file lispref.texi for copying conditions. |
| 5 @setfilename ../../info/strings.info | |
| 6 @node Strings and Characters, Lists, Numbers, Top | |
| 7 @chapter Strings and Characters | |
| 8 @cindex strings | |
| 9 @cindex character arrays | |
| 10 @cindex characters | |
| 11 @cindex bytes | |
| 12 | |
| 13 A string in XEmacs Lisp is an array that contains an ordered sequence | |
| 14 of characters. Strings are used as names of symbols, buffers, and | |
| 15 files, to send messages to users, to hold text being copied between | |
| 16 buffers, and for many other purposes. Because strings are so important, | |
| 17 XEmacs Lisp has many functions expressly for manipulating them. XEmacs | |
| 18 Lisp programs use strings more often than individual characters. | |
| 19 | |
| 20 @menu | |
| 440 | 21 * String Basics:: Basic properties of strings and characters. |
| 428 | 22 * Predicates for Strings:: Testing whether an object is a string or char. |
| 23 * Creating Strings:: Functions to allocate new strings. | |
| 24 * Predicates for Characters:: Testing whether an object is a character. | |
| 25 * Character Codes:: Each character has an equivalent integer. | |
| 26 * Text Comparison:: Comparing characters or strings. | |
| 27 * String Conversion:: Converting characters or strings and vice versa. | |
| 28 * Modifying Strings:: Changing characters in a string. | |
| 29 * String Properties:: Additional information attached to strings. | |
| 30 * Formatting Strings:: @code{format}: XEmacs's analog of @code{printf}. | |
| 31 * Character Case:: Case conversion functions. | |
| 32 * Case Tables:: Customizing case conversion. | |
| 33 * Char Tables:: Mapping from characters to Lisp objects. | |
| 34 @end menu | |
| 35 | |
| 36 @node String Basics | |
| 37 @section String and Character Basics | |
| 38 | |
| 39 Strings in XEmacs Lisp are arrays that contain an ordered sequence of | |
| 40 characters. Characters are their own primitive object type in XEmacs | |
| 41 20. However, in XEmacs 19, characters are represented in XEmacs Lisp as | |
| 42 integers; whether an integer was intended as a character or not is | |
| 43 determined only by how it is used. @xref{Character Type}. | |
| 44 | |
| 45 The length of a string (like any array) is fixed and independent of | |
| 46 the string contents, and cannot be altered. Strings in Lisp are | |
| 47 @emph{not} terminated by a distinguished character code. (By contrast, | |
| 48 strings in C are terminated by a character with @sc{ascii} code 0.) | |
| 49 This means that any character, including the null character (@sc{ascii} | |
| 50 code 0), is a valid element of a string.@refill | |
| 51 | |
| 52 Since strings are considered arrays, you can operate on them with the | |
| 53 general array functions. (@xref{Sequences Arrays Vectors}.) For | |
| 54 example, you can access or change individual characters in a string | |
| 55 using the functions @code{aref} and @code{aset} (@pxref{Array | |
| 56 Functions}). | |
| 57 | |
| 58 Strings use an efficient representation for storing the characters | |
| 59 in them, and thus take up much less memory than a vector of the same | |
| 60 length. | |
| 61 | |
| 62 Sometimes you will see strings used to hold key sequences. This | |
| 63 exists for backward compatibility with Emacs 18, but should @emph{not} | |
| 64 be used in new code, since many key chords can't be represented at | |
| 65 all and others (in particular meta key chords) are confused with | |
| 66 accented characters. | |
| 67 | |
| 68 @ignore @c Not accurate any more | |
| 69 Each character in a string is stored in a single byte. Therefore, | |
| 70 numbers not in the range 0 to 255 are truncated when stored into a | |
| 71 string. This means that a string takes up much less memory than a | |
| 72 vector of the same length. | |
| 73 | |
| 74 Sometimes key sequences are represented as strings. When a string is | |
| 75 a key sequence, string elements in the range 128 to 255 represent meta | |
| 76 characters (which are extremely large integers) rather than keyboard | |
| 77 events in the range 128 to 255. | |
| 78 | |
| 79 Strings cannot hold characters that have the hyper, super or alt | |
| 80 modifiers; they can hold @sc{ASCII} control characters, but no other | |
| 81 control characters. They do not distinguish case in @sc{ASCII} control | |
| 82 characters. @xref{Character Type}, for more information about | |
| 83 representation of meta and other modifiers for keyboard input | |
| 84 characters. | |
| 85 @end ignore | |
| 86 | |
| 87 Strings are useful for holding regular expressions. You can also | |
| 88 match regular expressions against strings (@pxref{Regexp Search}). The | |
| 89 functions @code{match-string} (@pxref{Simple Match Data}) and | |
| 90 @code{replace-match} (@pxref{Replacing Match}) are useful for | |
| 91 decomposing and modifying strings based on regular expression matching. | |
| 92 | |
| 93 Like a buffer, a string can contain extents in it. These extents are | |
| 94 created when a function such as @code{buffer-substring} is called on a | |
| 95 region with duplicable extents in it. When the string is inserted into | |
| 96 a buffer, the extents are inserted along with it. @xref{Duplicable | |
| 97 Extents}. | |
| 98 | |
| 99 @xref{Text}, for information about functions that display strings or | |
| 100 copy them into buffers. @xref{Character Type}, and @ref{String Type}, | |
| 101 for information about the syntax of characters and strings. | |
| 102 | |
| 103 @node Predicates for Strings | |
| 104 @section The Predicates for Strings | |
| 105 | |
| 106 For more information about general sequence and array predicates, | |
| 107 see @ref{Sequences Arrays Vectors}, and @ref{Arrays}. | |
| 108 | |
| 109 @defun stringp object | |
| 110 This function returns @code{t} if @var{object} is a string, @code{nil} | |
| 111 otherwise. | |
| 112 @end defun | |
| 113 | |
| 114 @defun char-or-string-p object | |
| 115 This function returns @code{t} if @var{object} is a string or a | |
| 116 character, @code{nil} otherwise. | |
| 117 | |
| 118 In XEmacs addition, this function also returns @code{t} if @var{object} | |
| 119 is an integer that can be represented as a character. This is because | |
| 120 of compatibility with previous XEmacs and should not be depended on. | |
| 121 @end defun | |
| 122 | |
| 123 @node Creating Strings | |
| 124 @section Creating Strings | |
| 125 | |
| 126 The following functions create strings, either from scratch, or by | |
| 127 putting strings together, or by taking them apart. | |
| 128 | |
| 129 @defun string &rest characters | |
| 130 This function returns a new string made up of @var{characters}. | |
| 131 | |
| 132 @example | |
| 133 (string ?X ?E ?m ?a ?c ?s) | |
| 134 @result{} "XEmacs" | |
| 135 (string) | |
| 136 @result{} "" | |
| 137 @end example | |
| 138 | |
| 139 Analogous functions operating on other data types include @code{list}, | |
| 140 @code{cons} (@pxref{Building Lists}), @code{vector} (@pxref{Vectors}) | |
| 444 | 141 and @code{bit-vector} (@pxref{Bit Vectors}). This function has not been |
