src/getargs.c

   1 /* Parse command line arguments for Bison.
   2
   3    Copyright (C) 1984, 1986, 1989, 1992, 2000-2012 Free Software
   4    Foundation, Inc.
   5
   6    This file is part of Bison, the GNU Compiler Compiler.
   7
   8    This program is free software: you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation, either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include <config.h>
  22 #include "system.h"
  23 #include "output.h"
  24
  25 #include <argmatch.h>
  26 #include <c-strcase.h>
  27 #include <configmake.h>
  28 #include <error.h>
  29 #include <getopt.h>
  30 #include <progname.h>
  31
  32 #include "complain.h"
  33 #include "files.h"
  34 #include "getargs.h"
  35 #include "muscle-tab.h"
  36 #include "quote.h"
  37 #include "uniqstr.h"
  38
  39 bool defines_flag;
  40 bool graph_flag;
  41 bool xml_flag;
  42 bool no_lines_flag;
  43 bool token_table_flag;
  44 bool yacc_flag; /* for -y */
  45
  46 bool nondeterministic_parser = false;
  47 bool glr_parser = false;
  48
  49 int report_flag = report_none;
  50 int trace_flag = trace_none;
  51
  52 static struct bison_language const valid_languages[] = {
  53   { "c", "c-skel.m4", ".c", ".h", true },
  54   { "c++", "c++-skel.m4", ".cc", ".hh", true },
  55   { "java", "java-skel.m4", ".java", ".java", false },
  56   { "", "", "", "", false }
  57 };
  58
  59 int skeleton_prio = default_prio;
  60 const char *skeleton = NULL;
  61 int language_prio = default_prio;
  62 struct bison_language const *language = &valid_languages[0];
  63 const char *include = NULL;
  64
  65
  66 /** Decode an option's set of keys.
  67  *
  68  *  \param option   option being decoded.
  69  *  \param keys     array of valid subarguments.
  70  *  \param values   array of corresponding (int) values.
  71  *  \param all      the all value.
  72  *  \param flags    the flags to update
  73  *  \param args     comma separated list of effective subarguments to decode.
  74  *                  If 0, then activate all the flags.
  75  *
  76  *  If VALUE != 0 then KEY sets flags and no-KEY clears them.
  77  *  If VALUE == 0 then KEY clears all flags from \c all and no-KEY sets all
  78  *  flags from \c all.  Thus no-none = all and no-all = none.
  79  */
  80 static void
  81 flags_argmatch (const char *option,
  82                 const char * const keys[], const int values[],
  83                 int all, int *flags, char *args)
  84 {
  85   if (args)
  86   {
  87     args = strtok (args, ",");
  88
  89      /* Not sure whether we should keep this : -Werror=no-bar */
  90     int no = STRPREFIX_LIT ("no-", args) ? 3 : 0;
  91     args += no;
  92     int value = 0;
  93
  94     while (args)
  95     {
  96       int err = STRPREFIX_LIT ("error", args);
  97       if (err)
  98         args += (args[5] == '=') ? 6 : 5;
  99
 100       if (!err || args[-1] == '=')
 101         value = XARGMATCH (option, args, keys, values);
 102       if (value == 0)
 103       {
 104         if (no)
 105         {
 106           if (err)
 107             /* Using &= ~all activates complaint, silent and fatal */
 108             errors_flag = Wnone;
 109           else
 110             *flags |= all;
 111         }
 112         else
 113         {
 114           if (err)
 115             errors_flag |= all;
 116           else
 117             *flags &= ~all;
 118         }
 119       }
 120       else
 121       {
 122         if (no)
 123         {
 124           if (err)
 125             errors_flag &= ~value;
 126           else
 127             *flags &= ~value;
 128         }
 129         else
 130         {
 131           if (err)
 132           {
 133             errors_flag |= value;
 134             warnings_flag |= value;
 135           }
 136           else
 137             *flags |= value;
 138         }
 139       }
 140       args = strtok (NULL, ",");
 141     }
 142   }
 143 }
 144
 145 /** Decode a set of sub arguments.
 146  *
 147  *  \param FlagName  the flag familly to update.
 148  *  \param Args      the effective sub arguments to decode.
