git.gag.com Git - fw/altos/blob - src/scheme/ao_scheme_read.c

   1 /*
   2  * Copyright © 2016 Keith Packard <keithp@keithp.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  */
  14
  15 #include "ao_scheme.h"
  16 #include "ao_scheme_read.h"
  17 #include <math.h>
  18 #include <stdlib.h>
  19
  20 static const uint16_t   lex_classes[128] = {
  21         IGNORE,                         /* ^@ */
  22         IGNORE,                         /* ^A */
  23         IGNORE,                         /* ^B */
  24         IGNORE,                         /* ^C */
  25         IGNORE,                         /* ^D */
  26         IGNORE,                         /* ^E */
  27         IGNORE,                         /* ^F */
  28         IGNORE,                         /* ^G */
  29         IGNORE,                         /* ^H */
  30         WHITE,                          /* ^I */
  31         WHITE,                          /* ^J */
  32         WHITE,                          /* ^K */
  33         WHITE,                          /* ^L */
  34         WHITE,                          /* ^M */
  35         IGNORE,                         /* ^N */
  36         IGNORE,                         /* ^O */
  37         IGNORE,                         /* ^P */
  38         IGNORE,                         /* ^Q */
  39         IGNORE,                         /* ^R */
  40         IGNORE,                         /* ^S */
  41         IGNORE,                         /* ^T */
  42         IGNORE,                         /* ^U */
  43         IGNORE,                         /* ^V */
  44         IGNORE,                         /* ^W */
  45         IGNORE,                         /* ^X */
  46         IGNORE,                         /* ^Y */
  47         IGNORE,                         /* ^Z */
  48         IGNORE,                         /* ^[ */
  49         IGNORE,                         /* ^\ */
  50         IGNORE,                         /* ^] */
  51         IGNORE,                         /* ^^ */
  52         IGNORE,                         /* ^_ */
  53         PRINTABLE|WHITE,                /*    */
  54         PRINTABLE,                      /* ! */
  55         PRINTABLE|STRINGC,              /* " */
  56         PRINTABLE,                      /* # */
  57         PRINTABLE,                      /* $ */
  58         PRINTABLE,                      /* % */
  59         PRINTABLE,                      /* & */
  60         PRINTABLE|SPECIAL,              /* ' */
  61         PRINTABLE|SPECIAL,              /* ( */
  62         PRINTABLE|SPECIAL,              /* ) */
  63         PRINTABLE,                      /* * */
  64         PRINTABLE|SIGN,                 /* + */
  65         PRINTABLE|SPECIAL_QUASI,        /* , */
  66         PRINTABLE|SIGN,                 /* - */
  67         PRINTABLE|SPECIAL|FLOATC,       /* . */
  68         PRINTABLE,                      /* / */
  69         PRINTABLE|DIGIT,                /* 0 */
  70         PRINTABLE|DIGIT,                /* 1 */
  71         PRINTABLE|DIGIT,                /* 2 */
  72         PRINTABLE|DIGIT,                /* 3 */
  73         PRINTABLE|DIGIT,                /* 4 */
  74         PRINTABLE|DIGIT,                /* 5 */
  75         PRINTABLE|DIGIT,                /* 6 */
  76         PRINTABLE|DIGIT,                /* 7 */
  77         PRINTABLE|DIGIT,                /* 8 */
  78         PRINTABLE|DIGIT,                /* 9 */
  79         PRINTABLE,                      /* : */
  80         PRINTABLE|COMMENT,              /* ; */
  81         PRINTABLE,                      /* < */
  82         PRINTABLE,                      /* = */
  83         PRINTABLE,                      /* > */
  84         PRINTABLE,                      /* ? */
  85         PRINTABLE,                      /*  @ */
  86         PRINTABLE|ALPHA|HEX_LETTER,     /*  A */
  87         PRINTABLE|ALPHA|HEX_LETTER,     /*  B */
  88         PRINTABLE|ALPHA|HEX_LETTER,     /*  C */
  89         PRINTABLE|ALPHA|HEX_LETTER,     /*  D */
  90         PRINTABLE|ALPHA|FLOATC|HEX_LETTER,/*  E */
  91         PRINTABLE|ALPHA|HEX_LETTER,     /*  F */
  92         PRINTABLE|ALPHA,                /*  G */
  93         PRINTABLE|ALPHA,                /*  H */
  94         PRINTABLE|ALPHA,                /*  I */
  95         PRINTABLE|ALPHA,                /*  J */
  96         PRINTABLE|ALPHA,                /*  K */
  97         PRINTABLE|ALPHA,                /*  L */