| 428 | 142 available in XEmacs prior to 21.0 and FSF Emacs prior to 20.3. |
| 143 @end defun | |
| 144 | |
| 444 | 145 @defun make-string length character |
| 146 This function returns a new string consisting entirely of @var{length} | |
| 147 successive copies of @var{character}. @var{length} must be a | |
|
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148 non-negative fixnum. |
| 428 | 149 |
| 150 @example | |
| 151 (make-string 5 ?x) | |
| 152 @result{} "xxxxx" | |
| 153 (make-string 0 ?x) | |
| 154 @result{} "" | |
| 155 @end example | |
| 156 | |
| 157 Other functions to compare with this one include @code{char-to-string} | |
| 158 (@pxref{String Conversion}), @code{make-vector} (@pxref{Vectors}), and | |
| 159 @code{make-list} (@pxref{Building Lists}). | |
| 160 @end defun | |
| 161 | |
| 162 @defun substring string start &optional end | |
| 163 This function returns a new string which consists of those characters | |
| 164 from @var{string} in the range from (and including) the character at the | |
| 165 index @var{start} up to (but excluding) the character at the index | |
| 166 @var{end}. The first character is at index zero. | |
| 167 | |
|
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168 In this implementation, @code{substring} is an alias for @code{subseq}, |
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169 so @var{string} can be any sequence. In GNU Emacs, @var{string} can be |
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170 a string or a vector, and in older XEmacs it can only be a string. |
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171 |
| 428 | 172 @example |
| 173 @group | |
| 174 (substring "abcdefg" 0 3) | |
| 175 @result{} "abc" | |
| 176 @end group | |
| 177 @end example | |
| 178 | |
| 179 @noindent | |
| 180 Here the index for @samp{a} is 0, the index for @samp{b} is 1, and the | |
| 181 index for @samp{c} is 2. Thus, three letters, @samp{abc}, are copied | |
| 182 from the string @code{"abcdefg"}. The index 3 marks the character | |
| 183 position up to which the substring is copied. The character whose index | |
| 184 is 3 is actually the fourth character in the string. | |
| 185 | |
| 186 A negative number counts from the end of the string, so that @minus{}1 | |
| 444 | 187 signifies the index of the last character of the string. For example: |
| 428 | 188 |
| 189 @example | |
| 190 @group | |
| 191 (substring "abcdefg" -3 -1) | |
| 192 @result{} "ef" | |
| 193 @end group | |
| 194 @end example | |
| 195 | |
| 196 @noindent | |
| 197 In this example, the index for @samp{e} is @minus{}3, the index for | |
| 198 @samp{f} is @minus{}2, and the index for @samp{g} is @minus{}1. | |
| 199 Therefore, @samp{e} and @samp{f} are included, and @samp{g} is excluded. | |
| 200 | |
| 201 When @code{nil} is used as an index, it stands for the length of the | |
| 202 string. Thus, | |
| 203 | |
| 204 @example | |
| 205 @group | |
| 206 (substring "abcdefg" -3 nil) | |
| 207 @result{} "efg" | |
| 208 @end group | |
| 209 @end example | |
| 210 | |
| 211 Omitting the argument @var{end} is equivalent to specifying @code{nil}. | |
| 212 It follows that @code{(substring @var{string} 0)} returns a copy of all | |
| 213 of @var{string}. | |
| 214 | |
| 215 @example | |
| 216 @group | |
| 217 (substring "abcdefg" 0) | |
| 218 @result{} "abcdefg" | |
| 219 @end group | |
| 220 @end example | |
| 221 | |
| 222 @noindent | |
| 223 But we recommend @code{copy-sequence} for this purpose (@pxref{Sequence | |
| 224 Functions}). | |
| 225 | |
| 226 If the characters copied from @var{string} have duplicable extents or | |
| 227 text properties, those are copied into the new string also. | |
| 228 @xref{Duplicable Extents}. | |
| 229 | |
| 230 A @code{wrong-type-argument} error is signaled if either @var{start} or | |
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231 @var{end} is not a fixnum or @code{nil}. An @code{args-out-of-range} |
| 428 | 232 error is signaled if @var{start} indicates a character following |
| 233 @var{end}, or if either integer is out of range for @var{string}. | |
| 234 | |
| 235 Contrast this function with @code{buffer-substring} (@pxref{Buffer | |
| 236 Contents}), which returns a string containing a portion of the text in | |
| 237 the current buffer. The beginning of a string is at index 0, but the | |
| 238 beginning of a buffer is at index 1. | |
| 239 @end defun | |
| 240 | |
| 241 @defun concat &rest sequences | |
| 242 @cindex copying strings | |
| 243 @cindex concatenating strings | |
| 244 This function returns a new string consisting of the characters in the | |
| 245 arguments passed to it (along with their text properties, if any). The | |
| 246 arguments may be strings, lists of numbers, or vectors of numbers; they | |
| 247 are not themselves changed. If @code{concat} receives no arguments, it | |
| 248 returns an empty string. | |
| 249 | |
| 250 @example | |
| 251 (concat "abc" "-def") | |
| 252 @result{} "abc-def" | |
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253 (equal (concat "abc" (list 120 (+ 256 121)) [122]) (format "abcx%cz" 377)) |
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254 @result{} t |
| 428 | 255 ;; @r{@code{nil} is an empty sequence.} |
| 256 (concat "abc" nil "-def") | |
| 257 @result{} "abc-def" | |
| 258 (concat "The " "quick brown " "fox.") | |
| 259 @result{} "The quick brown fox." | |
| 260 (concat) | |
| 261 @result{} "" | |
| 262 @end example | |
| 263 | |
| 264 @noindent | |
| 265 The @code{concat} function always constructs a new string that is | |
| 266 not @code{eq} to any existing string. | |
| 267 | |
| 268 For information about other concatenation functions, see the description | |
| 269 of @code{mapconcat} in @ref{Mapping Functions}, @code{vconcat} in | |
| 270 @ref{Vectors}, @code{bvconcat} in @ref{Bit Vectors}, and @code{append} | |
| 271 in @ref{Building Lists}. | |
| 272 @end defun | |
| 273 | |
| 1495 | 274 The function @code{split-string}, in @ref{Regexp Search}, generates a |
| 275 list of strings by splitting a string on occurances of a regular | |
| 276 expression. | |
| 277 | |
| 428 | 278 @node Predicates for Characters |
| 279 @section The Predicates for Characters | |
| 280 | |
| 281 @defun characterp object | |
| 282 This function returns @code{t} if @var{object} is a character. | |
| 283 | |
| 284 Some functions that work on integers (e.g. the comparison functions | |
| 285 <, <=, =, /=, etc. and the arithmetic functions +, -, *, etc.) | |
| 286 accept characters and implicitly convert them into integers. In | |
| 287 general, functions that work on characters also accept char-ints and | |
| 288 implicitly convert them into characters. WARNING: Neither of these | |
| 289 behaviors is very desirable, and they are maintained for backward | |
| 290 compatibility with old E-Lisp programs that confounded characters and | |
| 291 integers willy-nilly. These behaviors may change in the future; therefore, | |
| 292 do not rely on them. Instead, convert the characters explicitly | |
| 293 using @code{char-int}. | |