 149  *  \param All       the "all" value.
 150  *
 151  *  \arg FlagName_args   the list of keys.
 152  *  \arg FlagName_types  the list of values.
 153  *  \arg FlagName_flag   the flag to update.
 154  */
 155 #define FLAGS_ARGMATCH(FlagName, Args, All)                             \
 156   flags_argmatch ("--" #FlagName, FlagName ## _args, FlagName ## _types, \
 157                   All, &FlagName ## _flag, Args)
 158
 159
 160 /*----------------------.
 161 | --report's handling.  |
 162 `----------------------*/
 163
 164 static const char * const report_args[] =
 165 {
 166   /* In a series of synonyms, present the most meaningful first, so
 167      that argmatch_valid be more readable.  */
 168   "none",
 169   "state", "states",
 170   "itemset", "itemsets",
 171   "lookahead", "lookaheads", "look-ahead",
 172   "solved",
 173   "all",
 174   0
 175 };
 176
 177 static const int report_types[] =
 178 {
 179   report_none,
 180   report_states, report_states,
 181   report_states | report_itemsets, report_states | report_itemsets,
 182   report_states | report_lookahead_tokens,
 183   report_states | report_lookahead_tokens,
 184   report_states | report_lookahead_tokens,
 185   report_states | report_solved_conflicts,
 186   report_all
 187 };
 188
 189 ARGMATCH_VERIFY (report_args, report_types);
 190
 191
 192 /*---------------------.
 193 | --trace's handling.  |
 194 `---------------------*/
 195
 196 static const char * const trace_args[] =
 197 {
 198   /* In a series of synonyms, present the most meaningful first, so
 199      that argmatch_valid be more readable.  */
 200   "none       - no traces",
 201   "scan       - grammar scanner traces",
 202   "parse      - grammar parser traces",
 203   "automaton  - construction of the automaton",
 204   "bitsets    - use of bitsets",
 205   "grammar    - reading, reducing the grammar",
 206   "resource   - memory consumption (where available)",
 207   "sets       - grammar sets: firsts, nullable etc.",
 208   "muscles    - m4 definitions passed to the skeleton",
 209   "tools      - m4 invocation",
 210   "m4         - m4 traces",
 211   "skeleton   - skeleton postprocessing",
 212   "time       - time consumption",
 213   "ielr       - IELR conversion",
 214   "all        - all of the above",
 215   0
 216 };
 217
 218 static const int trace_types[] =
 219 {
 220   trace_none,
 221   trace_scan,
 222   trace_parse,
 223   trace_automaton,
 224   trace_bitsets,
 225   trace_grammar,
 226   trace_resource,
 227   trace_sets,
 228   trace_muscles,
 229   trace_tools,
 230   trace_m4,
 231   trace_skeleton,
 232   trace_time,
 233   trace_ielr,
 234   trace_all
 235 };
 236
 237 ARGMATCH_VERIFY (trace_args, trace_types);
 238
 239
 240 /*------------------------.
 241 | --warnings's handling.  |
 242 `------------------------*/
 243
 244 static const char * const warnings_args[] =
 245 {
 246   /* In a series of synonyms, present the most meaningful first, so
 247      that argmatch_valid be more readable.  */
 248   "none            - no warnings",
 249   "midrule-values  - unset or unused midrule values",
 250   "yacc            - incompatibilities with POSIX Yacc",
 251   "conflicts-sr    - S/R conflicts",
 252   "conflicts-rr    - R/R conflicts",
 253   "deprecated      - obsolete constructs",
 254   "other           - all other warnings",
 255   "all             - all of the above",
 256   "error           - warnings are errors",
 257   0
 258 };
 259
 260 static const int warnings_types[] =
 261 {
 262   Wnone,
 263   Wmidrule_values,
 264   Wyacc,
 265   Wconflicts_sr,
 266   Wconflicts_rr,
 267   Wdeprecated,
 268   Wother,
 269   Wall,
 270   Werror
 271 };
 272
 273 ARGMATCH_VERIFY (warnings_args, warnings_types);
 274
 275 /*-------------------------------------------.
