fns.c 83.6 KB
Newer Older
Jim Blandy's avatar
Jim Blandy committed
1
/* Random utility Lisp functions.
Richard M. Stallman's avatar
Richard M. Stallman committed
2
   Copyright (C) 1985, 86, 87, 93, 94, 95, 97, 1998 Free Software Foundation, Inc.
Jim Blandy's avatar
Jim Blandy committed
3 4 5 6 7

This file is part of GNU Emacs.

GNU Emacs is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
8
the Free Software Foundation; either version 2, or (at your option)
Jim Blandy's avatar
Jim Blandy committed
9 10 11 12 13 14 15 16 17
any later version.

GNU Emacs is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Emacs; see the file COPYING.  If not, write to
18 19
the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */
Jim Blandy's avatar
Jim Blandy committed
20 21


22
#include <config.h>
Jim Blandy's avatar
Jim Blandy committed
23

Andreas Schwab's avatar
Andreas Schwab committed
24 25 26
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
Andreas Schwab's avatar
Andreas Schwab committed
27
#include <time.h>
Andreas Schwab's avatar
Andreas Schwab committed
28

Jim Blandy's avatar
Jim Blandy committed
29 30 31 32 33 34 35
/* Note on some machines this defines `vector' as a typedef,
   so make sure we don't use that name in this file.  */
#undef vector
#define vector *****

#include "lisp.h"
#include "commands.h"
36
#include "charset.h"
Jim Blandy's avatar
Jim Blandy committed
37 38

#include "buffer.h"
Jim Blandy's avatar
Jim Blandy committed
39
#include "keyboard.h"
40
#include "intervals.h"
41 42
#include "frame.h"
#include "window.h"
43
#if defined (HAVE_MENUS) && defined (HAVE_X_WINDOWS)
Andreas Schwab's avatar
Andreas Schwab committed
44 45
#include "xterm.h"
#endif
Jim Blandy's avatar
Jim Blandy committed
46

Karl Heuer's avatar
Karl Heuer committed
47 48 49 50
#ifndef NULL
#define NULL (void *)0
#endif

51 52 53 54
/* Nonzero enables use of dialog boxes for questions
   asked by mouse commands.  */
int use_dialog_box;

55 56 57
extern int minibuffer_auto_raise;
extern Lisp_Object minibuf_window;

58
Lisp_Object Qstring_lessp, Qprovide, Qrequire;
59
Lisp_Object Qyes_or_no_p_history;
60
Lisp_Object Qcursor_in_echo_area;
Karl Heuer's avatar
Karl Heuer committed
61
Lisp_Object Qwidget_type;
Jim Blandy's avatar
Jim Blandy committed
62

63 64
extern Lisp_Object Qinput_method_function;

65
static int internal_equal ();
66 67 68 69 70 71 72

extern long get_random ();
extern void seed_random ();

#ifndef HAVE_UNISTD_H
extern long time ();
#endif
73

Jim Blandy's avatar
Jim Blandy committed
74 75 76 77 78 79 80 81 82 83
DEFUN ("identity", Fidentity, Sidentity, 1, 1, 0,
  "Return the argument unchanged.")
  (arg)
     Lisp_Object arg;
{
  return arg;
}

DEFUN ("random", Frandom, Srandom, 0, 1, 0,
  "Return a pseudo-random number.\n\
84 85
All integers representable in Lisp are equally likely.\n\
  On most systems, this is 28 bits' worth.\n\
86
With positive integer argument N, return random number in interval [0,N).\n\
Jim Blandy's avatar
Jim Blandy committed
87
With argument t, set the random number seed from the current time and pid.")
88 89
  (n)
     Lisp_Object n;
Jim Blandy's avatar
Jim Blandy committed
90
{
91 92
  EMACS_INT val;
  Lisp_Object lispy_val;
93
  unsigned long denominator;
Jim Blandy's avatar
Jim Blandy committed
94

95
  if (EQ (n, Qt))
96
    seed_random (getpid () + time (NULL));
97
  if (NATNUMP (n) && XFASTINT (n) != 0)
Jim Blandy's avatar
Jim Blandy committed
98
    {
99 100 101 102
      /* Try to take our random number from the higher bits of VAL,
	 not the lower, since (says Gentzel) the low bits of `random'
	 are less random than the higher ones.  We do this by using the
	 quotient rather than the remainder.  At the high end of the RNG
103
	 it's possible to get a quotient larger than n; discarding
104
	 these values eliminates the bias that would otherwise appear
105 106
	 when using a large n.  */
      denominator = ((unsigned long)1 << VALBITS) / XFASTINT (n);
107
      do
108
	val = get_random () / denominator;
109
      while (val >= XFASTINT (n));
Jim Blandy's avatar
Jim Blandy committed
110
    }
111
  else
112
    val = get_random ();
113 114
  XSETINT (lispy_val, val);
  return lispy_val;
Jim Blandy's avatar
Jim Blandy committed
115 116 117 118 119 120
}

/* Random data-structure functions */

DEFUN ("length", Flength, Slength, 1, 1, 0,
  "Return the length of vector, list or string SEQUENCE.\n\
Richard M. Stallman's avatar
Richard M. Stallman committed
121 122
A byte-code function object is also allowed.\n\
If the string contains multibyte characters, this is not the necessarily\n\
Andreas Schwab's avatar
Andreas Schwab committed
123 124
the number of bytes in the string; it is the number of characters.\n\
To get the number of bytes, use `string-bytes'")
125 126
  (sequence)
     register Lisp_Object sequence;
Jim Blandy's avatar
Jim Blandy committed
127 128 129 130 131
{
  register Lisp_Object tail, val;
  register int i;

 retry:
132 133 134 135 136
  if (STRINGP (sequence))
    XSETFASTINT (val, XSTRING (sequence)->size);
  else if (VECTORP (sequence))
    XSETFASTINT (val, XVECTOR (sequence)->size);
  else if (CHAR_TABLE_P (sequence))
Karl Heuer's avatar
Karl Heuer committed
137 138 139
    XSETFASTINT (val, (MIN_CHAR_COMPOSITION
		       + (CHAR_FIELD2_MASK | CHAR_FIELD3_MASK)
		       - 1));
140 141 142 143 144
  else if (BOOL_VECTOR_P (sequence))
    XSETFASTINT (val, XBOOL_VECTOR (sequence)->size);
  else if (COMPILEDP (sequence))
    XSETFASTINT (val, XVECTOR (sequence)->size & PSEUDOVECTOR_SIZE_MASK);
  else if (CONSP (sequence))
Jim Blandy's avatar
Jim Blandy committed
145
    {
146
      for (i = 0, tail = sequence; !NILP (tail); i++)
Jim Blandy's avatar
Jim Blandy committed
147 148 149 150 151
	{
	  QUIT;
	  tail = Fcdr (tail);
	}