| 294 @end defun | |
| 295 | |
| 296 @defun integer-or-char-p object | |
| 297 This function returns @code{t} if @var{object} is an integer or character. | |
| 298 @end defun | |
| 299 | |
| 300 @node Character Codes | |
| 301 @section Character Codes | |
| 302 | |
| 444 | 303 @defun char-int character |
| 428 | 304 This function converts a character into an equivalent integer. |
| 305 The resulting integer will always be non-negative. The integers in | |
| 306 the range 0 - 255 map to characters as follows: | |
| 307 | |
| 308 @table @asis | |
| 309 @item 0 - 31 | |
| 310 Control set 0 | |
| 311 @item 32 - 127 | |
| 312 @sc{ascii} | |
| 313 @item 128 - 159 | |
| 314 Control set 1 | |
| 315 @item 160 - 255 | |
| 316 Right half of ISO-8859-1 | |
| 317 @end table | |
| 318 | |
| 319 If support for @sc{mule} does not exist, these are the only valid | |
| 320 character values. When @sc{mule} support exists, the values assigned to | |
| 321 other characters may vary depending on the particular version of XEmacs, | |
| 322 the order in which character sets were loaded, etc., and you should not | |
| 323 depend on them. | |
| 324 @end defun | |
| 325 | |
| 326 @defun int-char integer | |
| 327 This function converts an integer into the equivalent character. Not | |
| 328 all integers correspond to valid characters; use @code{char-int-p} to | |
| 329 determine whether this is the case. If the integer cannot be converted, | |
| 330 @code{nil} is returned. | |
| 331 @end defun | |
| 332 | |
| 333 @defun char-int-p object | |
| 334 This function returns @code{t} if @var{object} is an integer that can be | |
| 335 converted into a character. | |
| 336 @end defun | |
| 337 | |
| 338 @defun char-or-char-int-p object | |
| 339 This function returns @code{t} if @var{object} is a character or an | |
| 340 integer that can be converted into one. | |
| 341 @end defun | |
| 342 | |
| 343 @need 2000 | |
| 344 @node Text Comparison | |
| 345 @section Comparison of Characters and Strings | |
| 346 @cindex string equality | |
| 347 | |
| 444 | 348 @defun char-equal character1 character2 &optional buffer |
| 428 | 349 This function returns @code{t} if the arguments represent the same |
| 350 character, @code{nil} otherwise. This function ignores differences | |
| 444 | 351 in case if the value of @code{case-fold-search} is non-@code{nil} in |
| 352 @var{buffer}, which defaults to the current buffer. | |
| 428 | 353 |
| 354 @example | |
| 355 (char-equal ?x ?x) | |
| 356 @result{} t | |
| 357 (let ((case-fold-search t)) | |
| 358 (char-equal ?x ?X)) | |
| 359 @result{} t | |
| 360 (let ((case-fold-search nil)) | |
| 361 (char-equal ?x ?X)) | |
| 362 @result{} nil | |
| 363 @end example | |
| 364 @end defun | |
| 365 | |
| 366 @defun char= character1 character2 | |
| 367 This function returns @code{t} if the arguments represent the same | |
| 368 character, @code{nil} otherwise. Case is significant. | |
| 369 | |
| 370 @example | |
| 371 (char= ?x ?x) | |
| 372 @result{} t | |
| 373 (char= ?x ?X) | |
| 374 @result{} nil | |
| 375 (let ((case-fold-search t)) | |
| 376 (char-equal ?x ?X)) | |
| 377 @result{} nil | |
| 378 (let ((case-fold-search nil)) | |
| 379 (char-equal ?x ?X)) | |
| 380 @result{} nil | |
| 381 @end example | |
| 382 @end defun | |
| 383 | |
| 384 @defun string= string1 string2 | |
| 385 This function returns @code{t} if the characters of the two strings | |
| 386 match exactly; case is significant. | |
| 387 | |
| 388 @example | |
| 389 (string= "abc" "abc") | |
| 390 @result{} t | |
| 391 (string= "abc" "ABC") | |
| 392 @result{} nil | |
| 393 (string= "ab" "ABC") | |
| 394 @result{} nil | |
| 395 @end example | |
| 396 | |
| 397 @ignore @c `equal' in XEmacs does not compare text properties | |
| 398 The function @code{string=} ignores the text properties of the | |
| 399 two strings. To compare strings in a way that compares their text | |
| 400 properties also, use @code{equal} (@pxref{Equality Predicates}). | |
| 401 @end ignore | |
| 402 @end defun | |
| 403 | |
| 404 @defun string-equal string1 string2 | |
| 405 @code{string-equal} is another name for @code{string=}. | |
| 406 @end defun | |
| 407 | |
| 408 @cindex lexical comparison | |
| 409 @defun string< string1 string2 | |
| 410 @c (findex string< causes problems for permuted index!!) | |
| 411 This function compares two strings a character at a time. First it | |
| 412 scans both the strings at once to find the first pair of corresponding | |
| 413 characters that do not match. If the lesser character of those two is | |
| 414 the character from @var{string1}, then @var{string1} is less, and this | |
| 415 function returns @code{t}. If the lesser character is the one from | |
| 416 @var{string2}, then @var{string1} is greater, and this function returns | |
| 417 @code{nil}. If the two strings match entirely, the value is @code{nil}. | |
| 418 | |
| 419 Pairs of characters are compared by their @sc{ascii} codes. Keep in | |
| 420 mind that lower case letters have higher numeric values in the | |
| 421 @sc{ascii} character set than their upper case counterparts; numbers and | |
| 422 many punctuation characters have a lower numeric value than upper case | |
| 423 letters. | |
| 424 | |
| 425 @example | |
| 426 @group | |
| 427 (string< "abc" "abd") | |
| 428 @result{} t | |
| 429 (string< "abd" "abc") | |
| 430 @result{} nil | |
| 431 (string< "123" "abc") | |
| 432 @result{} t | |
| 433 @end group | |
| 434 @end example | |
| 435 | |
| 436 When the strings have different lengths, and they match up to the | |
| 437 length of @var{string1}, then the result is @code{t}. If they match up | |
| 438 to the length of @var{string2}, the result is @code{nil}. A string of | |
| 439 no characters is less than any other string. | |
| 440 | |
| 441 @example | |
| 442 @group | |
| 443 (string< "" "abc") | |
| 444 @result{} t | |
| 445 (string< "ab" "abc") | |
| 446 @result{} t | |
| 447 (string< "abc" "") | |
| 448 @result{} nil | |
| 449 (string< "abc" "ab") | |
| 450 @result{} nil | |
| 451 (string< "" "") | |
| 444 | 452 @result{} nil |
| 428 | 453 @end group |
| 454 @end example | |
| 455 @end defun | |
| 456 | |
| 457 @defun string-lessp string1 string2 | |
| 458 @code{string-lessp} is another name for @code{string<}. | |
| 459 @end defun | |
| 460 | |
| 461 See also @code{compare-buffer-substrings} in @ref{Comparing Text}, for | |
| 462 a way to compare text in buffers. The function @code{string-match}, | |
| 463 which matches a regular expression against a string, can be used | |
| 464 for a kind of string comparison; see @ref{Regexp Search}. | |
| 465 | |
| 466 @node String Conversion | |
| 467 @section Conversion of Characters and Strings | |
| 468 @cindex conversion of strings | |
| 469 | |
| 470 This section describes functions for conversions between characters, | |
| 471 strings and integers. @code{format} and @code{prin1-to-string} | |
| 472 (@pxref{Output Functions}) can also convert Lisp objects into strings. | |
| 473 @code{read-from-string} (@pxref{Input Functions}) can ``convert'' a | |
