arrayfunc.c

   1 /* arrayfunc.c -- High-level array functions used by other parts of the shell. */
   2
   3 /* Copyright (C) 2001-2009 Free Software Foundation, Inc.
   4
   5    This file is part of GNU Bash, the Bourne Again SHell.
   6
   7    Bash is free software: you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation, either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    Bash is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with Bash.  If not, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21 #include "config.h"
  22
  23 #if defined (ARRAY_VARS)
  24
  25 #if defined (HAVE_UNISTD_H)
  26 #  include <unistd.h>
  27 #endif
  28 #include <stdio.h>
  29
  30 #include "bashintl.h"
  31
  32 #include "shell.h"
  33 #include "pathexp.h"
  34
  35 #include "shmbutil.h"
  36
  37 #include "builtins/common.h"
  38
  39 extern char *this_command_name;
  40 extern int last_command_exit_value;
  41 extern int array_needs_making;
  42
  43 static SHELL_VAR *bind_array_var_internal __P((SHELL_VAR *, arrayind_t, char *, char *, int));
  44
  45 static char *quote_assign __P((const char *));
  46 static void quote_array_assignment_chars __P((WORD_LIST *));
  47 static char *array_value_internal __P((char *, int, int, int *));
  48
  49 /* Standard error message to use when encountering an invalid array subscript */
  50 const char * const bash_badsub_errmsg = N_("bad array subscript");
  51
  52 /* **************************************************************** */
  53 /*                                                                  */
  54 /*  Functions to manipulate array variables and perform assignments */
  55 /*                                                                  */
  56 /* **************************************************************** */
  57
  58 /* Convert a shell variable to an array variable.  The original value is
  59    saved as array[0]. */
  60 SHELL_VAR *
  61 convert_var_to_array (var)
  62      SHELL_VAR *var;
  63 {
  64   char *oldval;
  65   ARRAY *array;
  66
  67   oldval = value_cell (var);
  68   array = array_create ();
  69   if (oldval)
  70     array_insert (array, 0, oldval);
  71
  72   FREE (value_cell (var));
  73   var_setarray (var, array);
  74
  75   /* these aren't valid anymore */
  76   var->dynamic_value = (sh_var_value_func_t *)NULL;
  77   var->assign_func = (sh_var_assign_func_t *)NULL;
  78
  79   INVALIDATE_EXPORTSTR (var);
  80   if (exported_p (var))
  81     array_needs_making++;
  82
  83   VSETATTR (var, att_array);
  84   VUNSETATTR (var, att_invisible);
  85
  86   return var;
  87 }
  88
  89 /* Convert a shell variable to an array variable.  The original value is
  90    saved as array[0]. */
  91 SHELL_VAR *
  92 convert_var_to_assoc (var)
  93      SHELL_VAR *var;
  94 {
  95   char *oldval;
  96   HASH_TABLE *hash;
  97
  98   oldval = value_cell (var);
  99   hash = assoc_create (0);
 100   if (oldval)
 101     assoc_insert (hash, "0", oldval);
 102
 103   FREE (value_cell (var));
 104   var_setassoc (var, hash);
 105
 106   /* these aren't valid anymore */
 107   var->dynamic_value = (sh_var_value_func_t *)NULL;
 108   var->assign_func = (sh_var_assign_func_t *)NULL;
 109
 110   INVALIDATE_EXPORTSTR (var);
 111   if (exported_p (var))
 112     array_needs_making++;
 113
 114   VSETATTR (var, att_assoc);
 115   VUNSETATTR (var, att_invisible);
 116
 117   return var;
 118 }
 119
 120 static SHELL_VAR *
 121 bind_array_var_internal (entry, ind, key, value, flags)
 122      SHELL_VAR *entry;
 123      arrayind_t ind;
 124      char *key;
 125      char *value;
 126      int flags;
 127 {
 128   SHELL_VAR *dentry;
 129   char *newval;
 130
 131   /* If we're appending, we need the old value of the array reference, so
 132      fake out make_variable_value with a dummy SHELL_VAR */
 133   if (flags & ASS_APPEND)