  98         PRINTABLE|ALPHA,                /*  M */
  99         PRINTABLE|ALPHA,                /*  N */
 100         PRINTABLE|ALPHA,                /*  O */
 101         PRINTABLE|ALPHA,                /*  P */
 102         PRINTABLE|ALPHA,                /*  Q */
 103         PRINTABLE|ALPHA,                /*  R */
 104         PRINTABLE|ALPHA,                /*  S */
 105         PRINTABLE|ALPHA,                /*  T */
 106         PRINTABLE|ALPHA,                /*  U */
 107         PRINTABLE|ALPHA,                /*  V */
 108         PRINTABLE|ALPHA,                /*  W */
 109         PRINTABLE|ALPHA,                /*  X */
 110         PRINTABLE|ALPHA,                /*  Y */
 111         PRINTABLE|ALPHA,                /*  Z */
 112         PRINTABLE,                      /*  [ */
 113         PRINTABLE,                      /*  \ */
 114         PRINTABLE,                      /*  ] */
 115         PRINTABLE,                      /*  ^ */
 116         PRINTABLE,                      /*  _ */
 117         PRINTABLE|SPECIAL_QUASI,        /*  ` */
 118         PRINTABLE|ALPHA|HEX_LETTER,     /*  a */
 119         PRINTABLE|ALPHA|HEX_LETTER,     /*  b */
 120         PRINTABLE|ALPHA|HEX_LETTER,     /*  c */
 121         PRINTABLE|ALPHA|HEX_LETTER,     /*  d */
 122         PRINTABLE|ALPHA|FLOATC|HEX_LETTER,/*  e */
 123         PRINTABLE|ALPHA|HEX_LETTER,     /*  f */
 124         PRINTABLE|ALPHA,                /*  g */
 125         PRINTABLE|ALPHA,                /*  h */
 126         PRINTABLE|ALPHA,                /*  i */
 127         PRINTABLE|ALPHA,                /*  j */
 128         PRINTABLE|ALPHA,                /*  k */
 129         PRINTABLE|ALPHA,                /*  l */
 130         PRINTABLE|ALPHA,                /*  m */
 131         PRINTABLE|ALPHA,                /*  n */
 132         PRINTABLE|ALPHA,                /*  o */
 133         PRINTABLE|ALPHA,                /*  p */
 134         PRINTABLE|ALPHA,                /*  q */
 135         PRINTABLE|ALPHA,                /*  r */
 136         PRINTABLE|ALPHA,                /*  s */
 137         PRINTABLE|ALPHA,                /*  t */
 138         PRINTABLE|ALPHA,                /*  u */
 139         PRINTABLE|ALPHA,                /*  v */
 140         PRINTABLE|ALPHA,                /*  w */
 141         PRINTABLE|ALPHA,                /*  x */
 142         PRINTABLE|ALPHA,                /*  y */
 143         PRINTABLE|ALPHA,                /*  z */
 144         PRINTABLE,                      /*  { */
 145         PRINTABLE,                      /*  | */
 146         PRINTABLE,                      /*  } */
 147         PRINTABLE,                      /*  ~ */
 148         IGNORE,                         /*  ^? */
 149 };
 150
 151 static int lex_unget_c;
 152
 153 static inline int
 154 lex_get(FILE *in)
 155 {
 156         int     c;
 157         if (lex_unget_c) {
 158                 c = lex_unget_c;
 159                 lex_unget_c = 0;
 160         } else {
 161                 c = getc(in);
 162         }
 163         return c;
 164 }
 165
 166 static inline void
 167 lex_unget(int c)
 168 {
 169         if (c != EOF)
 170                 lex_unget_c = c;
 171 }
 172
 173 static uint16_t lex_class;
 174
 175 static int
 176 lexc(FILE *in)
 177 {
 178         int     c;
 179         do {
 180                 c = lex_get(in);
 181                 if (c == EOF) {
 182                         c = 0;
 183                         lex_class = ENDOFFILE;
 184                 } else {
 185                         c &= 0x7f;
 186                         lex_class = lex_classes[c];
 187                 }
 188         } while (lex_class & IGNORE);
 189         return c;
 190 }
 191
 192 static int
 193 lex_quoted(FILE *in)
 194 {
 195         int     c;
 196         int     v;
 197         int     count;
 198
 199         c = lex_get(in);
 200         if (c == EOF) {
 201         eof:
 202                 lex_class = ENDOFFILE;
 203                 return 0;
 204         }
 205         lex_class = 0;
 206         c &= 0x7f;
 207         switch (c) {
 208         case 'a':
 209                 return '\a';
 210         case 'b':
 211                 return '\b';
 212         case 't':
 213                 return '\t';
 214         case 'n':
 215                 return '\n';
 216         case 'r':
 217                 return '\r';
 218         case 'f':
 219                 return '\f';
 220         case 'v':