| 474 string representation of a Lisp object into an object. | |
| 475 | |
| 476 @xref{Documentation}, for functions that produce textual descriptions | |
| 477 of text characters and general input events | |
| 478 (@code{single-key-description} and @code{text-char-description}). These | |
| 479 functions are used primarily for making help messages. | |
| 480 | |
| 481 @defun char-to-string character | |
| 482 @cindex character to string | |
| 483 This function returns a new string with a length of one character. | |
| 484 The value of @var{character}, modulo 256, is used to initialize the | |
| 485 element of the string. | |
| 486 | |
| 487 This function is similar to @code{make-string} with an integer argument | |
| 488 of 1. (@xref{Creating Strings}.) This conversion can also be done with | |
| 489 @code{format} using the @samp{%c} format specification. | |
| 490 (@xref{Formatting Strings}.) | |
| 491 | |
| 492 @example | |
| 493 (char-to-string ?x) | |
| 494 @result{} "x" | |
| 495 (char-to-string (+ 256 ?x)) | |
| 496 @result{} "x" | |
| 497 (make-string 1 ?x) | |
| 498 @result{} "x" | |
| 499 @end example | |
| 500 @end defun | |
| 501 | |
| 502 @defun string-to-char string | |
| 503 @cindex string to character | |
| 504 This function returns the first character in @var{string}. If the | |
| 505 string is empty, the function returns 0. (Under XEmacs 19, the value is | |
| 506 also 0 when the first character of @var{string} is the null character, | |
| 507 @sc{ascii} code 0.) | |
| 508 | |
| 509 @example | |
| 510 (string-to-char "ABC") | |
| 511 @result{} ?A ;; @r{Under XEmacs 20.} | |
| 512 @result{} 65 ;; @r{Under XEmacs 19.} | |
| 513 (string-to-char "xyz") | |
| 514 @result{} ?x ;; @r{Under XEmacs 20.} | |
| 515 @result{} 120 ;; @r{Under XEmacs 19.} | |
| 516 (string-to-char "") | |
| 517 @result{} 0 | |
| 518 (string-to-char "\000") | |
| 519 @result{} ?\^@ ;; @r{Under XEmacs 20.} | |
| 520 @result{} 0 ;; @r{Under XEmacs 20.} | |
| 521 @end example | |
| 522 | |
| 523 This function may be eliminated in the future if it does not seem useful | |
| 524 enough to retain. | |
| 525 @end defun | |
| 526 | |
| 527 @defun number-to-string number | |
| 528 @cindex integer to string | |
| 529 @cindex integer to decimal | |
| 530 This function returns a string consisting of the printed | |
| 531 representation of @var{number}, which may be an integer or a floating | |
| 532 point number. The value starts with a sign if the argument is | |
| 533 negative. | |
| 534 | |
| 535 @example | |
| 536 (number-to-string 256) | |
| 537 @result{} "256" | |
| 538 (number-to-string -23) | |
| 539 @result{} "-23" | |
| 540 (number-to-string -23.5) | |
| 541 @result{} "-23.5" | |
| 542 @end example | |
| 543 | |
| 544 @cindex int-to-string | |
| 545 @code{int-to-string} is a semi-obsolete alias for this function. | |
| 546 | |
| 547 See also the function @code{format} in @ref{Formatting Strings}. | |
| 548 @end defun | |
| 549 | |
| 550 @defun string-to-number string &optional base | |
| 551 @cindex string to number | |
| 444 | 552 This function returns the numeric value represented by @var{string}, |
| 553 read in @var{base}. It skips spaces and tabs at the beginning of | |
| 554 @var{string}, then reads as much of @var{string} as it can interpret as | |
| 555 a number. (On some systems it ignores other whitespace at the | |
| 556 beginning, not just spaces and tabs.) If the first character after the | |
| 557 ignored whitespace is not a digit or a minus sign, this function returns | |
| 558 0. | |
| 428 | 559 |
| 560 If @var{base} is not specified, it defaults to ten. With @var{base} | |
| 561 other than ten, only integers can be read. | |
| 562 | |
| 563 @example | |
| 564 (string-to-number "256") | |
| 565 @result{} 256 | |
| 566 (string-to-number "25 is a perfect square.") | |
| 567 @result{} 25 | |
| 568 (string-to-number "X256") | |
| 569 @result{} 0 | |
| 570 (string-to-number "-4.5") | |
| 571 @result{} -4.5 | |
| 572 (string-to-number "ffff" 16) | |
| 573 @result{} 65535 | |
| 574 @end example | |
| 575 | |
| 576 @findex string-to-int | |
| 577 @code{string-to-int} is an obsolete alias for this function. | |
| 578 @end defun | |
| 579 | |
| 580 @node Modifying Strings | |
| 581 @section Modifying Strings | |
| 582 @cindex strings, modifying | |
| 583 | |
| 584 You can modify a string using the general array-modifying primitives. | |
| 585 @xref{Arrays}. The function @code{aset} modifies a single character; | |
| 586 the function @code{fillarray} sets all characters in the string to | |
| 587 a specified character. | |
| 588 | |
| 589 Each string has a tick counter that starts out at zero (when the string | |
| 590 is created) and is incremented each time a change is made to that | |
| 591 string. | |
| 592 | |
| 593 @defun string-modified-tick string | |
| 594 This function returns the tick counter for @samp{string}. | |
| 595 @end defun | |
| 596 | |
| 597 @node String Properties | |
| 598 @section String Properties | |
| 599 @cindex string properties | |
| 600 @cindex properties of strings | |
| 601 | |
| 442 | 602 Just as with symbols, extents, faces, and glyphs, you can attach |
| 428 | 603 additional information to strings in the form of @dfn{string |
| 604 properties}. These differ from text properties, which are logically | |
| 605 attached to particular characters in the string. | |
| 606 | |
| 607 To attach a property to a string, use @code{put}. To retrieve a property | |
| 608 from a string, use @code{get}. You can also use @code{remprop} to remove | |
| 442 | 609 a property from a string and @code{object-plist} to retrieve a list of |
| 428 | 610 all the properties in a string. |
| 611 | |
| 612 @node Formatting Strings | |
| 613 @section Formatting Strings | |
| 614 @cindex formatting strings | |
| 615 @cindex strings, formatting them | |
| 616 | |
| 617 @dfn{Formatting} means constructing a string by substitution of | |
| 618 computed values at various places in a constant string. This string | |
| 619 controls how the other values are printed as well as where they appear; | |
| 620 it is called a @dfn{format string}. | |
| 621 | |
| 622 Formatting is often useful for computing messages to be displayed. In | |
| 623 fact, the functions @code{message} and @code{error} provide the same | |
| 624 formatting feature described here; they differ from @code{format} only | |
| 625 in how they use the result of formatting. | |
| 626 | |
| 627 @defun format string &rest objects | |
| 628 This function returns a new string that is made by copying | |
| 444 | 629 @var{string} and then replacing any format specification |
| 428 | 630 in the copy with encodings of the corresponding @var{objects}. The |
| 631 arguments @var{objects} are the computed values to be formatted. | |
| 632 @end defun | |
| 633 | |
| 634 @cindex @samp{%} in format | |
| 635 @cindex format specification | |
| 636 A format specification is a sequence of characters beginning with a | |
| 637 @samp{%}. Thus, if there is a @samp{%d} in @var{string}, the | |
| 638 @code{format} function replaces it with the printed representation of | |
