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
  43 \f
  44
  45 #include <stdio.h>
  46 #include "libguile/_scm.h"
  47 #include "libguile/chars.h"
  48 #include "libguile/eval.h"
  49 #include "libguile/unif.h"
  50 #include "libguile/keywords.h"
  51 #include "libguile/alist.h"
  52 #include "libguile/srcprop.h"
  53 #include "libguile/hashtab.h"
  54 #include "libguile/hash.h"
  55 #include "libguile/ports.h"
  56 #include "libguile/root.h"
  57 #include "libguile/strings.h"
  58 #include "libguile/strports.h"
  59 #include "libguile/vectors.h"
  60 #include "libguile/validate.h"
  61
  62 #include "libguile/read.h"
  63
  64 \f
  65
  66 SCM_SYMBOL (scm_keyword_prefix, "prefix");
  67
  68 scm_t_option scm_read_opts[] = {
  69   { SCM_OPTION_BOOLEAN, "copy", 0,
  70     "Copy source code expressions." },
  71   { SCM_OPTION_BOOLEAN, "positions", 0,
  72     "Record positions of source code expressions." },
  73   { SCM_OPTION_BOOLEAN, "case-insensitive", 0,
  74     "Convert symbols to lower case."},
  75   { SCM_OPTION_SCM, "keywords", SCM_UNPACK (SCM_BOOL_F),
  76     "Style of keyword recognition: #f or 'prefix."}
  77 };
  78
  79 /*
  80   Give meaningful error messages for errors
  81
  82   We use the format
  83
  84   FILE:LINE:COL: MESSAGE
  85   This happened in ....
  86
  87   This is not standard GNU format, but the test-suite likes the real
  88   message to be in front.
  89
  90  */
  91
  92
  93 static void
  94 scm_input_error(char const * function,
  95                 SCM port, const char * message, SCM arg)
  96 {
  97   char *fn = SCM_STRINGP (SCM_FILENAME(port))
  98     ? SCM_STRING_CHARS(SCM_FILENAME(port))
  99     : "#<unknown port>";
 100
 101   SCM string_port =  scm_open_output_string ();
 102   SCM string = SCM_EOL;
 103   scm_simple_format (string_port,
 104                      scm_makfrom0str ("~A:~S:~S: ~A"),
 105                      scm_list_4 (scm_makfrom0str (fn),
 106                                  scm_int2num (SCM_LINUM (port) + 1),
 107                                  scm_int2num (SCM_COL (port) + 1),
 108                                  scm_makfrom0str (message)));
 109
 110
 111   string = scm_get_output_string (string_port);
 112   scm_close_output_port (string_port);
 113   scm_error_scm (scm_str2symbol ("read-error"),
 114                  scm_makfrom0str (function),
 115                  string,
 116                  SCM_EOL,
 117                  SCM_BOOL_F);
 118 }
 119
 120
 121 SCM_DEFINE (scm_read_options, "read-options-interface", 0, 1, 0,
 122             (SCM setting),
 123             "Option interface for the read options. Instead of using\n"
 124             "this procedure directly, use the procedures @code{read-enable},\n"
 125             "@code{read-disable}, @code{read-set!} and @code{read-options}.")
 126 #define FUNC_NAME s_scm_read_options
 127 {
 128   SCM ans = scm_options (setting,
 129                          scm_read_opts,
 130                          SCM_N_READ_OPTIONS,
 131                          FUNC_NAME);
 132   if (SCM_COPY_SOURCE_P)
 133     SCM_RECORD_POSITIONS_P = 1;
 134   return ans;
 135 }
 136 #undef FUNC_NAME
 137
 138 /* An association list mapping extra hash characters to procedures.  */
 139 static SCM *scm_read_hash_procedures;
 140
 141 SCM_DEFINE (scm_read, "read", 0, 1, 0,
 142             (SCM port),
 143             "Read an s-expression from the input port @var{port}, or from\n"
 144             "the current input port if @var{port} is not specified.\n"
 145             "Any whitespace before the next token is discarded.")
