libguile/read.c

   1 /* Copyright (C) 1995,1996,1997,1999,2000,2001 Free Software Foundation, Inc.
   2  *
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation; either version 2, or (at your option)
   6  * any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this software; see the file COPYING.  If not, write to
  15  * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  16  * Boston, MA 02111-1307 USA
  17  *
  18  * As a special exception, the Free Software Foundation gives permission
  19  * for additional uses of the text contained in its release of GUILE.
  20  *
  21  * The exception is that, if you link the GUILE library with other files
  22  * to produce an executable, this does not by itself cause the
  23  * resulting executable to be covered by the GNU General Public License.
  24  * Your use of that executable is in no way restricted on account of
  25  * linking the GUILE library code into it.
  26  *
  27  * This exception does not however invalidate any other reasons why
  28  * the executable file might be covered by the GNU General Public License.
  29  *
  30  * This exception applies only to the code released by the
  31  * Free Software Foundation under the name GUILE.  If you copy
  32  * code from other Free Software Foundation releases into a copy of
  33  * GUILE, as the General Public License permits, the exception does
  34  * not apply to the code that you add in this way.  To avoid misleading
  35  * anyone as to the status of such modified files, you must delete
  36  * this exception notice from them.
  37  *
  38  * If you write modifications of your own for GUILE, it is your choice
  39  * whether to permit this exception to apply to your modifications.
  40  * If you do not wish that, delete this exception notice.  */
  41
  42 /* Software engineering face-lift by Greg J. Badros, 11-Dec-1999,
  43    gjb@cs.washington.edu, http://www.cs.washington.edu/homes/gjb */
  44
  45 \f
  46
  47 #include <stdio.h>
  48 #include "libguile/_scm.h"
  49 #include "libguile/chars.h"
  50 #include "libguile/eval.h"
  51 #include "libguile/unif.h"
  52 #include "libguile/keywords.h"
  53 #include "libguile/alist.h"
  54 #include "libguile/srcprop.h"
  55 #include "libguile/hashtab.h"
  56 #include "libguile/hash.h"
  57 #include "libguile/ports.h"
  58 #include "libguile/root.h"
  59 #include "libguile/strings.h"
  60 #include "libguile/vectors.h"
  61
  62 #include "libguile/validate.h"
  63 #include "libguile/read.h"
  64
  65 \f
  66
  67 SCM_SYMBOL (scm_keyword_prefix, "prefix");
  68
  69 scm_t_option scm_read_opts[] = {
  70   { SCM_OPTION_BOOLEAN, "copy", 0,
  71     "Copy source code expressions." },
  72   { SCM_OPTION_BOOLEAN, "positions", 0,
  73     "Record positions of source code expressions." },
  74   { SCM_OPTION_BOOLEAN, "case-insensitive", 0,
  75     "Convert symbols to lower case."},
  76   { SCM_OPTION_SCM, "keywords", SCM_UNPACK (SCM_BOOL_F),
  77     "Style of keyword recognition: #f or 'prefix"}
  78 };
  79
  80 SCM_DEFINE (scm_read_options, "read-options-interface", 0, 1, 0,
  81             (SCM setting),
  82             "Option interface for the read options. Instead of using\n"
  83             "this procedure directly, use the procedures @code{read-enable},\n"
  84             "@code{read-disable}, @code{read-set!} and @var{read-options}.")
  85 #define FUNC_NAME s_scm_read_options
  86 {
  87   SCM ans = scm_options (setting,
  88                          scm_read_opts,
  89                          SCM_N_READ_OPTIONS,
  90                          FUNC_NAME);
  91   if (SCM_COPY_SOURCE_P)
  92     SCM_RECORD_POSITIONS_P = 1;
  93   return ans;
  94 }
  95 #undef FUNC_NAME
  96
  97 /* An association list mapping extra hash characters to procedures.  */
  98 static SCM *scm_read_hash_procedures;
  99
 100 SCM_DEFINE (scm_read, "read", 0, 1, 0,
 101             (SCM port),
 102             "Read an s-expression from the input port @var{port}, or from\n"
 103             "the current input port if @var{port} is not specified.\n"
 104             "Any whitespace before the next token is discarded.")