| 639 one of the values to be formatted (one of the arguments @var{objects}). | |
| 640 For example: | |
| 641 | |
| 642 @example | |
| 643 @group | |
| 644 (format "The value of fill-column is %d." fill-column) | |
| 645 @result{} "The value of fill-column is 72." | |
| 646 @end group | |
| 647 @end example | |
| 648 | |
| 649 If @var{string} contains more than one format specification, the | |
| 650 format specifications correspond with successive values from | |
| 651 @var{objects}. Thus, the first format specification in @var{string} | |
| 652 uses the first such value, the second format specification uses the | |
| 653 second such value, and so on. Any extra format specifications (those | |
| 654 for which there are no corresponding values) cause unpredictable | |
| 655 behavior. Any extra values to be formatted are ignored. | |
| 656 | |
| 657 Certain format specifications require values of particular types. | |
| 658 However, no error is signaled if the value actually supplied fails to | |
| 659 have the expected type. Instead, the output is likely to be | |
| 660 meaningless. | |
| 661 | |
| 662 Here is a table of valid format specifications: | |
| 663 | |
| 664 @table @samp | |
| 665 @item %s | |
| 666 Replace the specification with the printed representation of the object, | |
| 667 made without quoting. Thus, strings are represented by their contents | |
| 668 alone, with no @samp{"} characters, and symbols appear without @samp{\} | |
| 669 characters. This is equivalent to printing the object with @code{princ}. | |
| 670 | |
| 671 If there is no corresponding object, the empty string is used. | |
| 672 | |
| 673 @item %S | |
| 674 Replace the specification with the printed representation of the object, | |
| 675 made with quoting. Thus, strings are enclosed in @samp{"} characters, | |
| 676 and @samp{\} characters appear where necessary before special characters. | |
| 677 This is equivalent to printing the object with @code{prin1}. | |
| 678 | |
| 679 If there is no corresponding object, the empty string is used. | |
| 680 | |
| 681 @item %o | |
| 682 @cindex integer to octal | |
| 683 Replace the specification with the base-eight representation of an | |
| 684 integer. | |
| 685 | |
| 686 @item %d | |
| 687 @itemx %i | |
| 688 Replace the specification with the base-ten representation of an | |
| 689 integer. | |
| 690 | |
| 691 @item %x | |
| 692 @cindex integer to hexadecimal | |
| 693 Replace the specification with the base-sixteen representation of an | |
| 694 integer, using lowercase letters. | |
| 695 | |
| 696 @item %X | |
| 697 @cindex integer to hexadecimal | |
| 698 Replace the specification with the base-sixteen representation of an | |
| 699 integer, using uppercase letters. | |
| 700 | |
|
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701 @item %b |
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702 @cindex integer to binary |
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703 Replace the specification with the base-two representation of an |
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704 integer. |
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705 |
| 428 | 706 @item %c |
| 707 Replace the specification with the character which is the value given. | |
| 708 | |
| 709 @item %e | |
| 710 Replace the specification with the exponential notation for a floating | |
| 711 point number (e.g. @samp{7.85200e+03}). | |
| 712 | |
| 713 @item %f | |
| 714 Replace the specification with the decimal-point notation for a floating | |
| 715 point number. | |
| 716 | |
| 717 @item %g | |
| 718 Replace the specification with notation for a floating point number, | |
| 719 using a ``pretty format''. Either exponential notation or decimal-point | |
| 720 notation will be used (usually whichever is shorter), and trailing | |
| 721 zeroes are removed from the fractional part. | |
| 722 | |
| 723 @item %% | |
| 724 A single @samp{%} is placed in the string. This format specification is | |
| 725 unusual in that it does not use a value. For example, @code{(format "%% | |
| 726 %d" 30)} returns @code{"% 30"}. | |
| 727 @end table | |
| 728 | |
| 729 Any other format character results in an @samp{Invalid format | |
| 730 operation} error. | |
| 731 | |
| 732 Here are several examples: | |
| 733 | |
| 734 @example | |
| 735 @group | |
| 736 (format "The name of this buffer is %s." (buffer-name)) | |
| 737 @result{} "The name of this buffer is strings.texi." | |
| 738 | |
| 739 (format "The buffer object prints as %s." (current-buffer)) | |
| 740 @result{} "The buffer object prints as #<buffer strings.texi>." | |
| 741 | |
| 444 | 742 (format "The octal value of %d is %o, |
| 428 | 743 and the hex value is %x." 18 18 18) |
| 444 | 744 @result{} "The octal value of 18 is 22, |
| 428 | 745 and the hex value is 12." |
| 746 @end group | |
| 747 @end example | |
| 748 | |
| 749 There are many additional flags and specifications that can occur | |
| 750 between the @samp{%} and the format character, in the following order: | |
| 751 | |
| 752 @enumerate | |
| 753 @item | |
| 754 An optional repositioning specification, which is a positive | |
| 755 integer followed by a @samp{$}. | |
| 756 | |
| 757 @item | |
| 758 Zero or more of the optional flag characters @samp{-}, @samp{+}, | |
| 759 @samp{ }, @samp{0}, and @samp{#}. | |
| 760 | |
| 761 @item | |
| 762 An asterisk (@samp{*}, meaning that the field width is now assumed to | |
| 763 have been specified as an argument. | |
| 764 | |
| 765 @item | |
| 766 An optional minimum field width. | |
| 767 | |
| 768 @item | |
| 769 An optional precision, preceded by a @samp{.} character. | |
| 770 @end enumerate | |
| 771 | |
| 772 @cindex repositioning format arguments | |
| 773 @cindex multilingual string formatting | |
| 774 A @dfn{repositioning} specification changes which argument to | |
| 775 @code{format} is used by the current and all following format | |
| 776 specifications. Normally the first specification uses the first | |
| 777 argument, the second specification uses the second argument, etc. Using | |
| 778 a repositioning specification, you can change this. By placing a number | |
| 444 | 779 @var{n} followed by a @samp{$} between the @samp{%} and the format |
| 780 character, you cause the specification to use the @var{n}th argument. | |
| 781 The next specification will use the @var{n}+1'th argument, etc. | |
| 428 | 782 |
| 783 For example: | |
| 784 | |
| 785 @example | |
| 786 @group | |
| 787 (format "Can't find file `%s' in directory `%s'." | |
| 788 "ignatius.c" "loyola/") | |
| 789 @result{} "Can't find file `ignatius.c' in directory `loyola/'." | |
| 790 | |
| 791 (format "In directory `%2$s', the file `%1$s' was not found." | |
| 792 "ignatius.c" "loyola/") | |
| 793 @result{} "In directory `loyola/', the file `ignatius.c' was not found." | |
| 794 | |
| 795 (format | |
| 796 "The numbers %d and %d are %1$x and %x in hex and %1$o and %o in octal." | |
| 797 37 12) | |
| 798 @result{} "The numbers 37 and 12 are 25 and c in hex and 45 and 14 in octal." | |