 146 #define FUNC_NAME s_scm_read
 147 {
 148   int c;
 149   SCM tok_buf, copy;
 150
 151   if (SCM_UNBNDP (port))
 152     port = scm_cur_inp;
 153   SCM_VALIDATE_OPINPORT (1, port);
 154
 155   c = scm_flush_ws (port, (char *) NULL);
 156   if (EOF == c)
 157     return SCM_EOF_VAL;
 158   scm_ungetc (c, port);
 159
 160   tok_buf = scm_allocate_string (30);
 161   return scm_lreadr (&tok_buf, port, &copy);
 162 }
 163 #undef FUNC_NAME
 164
 165
 166
 167 char *
 168 scm_grow_tok_buf (SCM *tok_buf)
 169 {
 170   size_t oldlen = SCM_STRING_LENGTH (*tok_buf);
 171   SCM newstr = scm_allocate_string (2 * oldlen);
 172   size_t i;
 173
 174   for (i = 0; i != oldlen; ++i)
 175     SCM_STRING_CHARS (newstr) [i] = SCM_STRING_CHARS (*tok_buf) [i];
 176
 177   *tok_buf = newstr;
 178   return SCM_STRING_CHARS (newstr);
 179 }
 180
 181
 182
 183 int
 184 scm_flush_ws (SCM port, const char *eoferr)
 185 {
 186   register int c;
 187   while (1)
 188     switch (c = scm_getc (port))
 189       {
 190       case EOF:
 191       goteof:
 192         if (eoferr)
 193           {
 194             scm_input_error (eoferr,
 195                              port,
 196                              "end of file",
 197                              SCM_EOL);
 198           }
 199         return c;
 200       case ';':
 201       lp:
 202         switch (c = scm_getc (port))
 203           {
 204           case EOF:
 205             goto goteof;
 206           default:
 207             goto lp;
 208           case SCM_LINE_INCREMENTORS:
 209             break;
 210           }
 211         break;
 212       case SCM_LINE_INCREMENTORS:
 213       case SCM_SINGLE_SPACES:
 214       case '\t':
 215         break;
 216       default:
 217         return c;
 218       }
 219 }
 220
 221
 222
 223 int
 224 scm_casei_streq (char *s1, char *s2)
 225 {
 226   while (*s1 && *s2)
 227     if (scm_downcase((int)*s1) != scm_downcase((int)*s2))
 228       return 0;
 229     else
 230       {
 231         ++s1;
 232         ++s2;
 233       }
 234   return !(*s1 || *s2);
 235 }
 236
 237
 238 /* recsexpr is used when recording expressions
 239  * constructed by read:sharp.
 240  */
 241 #ifndef DEBUG_EXTENSIONS
 242 #define recsexpr(obj, line, column, filename) (obj)
 243 #else
 244 static SCM
 245 recsexpr (SCM obj, long line, int column, SCM filename)
 246 {
 247   if (!SCM_CONSP(obj)) {
 248     return obj;
 249   } else {
 250     SCM tmp = obj, copy;
 251     /* If this sexpr is visible in the read:sharp source, we want to
 252        keep that information, so only record non-constant cons cells
 253        which haven't previously been read by the reader. */
 254     if (SCM_FALSEP (scm_whash_lookup (scm_source_whash, obj)))
 255       {
 256         if (SCM_COPY_SOURCE_P)
 257           {
 258             copy = scm_cons (recsexpr (SCM_CAR (obj), line, column, filename),
 259                              SCM_UNDEFINED);
 260             while ((tmp = SCM_CDR (tmp)) && SCM_CONSP (tmp))
 261               {
 262                 SCM_SETCDR (copy, scm_cons (recsexpr (SCM_CAR (tmp),
 263                                                       line,
 264                                                       column,
 265                                                       filename),
 266                                             SCM_UNDEFINED));
 267                 copy = SCM_CDR (copy);
 268               }
 269             SCM_SETCDR (copy, tmp);
 270           }
 271         else
 272           {
 273             recsexpr (SCM_CAR (obj), line, column, filename);
 274             while ((tmp = SCM_CDR (tmp)) && SCM_CONSP (tmp))
 275               recsexpr (SCM_CAR (tmp), line, column, filename);