152
      XSETFASTINT (val, i);
Jim Blandy's avatar
Jim Blandy committed
153
    }
154
  else if (NILP (sequence))
155
    XSETFASTINT (val, 0);
Jim Blandy's avatar
Jim Blandy committed
156 157
  else
    {
158
      sequence = wrong_type_argument (Qsequencep, sequence);
Jim Blandy's avatar
Jim Blandy committed
159 160
      goto retry;
    }
161
  return val;
Jim Blandy's avatar
Jim Blandy committed
162 163
}

164 165 166 167 168 169 170 171
/* This does not check for quits.  That is safe
   since it must terminate.  */

DEFUN ("safe-length", Fsafe_length, Ssafe_length, 1, 1, 0,
  "Return the length of a list, but avoid error or infinite loop.\n\
This function never gets an error.  If LIST is not really a list,\n\
it returns 0.  If LIST is circular, it returns a finite value\n\
which is at least the number of distinct elements.")
Karl Heuer's avatar
Karl Heuer committed
172
  (list)
173 174 175 176 177 178 179 180 181 182
     Lisp_Object list;
{
  Lisp_Object tail, halftail, length;
  int len = 0;

  /* halftail is used to detect circular lists.  */
  halftail = list;
  for (tail = list; CONSP (tail); tail = XCONS (tail)->cdr)
    {
      if (EQ (tail, halftail) && len != 0)
183
	break;
184
      len++;
185
      if ((len & 1) == 0)
186 187 188 189 190 191 192
	halftail = XCONS (halftail)->cdr;
    }

  XSETINT (length, len);
  return length;
}

193 194 195 196
DEFUN ("string-bytes", Fstring_bytes, Sstring_bytes, 1, 1, 0,
  "Return the number of bytes in STRING.\n\
If STRING is a multibyte string, this is greater than the length of STRING.")
  (string)
197
     Lisp_Object string;
198 199
{
  CHECK_STRING (string, 1);
200
  return make_number (STRING_BYTES (XSTRING (string)));
201 202
}

Jim Blandy's avatar
Jim Blandy committed
203
DEFUN ("string-equal", Fstring_equal, Sstring_equal, 2, 2, 0,
204
  "Return t if two strings have identical contents.\n\
205
Case is significant, but text properties are ignored.\n\
Jim Blandy's avatar
Jim Blandy committed
206 207 208 209
Symbols are also allowed; their print names are used instead.")
  (s1, s2)
     register Lisp_Object s1, s2;
{
210
  if (SYMBOLP (s1))
211
    XSETSTRING (s1, XSYMBOL (s1)->name);
212
  if (SYMBOLP (s2))
213
    XSETSTRING (s2, XSYMBOL (s2)->name);
Jim Blandy's avatar
Jim Blandy committed
214 215 216
  CHECK_STRING (s1, 0);
  CHECK_STRING (s2, 1);

217
  if (XSTRING (s1)->size != XSTRING (s2)->size
218 219
      || STRING_BYTES (XSTRING (s1)) != STRING_BYTES (XSTRING (s2))
      || bcmp (XSTRING (s1)->data, XSTRING (s2)->data, STRING_BYTES (XSTRING (s1))))
Jim Blandy's avatar
Jim Blandy committed
220 221 222 223
    return Qnil;
  return Qt;
}

224
DEFUN ("compare-strings", Fcompare_strings,
225
       Scompare_strings, 6, 7, 0,
226 227 228
  "Compare the contents of two strings, converting to multibyte if needed.\n\
In string STR1, skip the first START1 characters and stop at END1.\n\
In string STR2, skip the first START2 characters and stop at END2.\n\
229 230
END1 and END2 default to the full lengths of the respective strings.\n\
\n\
231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326
Case is significant in this comparison if IGNORE-CASE is nil.\n\
Unibyte strings are converted to multibyte for comparison.\n\
\n\
The value is t if the strings (or specified portions) match.\n\
If string STR1 is less, the value is a negative number N;\n\
  - 1 - N is the number of characters that match at the beginning.\n\
If string STR1 is greater, the value is a positive number N;\n\
  N - 1 is the number of characters that match at the beginning.")
  (str1, start1, end1, str2, start2, end2, ignore_case)
     Lisp_Object str1, start1, end1, start2, str2, end2, ignore_case;
{
  register int end1_char, end2_char;
  register int i1, i1_byte, i2, i2_byte;

  CHECK_STRING (str1, 0);
  CHECK_STRING (str2, 1);
  if (NILP (start1))
    start1 = make_number (0);
  if (NILP (start2))
    start2 = make_number (0);
  CHECK_NATNUM (start1, 2);
  CHECK_NATNUM (start2, 3);
  if (! NILP (end1))
    CHECK_NATNUM (end1, 4);
  if (! NILP (end2))
    CHECK_NATNUM (end2, 4);

  i1 = XINT (start1);
  i2 = XINT (start2);

  i1_byte = string_char_to_byte (str1, i1);
  i2_byte = string_char_to_byte (str2, i2);

  end1_char = XSTRING (str1)->size;
  if (! NILP (end1) && end1_char > XINT (end1))
    end1_char = XINT (end1);

  end2_char = XSTRING (str2)->size;
  if (! NILP (end2) && end2_char > XINT (end2))
    end2_char = XINT (end2);

  while (i1 < end1_char && i2 < end2_char)
    {
      /* When we find a mismatch, we must compare the
	 characters, not just the bytes.  */
      int c1, c2;