 105 #define FUNC_NAME s_scm_read
 106 {
 107   int c;
 108   SCM tok_buf, copy;
 109
 110   if (SCM_UNBNDP (port))
 111     port = scm_cur_inp;
 112   SCM_VALIDATE_OPINPORT (1,port);
 113
 114   c = scm_flush_ws (port, (char *) NULL);
 115   if (EOF == c)
 116     return SCM_EOF_VAL;
 117   scm_ungetc (c, port);
 118
 119   tok_buf = scm_allocate_string (30);
 120   return scm_lreadr (&tok_buf, port, &copy);
 121 }
 122 #undef FUNC_NAME
 123
 124
 125
 126 char *
 127 scm_grow_tok_buf (SCM *tok_buf)
 128 {
 129   size_t oldlen = SCM_STRING_LENGTH (*tok_buf);
 130   SCM newstr = scm_allocate_string (2 * oldlen);
 131   size_t i;
 132
 133   for (i = 0; i != oldlen; ++i)
 134     SCM_STRING_CHARS (newstr) [i] = SCM_STRING_CHARS (*tok_buf) [i];
 135
 136   *tok_buf = newstr;
 137   return SCM_STRING_CHARS (newstr);
 138 }
 139
 140
 141
 142 int
 143 scm_flush_ws (SCM port, const char *eoferr)
 144 {
 145   register int c;
 146   while (1)
 147     switch (c = scm_getc (port))
 148       {
 149       case EOF:
 150       goteof:
 151         if (eoferr)
 152           {
 153             if (!SCM_FALSEP (SCM_FILENAME (port)))
 154               scm_misc_error (eoferr,
 155                               "end of file in ~A",
 156                               SCM_LIST1 (SCM_FILENAME (port)));
 157             else
 158               scm_misc_error (eoferr, "end of file", SCM_EOL);
 159           }
 160         return c;
 161       case ';':
 162       lp:
 163         switch (c = scm_getc (port))
 164           {
 165           case EOF:
 166             goto goteof;
 167           default:
 168             goto lp;
 169           case SCM_LINE_INCREMENTORS:
 170             break;
 171           }
 172         break;
 173       case SCM_LINE_INCREMENTORS:
 174       case SCM_SINGLE_SPACES:
 175       case '\t':
 176         break;
 177       default:
 178         return c;
 179       }
 180 }
 181
 182
 183
 184 int
 185 scm_casei_streq (char *s1, char *s2)
 186 {
 187   while (*s1 && *s2)
 188     if (scm_downcase((int)*s1) != scm_downcase((int)*s2))
 189       return 0;
 190     else
 191       {
 192         ++s1;
 193         ++s2;
 194       }
 195   return !(*s1 || *s2);
 196 }
 197
 198
 199 /* recsexpr is used when recording expressions
 200  * constructed by read:sharp.
 201  */
 202 #ifndef DEBUG_EXTENSIONS
 203 #define recsexpr(obj, line, column, filename) (obj)
 204 #else
 205 static SCM
 206 recsexpr (SCM obj, long line, int column, SCM filename)
 207 {
 208   if (!SCM_CONSP(obj)) {
 209     return obj;
 210   } else {
 211     SCM tmp = obj, copy;
 212     /* If this sexpr is visible in the read:sharp source, we want to
 213        keep that information, so only record non-constant cons cells
 214        which haven't previously been read by the reader. */
 215     if (SCM_FALSEP (scm_whash_lookup (scm_source_whash, obj)))
 216       {
 217         if (SCM_COPY_SOURCE_P)
 218           {
 219             copy = scm_cons (recsexpr (SCM_CAR (obj), line, column, filename),
 220                              SCM_UNDEFINED);
 221             while ((tmp = SCM_CDR (tmp)) && SCM_CONSP (tmp))
 222               {
 223                 SCM_SETCDR (copy, scm_cons (recsexpr (SCM_CAR (tmp),
 224                                                       line,
 225                                                       column,
 226                                                       filename),
 227                                             SCM_UNDEFINED));
 228                 copy = SCM_CDR (copy);
 229               }
 230             SCM_SETCDR (copy, tmp);
 231           }
 232         else
 233           {
 234             recsexpr (SCM_CAR (obj), line, column, filename);
 235             while ((tmp = SCM_CDR (tmp)) && SCM_CONSP (tmp))
 236               recsexpr (SCM_CAR (tmp), line, column, filename);
 237             copy = SCM_UNDEFINED;
 238           }
 239         scm_whash_insert (scm_source_whash,