 276             copy = SCM_UNDEFINED;
 277           }
 278         scm_whash_insert (scm_source_whash,
 279                           obj,
 280                           scm_make_srcprops (line,
 281                                              column,
 282                                              filename,
 283                                              copy,
 284                                              SCM_EOL));
 285       }
 286     return obj;
 287   }
 288 }
 289 #endif
 290
 291 /* Consume an SCSH-style block comment.  Assume that we've already
 292    read the initial `#!', and eat characters until we get a
 293    newline/exclamation-point/sharp-sign/newline sequence.  */
 294
 295 static void
 296 skip_scsh_block_comment (SCM port)
 297 #define FUNC_NAME "skip_scsh_block_comment"
 298 {
 299   /* Is this portable?  Dear God, spare me from the non-eight-bit
 300      characters.  But is it tasteful?  */
 301   long history = 0;
 302
 303   for (;;)
 304     {
 305       int c = scm_getc (port);
 306
 307       if (c == EOF)
 308         SCM_MISC_ERROR ("unterminated `#! ... !#' comment", SCM_EOL);
 309       history = ((history << 8) | (c & 0xff)) & 0xffffffff;
 310
 311       /* Were the last four characters read "\n!#\n"?  */
 312       if (history == (('\n' << 24) | ('!' << 16) | ('#' << 8) | '\n'))
 313         return;
 314     }
 315 }
 316 #undef FUNC_NAME
 317
 318
 319 static SCM scm_get_hash_procedure(int c);
 320
 321 static char s_list[]="list";
 322
 323 SCM
 324 scm_lreadr (SCM *tok_buf, SCM port, SCM *copy)
 325 #define FUNC_NAME "scm_lreadr"
 326 {
 327   int c;
 328   size_t j;
 329   SCM p;
 330
 331  tryagain:
 332   c = scm_flush_ws (port, s_scm_read);
 333  tryagain_no_flush_ws:
 334   switch (c)
 335     {
 336     case EOF:
 337       return SCM_EOF_VAL;
 338
 339     case '(':
 340       return SCM_RECORD_POSITIONS_P
 341         ? scm_lreadrecparen (tok_buf, port, s_list, copy)
 342         : scm_lreadparen (tok_buf, port, s_list, copy SCM_ELISP_CLOSE);
 343     case ')':
 344       scm_input_error (FUNC_NAME, port,"unexpected \")\"", SCM_EOL);
 345       goto tryagain;
 346
 347 #ifdef SCM_ELISP_READ_EXTENSIONS
 348     case '[':
 349       p = scm_lreadparen (tok_buf, port, "vector", copy, ']');
 350       return SCM_NULLP (p) ? scm_nullvect : scm_vector (p);
 351 #endif
 352     case '\'':
 353       p = scm_sym_quote;
 354       goto recquote;
 355     case '`':
 356       p = scm_sym_quasiquote;
 357       goto recquote;
 358     case ',':
 359       c = scm_getc (port);
 360       if ('@' == c)
 361         p = scm_sym_uq_splicing;
 362       else
 363         {
 364           scm_ungetc (c, port);
 365           p = scm_sym_unquote;
 366         }
 367     recquote:
 368       p = scm_cons2 (p,
 369                      scm_lreadr (tok_buf, port, copy),
 370                      SCM_EOL);
 371       if (SCM_RECORD_POSITIONS_P)
 372         scm_whash_insert (scm_source_whash,
 373                           p,
 374                           scm_make_srcprops (SCM_LINUM (port),
 375                                              SCM_COL (port) - 1,
 376                                              SCM_FILENAME (port),
 377                                              SCM_COPY_SOURCE_P
 378                                              ? (*copy = scm_cons2 (SCM_CAR (p),
 379                                                                    SCM_CAR (SCM_CDR (p)),
 380                                                                    SCM_EOL))
 381                                              : SCM_UNDEFINED,
 382                                              SCM_EOL));