 134     {
 135       dentry = (SHELL_VAR *)xmalloc (sizeof (SHELL_VAR));
 136       dentry->name = savestring (entry->name);
 137       if (assoc_p (entry))
 138         newval = assoc_reference (assoc_cell (entry), key);
 139       else
 140         newval = array_reference (array_cell (entry), ind);
 141       if (newval)
 142         dentry->value = savestring (newval);
 143       else
 144         {
 145           dentry->value = (char *)xmalloc (1);
 146           dentry->value[0] = '\0';
 147         }
 148       dentry->exportstr = 0;
 149       dentry->attributes = entry->attributes & ~(att_array|att_assoc|att_exported);
 150       /* Leave the rest of the members uninitialized; the code doesn't look
 151          at them. */
 152       newval = make_variable_value (dentry, value, flags);
 153       dispose_variable (dentry);
 154     }
 155   else
 156     newval = make_variable_value (entry, value, flags);
 157
 158   if (entry->assign_func)
 159     (*entry->assign_func) (entry, newval, ind, key);
 160   else if (assoc_p (entry))
 161     assoc_insert (assoc_cell (entry), key, newval);
 162   else
 163     array_insert (array_cell (entry), ind, newval);
 164   FREE (newval);
 165
 166   return (entry);
 167 }
 168
 169 /* Perform an array assignment name[ind]=value.  If NAME already exists and
 170    is not an array, and IND is 0, perform name=value instead.  If NAME exists
 171    and is not an array, and IND is not 0, convert it into an array with the
 172    existing value as name[0].
 173
 174    If NAME does not exist, just create an array variable, no matter what
 175    IND's value may be. */
 176 SHELL_VAR *
 177 bind_array_variable (name, ind, value, flags)
 178      char *name;
 179      arrayind_t ind;
 180      char *value;
 181      int flags;
 182 {
 183   SHELL_VAR *entry;
 184
 185   entry = var_lookup (name, shell_variables);
 186
 187   if (entry == (SHELL_VAR *) 0)
 188     entry = make_new_array_variable (name);
 189   else if (readonly_p (entry) || noassign_p (entry))
 190     {
 191       if (readonly_p (entry))
 192         err_readonly (name);
 193       return (entry);
 194     }
 195   else if (array_p (entry) == 0)
 196     entry = convert_var_to_array (entry);
 197
 198   /* ENTRY is an array variable, and ARRAY points to the value. */
 199   return (bind_array_var_internal (entry, ind, 0, value, flags));
 200 }
 201
 202 SHELL_VAR *
 203 bind_array_element (entry, ind, value, flags)
 204      SHELL_VAR *entry;
 205      arrayind_t ind;
 206      char *value;
 207      int flags;
 208 {
 209   return (bind_array_var_internal (entry, ind, 0, value, flags));
 210 }
 211
 212 SHELL_VAR *
 213 bind_assoc_variable (entry, name, key, value, flags)
 214      SHELL_VAR *entry;
 215      char *name;
 216      char *key;
 217      char *value;
 218      int flags;
 219 {
 220   SHELL_VAR *dentry;
 221   char *newval;
 222
 223   if (readonly_p (entry) || noassign_p (entry))
 224     {
 225       if (readonly_p (entry))
 226         err_readonly (name);
 227       return (entry);
 228     }
 229
 230   return (bind_array_var_internal (entry, 0, key, value, flags));
 231 }
 232
 233 /* Parse NAME, a lhs of an assignment statement of the form v[s], and
 234    assign VALUE to that array element by calling bind_array_variable(). */
 235 SHELL_VAR *
 236 assign_array_element (name, value, flags)
 237      char *name, *value;
 238      int flags;
 239 {
 240   char *sub, *vname, *akey;
 241   arrayind_t ind;
 242   int sublen;
 243   SHELL_VAR *entry;
 244
 245   vname = array_variable_name (name, &sub, &sublen);
 246
 247   if (vname == 0)
 248     return ((SHELL_VAR *)NULL);
 249
 250   if ((ALL_ELEMENT_SUB (sub[0]) && sub[1] == ']') || (sublen <= 1))
 251     {
 252       free (vname);
 253       err_badarraysub (name);
 254       return ((SHELL_VAR *)NULL);