      if (STRING_MULTIBYTE (str1))
	FETCH_STRING_CHAR_ADVANCE (c1, str1, i1, i1_byte);
      else
	{
	  c1 = XSTRING (str1)->data[i1++];
	  c1 = unibyte_char_to_multibyte (c1);
	}

      if (STRING_MULTIBYTE (str2))
	FETCH_STRING_CHAR_ADVANCE (c2, str2, i2, i2_byte);
      else
	{
	  c2 = XSTRING (str2)->data[i2++];
	  c2 = unibyte_char_to_multibyte (c2);
	}

      if (c1 == c2)
	continue;

      if (! NILP (ignore_case))
	{
	  Lisp_Object tem;

	  tem = Fupcase (make_number (c1));
	  c1 = XINT (tem);
	  tem = Fupcase (make_number (c2));
	  c2 = XINT (tem);
	}

      if (c1 == c2)
	continue;

      /* Note that I1 has already been incremented
	 past the character that we are comparing;
	 hence we don't add or subtract 1 here.  */
      if (c1 < c2)
	return make_number (- i1);
      else
	return make_number (i1);
    }

  if (i1 < end1_char)
    return make_number (i1 - XINT (start1) + 1);
  if (i2 < end2_char)
    return make_number (- i1 + XINT (start1) - 1);

  return Qt;
}

Jim Blandy's avatar
Jim Blandy committed
327
DEFUN ("string-lessp", Fstring_lessp, Sstring_lessp, 2, 2, 0,
328
  "Return t if first arg string is less than second in lexicographic order.\n\
Jim Blandy's avatar
Jim Blandy committed
329 330 331 332 333 334
Case is significant.\n\
Symbols are also allowed; their print names are used instead.")
  (s1, s2)
     register Lisp_Object s1, s2;
{
  register int end;
335
  register int i1, i1_byte, i2, i2_byte;
Jim Blandy's avatar
Jim Blandy committed
336

337
  if (SYMBOLP (s1))
338
    XSETSTRING (s1, XSYMBOL (s1)->name);
339
  if (SYMBOLP (s2))
340
    XSETSTRING (s2, XSYMBOL (s2)->name);
Jim Blandy's avatar
Jim Blandy committed
341 342 343
  CHECK_STRING (s1, 0);
  CHECK_STRING (s2, 1);

344 345 346 347 348
  i1 = i1_byte = i2 = i2_byte = 0;

  end = XSTRING (s1)->size;
  if (end > XSTRING (s2)->size)
    end = XSTRING (s2)->size;
Jim Blandy's avatar
Jim Blandy committed
349

350
  while (i1 < end)
Jim Blandy's avatar
Jim Blandy committed
351
    {
352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367
      /* When we find a mismatch, we must compare the
	 characters, not just the bytes.  */
      int c1, c2;

      if (STRING_MULTIBYTE (s1))
	FETCH_STRING_CHAR_ADVANCE (c1, s1, i1, i1_byte);
      else
	c1 = XSTRING (s1)->data[i1++];

      if (STRING_MULTIBYTE (s2))
	FETCH_STRING_CHAR_ADVANCE (c2, s2, i2, i2_byte);
      else
	c2 = XSTRING (s2)->data[i2++];

      if (c1 != c2)
	return c1 < c2 ? Qt : Qnil;
Jim Blandy's avatar
Jim Blandy committed
368
    }
369
  return i1 < XSTRING (s2)->size ? Qt : Qnil;
Jim Blandy's avatar
Jim Blandy committed
370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388
}

static Lisp_Object concat ();

/* ARGSUSED */
Lisp_Object
concat2 (s1, s2)
     Lisp_Object s1, s2;
{
#ifdef NO_ARG_ARRAY
  Lisp_Object args[2];
  args[0] = s1;
  args[1] = s2;
  return concat (2, args, Lisp_String, 0);
#else
  return concat (2, &s1, Lisp_String, 0);
#endif /* NO_ARG_ARRAY */
}

Richard M. Stallman's avatar
Richard M. Stallman committed
389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404
/* ARGSUSED */
Lisp_Object
concat3 (s1, s2, s3)
     Lisp_Object s1, s2, s3;
{
#ifdef NO_ARG_ARRAY
  Lisp_Object args[3];
  args[0] = s1;
  args[1] = s2;
  args[2] = s3;
  return concat (3, args, Lisp_String, 0);
#else
  return concat (3, &s1, Lisp_String, 0);
#endif /* NO_ARG_ARRAY */
}

Jim Blandy's avatar
Jim Blandy committed
405 406 407 408
DEFUN ("append", Fappend, Sappend, 0, MANY, 0,
  "Concatenate all the arguments and make the result a list.\n\
The result is a list whose elements are the elements of all the arguments.\n\
Each argument may be a list, vector or string.\n\
Richard M. Stallman's avatar
Richard M. Stallman committed
409
The last argument is not copied, just used as the tail of the new list.")
Jim Blandy's avatar
Jim Blandy committed
410 411 412 413 414 415 416 417 418 419
  (nargs, args)
     int nargs;
     Lisp_Object *args;
{
  return concat (nargs, args, Lisp_Cons, 1);
}

DEFUN ("concat", Fconcat, Sconcat, 0, MANY, 0,
  "Concatenate all the arguments and make the result a string.\n\
The result is a string whose elements are the elements of all the arguments.\n\
420 421 422 423 424 425
Each argument may be a string or a list or vector of characters (integers).\n\
\n\
Do not use individual integers as arguments!\n\
The behavior of `concat' in that case will be changed later!\n\
If your program passes an integer as an argument to `concat',\n\
you should change it right away not to do so.")
Jim Blandy's avatar
Jim Blandy committed
426 427 428 429 430 431 432 433 434 435 436 437 438 439 440
  (nargs, args)
     int nargs;
     Lisp_Object *args;
{
  return concat (nargs, args, Lisp_String, 0);
}