 383       return p;
 384     case '#':
 385       c = scm_getc (port);
 386
 387       {
 388         /* Check for user-defined hash procedure first, to allow
 389            overriding of builtin hash read syntaxes.  */
 390         SCM sharp = scm_get_hash_procedure (c);
 391         if (!SCM_FALSEP (sharp))
 392           {
 393             int line = SCM_LINUM (port);
 394             int column = SCM_COL (port) - 2;
 395             SCM got;
 396
 397             got = scm_call_2 (sharp, SCM_MAKE_CHAR (c), port);
 398             if (SCM_EQ_P (got, SCM_UNSPECIFIED))
 399               goto handle_sharp;
 400             if (SCM_RECORD_POSITIONS_P)
 401               return *copy = recsexpr (got, line, column,
 402                                        SCM_FILENAME (port));
 403             else
 404               return got;
 405           }
 406       }
 407     handle_sharp:
 408       switch (c)
 409         {
 410         case '(':
 411           p = scm_lreadparen (tok_buf, port, "vector", copy SCM_ELISP_CLOSE);
 412           return SCM_NULLP (p) ? scm_nullvect : scm_vector (p);
 413
 414         case 't':
 415         case 'T':
 416           return SCM_BOOL_T;
 417         case 'f':
 418         case 'F':
 419           return SCM_BOOL_F;
 420
 421         case 'b':
 422         case 'B':
 423         case 'o':
 424         case 'O':
 425         case 'd':
 426         case 'D':
 427         case 'x':
 428         case 'X':
 429         case 'i':
 430         case 'I':
 431         case 'e':
 432         case 'E':
 433           scm_ungetc (c, port);
 434           c = '#';
 435           goto num;
 436
 437         case '!':
 438           /* start of a shell script.  Parse as a block comment,
 439              terminated by !#, just like SCSH.  */
 440           skip_scsh_block_comment (port);
 441           /* EOF is not an error here */
 442           c = scm_flush_ws (port, (char *)NULL);
 443           goto tryagain_no_flush_ws;
 444
 445 #if SCM_HAVE_ARRAYS
 446         case '*':
 447           j = scm_read_token (c, tok_buf, port, 0);
 448           p = scm_istr2bve (SCM_STRING_CHARS (*tok_buf) + 1, (long) (j - 1));
 449           if (!SCM_FALSEP (p))
 450             return p;
 451           else
 452             goto unkshrp;
 453 #endif
 454
 455         case '{':
 456           j = scm_read_token (c, tok_buf, port, 1);
 457           return scm_mem2symbol (SCM_STRING_CHARS (*tok_buf), j);
 458
 459         case '\\':
 460           c = scm_getc (port);
 461           j = scm_read_token (c, tok_buf, port, 0);
 462           if (j == 1)
 463             return SCM_MAKE_CHAR (c);
 464           if (c >= '0' && c < '8')
 465             {
 466               /* Dirk:FIXME::  This type of character syntax is not R5RS
 467                * compliant.  Further, it should be verified that the constant
 468                * does only consist of octal digits.  Finally, it should be
 469                * checked whether the resulting fixnum is in the range of
 470                * characters.  */
 471               p = scm_i_mem2number (SCM_STRING_CHARS (*tok_buf), j, 8);
 472               if (SCM_INUMP (p))
 473                 return SCM_MAKE_CHAR (SCM_INUM (p));
 474             }
 475           for (c = 0; c < scm_n_charnames; c++)
 476             if (scm_charnames[c]
 477                 && (scm_casei_streq (scm_charnames[c], SCM_STRING_CHARS (*tok_buf))))
 478               return SCM_MAKE_CHAR (scm_charnums[c]);
 479           scm_input_error (FUNC_NAME, port, "unknown # object", SCM_EOL);
 480
 481           /* #:SYMBOL is a syntax for keywords supported in all contexts.  */
 482         case ':':