 221                 return '\v';
 222         case '0':
 223         case '1':
 224         case '2':
 225         case '3':
 226         case '4':
 227         case '5':
 228         case '6':
 229         case '7':
 230                 v = c - '0';
 231                 count = 1;
 232                 while (count <= 3) {
 233                         c = lex_get(in);
 234                         if (c == EOF)
 235                                 goto eof;
 236                         c &= 0x7f;
 237                         if (c < '0' || '7' < c) {
 238                                 lex_unget(c);
 239                                 break;
 240                         }
 241                         v = (v << 3) + c - '0';
 242                         ++count;
 243                 }
 244                 return v;
 245         default:
 246                 return c;
 247         }
 248 }
 249
 250 #ifndef AO_SCHEME_TOKEN_MAX
 251 #define AO_SCHEME_TOKEN_MAX     128
 252 #endif
 253
 254 static char     token_string[AO_SCHEME_TOKEN_MAX];
 255 static int32_t  token_int;
 256 static int      token_len;
 257
 258 static void start_token(void) {
 259         token_len = 0;
 260 }
 261
 262 static void add_token(int c) {
 263         if (c && token_len < AO_SCHEME_TOKEN_MAX - 1)
 264                 token_string[token_len++] = c;
 265 }
 266
 267 static void end_token(void) {
 268         token_string[token_len] = '\0';
 269 }
 270
 271 #ifdef AO_SCHEME_FEATURE_FLOAT
 272 static float    token_float;
 273
 274 struct namedfloat {
 275         const char      *name;
 276         float           value;
 277 };
 278
 279 static const struct namedfloat namedfloats[] = {
 280         { .name = "+inf.0", .value = INFINITY },
 281         { .name = "-inf.0", .value = -INFINITY },
 282         { .name = "+nan.0", .value = NAN },
 283         { .name = "-nan.0", .value = NAN },
 284 };
 285
 286 #define NUM_NAMED_FLOATS        (sizeof namedfloats / sizeof namedfloats[0])
 287 #endif
 288
 289 static int
 290 parse_int(FILE *in, int base)
 291 {
 292         int     cval;
 293         int     c;
 294
 295         token_int = 0;
 296         for (;;) {
 297                 c = lexc(in);
 298                 if ((lex_class & HEX_DIGIT) == 0) {
 299                         lex_unget(c);
 300                         return NUM;
 301                 }
 302                 if ('0' <= c && c <= '9')
 303                         cval = c - '0';
 304                 else
 305                         cval = (c | ('a' - 'A')) - 'a' + 10;
 306                 token_int = token_int * base + cval;
 307         }
 308         return NUM;
 309 }
 310
 311 static int
 312 _lex(FILE *in)
 313 {
 314         int     c;
 315
 316         start_token();
 317         for (;;) {
 318                 c = lexc(in);
 319                 if (lex_class & ENDOFFILE)
 320                         return END;
 321
 322                 if (lex_class & WHITE)
 323                         continue;
 324
 325                 if (lex_class & COMMENT) {
 326                         while ((c = lexc(in)) != '\n') {
 327                                 if (lex_class & ENDOFFILE)
 328                                         return END;
 329                         }
 330                         continue;
 331                 }
 332
 333                 if (lex_class & SPECIAL) {
 334                         switch (c) {
 335                         case '(':
 336                         case '[':
 337                                 return OPEN;
 338                         case ')':
 339                         case ']':
 340                                 return CLOSE;
 341                         case '\'':
 342                                 return QUOTE;
 343                         case '.':
 344                                 return DOT;
 345 #ifdef AO_SCHEME_FEATURE_QUASI
 346                         case '`':
 347                                 return QUASIQUOTE;
 348                         case ',':
 349                                 c = lexc(in);
 350                                 if (c == '@') {
 351                                         return UNQUOTE_SPLICING;
 352                                 } else {
 353                                         lex_unget(c);
 354                                         return UNQUOTE;
 355                                 }
 356 #endif
 357                         }
 358                 }