DEFUN ("vconcat", Fvconcat, Svconcat, 0, MANY, 0,
  "Concatenate all the arguments and make the result a vector.\n\
The result is a vector whose elements are the elements of all the arguments.\n\
Each argument may be a list, vector or string.")
  (nargs, args)
     int nargs;
     Lisp_Object *args;
{
441
  return concat (nargs, args, Lisp_Vectorlike, 0);
Jim Blandy's avatar
Jim Blandy committed
442 443
}

444 445 446 447
/* Retrun a copy of a sub char table ARG.  The elements except for a
   nested sub char table are not copied.  */
static Lisp_Object
copy_sub_char_table (arg)
448
     Lisp_Object arg;
449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465
{
  Lisp_Object copy = make_sub_char_table (XCHAR_TABLE (arg)->defalt);
  int i;

  /* Copy all the contents.  */
  bcopy (XCHAR_TABLE (arg)->contents, XCHAR_TABLE (copy)->contents,
	 SUB_CHAR_TABLE_ORDINARY_SLOTS * sizeof (Lisp_Object));
  /* Recursively copy any sub char-tables in the ordinary slots.  */
  for (i = 32; i < SUB_CHAR_TABLE_ORDINARY_SLOTS; i++)
    if (SUB_CHAR_TABLE_P (XCHAR_TABLE (arg)->contents[i]))
      XCHAR_TABLE (copy)->contents[i]
	= copy_sub_char_table (XCHAR_TABLE (copy)->contents[i]);

  return copy;
}


Jim Blandy's avatar
Jim Blandy committed
466 467 468 469 470 471 472
DEFUN ("copy-sequence", Fcopy_sequence, Scopy_sequence, 1, 1, 0,
  "Return a copy of a list, vector or string.\n\
The elements of a list or vector are not copied; they are shared\n\
with the original.")
  (arg)
     Lisp_Object arg;
{
Jim Blandy's avatar
Jim Blandy committed
473
  if (NILP (arg)) return arg;
474 475 476

  if (CHAR_TABLE_P (arg))
    {
477
      int i;
478 479
      Lisp_Object copy;

480
      copy = Fmake_char_table (XCHAR_TABLE (arg)->purpose, Qnil);
481
      /* Copy all the slots, including the extra ones.  */
482
      bcopy (XVECTOR (arg)->contents, XVECTOR (copy)->contents,
483 484
	     ((XCHAR_TABLE (arg)->size & PSEUDOVECTOR_SIZE_MASK)
	      * sizeof (Lisp_Object)));
485

486 487 488 489 490
      /* Recursively copy any sub char tables in the ordinary slots
         for multibyte characters.  */
      for (i = CHAR_TABLE_SINGLE_BYTE_SLOTS;
	   i < CHAR_TABLE_ORDINARY_SLOTS; i++)
	if (SUB_CHAR_TABLE_P (XCHAR_TABLE (arg)->contents[i]))
491
	  XCHAR_TABLE (copy)->contents[i]
492
	    = copy_sub_char_table (XCHAR_TABLE (copy)->contents[i]);
493 494 495 496 497 498 499 500

      return copy;
    }

  if (BOOL_VECTOR_P (arg))
    {
      Lisp_Object val;
      int size_in_chars
501
	= (XBOOL_VECTOR (arg)->size + BITS_PER_CHAR - 1) / BITS_PER_CHAR;
502 503 504 505 506 507 508

      val = Fmake_bool_vector (Flength (arg), Qnil);
      bcopy (XBOOL_VECTOR (arg)->data, XBOOL_VECTOR (val)->data,
	     size_in_chars);
      return val;
    }

509
  if (!CONSP (arg) && !VECTORP (arg) && !STRINGP (arg))
Jim Blandy's avatar
Jim Blandy committed
510 511 512 513 514 515 516 517 518 519 520 521 522 523 524
    arg = wrong_type_argument (Qsequencep, arg);
  return concat (1, &arg, CONSP (arg) ? Lisp_Cons : XTYPE (arg), 0);
}

static Lisp_Object
concat (nargs, args, target_type, last_special)
     int nargs;
     Lisp_Object *args;
     enum Lisp_Type target_type;
     int last_special;
{
  Lisp_Object val;
  register Lisp_Object tail;
  register Lisp_Object this;
  int toindex;
525 526 527
  int toindex_byte;
  register int result_len;
  register int result_len_byte;
Jim Blandy's avatar
Jim Blandy committed
528 529 530
  register int argnum;
  Lisp_Object last_tail;
  Lisp_Object prev;
531
  int some_multibyte;
532 533 534 535 536
  /* When we make a multibyte string, we must pay attention to the
     byte combining problem, i.e., a byte may be combined with a
     multibyte charcter of the previous string.  This flag tells if we
     must consider such a situation or not.  */
  int maybe_combine_byte;
Jim Blandy's avatar
Jim Blandy committed
537 538 539 540 541 542 543 544 545 546

  /* In append, the last arg isn't treated like the others */
  if (last_special && nargs > 0)
    {
      nargs--;
      last_tail = args[nargs];
    }
  else
    last_tail = Qnil;

547
  /* Canonicalize each argument.  */
Jim Blandy's avatar
Jim Blandy committed
548 549 550
  for (argnum = 0; argnum < nargs; argnum++)
    {
      this = args[argnum];
551
      if (!(CONSP (this) || NILP (this) || VECTORP (this) || STRINGP (this)
552
	    || COMPILEDP (this) || BOOL_VECTOR_P (this)))
Jim Blandy's avatar
Jim Blandy committed
553
	{
554
	  if (INTEGERP (this))
555
            args[argnum] = Fnumber_to_string (this);
Jim Blandy's avatar
Jim Blandy committed
556 557 558 559 560
	  else
	    args[argnum] = wrong_type_argument (Qsequencep, this);
	}
    }

561 562 563 564 565 566 567 568
  /* Compute total length in chars of arguments in RESULT_LEN.
     If desired output is a string, also compute length in bytes
     in RESULT_LEN_BYTE, and determine in SOME_MULTIBYTE
     whether the result should be a multibyte string.  */
  result_len_byte = 0;
  result_len = 0;
  some_multibyte = 0;
  for (argnum = 0; argnum < nargs; argnum++)
Jim Blandy's avatar
Jim Blandy committed
569
    {
570
      int len;
Jim Blandy's avatar
Jim Blandy committed
571
      this = args[argnum];
572 573
      len = XFASTINT (Flength (this));
      if (target_type == Lisp_String)
574
	{
575 576
	  /* We must count the number of bytes needed in the string
	     as well as the number of characters.  */
577 578
	  int i;
	  Lisp_Object ch;
579
	  int this_len_byte;
580