 483           j = scm_read_token ('-', tok_buf, port, 0);
 484           p = scm_mem2symbol (SCM_STRING_CHARS (*tok_buf), j);
 485           return scm_make_keyword_from_dash_symbol (p);
 486
 487         default:
 488         callshrp:
 489           {
 490             SCM sharp = scm_get_hash_procedure (c);
 491
 492             if (!SCM_FALSEP (sharp))
 493               {
 494                 int line = SCM_LINUM (port);
 495                 int column = SCM_COL (port) - 2;
 496                 SCM got;
 497
 498                 got = scm_call_2 (sharp, SCM_MAKE_CHAR (c), port);
 499                 if (SCM_EQ_P (got, SCM_UNSPECIFIED))
 500                   goto unkshrp;
 501                 if (SCM_RECORD_POSITIONS_P)
 502                   return *copy = recsexpr (got, line, column,
 503                                            SCM_FILENAME (port));
 504                 else
 505                   return got;
 506               }
 507           }
 508         unkshrp:
 509         scm_input_error (FUNC_NAME, port, "Unknown # object: ~S",
 510                      scm_list_1 (SCM_MAKE_CHAR (c)));
 511         }
 512
 513     case '"':
 514       j = 0;
 515       while ('"' != (c = scm_getc (port)))
 516         {
 517           if (c == EOF)
 518             scm_input_error (FUNC_NAME, port, "end of file in string constant", SCM_EOL);
 519
 520           while (j + 2 >= SCM_STRING_LENGTH (*tok_buf))
 521             scm_grow_tok_buf (tok_buf);
 522
 523           if (c == '\\')
 524             switch (c = scm_getc (port))
 525               {
 526               case '\n':
 527                 continue;
 528               case '0':
 529                 c = '\0';
 530                 break;
 531               case 'f':
 532                 c = '\f';
 533                 break;
 534               case 'n':
 535                 c = '\n';
 536                 break;
 537               case 'r':
 538                 c = '\r';
 539                 break;
 540               case 't':
 541                 c = '\t';
 542                 break;
 543               case 'a':
 544                 c = '\007';
 545                 break;
 546               case 'v':
 547                 c = '\v';
 548                 break;
 549               }
 550           SCM_STRING_CHARS (*tok_buf)[j] = c;
 551           ++j;
 552         }
 553       if (j == 0)
 554         return scm_nullstr;
 555       SCM_STRING_CHARS (*tok_buf)[j] = 0;
 556       return scm_mem2string (SCM_STRING_CHARS (*tok_buf), j);
 557
 558     case '0': case '1': case '2': case '3': case '4':
 559     case '5': case '6': case '7': case '8': case '9':
 560     case '.':
 561     case '-':
 562     case '+':
 563     num:
 564       j = scm_read_token (c, tok_buf, port, 0);
 565       if (j == 1 && (c == '+' || c == '-'))
 566         /* Shortcut:  Detected symbol '+ or '- */
 567         goto tok;
 568
 569       p = scm_i_mem2number (SCM_STRING_CHARS (*tok_buf), j, 10);
 570       if (!SCM_FALSEP (p))
 571         return p;
 572       if (c == '#')
 573         {
 574           if ((j == 2) && (scm_getc (port) == '('))
 575             {
 576               scm_ungetc ('(', port);
 577               c = SCM_STRING_CHARS (*tok_buf)[1];
 578               goto callshrp;
 579             }
 580           scm_input_error (FUNC_NAME, port, "unknown # object", SCM_EOL);
 581         }
 582       goto tok;
 583
 584     case ':':
 585       if (SCM_EQ_P (SCM_PACK (SCM_KEYWORD_STYLE), scm_keyword_prefix))
 586         {
 587           j = scm_read_token ('-', tok_buf, port, 0);
 588           p = scm_mem2symbol (SCM_STRING_CHARS (*tok_buf), j);
 589           return scm_make_keyword_from_dash_symbol (p);