 359                 if (c == '#') {
 360                         c = lexc(in);
 361                         switch (c) {
 362                         case 't':
 363                                 return TRUE_TOKEN;
 364                         case 'f':
 365                                 return FALSE_TOKEN;
 366 #ifdef AO_SCHEME_FEATURE_VECTOR
 367                         case '(':
 368                                 return OPEN_VECTOR;
 369 #endif
 370                         case '\\':
 371                                 for (;;) {
 372                                         c = lexc(in);
 373                                         if (token_len == 0) {
 374                                                 add_token(c);
 375                                                 if (!(lex_class & ALPHA))
 376                                                         break;
 377                                         } else {
 378                                                 if (lex_class & ALPHA)
 379                                                         add_token(c);
 380                                                 else {
 381                                                         lex_unget(c);
 382                                                         break;
 383                                                 }
 384                                         }
 385                                 }
 386                                 end_token();
 387                                 if (token_len == 1)
 388                                         token_int = token_string[0];
 389                                 else if (!strcmp(token_string, "space"))
 390                                         token_int = ' ';
 391                                 else if (!strcmp(token_string, "newline"))
 392                                         token_int = '\n';
 393                                 else if (!strcmp(token_string, "tab"))
 394                                         token_int = '\t';
 395                                 else if (!strcmp(token_string, "return"))
 396                                         token_int = '\r';
 397                                 else if (!strcmp(token_string, "formfeed"))
 398                                         token_int = '\f';
 399                                 else {
 400                                         ao_scheme_error(AO_SCHEME_INVALID, "invalid character token #\\%s", token_string);
 401                                         continue;
 402                                 }
 403                                 return NUM;
 404                         case 'x':
 405                                 return parse_int(in, 16);
 406                         case 'o':
 407                                 return parse_int(in, 8);
 408                         case 'b':
 409                                 return parse_int(in, 2);
 410                         }
 411                 }
 412                 if (lex_class & STRINGC) {
 413                         for (;;) {
 414                                 c = lexc(in);
 415                                 if (c == '\\')
 416                                         c = lex_quoted(in);
 417                                 if (lex_class & (STRINGC|ENDOFFILE)) {
 418                                         end_token();
 419                                         return STRING;
 420                                 }
 421                                 add_token(c);
 422                         }
 423                 }
 424                 if (lex_class & PRINTABLE) {
 425 #ifdef AO_SCHEME_FEATURE_FLOAT
 426                         int     isfloat = 1;
 427                         int     epos = 0;
 428 #endif
 429                         int     hasdigit = 0;
 430                         int     isneg = 0;
 431                         int     isint = 1;
 432
 433                         token_int = 0;
 434                         for (;;) {
 435                                 if (!(lex_class & NUMBER)) {
 436                                         isint = 0;
 437 #ifdef AO_SCHEME_FEATURE_FLOAT
 438                                         isfloat = 0;
 439 #endif
 440                                 } else {
 441 #ifdef AO_SCHEME_FEATURE_FLOAT
 442                                         if (!(lex_class & INTEGER))
 443                                                 isint = 0;