 276 | Display the help message and exit STATUS.  |
 277 `-------------------------------------------*/
 278
 279 static void usage (int) ATTRIBUTE_NORETURN;
 280
 281 static void
 282 usage (int status)
 283 {
 284   if (status != 0)
 285     fprintf (stderr, _("Try `%s --help' for more information.\n"),
 286              program_name);
 287   else
 288     {
 289       /* For ../build-aux/cross-options.pl to work, use the format:
 290                 ^  -S, --long[=ARGS] (whitespace)
 291          A --long option is required.
 292          Otherwise, add exceptions to ../build-aux/cross-options.pl.  */
 293
 294       printf (_("Usage: %s [OPTION]... FILE\n"), program_name);
 295       fputs (_("\
 296 Generate a deterministic LR or generalized LR (GLR) parser employing\n\
 297 LALR(1), IELR(1), or canonical LR(1) parser tables.  IELR(1) and\n\
 298 canonical LR(1) support is experimental.\n\
 299 \n\
 300 "), stdout);
 301
 302       fputs (_("\
 303 Mandatory arguments to long options are mandatory for short options too.\n\
 304 "), stdout);
 305       fputs (_("\
 306 The same is true for optional arguments.\n\
 307 "), stdout);
 308
 309       fputs (_("\
 310 \n\
 311 Operation modes:\n\
 312   -h, --help                 display this help and exit\n\
 313   -V, --version              output version information and exit\n\
 314       --print-localedir      output directory containing locale-dependent data\n\
 315       --print-datadir        output directory containing skeletons and XSLT\n\
 316   -y, --yacc                 emulate POSIX Yacc\n\
 317   -W, --warnings[=CATEGORY]  report the warnings falling in CATEGORY\n\
 318 \n\
 319 "), stdout);
 320
 321       fputs (_("\
 322 Parser:\n\
 323   -L, --language=LANGUAGE          specify the output programming language\n\
 324                                    (this is an experimental feature)\n\
 325   -S, --skeleton=FILE              specify the skeleton to use\n\
 326   -t, --debug                      instrument the parser for tracing\n\
 327                                    same as `-Dparse.trace'\n\
 328       --locations                  enable location support\n\
 329   -D, --define=NAME[=VALUE]        similar to '%define NAME \"VALUE\"'\n\
 330   -F, --force-define=NAME[=VALUE]  override '%define NAME \"VALUE\"'\n\
 331   -p, --name-prefix=PREFIX         prepend PREFIX to the external symbols\n\
 332                                    deprecated by '-Dapi.prefix=PREFIX'\n\
 333   -l, --no-lines                   don't generate '#line' directives\n\
 334   -k, --token-table                include a table of token names\n\
 335 \n\
 336 "), stdout);
 337
 338       /* Keep -d and --defines separate so that ../build-aux/cross-options.pl
 339        * won't assume that -d also takes an argument.  */
 340       fputs (_("\
 341 Output:\n\
 342       --defines[=FILE]       also produce a header file\n\
 343   -d                         likewise but cannot specify FILE (for POSIX Yacc)\n\
 344   -r, --report=THINGS        also produce details on the automaton\n\
 345       --report-file=FILE     write report to FILE\n\
 346   -v, --verbose              same as `--report=state'\n\
 347   -b, --file-prefix=PREFIX   specify a PREFIX for output files\n\
 348   -o, --output=FILE          leave output to FILE\n\
 349   -g, --graph[=FILE]         also output a graph of the automaton\n\
 350   -x, --xml[=FILE]           also output an XML report of the automaton\n\
 351                              (the XML schema is experimental)\n\
 352 \n\
 353 "), stdout);
 354
 355       fputs (_("\
 356 Warning categories include:\n\
 357   `midrule-values'  unset or unused midrule values\n\
 358   `yacc'            incompatibilities with POSIX Yacc\n\
 359   `conflicts-sr'    S/R conflicts (enabled by default)\n\
 360   `conflicts-rr'    R/R conflicts (enabled by default)\n\
 361   `other'           all other warnings (enabled by default)\n\
 362   `all'             all the warnings\n\
 363   `no-CATEGORY'     turn off warnings in CATEGORY\n\
 364   `none'            turn off all the warnings\n\
 365   `error'           treat warnings as errors\n\
 366 \n\
 367 "), stdout);
 368
 369       fputs (_("\
 370 THINGS is a list of comma separated words that can include:\n\
 371   `state'        describe the states\n\
 372   `itemset'      complete the core item sets with their closure\n\
 373   `lookahead'    explicitly associate lookahead tokens to items\n\
 374   `solved'       describe shift/reduce conflicts solving\n\
 375   `all'          include all the above information\n\
 376   `none'         disable the report\n\
 377 "), stdout);
 378
 379       putc ('\n', stdout);
 380       printf (_("Report bugs to <%s>.\n"), PACKAGE_BUGREPORT);
 381       printf (_("%s home page: <%s>.\n"), PACKAGE_NAME, PACKAGE_URL);
 382       fputs (_("General help using GNU software: "
 383                "<http://www.gnu.org/gethelp/>.\n"),
 384              stdout);
 385       /* Don't output this redundant message for English locales.