 255     }
 256
 257   entry = find_variable (vname);
 258
 259   if (entry && assoc_p (entry))
 260     {
 261       sub[sublen-1] = '\0';
 262       akey = expand_assignment_string_to_string (sub, 0);       /* [ */
 263       sub[sublen-1] = ']';
 264       if (akey == 0 || *akey == 0)
 265         {
 266           free (vname);
 267           err_badarraysub (name);
 268           return ((SHELL_VAR *)NULL);
 269         }
 270       entry = bind_assoc_variable (entry, vname, akey, value, flags);
 271     }
 272   else
 273     {
 274       ind = array_expand_index (sub, sublen);
 275       if (ind < 0)
 276         {
 277           free (vname);
 278           err_badarraysub (name);
 279           return ((SHELL_VAR *)NULL);
 280         }
 281       entry = bind_array_variable (vname, ind, value, flags);
 282     }
 283
 284   free (vname);
 285   return (entry);
 286 }
 287
 288 /* Find the array variable corresponding to NAME.  If there is no variable,
 289    create a new array variable.  If the variable exists but is not an array,
 290    convert it to an indexed array.  If FLAGS&1 is non-zero, an existing
 291    variable is checked for the readonly or noassign attribute in preparation
 292    for assignment (e.g., by the `read' builtin).  If FLAGS&2 is non-zero, we
 293    create an associative array. */
 294 SHELL_VAR *
 295 find_or_make_array_variable (name, flags)
 296      char *name;
 297      int flags;
 298 {
 299   SHELL_VAR *var;
 300
 301   var = find_variable (name);
 302
 303   if (var == 0)
 304     var = (flags & 2) ? make_new_assoc_variable (name) : make_new_array_variable (name);
 305   else if ((flags & 1) && (readonly_p (var) || noassign_p (var)))
 306     {
 307       if (readonly_p (var))
 308         err_readonly (name);
 309       return ((SHELL_VAR *)NULL);
 310     }
 311   else if ((flags & 2) && array_p (var))
 312     {
 313       report_error (_("%s: cannot convert indexed to associative array"), name);
 314       return ((SHELL_VAR *)NULL);
 315     }
 316   else if (array_p (var) == 0 && assoc_p (var) == 0)
 317     var = convert_var_to_array (var);
 318
 319   return (var);
 320 }
 321
 322 /* Perform a compound assignment statement for array NAME, where VALUE is
 323    the text between the parens:  NAME=( VALUE ) */
 324 SHELL_VAR *
 325 assign_array_from_string (name, value, flags)
 326      char *name, *value;
 327      int flags;
 328 {
 329   SHELL_VAR *var;
 330   int vflags;
 331
 332   vflags = 1;
 333   if (flags & ASS_MKASSOC)
 334     vflags |= 2;
 335
 336   var = find_or_make_array_variable (name, vflags);
 337   if (var == 0)
 338     return ((SHELL_VAR *)NULL);
 339
 340   return (assign_array_var_from_string (var, value, flags));
 341 }
 342
 343 /* Sequentially assign the indices of indexed array variable VAR from the
 344    words in LIST. */
 345 SHELL_VAR *
 346 assign_array_var_from_word_list (var, list, flags)
 347      SHELL_VAR *var;
 348      WORD_LIST *list;
 349      int flags;
 350 {
 351   register arrayind_t i;
 352   register WORD_LIST *l;
 353   ARRAY *a;
 354
 355   a = array_cell (var);
 356   i = (flags & ASS_APPEND) ? array_max_index (a) + 1 : 0;
 357
 358   for (l = list; l; l = l->next, i++)
 359     if (var->assign_func)
 360       (*var->assign_func) (var, l->word->word, i, 0);
 361     else
 362       array_insert (a, i, l->word->word);
 363   return var;
 364 }
 365
 366 WORD_LIST *
 367 expand_compound_array_assignment (var, value, flags)
 368      SHELL_VAR *var;
 369      char *value;
 370      int flags;
 371 {
 372   WORD_LIST *list, *nlist;
 373   char *val;
 374   int ni;
 375
 376   /* I don't believe this condition is ever true any more. */
 377   if (*value == '(')    /*)*/
 378     {
 379       ni = 1;
 380       val = extract_array_assignment_list (value, &ni);
 381       if (val == 0)
 382         return (WORD_LIST *)NULL;