581
	  if (VECTORP (this))
582
	    for (i = 0; i < len; i++)
583 584 585 586
	      {
		ch = XVECTOR (this)->contents[i];
		if (! INTEGERP (ch))
		  wrong_type_argument (Qintegerp, ch);
587
		this_len_byte = CHAR_BYTES (XINT (ch));
588 589 590
		result_len_byte += this_len_byte;
		if (this_len_byte > 1)
		  some_multibyte = 1;
591
	      }
592 593
	  else if (BOOL_VECTOR_P (this) && XBOOL_VECTOR (this)->size > 0)
	    wrong_type_argument (Qintegerp, Faref (this, make_number (0)));
594
	  else if (CONSP (this))
595 596 597 598 599
	    for (; CONSP (this); this = XCONS (this)->cdr)
	      {
		ch = XCONS (this)->car;
		if (! INTEGERP (ch))
		  wrong_type_argument (Qintegerp, ch);
600
		this_len_byte = CHAR_BYTES (XINT (ch));
601 602 603
		result_len_byte += this_len_byte;
		if (this_len_byte > 1)
		  some_multibyte = 1;
604
	      }
605
	  else if (STRINGP (this))
606
	    {
607
	      if (STRING_MULTIBYTE (this))
608 609
		{
		  some_multibyte = 1;
610
		  result_len_byte += STRING_BYTES (XSTRING (this));
611 612 613 614
		}
	      else
		result_len_byte += count_size_as_multibyte (XSTRING (this)->data,
							    XSTRING (this)->size);
615
	    }
616
	}
617 618

      result_len += len;
Jim Blandy's avatar
Jim Blandy committed
619 620
    }

621 622
  if (! some_multibyte)
    result_len_byte = result_len;
Jim Blandy's avatar
Jim Blandy committed
623

624
  /* Create the output object.  */
Jim Blandy's avatar
Jim Blandy committed
625
  if (target_type == Lisp_Cons)
626
    val = Fmake_list (make_number (result_len), Qnil);
627
  else if (target_type == Lisp_Vectorlike)
628
    val = Fmake_vector (make_number (result_len), Qnil);
629
  else if (some_multibyte)
630
    val = make_uninit_multibyte_string (result_len, result_len_byte);
631 632
  else
    val = make_uninit_string (result_len);
Jim Blandy's avatar
Jim Blandy committed
633

634 635 636
  /* In `append', if all but last arg are nil, return last arg.  */
  if (target_type == Lisp_Cons && EQ (val, Qnil))
    return last_tail;
Jim Blandy's avatar
Jim Blandy committed
637

638
  /* Copy the contents of the args into the result.  */
Jim Blandy's avatar
Jim Blandy committed
639 640 641
  if (CONSP (val))
    tail = val, toindex = -1;		/* -1 in toindex is flag we are making a list */
  else
642
    toindex = 0, toindex_byte = 0;
Jim Blandy's avatar
Jim Blandy committed
643 644 645

  prev = Qnil;

646
  maybe_combine_byte = 0;
Jim Blandy's avatar
Jim Blandy committed
647 648 649 650
  for (argnum = 0; argnum < nargs; argnum++)
    {
      Lisp_Object thislen;
      int thisleni;
651
      register unsigned int thisindex = 0;
652
      register unsigned int thisindex_byte = 0;
Jim Blandy's avatar
Jim Blandy committed
653 654 655 656 657

      this = args[argnum];
      if (!CONSP (this))
	thislen = Flength (this), thisleni = XINT (thislen);

658
      if (STRINGP (this) && STRINGP (val)
659
	  && ! NULL_INTERVAL_P (XSTRING (this)->intervals))
660 661
	copy_text_properties (make_number (0), thislen, this,
			      make_number (toindex), val, Qnil);
662

663 664 665
      /* Between strings of the same kind, copy fast.  */
      if (STRINGP (this) && STRINGP (val)
	  && STRING_MULTIBYTE (this) == some_multibyte)
Jim Blandy's avatar
Jim Blandy committed
666
	{
667
	  int thislen_byte = STRING_BYTES (XSTRING (this));
668
	  bcopy (XSTRING (this)->data, XSTRING (val)->data + toindex_byte,
669
		 STRING_BYTES (XSTRING (this)));
670 671
	  if (some_multibyte
	      && toindex_byte > 0
672
	      && !ASCII_BYTE_P (XSTRING (val)->data[toindex_byte - 1])
Kenichi Handa's avatar
Kenichi Handa committed
673
	      && !CHAR_HEAD_P (XSTRING (this)->data[0]))
674
	    maybe_combine_byte = 1;
675 676 677
	  toindex_byte += thislen_byte;
	  toindex += thisleni;
	}
678 679 680 681 682 683 684 685
      /* Copy a single-byte string to a multibyte string.  */
      else if (STRINGP (this) && STRINGP (val))
	{
	  toindex_byte += copy_text (XSTRING (this)->data,
				     XSTRING (val)->data + toindex_byte,
				     XSTRING (this)->size, 0, 1);
	  toindex += thisleni;
	}
686 687 688 689 690 691 692 693 694 695 696
      else
	/* Copy element by element.  */
	while (1)
	  {
	    register Lisp_Object elt;