| 799 @end group | |
| 800 @end example | |
| 801 | |
| 802 As you can see, this lets you reprocess arguments more than once or | |
| 803 reword a format specification (thereby moving the arguments around) | |
| 804 without having to actually reorder the arguments. This is especially | |
| 805 useful in translating messages from one language to another: Different | |
| 806 languages use different word orders, and this sometimes entails changing | |
| 807 the order of the arguments. By using repositioning specifications, | |
| 808 this can be accomplished without having to embed knowledge of particular | |
| 809 languages into the location in the program's code where the message is | |
| 810 displayed. | |
| 811 | |
| 812 @cindex numeric prefix | |
| 813 @cindex field width | |
| 814 @cindex padding | |
| 815 All the specification characters allow an optional numeric prefix | |
| 816 between the @samp{%} and the character, and following any repositioning | |
| 817 specification or flag. The optional numeric prefix defines the minimum | |
| 818 width for the object. If the printed representation of the object | |
| 819 contains fewer characters than this, then it is padded. The padding is | |
| 820 normally on the left, but will be on the right if the @samp{-} flag | |
| 821 character is given. The padding character is normally a space, but if | |
| 822 the @samp{0} flag character is given, zeros are used for padding. | |
| 823 | |
| 824 @example | |
| 825 (format "%06d is padded on the left with zeros" 123) | |
| 826 @result{} "000123 is padded on the left with zeros" | |
| 827 | |
| 828 (format "%-6d is padded on the right" 123) | |
| 829 @result{} "123 is padded on the right" | |
| 830 @end example | |
| 831 | |
| 832 @code{format} never truncates an object's printed representation, no | |
| 833 matter what width you specify. Thus, you can use a numeric prefix to | |
| 834 specify a minimum spacing between columns with no risk of losing | |
| 835 information. | |
| 836 | |
| 837 In the following three examples, @samp{%7s} specifies a minimum width | |
| 838 of 7. In the first case, the string inserted in place of @samp{%7s} has | |
| 839 only 3 letters, so 4 blank spaces are inserted for padding. In the | |
| 840 second case, the string @code{"specification"} is 13 letters wide but is | |
| 841 not truncated. In the third case, the padding is on the right. | |
| 842 | |
| 444 | 843 @smallexample |
| 428 | 844 @group |
| 845 (format "The word `%7s' actually has %d letters in it." | |
| 846 "foo" (length "foo")) | |
| 444 | 847 @result{} "The word ` foo' actually has 3 letters in it." |
| 428 | 848 @end group |
| 849 | |
| 850 @group | |
| 851 (format "The word `%7s' actually has %d letters in it." | |
| 444 | 852 "specification" (length "specification")) |
| 853 @result{} "The word `specification' actually has 13 letters in it." | |
| 428 | 854 @end group |
| 855 | |
| 856 @group | |
| 857 (format "The word `%-7s' actually has %d letters in it." | |
| 858 "foo" (length "foo")) | |
| 444 | 859 @result{} "The word `foo ' actually has 3 letters in it." |
| 428 | 860 @end group |
| 861 @end smallexample | |
| 862 | |
| 863 @cindex format precision | |
| 864 @cindex precision of formatted numbers | |
| 865 After any minimum field width, a precision may be specified by | |
| 866 preceding it with a @samp{.} character. The precision specifies the | |
| 867 minimum number of digits to appear in @samp{%d}, @samp{%i}, @samp{%o}, | |
| 868 @samp{%x}, and @samp{%X} conversions (the number is padded on the left | |
| 869 with zeroes as necessary); the number of digits printed after the | |
| 870 decimal point for @samp{%f}, @samp{%e}, and @samp{%E} conversions; the | |
| 871 number of significant digits printed in @samp{%g} and @samp{%G} | |
| 872 conversions; and the maximum number of non-padding characters printed in | |
| 873 @samp{%s} and @samp{%S} conversions. The default precision for | |
| 874 floating-point conversions is six. | |
| 875 | |
| 876 The other flag characters have the following meanings: | |
| 877 | |
| 878 @itemize @bullet | |
| 879 @item | |
| 880 The @samp{ } flag means prefix non-negative numbers with a space. | |
| 881 | |
| 882 @item | |
| 883 The @samp{+} flag means prefix non-negative numbers with a plus sign. | |
| 884 | |
| 885 @item | |
| 886 The @samp{#} flag means print numbers in an alternate, more verbose | |
| 887 format: octal numbers begin with zero; hex numbers begin with a | |
| 888 @samp{0x} or @samp{0X}; a decimal point is printed in @samp{%f}, | |
| 889 @samp{%e}, and @samp{%E} conversions even if no numbers are printed | |
| 890 after it; and trailing zeroes are not omitted in @samp{%g} and @samp{%G} | |
| 891 conversions. | |
| 892 @end itemize | |
| 893 | |
| 894 @node Character Case | |
| 895 @section Character Case | |
| 444 | 896 @cindex upper case |
| 897 @cindex lower case | |
| 898 @cindex character case | |
| 428 | 899 |
| 900 The character case functions change the case of single characters or | |
| 901 of the contents of strings. The functions convert only alphabetic | |
| 902 characters (the letters @samp{A} through @samp{Z} and @samp{a} through | |
| 903 @samp{z}); other characters are not altered. The functions do not | |
| 904 modify the strings that are passed to them as arguments. | |
| 905 | |
| 906 The examples below use the characters @samp{X} and @samp{x} which have | |
| 907 @sc{ascii} codes 88 and 120 respectively. | |
| 908 | |
| 444 | 909 @defun downcase string-or-char &optional buffer |
| 428 | 910 This function converts a character or a string to lower case. |
| 911 | |
| 912 When the argument to @code{downcase} is a string, the function creates | |
| 913 and returns a new string in which each letter in the argument that is | |
| 914 upper case is converted to lower case. When the argument to | |
| 915 @code{downcase} is a character, @code{downcase} returns the | |
| 916 corresponding lower case character. (This value is actually an integer | |
| 917 under XEmacs 19.) If the original character is lower case, or is not a | |
| 918 letter, then the value equals the original character. | |
| 919 | |
| 444 | 920 Optional second arg @var{buffer} specifies which buffer's case tables to |
| 921 use, and defaults to the current buffer. | |
| 922 | |
| 428 | 923 @example |
| 924 (downcase "The cat in the hat") | |
| 925 @result{} "the cat in the hat" | |
| 926 | |
| 927 (downcase ?X) | |
| 928 @result{} ?x ;; @r{Under XEmacs 20.} | |
| 929 @result{} 120 ;; @r{Under XEmacs 19.} | |
| 930 | |
| 931 @end example | |
| 932 @end defun | |
| 933 | |
| 444 | 934 @defun upcase string-or-char &optional buffer |
| 428 | 935 This function converts a character or a string to upper case. |
| 936 | |
| 937 When the argument to @code{upcase} is a string, the function creates | |
| 938 and returns a new string in which each letter in the argument that is | |
| 939 lower case is converted to upper case. | |
| 940 | |
| 941 When the argument to @code{upcase} is a character, @code{upcase} returns | |
| 942 the corresponding upper case character. (This value is actually an | |