 383     }
 384   else
 385     val = value;
 386
 387   /* Expand the value string into a list of words, performing all the
 388      shell expansions including pathname generation and word splitting. */
 389   /* First we split the string on whitespace, using the shell parser
 390      (ksh93 seems to do this). */
 391   list = parse_string_to_word_list (val, 1, "array assign");
 392
 393   /* If we're using [subscript]=value, we need to quote each [ and ] to
 394      prevent unwanted filename expansion. */
 395   if (list)
 396     quote_array_assignment_chars (list);
 397
 398   /* Now that we've split it, perform the shell expansions on each
 399      word in the list. */
 400   nlist = list ? expand_words_no_vars (list) : (WORD_LIST *)NULL;
 401
 402   dispose_words (list);
 403
 404   if (val != value)
 405     free (val);
 406
 407   return nlist;
 408 }
 409
 410 void
 411 assign_compound_array_list (var, nlist, flags)
 412      SHELL_VAR *var;
 413      WORD_LIST *nlist;
 414      int flags;
 415 {
 416   ARRAY *a;
 417   HASH_TABLE *h;
 418   WORD_LIST *list;
 419   char *w, *val, *nval;
 420   int len, iflags;
 421   arrayind_t ind, last_ind;
 422   char *akey;
 423
 424   a = (var && array_p (var)) ? array_cell (var) : (ARRAY *)0;
 425   h = (var && assoc_p (var)) ? assoc_cell (var) : (HASH_TABLE *)0;
 426
 427   akey = (char *)0;
 428   ind = 0;
 429
 430   /* Now that we are ready to assign values to the array, kill the existing
 431      value. */
 432   if ((flags & ASS_APPEND) == 0)
 433     {
 434       if (array_p (var) && a)
 435         array_flush (a);
 436       else if (assoc_p (var) && h)
 437         assoc_flush (h);
 438     }
 439
 440   last_ind = (a && (flags & ASS_APPEND)) ? array_max_index (a) + 1 : 0;
 441
 442   for (list = nlist; list; list = list->next)
 443     {
 444       iflags = flags;
 445       w = list->word->word;
 446
 447       /* We have a word of the form [ind]=value */
 448       if ((list->word->flags & W_ASSIGNMENT) && w[0] == '[')
 449         {
 450           len = skipsubscript (w, 0);
 451
 452           /* XXX - changes for `+=' */
 453           if (w[len] != ']' || (w[len+1] != '=' && (w[len+1] != '+' || w[len+2] != '=')))
 454             {
 455               if (assoc_p (var))
 456                 {
 457                   err_badarraysub (w);
 458                   continue;
 459                 }
 460               nval = make_variable_value (var, w, flags);
 461               if (var->assign_func)
 462                 (*var->assign_func) (var, nval, last_ind, 0);
 463               else
 464                 array_insert (a, last_ind, nval);
 465               FREE (nval);
 466               last_ind++;
 467               continue;
 468             }
 469
 470           if (len == 1)
 471             {
 472               err_badarraysub (w);
 473               continue;
 474             }
 475
 476           if (ALL_ELEMENT_SUB (w[1]) && len == 2)
 477             {
 478               if (assoc_p (var))
 479                 report_error (_("%s: invalid associative array key"), w);
 480               else
 481                 report_error (_("%s: cannot assign to non-numeric index"), w);
 482               continue;
 483             }
 484
 485           if (array_p (var))
 486             {
 487               ind = array_expand_index (w + 1, len);
 488               if (ind < 0)
 489                 {
 490                   err_badarraysub (w);
 491                   continue;
 492                 }
 493
 494               last_ind = ind;
 495             }
 496           else if (assoc_p (var))
 497             {
 498               akey = substring (w, 1, len);
 499               if (akey == 0 || *akey == 0)
 500                 {
 501                   err_badarraysub (w);
 502                   continue;