	    /* Fetch next element of `this' arg into `elt', or break if
	       `this' is exhausted. */
	    if (NILP (this)) break;
	    if (CONSP (this))
	      elt = XCONS (this)->car, this = XCONS (this)->cdr;
697 698 699
	    else if (thisindex >= thisleni)
	      break;
	    else if (STRINGP (this))
700
	      {
701
		int c;
702
		if (STRING_MULTIBYTE (this))
703
		  {
704 705 706 707
		    FETCH_STRING_CHAR_ADVANCE (c, this,
					       thisindex,
					       thisindex_byte);
		    XSETFASTINT (elt, c);
708
		  }
709
		else
710
		  {
711
		    XSETFASTINT (elt, XSTRING (this)->data[thisindex++]);
712 713 714
		    if (some_multibyte
			&& (XINT (elt) >= 0240
			    || ! NILP (Vnonascii_translation_table))
715 716
			&& XINT (elt) < 0400)
		      {
717
			c = unibyte_char_to_multibyte (XINT (elt));
718 719
			XSETINT (elt, c);
		      }
720
		  }
721 722 723 724 725 726 727
	      }
	    else if (BOOL_VECTOR_P (this))
	      {
		int byte;
		byte = XBOOL_VECTOR (this)->data[thisindex / BITS_PER_CHAR];
		if (byte & (1 << (thisindex % BITS_PER_CHAR)))
		  elt = Qt;
728
		else
729 730
		  elt = Qnil;
		thisindex++;
731
	      }
732 733
	    else
	      elt = XVECTOR (this)->contents[thisindex++];
Jim Blandy's avatar
Jim Blandy committed
734

735 736
	    /* Store this element into the result.  */
	    if (toindex < 0)
Jim Blandy's avatar
Jim Blandy committed
737
	      {
738 739 740
		XCONS (tail)->car = elt;
		prev = tail;
		tail = XCONS (tail)->cdr;
Jim Blandy's avatar
Jim Blandy committed
741
	      }
742 743 744 745 746 747 748
	    else if (VECTORP (val))
	      XVECTOR (val)->contents[toindex++] = elt;
	    else
	      {
		CHECK_NUMBER (elt, 0);
		if (SINGLE_BYTE_CHAR_P (XINT (elt)))
		  {
749 750
		    if (some_multibyte
			&& toindex_byte > 0
751 752
			&& !ASCII_BYTE_P (XSTRING (val)->data[toindex_byte - 1])
			&& !CHAR_HEAD_P (XINT (elt)))
753
		      maybe_combine_byte = 1;
754 755
		    XSTRING (val)->data[toindex_byte++] = XINT (elt);
		    toindex++;
756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773
		  }
		else
		  /* If we have any multibyte characters,
		     we already decided to make a multibyte string.  */
		  {
		    int c = XINT (elt);
		    unsigned char work[4], *str;
		    int i = CHAR_STRING (c, work, str);

		    /* P exists as a variable
		       to avoid a bug on the Masscomp C compiler.  */
		    unsigned char *p = & XSTRING (val)->data[toindex_byte];
		    bcopy (str, p, i);
		    toindex_byte += i;
		    toindex++;
		  }
	      }
	  }
Jim Blandy's avatar
Jim Blandy committed
774
    }
Jim Blandy's avatar
Jim Blandy committed
775
  if (!NILP (prev))
Jim Blandy's avatar
Jim Blandy committed
776 777
    XCONS (prev)->cdr = last_tail;

778
  if (maybe_combine_byte)
Richard M. Stallman's avatar
Richard M. Stallman committed
779
    /* Character counter of the multibyte string VAL may be wrong
780 781 782 783
       because of byte combining problem.  We must re-calculate it.  */
    XSTRING (val)->size = multibyte_chars_in_text (XSTRING (val)->data,
						   XSTRING (val)->size_byte);

Karl Heuer's avatar
Karl Heuer committed
784
  return val;
Jim Blandy's avatar
Jim Blandy committed
785 786
}

787 788 789 790
static Lisp_Object string_char_byte_cache_string;
static int string_char_byte_cache_charpos;
static int string_char_byte_cache_bytepos;

791 792 793 794 795 796 797
/* Return the character index corresponding to CHAR_INDEX in STRING.  */

int
string_char_to_byte (string, char_index)
     Lisp_Object string;
     int char_index;
{
798 799 800
  int i, i_byte;
  int best_below, best_below_byte;
  int best_above, best_above_byte;
801 802 803 804

  if (! STRING_MULTIBYTE (string))
    return char_index;

805 806
  best_below = best_below_byte = 0;
  best_above = XSTRING (string)->size;
807
  best_above_byte = STRING_BYTES (XSTRING (string));
808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833

  if (EQ (string, string_char_byte_cache_string))
    {
      if (string_char_byte_cache_charpos < char_index)
	{
	  best_below = string_char_byte_cache_charpos;
	  best_below_byte = string_char_byte_cache_bytepos;
	}
      else
	{
	  best_above = string_char_byte_cache_charpos;
	  best_above_byte = string_char_byte_cache_bytepos;
	}
    }

  if (char_index - best_below < best_above - char_index)
    {
      while (best_below < char_index)
	{
	  int c;
	  FETCH_STRING_CHAR_ADVANCE (c, string, best_below, best_below_byte);
	}
      i = best_below;
      i_byte = best_below_byte;
    }
  else
834
    {
835 836 837 838 839 840 841 842 843 844 845 846 847
      while (best_above > char_index)
	{
	  int best_above_byte_saved = --best_above_byte;

	  while (best_above_byte > 0
		 && !CHAR_HEAD_P (XSTRING (string)->data[best_above_byte]))
	    best_above_byte--;
	  if (XSTRING (string)->data[best_above_byte] < 0x80)
	    best_above_byte = best_above_byte_saved;
	  best_above--;
	}
      i = best_above;
      i_byte = best_above_byte;
848 849
    }

850 851 852 853
  string_char_byte_cache_bytepos = i_byte;
  string_char_byte_cache_charpos = i;
  string_char_byte_cache_string = string;

854 855
  return i_byte;
}
856

857 858 859 860 861 862 863
/* Return the character index corresponding to BYTE_INDEX in STRING.  */

int
string_byte_to_char (string, byte_index)
     Lisp_Object string;
     int byte_index;
{
864 865 866
  int i, i_byte;
  int best_below, best_below_byte;
  int best_above, best_above_byte;
867 868 869 870

  if (! STRING_MULTIBYTE (string))
    return byte_index;