| 943 integer under XEmacs 19.) If the original character is upper case, or | |
| 944 is not a letter, then the value equals the original character. | |
| 945 | |
| 444 | 946 Optional second arg @var{buffer} specifies which buffer's case tables to |
| 947 use, and defaults to the current buffer. | |
| 948 | |
| 428 | 949 @example |
| 950 (upcase "The cat in the hat") | |
| 951 @result{} "THE CAT IN THE HAT" | |
| 952 | |
| 953 (upcase ?x) | |
| 954 @result{} ?X ;; @r{Under XEmacs 20.} | |
| 955 @result{} 88 ;; @r{Under XEmacs 19.} | |
| 956 @end example | |
| 957 @end defun | |
| 958 | |
| 444 | 959 @defun capitalize string-or-char &optional buffer |
| 428 | 960 @cindex capitalization |
| 961 This function capitalizes strings or characters. If | |
| 962 @var{string-or-char} is a string, the function creates and returns a new | |
| 963 string, whose contents are a copy of @var{string-or-char} in which each | |
| 964 word has been capitalized. This means that the first character of each | |
| 965 word is converted to upper case, and the rest are converted to lower | |
| 966 case. | |
| 967 | |
| 968 The definition of a word is any sequence of consecutive characters that | |
| 969 are assigned to the word constituent syntax class in the current syntax | |
| 970 table (@pxref{Syntax Class Table}). | |
| 971 | |
| 972 When the argument to @code{capitalize} is a character, @code{capitalize} | |
| 973 has the same result as @code{upcase}. | |
| 974 | |
| 444 | 975 Optional second arg @var{buffer} specifies which buffer's case tables to |
| 976 use, and defaults to the current buffer. | |
| 977 | |
| 428 | 978 @example |
| 979 (capitalize "The cat in the hat") | |
| 980 @result{} "The Cat In The Hat" | |
| 981 | |
| 982 (capitalize "THE 77TH-HATTED CAT") | |
| 983 @result{} "The 77th-Hatted Cat" | |
| 984 | |
| 985 @group | |
| 986 (capitalize ?x) | |
| 987 @result{} ?X ;; @r{Under XEmacs 20.} | |
| 988 @result{} 88 ;; @r{Under XEmacs 19.} | |
| 989 @end group | |
| 990 @end example | |
| 991 @end defun | |
| 992 | |
| 993 @node Case Tables | |
| 994 @section The Case Table | |
| 995 | |
| 996 You can customize case conversion by installing a special @dfn{case | |
| 997 table}. A case table specifies the mapping between upper case and lower | |
| 998 case letters. It affects both the string and character case conversion | |
| 999 functions (see the previous section) and those that apply to text in the | |
| 1000 buffer (@pxref{Case Changes}). You need a case table if you are using a | |
| 1001 language which has letters other than the standard @sc{ascii} letters. | |
| 1002 | |
| 1003 A case table is a list of this form: | |
| 1004 | |
| 1005 @example | |
| 1006 (@var{downcase} @var{upcase} @var{canonicalize} @var{equivalences}) | |
| 1007 @end example | |
| 1008 | |
| 1009 @noindent | |
| 1010 where each element is either @code{nil} or a string of length 256. The | |
| 1011 element @var{downcase} says how to map each character to its lower-case | |
| 1012 equivalent. The element @var{upcase} maps each character to its | |
| 1013 upper-case equivalent. If lower and upper case characters are in | |
| 1014 one-to-one correspondence, use @code{nil} for @var{upcase}; then XEmacs | |
| 1015 deduces the upcase table from @var{downcase}. | |
| 1016 | |
| 1017 For some languages, upper and lower case letters are not in one-to-one | |
| 1018 correspondence. There may be two different lower case letters with the | |
| 1019 same upper case equivalent. In these cases, you need to specify the | |
| 1020 maps for both directions. | |
| 1021 | |
| 1022 The element @var{canonicalize} maps each character to a canonical | |
| 1023 equivalent; any two characters that are related by case-conversion have | |
| 1024 the same canonical equivalent character. | |
| 1025 | |
| 1026 The element @var{equivalences} is a map that cyclicly permutes each | |
| 1027 equivalence class (of characters with the same canonical equivalent). | |
| 1028 (For ordinary @sc{ascii}, this would map @samp{a} into @samp{A} and | |
| 1029 @samp{A} into @samp{a}, and likewise for each set of equivalent | |
| 1030 characters.) | |
| 1031 | |
| 1032 When you construct a case table, you can provide @code{nil} for | |
| 1033 @var{canonicalize}; then Emacs fills in this string from @var{upcase} | |
| 1034 and @var{downcase}. You can also provide @code{nil} for | |
| 1035 @var{equivalences}; then Emacs fills in this string from | |
| 1036 @var{canonicalize}. In a case table that is actually in use, those | |
| 1037 components are non-@code{nil}. Do not try to specify @var{equivalences} | |
| 1038 without also specifying @var{canonicalize}. | |
| 1039 | |
| 1040 Each buffer has a case table. XEmacs also has a @dfn{standard case | |
| 1041 table} which is copied into each buffer when you create the buffer. | |
| 1042 Changing the standard case table doesn't affect any existing buffers. | |
| 1043 | |
| 1044 Here are the functions for working with case tables: | |
| 1045 | |
| 1046 @defun case-table-p object | |
| 1047 This predicate returns non-@code{nil} if @var{object} is a valid case | |
| 1048 table. | |
| 1049 @end defun | |
| 1050 | |
| 444 | 1051 @defun set-standard-case-table case-table |
| 1052 This function makes @var{case-table} the standard case table, so that it | |
| 1053 will apply to any buffers created subsequently. | |
| 428 | 1054 @end defun |
| 1055 | |
| 1056 @defun standard-case-table | |
| 1057 This returns the standard case table. | |
| 1058 @end defun | |
| 1059 | |
| 444 | 1060 @defun current-case-table &optional buffer |
| 1061 This function returns the case table of @var{buffer}, which defaults to | |
| 1062 the current buffer. | |
| 428 | 1063 @end defun |
| 1064 | |
| 444 | 1065 @defun set-case-table case-table |
| 1066 This sets the current buffer's case table to @var{case-table}. | |
| 428 | 1067 @end defun |
| 1068 | |
| 1069 The following three functions are convenient subroutines for packages | |
| 1070 that define non-@sc{ascii} character sets. They modify a string | |
| 1071 @var{downcase-table} provided as an argument; this should be a string to | |
| 1072 be used as the @var{downcase} part of a case table. They also modify | |
| 1073 the standard syntax table. @xref{Syntax Tables}. | |
| 1074 | |
| 1075 @defun set-case-syntax-pair uc lc downcase-table | |
| 1076 This function specifies a pair of corresponding letters, one upper case | |
| 1077 and one lower case. | |
| 1078 @end defun | |
| 1079 | |
| 1080 @defun set-case-syntax-delims l r downcase-table | |
| 1081 This function makes characters @var{l} and @var{r} a matching pair of | |
| 1082 case-invariant delimiters. | |
| 1083 @end defun | |
| 1084 | |
| 1085 @defun set-case-syntax char syntax downcase-table | |
| 1086 This function makes @var{char} case-invariant, with syntax | |
| 1087 @var{syntax}. | |
| 1088 @end defun | |
| 1089 | |
| 1090 @deffn Command describe-buffer-case-table | |
| 1091 This command displays a description of the contents of the current | |
| 1092 buffer's case table. | |