 240                           obj,
 241                           scm_make_srcprops (line,
 242                                              column,
 243                                              filename,
 244                                              copy,
 245                                              SCM_EOL));
 246       }
 247     return obj;
 248   }
 249 }
 250 #endif
 251
 252 /* Consume an SCSH-style block comment.  Assume that we've already
 253    read the initial `#!', and eat characters until we get a
 254    newline/exclamation-point/sharp-sign/newline sequence.  */
 255
 256 static void
 257 skip_scsh_block_comment (SCM port)
 258 #define FUNC_NAME "skip_scsh_block_comment"
 259 {
 260   /* Is this portable?  Dear God, spare me from the non-eight-bit
 261      characters.  But is it tasteful?  */
 262   long history = 0;
 263
 264   for (;;)
 265     {
 266       int c = scm_getc (port);
 267
 268       if (c == EOF)
 269         SCM_MISC_ERROR ("unterminated `#! ... !#' comment", SCM_EOL);
 270       history = ((history << 8) | (c & 0xff)) & 0xffffffff;
 271
 272       /* Were the last four characters read "\n!#\n"?  */
 273       if (history == (('\n' << 24) | ('!' << 16) | ('#' << 8) | '\n'))
 274         return;
 275     }
 276 }
 277 #undef FUNC_NAME
 278
 279
 280 static SCM scm_get_hash_procedure(int c);
 281
 282 static char s_list[]="list";
 283
 284 SCM
 285 scm_lreadr (SCM *tok_buf,SCM port,SCM *copy)
 286 #define FUNC_NAME "scm_lreadr"
 287 {
 288   int c;
 289   size_t j;
 290   SCM p;
 291
 292  tryagain:
 293   c = scm_flush_ws (port, s_scm_read);
 294  tryagain_no_flush_ws:
 295   switch (c)
 296     {
 297     case EOF:
 298       return SCM_EOF_VAL;
 299
 300     case '(':
 301       return SCM_RECORD_POSITIONS_P
 302         ? scm_lreadrecparen (tok_buf, port, s_list, copy)
 303         : scm_lreadparen (tok_buf, port, s_list, copy);
 304     case ')':
 305       SCM_MISC_ERROR ("unexpected \")\"", SCM_EOL);
 306       goto tryagain;
 307
 308     case '\'':
 309       p = scm_sym_quote;
 310       goto recquote;
 311     case '`':
 312       p = scm_sym_quasiquote;
 313       goto recquote;
 314     case ',':
 315       c = scm_getc (port);
 316       if ('@' == c)
 317         p = scm_sym_uq_splicing;
 318       else
 319         {
 320           scm_ungetc (c, port);
 321           p = scm_sym_unquote;
 322         }
 323     recquote:
 324       p = scm_cons2 (p,
 325                      scm_lreadr (tok_buf, port, copy),
 326                      SCM_EOL);
 327       if (SCM_RECORD_POSITIONS_P)
 328         scm_whash_insert (scm_source_whash,
 329                           p,
 330                           scm_make_srcprops (SCM_LINUM (port),
 331                                              SCM_COL (port) - 1,
 332                                              SCM_FILENAME (port),
 333                                              SCM_COPY_SOURCE_P
 334                                              ? (*copy = scm_cons2 (SCM_CAR (p),
 335                                                                    SCM_CAR (SCM_CDR (p)),
 336                                                                    SCM_EOL))
 337                                              : SCM_UNDEFINED,
 338                                              SCM_EOL));
 339       return p;
 340     case '#':
 341       c = scm_getc (port);
 342
 343       {
 344         /* Check for user-defined hash procedure first, to allow
 345            overriding of builtin hash read syntaxes.  */
 346         SCM sharp = scm_get_hash_procedure (c);
 347         if (!SCM_FALSEP (sharp))
 348           {
 349             int line = SCM_LINUM (port);
 350             int column = SCM_COL (port) - 2;
 351             SCM got;
 352
 353             got = scm_call_2 (sharp, SCM_MAKE_CHAR (c), port);
 354             if (SCM_EQ_P (got, SCM_UNSPECIFIED))
 355               goto unkshrp;