 590         }
 591       /* fallthrough */
 592     default:
 593       j = scm_read_token (c, tok_buf, port, 0);
 594       /* fallthrough */
 595
 596     tok:
 597       return scm_mem2symbol (SCM_STRING_CHARS (*tok_buf), j);
 598     }
 599 }
 600 #undef FUNC_NAME
 601
 602
 603 #ifdef _UNICOS
 604 _Pragma ("noopt");              /* # pragma _CRI noopt */
 605 #endif
 606
 607 size_t
 608 scm_read_token (int ic, SCM *tok_buf, SCM port, int weird)
 609 {
 610   register size_t j;
 611   register int c;
 612   register char *p;
 613
 614   c = (SCM_CASE_INSENSITIVE_P ? scm_downcase(ic) : ic);
 615   p = SCM_STRING_CHARS (*tok_buf);
 616
 617   if (weird)
 618     j = 0;
 619   else
 620     {
 621       j = 0;
 622       while (j + 2 >= SCM_STRING_LENGTH (*tok_buf))
 623         p = scm_grow_tok_buf (tok_buf);
 624       p[j] = c;
 625       ++j;
 626     }
 627
 628   while (1)
 629     {
 630       while (j + 2 >= SCM_STRING_LENGTH (*tok_buf))
 631         p = scm_grow_tok_buf (tok_buf);
 632       c = scm_getc (port);
 633       switch (c)
 634         {
 635         case '(':
 636         case ')':
 637 #ifdef SCM_ELISP_READ_EXTENSIONS
 638         case '[':
 639         case ']':
 640 #endif
 641         case '"':
 642         case ';':
 643         case SCM_WHITE_SPACES:
 644         case SCM_LINE_INCREMENTORS:
 645           if (weird)
 646             goto default_case;
 647
 648           scm_ungetc (c, port);
 649         case EOF:
 650         eof_case:
 651           p[j] = 0;
 652           return j;
 653         case '\\':
 654           if (!weird)
 655             goto default_case;
 656           else
 657             {
 658               c = scm_getc (port);
 659               if (c == EOF)
 660                 goto eof_case;
 661               else
 662                 goto default_case;
 663             }
 664         case '}':
 665           if (!weird)
 666             goto default_case;
 667
 668           c = scm_getc (port);
 669           if (c == '#')
 670             {
 671               p[j] = 0;
 672               return j;
 673             }
 674           else
 675             {
 676               scm_ungetc (c, port);
 677               c = '}';
 678               goto default_case;
 679             }
 680
 681         default:
 682         default_case:
 683           {
 684             c = (SCM_CASE_INSENSITIVE_P ? scm_downcase(c) : c);
 685             p[j] = c;
 686             ++j;
 687           }
 688
 689         }
 690     }
 691 }
 692
 693 #ifdef _UNICOS
 694 _Pragma ("opt");                /* # pragma _CRI opt */
 695 #endif
 696
 697 SCM
 698 scm_lreadparen (SCM *tok_buf, SCM port, char *name, SCM *copy
 699 #ifdef SCM_ELISP_READ_EXTENSIONS
 700                 , char term_char
 701 #else
 702 #define term_char ')'
 703 #endif
 704                 )
 705 #define FUNC_NAME "scm_lreadparen"
 706 {
 707   SCM tmp;
 708   SCM tl;
 709   SCM ans;
 710   int c;
 711
 712   c = scm_flush_ws (port, name);
 713   if (term_char == c)
 714     return SCM_EOL;
 715   scm_ungetc (c, port);
 716   if (SCM_EQ_P (scm_sym_dot, (tmp = scm_lreadr (tok_buf, port, copy))))
 717     {
 718       ans = scm_lreadr (tok_buf, port, copy);
 719     closeit:
 720       if (term_char != (c = scm_flush_ws (port, name)))
 721         scm_input_error (FUNC_NAME, port, "missing close paren", SCM_EOL);
 722       return ans;
 723     }
 724   ans = tl = scm_cons (tmp, SCM_EOL);
 725   while (term_char != (c = scm_flush_ws (port, name)))
 726     {
 727       scm_ungetc (c, port);
 728       if (SCM_EQ_P (scm_sym_dot, (tmp = scm_lreadr (tok_buf, port, copy))))
 729         {
 730           SCM_SETCDR (tl, scm_lreadr (tok_buf, port, copy));