 444                                         if (token_len != epos &&
 445                                             (lex_class & SIGN))
 446                                         {
 447                                                 isint = 0;
 448                                                 isfloat = 0;
 449                                         }
 450 #endif
 451                                         if (c == '-')
 452                                                 isneg = 1;
 453 #ifdef AO_SCHEME_FEATURE_FLOAT
 454                                         if (c == '.' && epos != 0)
 455                                                 isfloat = 0;
 456                                         if (c == 'e' || c == 'E') {
 457                                                 if (token_len == 0)
 458                                                         isfloat = 0;
 459                                                 else
 460                                                         epos = token_len + 1;
 461                                         }
 462 #endif
 463                                         if (lex_class & DIGIT) {
 464                                                 hasdigit = 1;
 465                                                 if (isint)
 466                                                         token_int = token_int * 10 + c - '0';
 467                                         }
 468                                 }
 469                                 add_token (c);
 470                                 c = lexc (in);
 471                                 if ((lex_class & (NOTNAME))
 472 #ifdef AO_SCHEME_FEATURE_FLOAT
 473                                     && (c != '.' || !isfloat)
 474 #endif
 475                                         ) {
 476 #ifdef AO_SCHEME_FEATURE_FLOAT
 477                                         unsigned int u;
 478 #endif
 479                                         lex_unget(c);
 480                                         end_token ();
 481                                         if (isint && hasdigit) {
 482                                                 if (isneg)
 483                                                         token_int = -token_int;
 484                                                 return NUM;
 485                                         }
 486 #ifdef AO_SCHEME_FEATURE_FLOAT
 487                                         if (isfloat && hasdigit) {
 488                                                 token_float = strtof(token_string, NULL);
 489                                                 return FLOAT;
 490                                         }
 491                                         for (u = 0; u < NUM_NAMED_FLOATS; u++)
 492                                                 if (!strcmp(namedfloats[u].name, token_string)) {
 493                                                         token_float = namedfloats[u].value;
 494                                                         return FLOAT;
 495                                                 }
 496 #endif
 497                                         return NAME;
 498                                 }
 499                         }
 500                 }
 501         }
 502 }
 503
 504 static inline int lex(FILE *in)
 505 {
 506         int     parse_token = _lex(in);
 507         RDBGI("token %d \"%s\"\n", parse_token, token_string);
 508         return parse_token;
 509 }
 510
 511 static int parse_token;
 512
 513 int                     ao_scheme_read_list;
 514 struct ao_scheme_cons   *ao_scheme_read_cons;
 515 struct ao_scheme_cons   *ao_scheme_read_cons_tail;
 516 struct ao_scheme_cons   *ao_scheme_read_stack;
 517 static int              ao_scheme_read_state;
 518
 519 #define READ_IN_QUOTE   0x01
 520 #define READ_SAW_DOT    0x02
 521 #define READ_DONE_DOT   0x04
 522 #define READ_SAW_VECTOR 0x08
 523
 524 static int
 525 push_read_stack(int read_state)
 526 {
 527         RDBGI("push read stack %p 0x%x\n", ao_scheme_read_cons, read_state);
 528         RDBG_IN();
 529         if (ao_scheme_read_list) {
 530                 ao_scheme_read_stack = ao_scheme_cons_cons(ao_scheme_cons_poly(ao_scheme_read_cons),
 531                                                        ao_scheme_cons(ao_scheme_int_poly(read_state),
 532                                                                      ao_scheme_cons_poly(ao_scheme_read_stack)));
 533                 if (!ao_scheme_read_stack)