 356             if (SCM_RECORD_POSITIONS_P)
 357               return *copy = recsexpr (got, line, column,
 358                                        SCM_FILENAME (port));
 359             else
 360               return got;
 361           }
 362       }
 363       switch (c)
 364         {
 365         case '(':
 366           p = scm_lreadparen (tok_buf, port, "vector", copy);
 367           return SCM_NULLP (p) ? scm_nullvect : scm_vector (p);
 368
 369         case 't':
 370         case 'T':
 371           return SCM_BOOL_T;
 372         case 'f':
 373         case 'F':
 374           return SCM_BOOL_F;
 375
 376         case 'b':
 377         case 'B':
 378         case 'o':
 379         case 'O':
 380         case 'd':
 381         case 'D':
 382         case 'x':
 383         case 'X':
 384         case 'i':
 385         case 'I':
 386         case 'e':
 387         case 'E':
 388           scm_ungetc (c, port);
 389           c = '#';
 390           goto num;
 391
 392         case '!':
 393           /* start of a shell script.  Parse as a block comment,
 394              terminated by !#, just like SCSH.  */
 395           skip_scsh_block_comment (port);
 396           /* EOF is not an error here */
 397           c = scm_flush_ws (port, (char *)NULL);
 398           goto tryagain_no_flush_ws;
 399
 400 #ifdef HAVE_ARRAYS
 401         case '*':
 402           j = scm_read_token (c, tok_buf, port, 0);
 403           p = scm_istr2bve (SCM_STRING_CHARS (*tok_buf) + 1, (long) (j - 1));
 404           if (!SCM_FALSEP (p))
 405             return p;
 406           else
 407             goto unkshrp;
 408 #endif
 409
 410         case '{':
 411           j = scm_read_token (c, tok_buf, port, 1);
 412           return scm_mem2symbol (SCM_STRING_CHARS (*tok_buf), j);
 413
 414         case '\\':
 415           c = scm_getc (port);
 416           j = scm_read_token (c, tok_buf, port, 0);
 417           if (j == 1)
 418             return SCM_MAKE_CHAR (c);
 419           if (c >= '0' && c < '8')
 420             {
 421               p = scm_istr2int (SCM_STRING_CHARS (*tok_buf), (long) j, 8);
 422               if (!SCM_FALSEP (p))
 423                 return SCM_MAKE_CHAR (SCM_INUM (p));
 424             }
 425           for (c = 0; c < scm_n_charnames; c++)
 426             if (scm_charnames[c]
 427                 && (scm_casei_streq (scm_charnames[c], SCM_STRING_CHARS (*tok_buf))))
 428               return SCM_MAKE_CHAR (scm_charnums[c]);
 429           SCM_MISC_ERROR ("unknown # object", SCM_EOL);
 430
 431           /* #:SYMBOL is a syntax for keywords supported in all contexts.  */
 432         case ':':
 433           j = scm_read_token ('-', tok_buf, port, 0);
 434           p = scm_mem2symbol (SCM_STRING_CHARS (*tok_buf), j);
 435           return scm_make_keyword_from_dash_symbol (p);
 436
 437         default:
 438         callshrp:
 439           {
 440             SCM sharp = scm_get_hash_procedure (c);
 441
 442             if (!SCM_FALSEP (sharp))
 443               {
 444                 int line = SCM_LINUM (port);
 445                 int column = SCM_COL (port) - 2;
 446                 SCM got;
 447
 448                 got = scm_call_2 (sharp, SCM_MAKE_CHAR (c), port);
 449                 if (SCM_EQ_P (got, SCM_UNSPECIFIED))
 450                   goto unkshrp;
 451                 if (SCM_RECORD_POSITIONS_P)
 452                   return *copy = recsexpr (got, line, column,
 453                                            SCM_FILENAME (port));
 454                 else
 455                   return got;
 456               }
 457           }
 458         unkshrp:
 459         scm_misc_error (s_scm_read, "Unknown # object: ~S",
 460                         SCM_LIST1 (SCM_MAKE_CHAR (c)));
 461         }
 462
 463     case '"':
 464       j = 0;
 465       while ('"' != (c = scm_getc (port)))
 466         {
 467           if (c == EOF)