 731           goto closeit;
 732         }
 733       SCM_SETCDR (tl, scm_cons (tmp, SCM_EOL));
 734       tl = SCM_CDR (tl);
 735     }
 736   return ans;
 737 }
 738 #undef FUNC_NAME
 739 #ifndef SCM_ELISP_READ_EXTENSIONS
 740 #undef term_char
 741 #endif
 742
 743
 744 SCM
 745 scm_lreadrecparen (SCM *tok_buf, SCM port, char *name, SCM *copy)
 746 #define FUNC_NAME "scm_lreadrecparen"
 747 {
 748   register int c;
 749   register SCM tmp;
 750   register SCM tl, tl2 = SCM_EOL;
 751   SCM ans, ans2 = SCM_EOL;
 752   /* Need to capture line and column numbers here. */
 753   int line = SCM_LINUM (port);
 754   int column = SCM_COL (port) - 1;
 755
 756   c = scm_flush_ws (port, name);
 757   if (')' == c)
 758     return SCM_EOL;
 759   scm_ungetc (c, port);
 760   if (SCM_EQ_P (scm_sym_dot, (tmp = scm_lreadr (tok_buf, port, copy))))
 761     {
 762       ans = scm_lreadr (tok_buf, port, copy);
 763       if (')' != (c = scm_flush_ws (port, name)))
 764         scm_input_error (FUNC_NAME, port, "missing close paren", SCM_EOL);
 765       return ans;
 766     }
 767   /* Build the head of the list structure. */
 768   ans = tl = scm_cons (tmp, SCM_EOL);
 769   if (SCM_COPY_SOURCE_P)
 770     ans2 = tl2 = scm_cons (SCM_CONSP (tmp)
 771                            ? *copy
 772                            : tmp,
 773                            SCM_EOL);
 774   while (')' != (c = scm_flush_ws (port, name)))
 775     {
 776       SCM new_tail;
 777
 778       scm_ungetc (c, port);
 779       if (SCM_EQ_P (scm_sym_dot, (tmp = scm_lreadr (tok_buf, port, copy))))
 780         {
 781           SCM_SETCDR (tl, tmp = scm_lreadr (tok_buf, port, copy));
 782           if (SCM_COPY_SOURCE_P)
 783             SCM_SETCDR (tl2, scm_cons (SCM_CONSP (tmp)
 784                                        ? *copy
 785                                        : tmp,
 786                                        SCM_EOL));
 787           if (')' != (c = scm_flush_ws (port, name)))
 788             scm_input_error (FUNC_NAME, port, "missing close paren", SCM_EOL);
 789           goto exit;
 790         }
 791
 792       new_tail = scm_cons (tmp, SCM_EOL);
 793       SCM_SETCDR (tl, new_tail);
 794       tl = new_tail;
 795
 796       if (SCM_COPY_SOURCE_P)
 797         {
 798           SCM new_tail2 = scm_cons (SCM_CONSP (tmp) ? *copy : tmp, SCM_EOL);
 799           SCM_SETCDR (tl2, new_tail2);
 800           tl2 = new_tail2;
 801         }
 802     }
 803 exit:
 804   scm_whash_insert (scm_source_whash,
 805                     ans,
 806                     scm_make_srcprops (line,
 807                                        column,
 808                                        SCM_FILENAME (port),
 809                                        SCM_COPY_SOURCE_P
 810                                        ? *copy = ans2
 811                                        : SCM_UNDEFINED,
 812                                        SCM_EOL));
 813   return ans;
 814 }
 815 #undef FUNC_NAME
 816
 817
 818 \f
 819
 820 /* Manipulate the read-hash-procedures alist.  This could be written in
 821    Scheme, but maybe it will also be used by C code during initialisation.  */
 822 SCM_DEFINE (scm_read_hash_extend, "read-hash-extend", 2, 0, 0,
 823             (SCM chr, SCM proc),
 824             "Install the procedure @var{proc} for reading expressions\n"
 825             "starting with the character sequence @code{#} and @var{chr}.\n"
 826             "@var{proc} will be called with two arguments:  the character\n"
 827             "@var{chr} and the port to read further data from. The object\n"
 828             "returned will be the return value of @code{read}.")