871 872
  best_below = best_below_byte = 0;
  best_above = XSTRING (string)->size;
873
  best_above_byte = STRING_BYTES (XSTRING (string));
874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899

  if (EQ (string, string_char_byte_cache_string))
    {
      if (string_char_byte_cache_bytepos < byte_index)
	{
	  best_below = string_char_byte_cache_charpos;
	  best_below_byte = string_char_byte_cache_bytepos;
	}
      else
	{
	  best_above = string_char_byte_cache_charpos;
	  best_above_byte = string_char_byte_cache_bytepos;
	}
    }

  if (byte_index - best_below_byte < best_above_byte - byte_index)
    {
      while (best_below_byte < byte_index)
	{
	  int c;
	  FETCH_STRING_CHAR_ADVANCE (c, string, best_below, best_below_byte);
	}
      i = best_below;
      i_byte = best_below_byte;
    }
  else
900
    {
901 902 903 904 905 906 907 908 909 910 911 912 913
      while (best_above_byte > byte_index)
	{
	  int best_above_byte_saved = --best_above_byte;

	  while (best_above_byte > 0
		 && !CHAR_HEAD_P (XSTRING (string)->data[best_above_byte]))
	    best_above_byte--;
	  if (XSTRING (string)->data[best_above_byte] < 0x80)
	    best_above_byte = best_above_byte_saved;
	  best_above--;
	}
      i = best_above;
      i_byte = best_above_byte;
914 915
    }

916 917 918 919
  string_char_byte_cache_bytepos = i_byte;
  string_char_byte_cache_charpos = i;
  string_char_byte_cache_string = string;

920 921
  return i;
}
922

923
/* Convert STRING to a multibyte string.
924
   Single-byte characters 0240 through 0377 are converted
925 926 927 928 929 930 931 932 933 934 935 936 937 938
   by adding nonascii_insert_offset to each.  */

Lisp_Object
string_make_multibyte (string)
     Lisp_Object string;
{
  unsigned char *buf;
  int nbytes;

  if (STRING_MULTIBYTE (string))
    return string;

  nbytes = count_size_as_multibyte (XSTRING (string)->data,
				    XSTRING (string)->size);
939 940
  /* If all the chars are ASCII, they won't need any more bytes
     once converted.  In that case, we can return STRING itself.  */
941
  if (nbytes == STRING_BYTES (XSTRING (string)))
942 943
    return string;

944
  buf = (unsigned char *) alloca (nbytes);
945
  copy_text (XSTRING (string)->data, buf, STRING_BYTES (XSTRING (string)),
946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963
	     0, 1);

  return make_multibyte_string (buf, XSTRING (string)->size, nbytes);
}

/* Convert STRING to a single-byte string.  */

Lisp_Object
string_make_unibyte (string)
     Lisp_Object string;
{
  unsigned char *buf;

  if (! STRING_MULTIBYTE (string))
    return string;

  buf = (unsigned char *) alloca (XSTRING (string)->size);

964
  copy_text (XSTRING (string)->data, buf, STRING_BYTES (XSTRING (string)),
965 966 967 968
	     1, 0);

  return make_unibyte_string (buf, XSTRING (string)->size);
}
969 970 971

DEFUN ("string-make-multibyte", Fstring_make_multibyte, Sstring_make_multibyte,
       1, 1, 0,
972 973 974
  "Return the multibyte equivalent of STRING.\n\
The function `unibyte-char-to-multibyte' is used to convert\n\
each unibyte character to a multibyte character.")
975 976 977
  (string)
     Lisp_Object string;
{
978 979
  CHECK_STRING (string, 0);

980 981 982 983 984
  return string_make_multibyte (string);
}

DEFUN ("string-make-unibyte", Fstring_make_unibyte, Sstring_make_unibyte,
       1, 1, 0,
985 986 987
  "Return the unibyte equivalent of STRING.\n\
Multibyte character codes are converted to unibyte\n\
by using just the low 8 bits.")
988 989 990
  (string)
     Lisp_Object string;
{
991 992
  CHECK_STRING (string, 0);

993 994
  return string_make_unibyte (string);
}
995 996 997 998 999 1000 1001 1002

DEFUN ("string-as-unibyte", Fstring_as_unibyte, Sstring_as_unibyte,
       1, 1, 0,
  "Return a unibyte string with the same individual bytes as STRING.\n\
If STRING is unibyte, the result is STRING itself.")
  (string)
     Lisp_Object string;
{
1003 1004
  CHECK_STRING (string, 0);

1005 1006 1007
  if (STRING_MULTIBYTE (string))
    {
      string = Fcopy_sequence (string);
1008
      XSTRING (string)->size = STRING_BYTES (XSTRING (string));
1009
      SET_STRING_BYTES (XSTRING (string), -1);
1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020
    }
  return string;
}

DEFUN ("string-as-multibyte", Fstring_as_multibyte, Sstring_as_multibyte,
       1, 1, 0,
  "Return a multibyte string with the same individual bytes as STRING.\n\
If STRING is multibyte, the result is STRING itself.")
  (string)
     Lisp_Object string;
{
1021 1022
  CHECK_STRING (string, 0);

1023 1024
  if (! STRING_MULTIBYTE (string))
    {
1025 1026 1027 1028 1029 1030
      int nbytes = STRING_BYTES (XSTRING (string));
      int newlen = multibyte_chars_in_text (XSTRING (string)->data, nbytes);

      string = Fcopy_sequence (string);
      XSTRING (string)->size = newlen;
      XSTRING (string)->size_byte = nbytes;
1031 1032 1033
    }
  return string;
}
1034

Jim Blandy's avatar
Jim Blandy committed
1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047
DEFUN ("copy-alist", Fcopy_alist, Scopy_alist, 1, 1, 0,
  "Return a copy of ALIST.\n\
This is an alist which represents the same mapping from objects to objects,\n\
but does not share the alist structure with ALIST.\n\
The objects mapped (cars and cdrs of elements of the alist)\n\
are shared, however.\n\
Elements of ALIST that are not conses are also shared.")
  (alist)
     Lisp_Object alist;
{
  register Lisp_Object tem;