 468             SCM_MISC_ERROR ("end of file in string constant", SCM_EOL);
 469
 470           while (j + 2 >= SCM_STRING_LENGTH (*tok_buf))
 471             scm_grow_tok_buf (tok_buf);
 472
 473           if (c == '\\')
 474             switch (c = scm_getc (port))
 475               {
 476               case '\n':
 477                 continue;
 478               case '0':
 479                 c = '\0';
 480                 break;
 481               case 'f':
 482                 c = '\f';
 483                 break;
 484               case 'n':
 485                 c = '\n';
 486                 break;
 487               case 'r':
 488                 c = '\r';
 489                 break;
 490               case 't':
 491                 c = '\t';
 492                 break;
 493               case 'a':
 494                 c = '\007';
 495                 break;
 496               case 'v':
 497                 c = '\v';
 498                 break;
 499               }
 500           SCM_STRING_CHARS (*tok_buf)[j] = c;
 501           ++j;
 502         }
 503       if (j == 0)
 504         return scm_nullstr;
 505       SCM_STRING_CHARS (*tok_buf)[j] = 0;
 506       return scm_mem2string (SCM_STRING_CHARS (*tok_buf), j);
 507
 508       case'0':case '1':case '2':case '3':case '4':
 509     case '5':case '6':case '7':case '8':case '9':
 510     case '.':
 511     case '-':
 512     case '+':
 513     num:
 514                 j = scm_read_token (c, tok_buf, port, 0);
 515                 p = scm_istring2number (SCM_STRING_CHARS (*tok_buf), (long) j, 10L);
 516                 if (!SCM_FALSEP (p))
 517                   return p;
 518                 if (c == '#')
 519                   {
 520                     if ((j == 2) && (scm_getc (port) == '('))
 521                       {
 522                         scm_ungetc ('(', port);
 523                         c = SCM_STRING_CHARS (*tok_buf)[1];
 524                         goto callshrp;
 525                       }
 526                     SCM_MISC_ERROR ("unknown # object", SCM_EOL);
 527                   }
 528                 goto tok;
 529
 530     case ':':
 531       if (SCM_EQ_P (SCM_PACK (SCM_KEYWORD_STYLE), scm_keyword_prefix))
 532         {
 533           j = scm_read_token ('-', tok_buf, port, 0);
 534           p = scm_mem2symbol (SCM_STRING_CHARS (*tok_buf), j);
 535           return scm_make_keyword_from_dash_symbol (p);
 536         }
 537       /* fallthrough */
 538     default:
 539       j = scm_read_token (c, tok_buf, port, 0);
 540       /* fallthrough */
 541
 542     tok:
 543       return scm_mem2symbol (SCM_STRING_CHARS (*tok_buf), j);
 544     }
 545 }
 546 #undef FUNC_NAME
 547
 548
 549 #ifdef _UNICOS
 550 _Pragma ("noopt");              /* # pragma _CRI noopt */
 551 #endif
 552
 553 size_t
 554 scm_read_token (int ic, SCM *tok_buf, SCM port, int weird)
 555 {
 556   register size_t j;
 557   register int c;
 558   register char *p;
 559
 560   c = (SCM_CASE_INSENSITIVE_P ? scm_downcase(ic) : ic);
 561   p = SCM_STRING_CHARS (*tok_buf);
 562
 563   if (weird)
 564     j = 0;
 565   else
 566     {
 567       j = 0;
 568       while (j + 2 >= SCM_STRING_LENGTH (*tok_buf))
 569         p = scm_grow_tok_buf (tok_buf);
 570       p[j] = c;
 571       ++j;
 572     }
 573
 574   while (1)
 575     {
 576       while (j + 2 >= SCM_STRING_LENGTH (*tok_buf))
 577         p = scm_grow_tok_buf (tok_buf);
 578       c = scm_getc (port);
 579       switch (c)
 580         {
 581         case '(':
 582         case ')':
 583         case '"':
 584         case ';':
 585         case SCM_WHITE_SPACES:
 586         case SCM_LINE_INCREMENTORS:
 587           if (weird)
 588             goto default_case;
 589
 590           scm_ungetc (c, port);
 591         case EOF:
 592         eof_case:
 593           p[j] = 0;
 594           return j;
 595         case '\\':
 596           if (!weird)
 597             goto default_case;