 829 #define FUNC_NAME s_scm_read_hash_extend
 830 {
 831   SCM this;
 832   SCM prev;
 833
 834   SCM_VALIDATE_CHAR (1, chr);
 835   SCM_ASSERT (SCM_FALSEP (proc)
 836               || SCM_EQ_P (scm_procedure_p (proc), SCM_BOOL_T),
 837               proc, SCM_ARG2, FUNC_NAME);
 838
 839   /* Check if chr is already in the alist.  */
 840   this = *scm_read_hash_procedures;
 841   prev = SCM_BOOL_F;
 842   while (1)
 843     {
 844       if (SCM_NULLP (this))
 845         {
 846           /* not found, so add it to the beginning.  */
 847           if (!SCM_FALSEP (proc))
 848             {
 849               *scm_read_hash_procedures =
 850                 scm_cons (scm_cons (chr, proc), *scm_read_hash_procedures);
 851             }
 852           break;
 853         }
 854       if (SCM_EQ_P (chr, SCM_CAAR (this)))
 855         {
 856           /* already in the alist.  */
 857           if (SCM_FALSEP (proc))
 858             {
 859               /* remove it.  */
 860               if (SCM_FALSEP (prev))
 861                 {
 862                   *scm_read_hash_procedures =
 863                     SCM_CDR (*scm_read_hash_procedures);
 864                 }
 865               else
 866                 scm_set_cdr_x (prev, SCM_CDR (this));
 867             }
 868           else
 869             {
 870               /* replace it.  */
 871               scm_set_cdr_x (SCM_CAR (this), proc);
 872             }
 873           break;
 874         }
 875       prev = this;
 876       this = SCM_CDR (this);
 877     }
 878
 879   return SCM_UNSPECIFIED;
 880 }
 881 #undef FUNC_NAME
 882
 883 /* Recover the read-hash procedure corresponding to char c.  */
 884 static SCM
 885 scm_get_hash_procedure (int c)
 886 {
 887   SCM rest = *scm_read_hash_procedures;
 888
 889   while (1)
 890     {
 891       if (SCM_NULLP (rest))
 892         return SCM_BOOL_F;
 893
 894       if (SCM_CHAR (SCM_CAAR (rest)) == c)
 895         return SCM_CDAR (rest);
 896
 897       rest = SCM_CDR (rest);
 898     }
 899 }
 900
 901 void
 902 scm_init_read ()
 903 {
 904   scm_read_hash_procedures =
 905     SCM_VARIABLE_LOC (scm_c_define ("read-hash-procedures", SCM_EOL));
 906
 907   scm_init_opts (scm_read_options, scm_read_opts, SCM_N_READ_OPTIONS);
 908 #include "libguile/read.x"
 909 }
 910
 911 /*
 912   Local Variables:
 913   c-file-style: "gnu"
 914   End:
 915 */