 386          Note we still output for 'C' so that it gets included in the
 387          man page.  */
 388       const char *lc_messages = setlocale (LC_MESSAGES, NULL);
 389       if (lc_messages && !STREQ (lc_messages, "en_"))
 390         /* TRANSLATORS: Replace LANG_CODE in this URL with your language
 391            code <http://translationproject.org/team/LANG_CODE.html> to
 392            form one of the URLs at http://translationproject.org/team/.
 393            Otherwise, replace the entire URL with your translation team's
 394            email address.  */
 395         fputs (_("Report translation bugs to "
 396                  "<http://translationproject.org/team/>.\n"), stdout);
 397       fputs (_("For complete documentation, run: info bison.\n"), stdout);
 398     }
 399
 400   exit (status);
 401 }
 402
 403
 404 /*------------------------------.
 405 | Display the version message.  |
 406 `------------------------------*/
 407
 408 static void
 409 version (void)
 410 {
 411   /* Some efforts were made to ease the translators' task, please
 412      continue.  */
 413   printf (_("bison (GNU Bison) %s"), VERSION);
 414   putc ('\n', stdout);
 415   fputs (_("Written by Robert Corbett and Richard Stallman.\n"), stdout);
 416   putc ('\n', stdout);
 417
 418   fprintf (stdout,
 419            _("Copyright (C) %d Free Software Foundation, Inc.\n"),
 420            PACKAGE_COPYRIGHT_YEAR);
 421
 422   fputs (_("\
 423 This is free software; see the source for copying conditions.  There is NO\n\
 424 warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n\
 425 "),
 426          stdout);
 427 }
 428
 429
 430 /*-------------------------------------.
 431 | --skeleton and --language handling.  |
 432 `--------------------------------------*/
 433
 434 void
 435 skeleton_arg (char const *arg, int prio, location loc)
 436 {
 437   if (prio < skeleton_prio)
 438     {
 439       skeleton_prio = prio;
 440       skeleton = arg;
 441     }
 442   else if (prio == skeleton_prio)
 443     complain_at (loc, complaint,
 444                  _("multiple skeleton declarations are invalid"));
 445 }
 446
 447 void
 448 language_argmatch (char const *arg, int prio, location loc)
 449 {
 450   char const *msg;
 451
 452   if (prio < language_prio)
 453     {
 454       int i;
 455       for (i = 0; valid_languages[i].language[0]; i++)
 456         if (c_strcasecmp (arg, valid_languages[i].language) == 0)
 457           {
 458             language_prio = prio;
 459             language = &valid_languages[i];
 460             return;
 461           }
 462       msg = _("%s: invalid language");
 463     }
 464   else if (language_prio == prio)
 465     msg = _("multiple language declarations are invalid");
 466   else
 467     return;
 468
 469   complain_at (loc, complaint, msg, quotearg_colon (arg));
 470 }
 471
 472 /*----------------------.
 473 | Process the options.  |
 474 `----------------------*/
 475
 476 /* Shorts options.