 598           else
 599             {
 600               c = scm_getc (port);
 601               if (c == EOF)
 602                 goto eof_case;
 603               else
 604                 goto default_case;
 605             }
 606         case '}':
 607           if (!weird)
 608             goto default_case;
 609
 610           c = scm_getc (port);
 611           if (c == '#')
 612             {
 613               p[j] = 0;
 614               return j;
 615             }
 616           else
 617             {
 618               scm_ungetc (c, port);
 619               c = '}';
 620               goto default_case;
 621             }
 622
 623         default:
 624         default_case:
 625           {
 626             c = (SCM_CASE_INSENSITIVE_P ? scm_downcase(c) : c);
 627             p[j] = c;
 628             ++j;
 629           }
 630
 631         }
 632     }
 633 }
 634
 635 #ifdef _UNICOS
 636 _Pragma ("opt");                /* # pragma _CRI opt */
 637 #endif
 638
 639 SCM
 640 scm_lreadparen (SCM *tok_buf, SCM port, char *name, SCM *copy)
 641 #define FUNC_NAME "scm_lreadparen"
 642 {
 643   SCM tmp;
 644   SCM tl;
 645   SCM ans;
 646   int c;
 647
 648   c = scm_flush_ws (port, name);
 649   if (')' == c)
 650     return SCM_EOL;
 651   scm_ungetc (c, port);
 652   if (SCM_EQ_P (scm_sym_dot, (tmp = scm_lreadr (tok_buf, port, copy))))
 653     {
 654       ans = scm_lreadr (tok_buf, port, copy);
 655     closeit:
 656       if (')' != (c = scm_flush_ws (port, name)))
 657         SCM_MISC_ERROR ("missing close paren", SCM_EOL);
 658       return ans;
 659     }
 660   ans = tl = scm_cons (tmp, SCM_EOL);
 661   while (')' != (c = scm_flush_ws (port, name)))
 662     {
 663       scm_ungetc (c, port);
 664       if (SCM_EQ_P (scm_sym_dot, (tmp = scm_lreadr (tok_buf, port, copy))))
 665         {
 666           SCM_SETCDR (tl, scm_lreadr (tok_buf, port, copy));
 667           goto closeit;
 668         }
 669       SCM_SETCDR (tl, scm_cons (tmp, SCM_EOL));
 670       tl = SCM_CDR (tl);
 671     }
 672   return ans;
 673 }
 674 #undef FUNC_NAME
 675
 676
 677 SCM
 678 scm_lreadrecparen (SCM *tok_buf, SCM port, char *name, SCM *copy)
 679 #define FUNC_NAME "scm_lreadrecparen"
 680 {
 681   register int c;
 682   register SCM tmp;
 683   register SCM tl, tl2 = SCM_EOL;
 684   SCM ans, ans2 = SCM_EOL;
 685   /* Need to capture line and column numbers here. */
 686   int line = SCM_LINUM (port);
 687   int column = SCM_COL (port) - 1;
 688
 689   c = scm_flush_ws (port, name);
 690   if (')' == c)
 691     return SCM_EOL;
 692   scm_ungetc (c, port);
 693   if (SCM_EQ_P (scm_sym_dot, (tmp = scm_lreadr (tok_buf, port, copy))))
 694     {
 695       ans = scm_lreadr (tok_buf, port, copy);
 696       if (')' != (c = scm_flush_ws (port, name)))
 697         SCM_MISC_ERROR ("missing close paren", SCM_EOL);
 698       return ans;
 699     }
 700   /* Build the head of the list structure. */
 701   ans = tl = scm_cons (tmp, SCM_EOL);
 702   if (SCM_COPY_SOURCE_P)
 703     ans2 = tl2 = scm_cons (SCM_CONSP (tmp)
 704                            ? *copy
 705                            : tmp,
 706                            SCM_EOL);
 707   while (')' != (c = scm_flush_ws (port, name)))
 708     {
 709       SCM new_tail;
 710
 711       scm_ungetc (c, port);
 712       if (SCM_EQ_P (scm_sym_dot, (tmp = scm_lreadr (tok_buf, port, copy))))
 713         {
 714           SCM_SETCDR (tl, tmp = scm_lreadr (tok_buf, port, copy));
 715           if (SCM_COPY_SOURCE_P)
 716             SCM_SETCDR (tl2, scm_cons (SCM_CONSP (tmp)
 717                                        ? *copy
 718                                        : tmp,
 719                                        SCM_EOL));
 720           if (')' != (c = scm_flush_ws (port, name)))
 721             SCM_MISC_ERROR ("missing close paren", SCM_EOL);
 722           goto exit;
 723         }
 724
 725       new_tail = scm_cons (tmp, SCM_EOL);