 503                 }
 504             }
 505
 506           /* XXX - changes for `+=' -- just accept the syntax.  ksh93 doesn't do this */
 507           if (w[len + 1] == '+' && w[len + 2] == '=')
 508             {
 509               iflags |= ASS_APPEND;
 510               val = w + len + 3;
 511             }
 512           else
 513             val = w + len + 2;
 514         }
 515       else if (assoc_p (var))
 516         {
 517           report_error (_("%s: %s: must use subscript when assigning associative array"), var->name, w);
 518           continue;
 519         }
 520       else              /* No [ind]=value, just a stray `=' */
 521         {
 522           ind = last_ind;
 523           val = w;
 524         }
 525
 526       if (integer_p (var))
 527         this_command_name = (char *)NULL;       /* no command name for errors */
 528       bind_array_var_internal (var, ind, akey, val, iflags);
 529       last_ind++;
 530     }
 531 }
 532
 533 /* Perform a compound array assignment:  VAR->name=( VALUE ).  The
 534    VALUE has already had the parentheses stripped. */
 535 SHELL_VAR *
 536 assign_array_var_from_string (var, value, flags)
 537      SHELL_VAR *var;
 538      char *value;
 539      int flags;
 540 {
 541   WORD_LIST *nlist;
 542
 543   if (value == 0)
 544     return var;
 545
 546   nlist = expand_compound_array_assignment (var, value, flags);
 547   assign_compound_array_list (var, nlist, flags);
 548
 549   if (nlist)
 550     dispose_words (nlist);
 551   return (var);
 552 }
 553
 554 /* Quote globbing chars and characters in $IFS before the `=' in an assignment
 555    statement (usually a compound array assignment) to protect them from
 556    unwanted filename expansion or word splitting. */
 557 static char *
 558 quote_assign (string)
 559      const char *string;
 560 {
 561   size_t slen;
 562   int saw_eq;
 563   char *temp, *t;
 564   const char *s, *send;
 565   DECLARE_MBSTATE;
 566
 567   slen = strlen (string);
 568   send = string + slen;
 569
 570   t = temp = (char *)xmalloc (slen * 2 + 1);
 571   saw_eq = 0;
 572   for (s = string; *s; )
 573     {
 574       if (*s == '=')
 575         saw_eq = 1;
 576       if (saw_eq == 0 && (glob_char_p (s) || isifs (*s)))
 577         *t++ = '\\';
 578
 579       COPY_CHAR_P (t, s, send);
 580     }
 581   *t = '\0';
 582   return temp;
 583 }
 584
 585 /* For each word in a compound array assignment, if the word looks like
 586    [ind]=value, quote globbing chars and characters in $IFS before the `='. */
 587 static void
 588 quote_array_assignment_chars (list)
 589      WORD_LIST *list;
 590 {
 591   char *nword;
 592   WORD_LIST *l;
 593
 594   for (l = list; l; l = l->next)
 595     {
 596       if (l->word == 0 || l->word->word == 0 || l->word->word[0] == '\0')
 597         continue;       /* should not happen, but just in case... */
 598       /* Don't bother if it doesn't look like [ind]=value */
 599       if (l->word->word[0] != '[' || xstrchr (l->word->word, '=') == 0) /* ] */
 600         continue;
 601       nword = quote_assign (l->word->word);
 602       free (l->word->word);
 603       l->word->word = nword;
 604     }
 605 }
 606
 607 /* skipsubscript moved to subst.c to use private functions. 2009/02/24. */
 608
 609 /* This function is called with SUB pointing to just after the beginning
 610    `[' of an array subscript and removes the array element to which SUB
 611    expands from array VAR.  A subscript of `*' or `@' unsets the array. */
 612 int
 613 unbind_array_element (var, sub)
 614      SHELL_VAR *var;
 615      char *sub;
 616 {
 617   int len;
 618   arrayind_t ind;
 619   char *akey;
 620   ARRAY_ELEMENT *ae;
 621
 622   len = skipsubscript (sub, 0);
 623   if (sub[len] != ']' || len == 0)
 624     {
 625       builtin_error ("%s[%s: %s", var->name, sub, _(bash_badsub_errmsg));