| 1093 @end deffn | |
| 1094 | |
| 1095 @cindex ISO Latin 1 | |
| 1096 @pindex iso-syntax | |
| 1097 You can load the library @file{iso-syntax} to set up the standard syntax | |
| 1098 table and define a case table for the 8-bit ISO Latin 1 character set. | |
| 1099 | |
| 1100 @node Char Tables | |
| 1101 @section The Char Table | |
| 1102 | |
| 1103 A char table is a table that maps characters (or ranges of characters) | |
| 1104 to values. Char tables are specialized for characters, only allowing | |
| 1105 particular sorts of ranges to be assigned values. Although this | |
| 1106 loses in generality, it makes for extremely fast (constant-time) | |
| 1107 lookups, and thus is feasible for applications that do an extremely | |
| 1108 large number of lookups (e.g. scanning a buffer for a character in | |
| 1109 a particular syntax, where a lookup in the syntax table must occur | |
| 1110 once per character). | |
| 1111 | |
| 1112 Note that char tables as a primitive type, and all of the functions in | |
| 1113 this section, exist only in XEmacs 20. In XEmacs 19, char tables are | |
| 1114 generally implemented using a vector of 256 elements. | |
| 1115 | |
| 1116 When @sc{mule} support exists, the types of ranges that can be assigned | |
| 1117 values are | |
| 1118 | |
| 1119 @itemize @bullet | |
| 1120 @item | |
| 1121 all characters | |
| 1122 @item | |
| 1123 an entire charset | |
| 1124 @item | |
| 1125 a single row in a two-octet charset | |
| 1126 @item | |
| 1127 a single character | |
| 1128 @end itemize | |
| 1129 | |
| 1130 When @sc{mule} support is not present, the types of ranges that can be | |
| 1131 assigned values are | |
| 1132 | |
| 1133 @itemize @bullet | |
| 1134 @item | |
| 1135 all characters | |
| 1136 @item | |
| 1137 a single character | |
| 1138 @end itemize | |
| 1139 | |
| 1140 @defun char-table-p object | |
| 1141 This function returns non-@code{nil} if @var{object} is a char table. | |
| 1142 @end defun | |
| 1143 | |
| 1144 @menu | |
| 1145 * Char Table Types:: Char tables have different uses. | |
| 1146 * Working With Char Tables:: Creating and working with char tables. | |
| 1147 @end menu | |
| 1148 | |
| 1149 @node Char Table Types | |
| 1150 @subsection Char Table Types | |
| 1151 | |
| 1152 Each char table type is used for a different purpose and allows different | |
| 1153 sorts of values. The different char table types are | |
| 1154 | |
| 1155 @table @code | |
| 1156 @item category | |
| 1157 Used for category tables, which specify the regexp categories | |
| 1158 that a character is in. The valid values are @code{nil} or a | |
| 1159 bit vector of 95 elements. Higher-level Lisp functions are | |
| 1160 provided for working with category tables. Currently categories | |
| 1161 and category tables only exist when @sc{mule} support is present. | |
| 1162 @item char | |
| 1163 A generalized char table, for mapping from one character to | |
| 1164 another. Used for case tables, syntax matching tables, | |
| 1165 @code{keyboard-translate-table}, etc. The valid values are characters. | |
| 1166 @item generic | |
| 1167 An even more generalized char table, for mapping from a | |
| 1168 character to anything. | |
| 1169 @item display | |
| 1170 Used for display tables, which specify how a particular character | |
| 1171 is to appear when displayed. #### Not yet implemented. | |
| 1172 @item syntax | |
| 1173 Used for syntax tables, which specify the syntax of a particular | |
| 1174 character. Higher-level Lisp functions are provided for | |
|
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Fix hash tables, #'member*, #'assoc*, #'eql compiler macros if bignums
Aidan Kehoe <kehoea@parhasard.net>
parents:
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|
1175 working with syntax tables. The valid values are fixnums. |
| 428 | 1176 @end table |
| 1177 | |
| 444 | 1178 @defun char-table-type char-table |
| 1179 This function returns the type of char table @var{char-table}. | |
| 428 | 1180 @end defun |
| 1181 | |
| 1182 @defun char-table-type-list | |
| 1183 This function returns a list of the recognized char table types. | |
| 1184 @end defun | |
| 1185 | |
| 1186 @defun valid-char-table-type-p type | |
| 1187 This function returns @code{t} if @var{type} if a recognized char table type. | |
| 1188 @end defun | |
| 1189 | |
| 1190 @node Working With Char Tables | |
| 1191 @subsection Working With Char Tables | |
| 1192 | |
| 1193 @defun make-char-table type | |
| 1194 This function makes a new, empty char table of type @var{type}. | |
| 1195 @var{type} should be a symbol, one of @code{char}, @code{category}, | |
| 1196 @code{display}, @code{generic}, or @code{syntax}. | |
| 1197 @end defun | |
| 1198 | |
| 444 | 1199 @defun put-char-table range value char-table |
| 1200 This function sets the value for chars in @var{range} to be @var{value} in | |
| 1201 @var{char-table}. | |
| 428 | 1202 |
| 1203 @var{range} specifies one or more characters to be affected and should be | |
| 1204 one of the following: | |
| 1205 | |
| 1206 @itemize @bullet | |
| 1207 @item | |
| 1208 @code{t} (all characters are affected) | |
| 1209 @item | |
| 1210 A charset (only allowed when @sc{mule} support is present) | |
| 1211 @item | |
| 1212 A vector of two elements: a two-octet charset and a row number | |
| 1213 (only allowed when @sc{mule} support is present) | |
| 1214 @item | |
| 1215 A single character | |
| 1216 @end itemize | |
| 1217 | |
| 444 | 1218 @var{value} must be a value appropriate for the type of @var{char-table}. |
| 428 | 1219 @end defun |
| 1220 | |
| 444 | 1221 @defun get-char-table character char-table |
| 1222 This function finds the value for @var{character} in @var{char-table}. | |
| 428 | 1223 @end defun |
| 1224 | |
| 444 | 1225 @defun get-range-char-table range char-table &optional multi |
| 1226 This function finds the value for a range in @var{char-table}. If there is | |
| 428 | 1227 more than one value, @var{multi} is returned (defaults to @code{nil}). |
| 1228 @end defun | |
| 1229 | |
| 444 | 1230 @defun reset-char-table char-table |
| 1231 This function resets @var{char-table} to its default state. | |
| 428 | 1232 @end defun |
| 1233 | |
| 444 | 1234 @defun map-char-table function char-table &optional range |
| 1235 This function maps @var{function} over entries in @var{char-table}, calling | |
| 428 | 1236 it with two args, each key and value in the table. |
| 1237 | |
| 1238 @var{range} specifies a subrange to map over and is in the same format | |
| 1239 as the @var{range} argument to @code{put-range-table}. If omitted or | |
| 1240 @code{t}, it defaults to the entire table. | |
| 1241 @end defun | |
| 1242 | |
| 1243 @defun valid-char-table-value-p value char-table-type | |
| 1244 This function returns non-@code{nil} if @var{value} is a valid value for | |
| 1245 @var{char-table-type}. | |
| 1246 @end defun | |
| 1247 | |
| 1248 @defun check-valid-char-table-value value char-table-type | |
| 1249 This function signals an error if @var{value} is not a valid value for | |
| 1250 @var{char-table-type}. | |
| 1251 @end defun |