  CHECK_LIST (alist, 0);
Jim Blandy's avatar
Jim Blandy committed
1048
  if (NILP (alist))
Jim Blandy's avatar
Jim Blandy committed
1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064
    return alist;
  alist = concat (1, &alist, Lisp_Cons, 0);
  for (tem = alist; CONSP (tem); tem = XCONS (tem)->cdr)
    {
      register Lisp_Object car;
      car = XCONS (tem)->car;

      if (CONSP (car))
	XCONS (tem)->car = Fcons (XCONS (car)->car, XCONS (car)->cdr);
    }
  return alist;
}

DEFUN ("substring", Fsubstring, Ssubstring, 2, 3, 0,
  "Return a substring of STRING, starting at index FROM and ending before TO.\n\
TO may be nil or omitted; then the substring runs to the end of STRING.\n\
1065 1066 1067
If FROM or TO is negative, it counts from the end.\n\
\n\
This function allows vectors as well as strings.")
Jim Blandy's avatar
Jim Blandy committed
1068 1069 1070 1071
  (string, from, to)
     Lisp_Object string;
     register Lisp_Object from, to;
{
1072
  Lisp_Object res;
1073
  int size;
1074 1075 1076
  int size_byte;
  int from_char, to_char;
  int from_byte, to_byte;
1077 1078 1079

  if (! (STRINGP (string) || VECTORP (string)))
    wrong_type_argument (Qarrayp, string);
1080

Jim Blandy's avatar
Jim Blandy committed
1081
  CHECK_NUMBER (from, 1);
1082 1083

  if (STRINGP (string))
1084 1085
    {
      size = XSTRING (string)->size;
1086
      size_byte = STRING_BYTES (XSTRING (string));
1087
    }
1088 1089 1090
  else
    size = XVECTOR (string)->size;

Jim Blandy's avatar
Jim Blandy committed
1091
  if (NILP (to))
1092 1093 1094 1095
    {
      to_char = size;
      to_byte = size_byte;
    }
Jim Blandy's avatar
Jim Blandy committed
1096
  else
1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112
    {
      CHECK_NUMBER (to, 2);

      to_char = XINT (to);
      if (to_char < 0)
	to_char += size;

      if (STRINGP (string))
	to_byte = string_char_to_byte (string, to_char);
    }

  from_char = XINT (from);
  if (from_char < 0)
    from_char += size;
  if (STRINGP (string))
    from_byte = string_char_to_byte (string, from_char);
Jim Blandy's avatar
Jim Blandy committed
1113

1114 1115 1116
  if (!(0 <= from_char && from_char <= to_char && to_char <= size))
    args_out_of_range_3 (string, make_number (from_char),
			 make_number (to_char));
Jim Blandy's avatar
Jim Blandy committed
1117

1118 1119
  if (STRINGP (string))
    {
1120 1121 1122
      res = make_specified_string (XSTRING (string)->data + from_byte,
				   to_char - from_char, to_byte - from_byte,
				   STRING_MULTIBYTE (string));
1123 1124
      copy_text_properties (make_number (from_char), make_number (to_char),
			    string, make_number (0), res, Qnil);
1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150
    }
  else
    res = Fvector (to_char - from_char,
		   XVECTOR (string)->contents + from_char);

  return res;
}

/* Extract a substring of STRING, giving start and end positions
   both in characters and in bytes.  */

Lisp_Object
substring_both (string, from, from_byte, to, to_byte)
     Lisp_Object string;
     int from, from_byte, to, to_byte;
{
  Lisp_Object res;
  int size;
  int size_byte;

  if (! (STRINGP (string) || VECTORP (string)))
    wrong_type_argument (Qarrayp, string);

  if (STRINGP (string))
    {
      size = XSTRING (string)->size;
1151
      size_byte = STRING_BYTES (XSTRING (string));
1152 1153 1154 1155 1156 1157 1158 1159 1160
    }
  else
    size = XVECTOR (string)->size;

  if (!(0 <= from && from <= to && to <= size))
    args_out_of_range_3 (string, make_number (from), make_number (to));

  if (STRINGP (string))
    {
1161 1162 1163
      res = make_specified_string (XSTRING (string)->data + from_byte,
				   to - from, to_byte - from_byte,
				   STRING_MULTIBYTE (string));
1164 1165
      copy_text_properties (make_number (from), make_number (to),
			    string, make_number (0), res, Qnil);
1166 1167
    }
  else
1168 1169
    res = Fvector (to - from,
		   XVECTOR (string)->contents + from);
Karl Heuer's avatar
Karl Heuer committed
1170

1171
  return res;
Jim Blandy's avatar
Jim Blandy committed
1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182
}

DEFUN ("nthcdr", Fnthcdr, Snthcdr, 2, 2, 0,
  "Take cdr N times on LIST, returns the result.")
  (n, list)
     Lisp_Object n;
     register Lisp_Object list;
{
  register int i, num;
  CHECK_NUMBER (n, 0);
  num = XINT (n);
Jim Blandy's avatar
Jim Blandy committed
1183
  for (i = 0; i < num && !NILP (list); i++)
Jim Blandy's avatar
Jim Blandy committed
1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201
    {
      QUIT;
      list = Fcdr (list);
    }
  return list;
}

DEFUN ("nth", Fnth, Snth, 2, 2, 0,
  "Return the Nth element of LIST.\n\
N counts from zero.  If LIST is not that long, nil is returned.")
  (n, list)
     Lisp_Object n, list;
{
  return Fcar (Fnthcdr (n, list));
}

DEFUN ("elt", Felt, Selt, 2, 2, 0,
  "Return element of SEQUENCE at index N.")
1202 1203
  (sequence, n)
     register Lisp_Object sequence, n;
Jim Blandy's avatar
Jim Blandy committed
1204 1205 1206 1207
{
  CHECK_NUMBER (n, 0);
  while (1)
    {
1208 1209 1210 1211 1212
      if (CONSP (sequence) || NILP (sequence))
	return Fcar (Fnthcdr (n, sequence));
      else if (STRINGP (sequence) || VECTORP (sequence)
	       || BOOL_VECTOR_P (sequence) || CHAR_TABLE_P (sequence))
	return Faref (sequence, n);
Jim Blandy's avatar
Jim Blandy committed
1213
      else