 626       return -1;
 627     }
 628   sub[len] = '\0';
 629
 630   if (ALL_ELEMENT_SUB (sub[0]) && sub[1] == 0)
 631     {
 632       unbind_variable (var->name);
 633       return (0);
 634     }
 635
 636   if (assoc_p (var))
 637     {
 638       akey = expand_assignment_string_to_string (sub, 0);     /* [ */
 639       if (akey == 0 || *akey == 0)
 640         {
 641           builtin_error ("[%s]: %s", sub, _(bash_badsub_errmsg));
 642           return -1;
 643         }
 644       assoc_remove (assoc_cell (var), akey);
 645     }
 646   else
 647     {
 648       ind = array_expand_index (sub, len+1);
 649       if (ind < 0)
 650         {
 651           builtin_error ("[%s]: %s", sub, _(bash_badsub_errmsg));
 652           return -1;
 653         }
 654       ae = array_remove (array_cell (var), ind);
 655       if (ae)
 656         array_dispose_element (ae);
 657     }
 658
 659   return 0;
 660 }
 661
 662 /* Format and output an array assignment in compound form VAR=(VALUES),
 663    suitable for re-use as input. */
 664 void
 665 print_array_assignment (var, quoted)
 666      SHELL_VAR *var;
 667      int quoted;
 668 {
 669   char *vstr;
 670
 671   vstr = array_to_assign (array_cell (var), quoted);
 672
 673   if (vstr == 0)
 674     printf ("%s=%s\n", var->name, quoted ? "'()'" : "()");
 675   else
 676     {
 677       printf ("%s=%s\n", var->name, vstr);
 678       free (vstr);
 679     }
 680 }
 681
 682 /* Format and output an associative array assignment in compound form
 683    VAR=(VALUES), suitable for re-use as input. */
 684 void
 685 print_assoc_assignment (var, quoted)
 686      SHELL_VAR *var;
 687      int quoted;
 688 {
 689   char *vstr;
 690
 691   vstr = assoc_to_assign (assoc_cell (var), quoted);
 692
 693   if (vstr == 0)
 694     printf ("%s=%s\n", var->name, quoted ? "'()'" : "()");
 695   else
 696     {
 697       printf ("%s=%s\n", var->name, vstr);
 698       free (vstr);
 699     }
 700 }
 701
 702 /***********************************************************************/
 703 /*                                                                     */
 704 /* Utility functions to manage arrays and their contents for expansion */
 705 /*                                                                     */
 706 /***********************************************************************/
 707
 708 /* Return 1 if NAME is a properly-formed array reference v[sub]. */
 709 int
 710 valid_array_reference (name)
 711      char *name;
 712 {
 713   char *t;
 714   int r, len;
 715
 716   t = xstrchr (name, '[');      /* ] */
 717   if (t)
 718     {
 719       *t = '\0';
 720       r = legal_identifier (name);
 721       *t = '[';
 722       if (r == 0)
 723         return 0;
 724       /* Check for a properly-terminated non-blank subscript. */
 725       len = skipsubscript (t, 0);
 726       if (t[len] != ']' || len == 1)
 727         return 0;
 728       for (r = 1; r < len; r++)
 729         if (whitespace (t[r]) == 0)
 730           return 1;
 731       return 0;
 732     }
 733   return 0;
 734 }
 735
 736 /* Expand the array index beginning at S and extending LEN characters. */
 737 arrayind_t
 738 array_expand_index (s, len)
 739      char *s;
 740      int len;
 741 {
 742   char *exp, *t;
 743   int expok;
 744   arrayind_t val;
 745
 746   exp = (char *)xmalloc (len);
 747   strncpy (exp, s, len - 1);
 748   exp[len - 1] = '\0';
 749   t = expand_arith_string (exp, 0);
 750   this_command_name = (char *)NULL;
 751   val = evalexp (t, &expok);
 752   free (t);
 753   free (exp);
 754   if (expok == 0)
 755     {
 756       last_command_exit_value = EXECUTION_FAILURE;
 757
 758       top_level_cleanup ();
 759       jump_to_top_level (DISCARD);
 760     }
 761   return val;
 762 }
 763
 764 /* Return the name of the variable specified by S without any subscript.