 477    Should be computed from long_options.  */
 478 static char const short_options[] =
 479   "D:"
 480   "F:"
 481   "L:"
 482   "S:"
 483   "T::"
 484   "V"
 485   "W::"
 486   "b:"
 487   "d"
 488   "e"
 489   "g::"
 490   "h"
 491   "k"
 492   "l"
 493   "n"
 494   "o:"
 495   "p:"
 496   "r:"
 497   "t"
 498   "v"
 499   "x::"
 500   "y"
 501   ;
 502
 503 /* Values for long options that do not have single-letter equivalents.  */
 504 enum
 505 {
 506   LOCATIONS_OPTION = CHAR_MAX + 1,
 507   PRINT_LOCALEDIR_OPTION,
 508   PRINT_DATADIR_OPTION,
 509   REPORT_FILE_OPTION
 510 };
 511
 512 static struct option const long_options[] =
 513 {
 514   /* Operation modes. */
 515   { "help",            no_argument,       0,   'h' },
 516   { "version",         no_argument,       0,   'V' },
 517   { "print-localedir", no_argument,       0,   PRINT_LOCALEDIR_OPTION },
 518   { "print-datadir",   no_argument,       0,   PRINT_DATADIR_OPTION   },
 519   { "warnings",        optional_argument, 0,   'W' },
 520
 521   /* Parser. */
 522   { "name-prefix",   required_argument,   0,   'p' },
 523   { "include",       required_argument,   0,   'I' },
 524
 525   /* Output. */
 526   { "file-prefix", required_argument,   0,   'b' },
 527   { "output",      required_argument,   0,   'o' },
 528   { "output-file", required_argument,   0,   'o' },
 529   { "graph",       optional_argument,   0,   'g' },
 530   { "xml",         optional_argument,   0,   'x' },
 531   { "report",      required_argument,   0,   'r' },
 532   { "report-file", required_argument,   0,   REPORT_FILE_OPTION },
 533   { "verbose",     no_argument,         0,   'v' },
 534
 535   /* Hidden. */
 536   { "trace",         optional_argument,   0,     'T' },
 537
 538   /* Output.  */
 539   { "defines",     optional_argument,   0,   'd' },
 540
 541   /* Operation modes.  */
 542   { "fixed-output-files", no_argument,  0,   'y' },
 543   { "yacc",               no_argument,  0,   'y' },
 544
 545   /* Parser.  */
 546   { "debug",          no_argument,               0,   't' },
 547   { "define",         required_argument,         0,   'D' },
 548   { "force-define",   required_argument,         0,   'F' },
 549   { "locations",      no_argument,               0, LOCATIONS_OPTION },
 550   { "no-lines",       no_argument,               0,   'l' },
 551   { "raw",            no_argument,               0,     0 },
 552   { "skeleton",       required_argument,         0,   'S' },
 553   { "language",       required_argument,         0,   'L' },
 554   { "token-table",    no_argument,               0,   'k' },
 555
 556   {0, 0, 0, 0}
 557 };
 558
 559 /* Under DOS, there is no difference on the case.  This can be
 560    troublesome when looking for `.tab' etc.  */
 561 #ifdef MSDOS
 562 # define AS_FILE_NAME(File) (strlwr (File), (File))
 563 #else
 564 # define AS_FILE_NAME(File) (File)
 565 #endif
 566
 567 /* Build a location for the current command line argument. */
 568 static
 569 location
 570 command_line_location (void)
 571 {
 572   location res;
 573   /* "<command line>" is used in GCC's messages about -D. */
 574   boundary_set (&res.start, uniqstr_new ("<command line>"), optind, -1);
 575   res.end = res.start;
 576   return res;
 577 }
 578
 579
 580 void
 581 getargs (int argc, char *argv[])
 582 {
 583   int c;
 584
 585   while ((c = getopt_long (argc, argv, short_options, long_options, NULL))
 586          != -1)
 587     switch (c)
 588       {
 589         /* ASCII Sorting for short options (i.e., upper case then
 590            lower case), and then long-only options.  */
 591
 592       case 0:
 593         /* Certain long options cause getopt_long to return 0.  */
 594         break;
 595
 596       case 'D': /* -DNAME[=VALUE]. */
 597       case 'F': /* -FNAME[=VALUE]. */
 598         {
 599           char* name = optarg;
 600           char* value = strchr (optarg, '=');
 601           if (value)
 602             *value++ = 0;
 603           muscle_percent_define_insert (name, command_line_location (),