 726       SCM_SETCDR (tl, new_tail);
 727       tl = new_tail;
 728
 729       if (SCM_COPY_SOURCE_P)
 730         {
 731           SCM new_tail2 = scm_cons (SCM_CONSP (tmp) ? *copy : tmp, SCM_EOL);
 732           SCM_SETCDR (tl2, new_tail2);
 733           tl2 = new_tail2;
 734         }
 735     }
 736 exit:
 737   scm_whash_insert (scm_source_whash,
 738                     ans,
 739                     scm_make_srcprops (line,
 740                                        column,
 741                                        SCM_FILENAME (port),
 742                                        SCM_COPY_SOURCE_P
 743                                        ? *copy = ans2
 744                                        : SCM_UNDEFINED,
 745                                        SCM_EOL));
 746   return ans;
 747 }
 748 #undef FUNC_NAME
 749
 750
 751 \f
 752
 753 /* Manipulate the read-hash-procedures alist.  This could be written in
 754    Scheme, but maybe it will also be used by C code during initialisation.  */
 755 SCM_DEFINE (scm_read_hash_extend, "read-hash-extend", 2, 0, 0,
 756             (SCM chr, SCM proc),
 757             "Install the procedure @var{proc} for reading expressions\n"
 758             "starting with the character sequence @code{#} and @var{chr}.\n"
 759             "@var{proc} will be called with two arguments:  the character\n"
 760             "@var{chr} and the port to read further data from. The object\n"
 761             "returned will be the return value of @code{read}.")
 762 #define FUNC_NAME s_scm_read_hash_extend
 763 {
 764   SCM this;
 765   SCM prev;
 766
 767   SCM_VALIDATE_CHAR (1, chr);
 768   SCM_ASSERT (SCM_FALSEP (proc)
 769               || SCM_EQ_P (scm_procedure_p (proc), SCM_BOOL_T),
 770               proc, SCM_ARG2, FUNC_NAME);
 771
 772   /* Check if chr is already in the alist.  */
 773   this = *scm_read_hash_procedures;
 774   prev = SCM_BOOL_F;
 775   while (1)
 776     {
 777       if (SCM_NULLP (this))
 778         {
 779           /* not found, so add it to the beginning.  */
 780           if (!SCM_FALSEP (proc))
 781             {
 782               *scm_read_hash_procedures =
 783                 scm_cons (scm_cons (chr, proc), *scm_read_hash_procedures);
 784             }
 785           break;
 786         }
 787       if (SCM_EQ_P (chr, SCM_CAAR (this)))
 788         {
 789           /* already in the alist.  */
 790           if (SCM_FALSEP (proc))
 791             {
 792               /* remove it.  */
 793               if (SCM_FALSEP (prev))
 794                 {
 795                   *scm_read_hash_procedures =
 796                     SCM_CDR (*scm_read_hash_procedures);
 797                 }
 798               else
 799                 scm_set_cdr_x (prev, SCM_CDR (this));
 800             }
 801           else
 802             {
 803               /* replace it.  */
 804               scm_set_cdr_x (SCM_CAR (this), proc);
 805             }
 806           break;
 807         }
 808       prev = this;
 809       this = SCM_CDR (this);
 810     }
 811
 812   return SCM_UNSPECIFIED;
 813 }
 814 #undef FUNC_NAME
 815
 816 /* Recover the read-hash procedure corresponding to char c.  */
 817 static SCM
 818 scm_get_hash_procedure (int c)
 819 {
 820   SCM rest = *scm_read_hash_procedures;
 821
 822   while (1)
 823     {
 824       if (SCM_NULLP (rest))
 825         return SCM_BOOL_F;
 826
 827       if (SCM_CHAR (SCM_CAAR (rest)) == c)
 828         return SCM_CDAR (rest);
 829
 830       rest = SCM_CDR (rest);
 831     }
 832 }
 833
 834 void
 835 scm_init_read ()
 836 {
 837   scm_read_hash_procedures =
 838     SCM_VARIABLE_LOC (scm_c_define ("read-hash-procedures", SCM_EOL));
 839
 840   scm_init_opts (scm_read_options, scm_read_opts, SCM_N_READ_OPTIONS);
 841 #ifndef SCM_MAGIC_SNARFER
 842 #include "libguile/read.x"
 843 #endif
 844 }
 845
 846 /*
 847   Local Variables:
 848   c-file-style: "gnu"
 849   End:
 850 */