 765    If SUBP is non-null, return a pointer to the start of the subscript
 766    in *SUBP. If LENP is non-null, the length of the subscript is returned
 767    in *LENP.  This returns newly-allocated memory. */
 768 char *
 769 array_variable_name (s, subp, lenp)
 770      char *s, **subp;
 771      int *lenp;
 772 {
 773   char *t, *ret;
 774   int ind, ni;
 775
 776   t = xstrchr (s, '[');
 777   if (t == 0)
 778     {
 779       if (subp)
 780         *subp = t;
 781       if (lenp)
 782         *lenp = 0;
 783       return ((char *)NULL);
 784     }
 785   ind = t - s;
 786   ni = skipsubscript (s, ind);
 787   if (ni <= ind + 1 || s[ni] != ']')
 788     {
 789       err_badarraysub (s);
 790       if (subp)
 791         *subp = t;
 792       if (lenp)
 793         *lenp = 0;
 794       return ((char *)NULL);
 795     }
 796
 797   *t = '\0';
 798   ret = savestring (s);
 799   *t++ = '[';           /* ] */
 800
 801   if (subp)
 802     *subp = t;
 803   if (lenp)
 804     *lenp = ni - ind;
 805
 806   return ret;
 807 }
 808
 809 /* Return the variable specified by S without any subscript.  If SUBP is
 810    non-null, return a pointer to the start of the subscript in *SUBP.
 811    If LENP is non-null, the length of the subscript is returned in *LENP. */
 812 SHELL_VAR *
 813 array_variable_part (s, subp, lenp)
 814      char *s, **subp;
 815      int *lenp;
 816 {
 817   char *t;
 818   SHELL_VAR *var;
 819
 820   t = array_variable_name (s, subp, lenp);
 821   if (t == 0)
 822     return ((SHELL_VAR *)NULL);
 823   var = find_variable (t);
 824
 825   free (t);
 826   return (var == 0 || invisible_p (var)) ? (SHELL_VAR *)0 : var;
 827 }
 828
 829 /* Return a string containing the elements in the array and subscript
 830    described by S.  If the subscript is * or @, obeys quoting rules akin
 831    to the expansion of $* and $@ including double quoting.  If RTYPE
 832    is non-null it gets 1 if the array reference is name[*], 2 if the
 833    reference is name[@], and 0 otherwise. */
 834 static char *
 835 array_value_internal (s, quoted, allow_all, rtype)
 836      char *s;
 837      int quoted, allow_all, *rtype;
 838 {
 839   int len;
 840   arrayind_t ind;
 841   char *akey;
 842   char *retval, *t, *temp;
 843   WORD_LIST *l;
 844   SHELL_VAR *var;
 845
 846   var = array_variable_part (s, &t, &len);
 847
 848   /* Expand the index, even if the variable doesn't exist, in case side
 849      effects are needed, like ${w[i++]} where w is unset. */
 850 #if 0
 851   if (var == 0)
 852     return (char *)NULL;
 853 #endif
 854
 855   if (len == 0)
 856     return ((char *)NULL);      /* error message already printed */
 857
 858   /* [ */
 859   if (ALL_ELEMENT_SUB (t[0]) && t[1] == ']')
 860     {
 861       if (rtype)
 862         *rtype = (t[0] == '*') ? 1 : 2;
 863       if (allow_all == 0)
 864         {
 865           err_badarraysub (s);
 866           return ((char *)NULL);
 867         }
 868       else if (var == 0 || value_cell (var) == 0)
 869         return ((char *)NULL);
 870       else if (array_p (var) == 0 && assoc_p (var) == 0)
 871         l = add_string_to_list (value_cell (var), (WORD_LIST *)NULL);
 872       else if (assoc_p (var))
 873         {
 874           l = assoc_to_word_list (assoc_cell (var));
 875           if (l == (WORD_LIST *)NULL)
 876             return ((char *)NULL);
 877         }
 878       else
 879         {
 880           l = array_to_word_list (array_cell (var));
 881           if (l == (WORD_LIST *)NULL)
 882             return ((char *) NULL);
 883         }