 604                                         value ? value : "",
 605                                         c == 'D' ? MUSCLE_PERCENT_DEFINE_D
 606                                                  : MUSCLE_PERCENT_DEFINE_F);
 607         }
 608         break;
 609
 610       case 'I':
 611         include = AS_FILE_NAME (optarg);
 612         break;
 613
 614       case 'L':
 615         language_argmatch (optarg, command_line_prio,
 616                            command_line_location ());
 617         break;
 618
 619       case 'S':
 620         skeleton_arg (AS_FILE_NAME (optarg), command_line_prio,
 621                       command_line_location ());
 622         break;
 623
 624       case 'T':
 625         FLAGS_ARGMATCH (trace, optarg, trace_all);
 626         break;
 627
 628       case 'V':
 629         version ();
 630         exit (EXIT_SUCCESS);
 631
 632       case 'W':
 633         FLAGS_ARGMATCH (warnings, optarg, Wall);
 634         break;
 635
 636       case 'b':
 637         spec_file_prefix = AS_FILE_NAME (optarg);
 638         break;
 639
 640       case 'd':
 641         /* Here, the -d and --defines options are differentiated.  */
 642         defines_flag = true;
 643         if (optarg)
 644           {
 645             free (spec_defines_file);
 646             spec_defines_file = xstrdup (AS_FILE_NAME (optarg));
 647           }
 648         break;
 649
 650       case 'g':
 651         graph_flag = true;
 652         if (optarg)
 653           {
 654             free (spec_graph_file);
 655             spec_graph_file = xstrdup (AS_FILE_NAME (optarg));
 656           }
 657         break;
 658
 659       case 'h':
 660         usage (EXIT_SUCCESS);
 661
 662       case 'k':
 663         token_table_flag = true;
 664         break;
 665
 666       case 'l':
 667         no_lines_flag = true;
 668         break;
 669
 670       case 'o':
 671         spec_outfile = AS_FILE_NAME (optarg);
 672         break;
 673
 674       case 'p':
 675         spec_name_prefix = optarg;
 676         break;
 677
 678       case 'r':
 679         FLAGS_ARGMATCH (report, optarg, report_all);
 680         break;
 681
 682       case 't':
 683         muscle_percent_define_insert ("parse.trace",
 684                                       command_line_location (), "",
 685                                       MUSCLE_PERCENT_DEFINE_D);
 686         break;
 687
 688       case 'v':
 689         report_flag |= report_states;
 690         break;
 691
 692       case 'x':
 693         xml_flag = true;
 694         if (optarg)
 695           {
 696             free (spec_xml_file);
 697             spec_xml_file = xstrdup (AS_FILE_NAME (optarg));
 698           }
 699         break;
 700
 701       case 'y':
 702         yacc_flag = true;
 703         break;
 704
 705       case LOCATIONS_OPTION:
 706         muscle_percent_define_ensure ("locations",
 707                                       command_line_location (), true);
 708         break;
 709
 710       case PRINT_LOCALEDIR_OPTION:
 711         printf ("%s\n", LOCALEDIR);
 712         exit (EXIT_SUCCESS);
 713
 714       case PRINT_DATADIR_OPTION:
 715         printf ("%s\n", pkgdatadir ());
 716         exit (EXIT_SUCCESS);
 717
 718       case REPORT_FILE_OPTION:
 719         free (spec_verbose_file);
 720         spec_verbose_file = xstrdup (AS_FILE_NAME (optarg));
 721         break;
 722
 723       default:
 724         usage (EXIT_FAILURE);
 725       }
 726
 727   if (argc - optind != 1)
 728     {
 729       if (argc - optind < 1)
 730         error (0, 0, _("%s: missing operand"), quotearg_colon (argv[argc - 1]));
 731       else
 732         error (0, 0, _("extra operand %s"), quote (argv[optind + 1]));
 733       usage (EXIT_FAILURE);
 734     }
 735
 736   current_file = grammar_file = uniqstr_new (argv[optind]);
 737   MUSCLE_INSERT_C_STRING ("file_name", grammar_file);
 738 }
 739
 740 void
 741 tr (char *s, char from, char to)
 742 {
 743   for (; *s; s++)
 744     if (*s == from)
 745       *s = to;
 746 }