 884
 885       if (t[0] == '*' && (quoted & (Q_HERE_DOCUMENT|Q_DOUBLE_QUOTES)))
 886         {
 887           temp = string_list_dollar_star (l);
 888           retval = quote_string (temp);
 889           free (temp);
 890         }
 891       else      /* ${name[@]} or unquoted ${name[*]} */
 892         retval = string_list_dollar_at (l, quoted);
 893
 894       dispose_words (l);
 895     }
 896   else
 897     {
 898       if (rtype)
 899         *rtype = 0;
 900       if (var == 0 || array_p (var) || assoc_p (var) == 0)
 901         {
 902           ind = array_expand_index (t, len);
 903           if (ind < 0)
 904             {
 905 index_error:
 906               if (var)
 907                 err_badarraysub (var->name);
 908               else
 909                 {
 910                   t[-1] = '\0';
 911                   err_badarraysub (s);
 912                   t[-1] = '[';  /* ] */
 913                 }
 914               return ((char *)NULL);
 915             }
 916         }
 917       else if (assoc_p (var))
 918         {
 919           t[len - 1] = '\0';
 920           akey = expand_assignment_string_to_string (t, 0);     /* [ */
 921           t[len - 1] = ']';
 922           if (akey == 0 || *akey == 0)
 923             goto index_error;
 924         }
 925
 926       if (var == 0)
 927         return ((char *)NULL);
 928       if (array_p (var) == 0 && assoc_p (var) == 0)
 929         return (ind == 0 ? value_cell (var) : (char *)NULL);
 930       else if (assoc_p (var))
 931         retval = assoc_reference (assoc_cell (var), akey);
 932       else
 933         retval = array_reference (array_cell (var), ind);
 934     }
 935
 936   return retval;
 937 }
 938
 939 /* Return a string containing the elements described by the array and
 940    subscript contained in S, obeying quoting for subscripts * and @. */
 941 char *
 942 array_value (s, quoted, rtype)
 943      char *s;
 944      int quoted, *rtype;
 945 {
 946   return (array_value_internal (s, quoted, 1, rtype));
 947 }
 948
 949 /* Return the value of the array indexing expression S as a single string.
 950    If ALLOW_ALL is 0, do not allow `@' and `*' subscripts.  This is used
 951    by other parts of the shell such as the arithmetic expression evaluator
 952    in expr.c. */
 953 char *
 954 get_array_value (s, allow_all, rtype)
 955      char *s;
 956      int allow_all, *rtype;
 957 {
 958   return (array_value_internal (s, 0, allow_all, rtype));
 959 }
 960
 961 char *
 962 array_keys (s, quoted)
 963      char *s;
 964      int quoted;
 965 {
 966   int len;
 967   char *retval, *t, *temp;
 968   WORD_LIST *l;
 969   SHELL_VAR *var;
 970
 971   var = array_variable_part (s, &t, &len);
 972
 973   /* [ */
 974   if (var == 0 || ALL_ELEMENT_SUB (t[0]) == 0 || t[1] != ']')
 975     return (char *)NULL;
 976
 977   if (array_p (var) == 0 && assoc_p (var) == 0)
 978     l = add_string_to_list ("0", (WORD_LIST *)NULL);
 979   else if (assoc_p (var))
 980     l = assoc_keys_to_word_list (assoc_cell (var));
 981   else
 982     l = array_keys_to_word_list (array_cell (var));
 983   if (l == (WORD_LIST *)NULL)
 984     return ((char *) NULL);
 985
 986   if (t[0] == '*' && (quoted & (Q_HERE_DOCUMENT|Q_DOUBLE_QUOTES)))
 987     {
 988       temp = string_list_dollar_star (l);
 989       retval = quote_string (temp);
 990       free (temp);
 991     }
 992   else  /* ${!name[@]} or unquoted ${!name[*]} */
 993     retval = string_list_dollar_at (l, quoted);
 994
 995   dispose_words (l);
 996   return retval;
 997 }
 998 #endif /* ARRAY_VARS */