 534                         return 0;
 535         } else
 536                 ao_scheme_read_state = read_state;
 537         ao_scheme_read_cons = NULL;
 538         ao_scheme_read_cons_tail = NULL;
 539         return 1;
 540 }
 541
 542 static int
 543 pop_read_stack(void)
 544 {
 545         int     read_state = 0;
 546         if (ao_scheme_read_list) {
 547                 ao_scheme_read_cons = ao_scheme_poly_cons(ao_scheme_read_stack->car);
 548                 ao_scheme_read_stack = ao_scheme_poly_cons(ao_scheme_read_stack->cdr);
 549                 read_state = ao_scheme_poly_int(ao_scheme_read_stack->car);
 550                 ao_scheme_read_stack = ao_scheme_poly_cons(ao_scheme_read_stack->cdr);
 551                 for (ao_scheme_read_cons_tail = ao_scheme_read_cons;
 552                      ao_scheme_read_cons_tail && ao_scheme_read_cons_tail->cdr;
 553                      ao_scheme_read_cons_tail = ao_scheme_poly_cons(ao_scheme_read_cons_tail->cdr))
 554                         ;
 555         } else {
 556                 read_state = ao_scheme_read_state;
 557                 ao_scheme_read_cons = NULL;
 558                 ao_scheme_read_cons_tail = NULL;
 559                 ao_scheme_read_stack = NULL;
 560                 ao_scheme_read_state = 0;
 561         }
 562         RDBG_OUT();
 563         RDBGI("pop read stack %p %d\n", ao_scheme_read_cons, read_state);
 564         return read_state;
 565 }
 566
 567 #ifdef AO_SCHEME_FEATURE_VECTOR
 568 #define is_open(t) ((t) == OPEN || (t) == OPEN_VECTOR)
 569 #else
 570 #define is_open(t) ((t) == OPEN)
 571 #endif
 572
 573 ao_poly
 574 ao_scheme_read(FILE *in)
 575 {
 576         struct ao_scheme_atom   *atom;
 577         struct ao_scheme_string *string;
 578         int                     read_state;
 579         ao_poly                 v = AO_SCHEME_NIL;
 580
 581         ao_scheme_read_list = 0;
 582         read_state = 0;
 583         ao_scheme_read_cons = ao_scheme_read_cons_tail = ao_scheme_read_stack = NULL;
 584         for (;;) {
 585                 parse_token = lex(in);
 586                 while (is_open(parse_token)) {
 587 #ifdef AO_SCHEME_FEATURE_VECTOR
 588                         if (parse_token == OPEN_VECTOR)
 589                                 read_state |= READ_SAW_VECTOR;
 590 #endif
 591                         if (!push_read_stack(read_state))
 592                                 return AO_SCHEME_NIL;
 593                         ao_scheme_read_list++;
 594                         read_state = 0;
 595                         parse_token = lex(in);
 596                 }
 597
 598                 switch (parse_token) {
 599                 case END:
 600                 default:
 601                         if (ao_scheme_read_list)
 602                                 ao_scheme_error(AO_SCHEME_EOF, "unexpected end of file");
 603                         return _ao_scheme_atom_eof;
 604                         break;
 605                 case NAME:
 606                         atom = ao_scheme_atom_intern(token_string);
 607                         if (atom)
 608                                 v = ao_scheme_atom_poly(atom);
 609                         else
 610                                 v = AO_SCHEME_NIL;
 611                         break;
 612                 case NUM:
 613                         v = ao_scheme_integer_poly(token_int);
 614                         break;
 615 #ifdef AO_SCHEME_FEATURE_FLOAT
 616                 case FLOAT:
 617                         v = ao_scheme_float_get(token_float);
 618                         break;
 619 #endif
 620                 case TRUE_TOKEN:
 621                         v = _ao_scheme_bool_true;
 622                         break;
 623                 case FALSE_TOKEN:
 624                         v = _ao_scheme_bool_false;
 625                         break;
 626                 case STRING:
 627                         string = ao_scheme_string_new(token_string);
 628                         if (string)
 629                                 v = ao_scheme_string_poly(string);
 630                         else
 631                                 v = AO_SCHEME_NIL;
 632                         break;
 633                 case QUOTE:
 634 #ifdef AO_SCHEME_FEATURE_QUASI
 635                 case QUASIQUOTE:
 636                 case UNQUOTE:
 637                 case UNQUOTE_SPLICING:
 638 #endif
 639                         if (!push_read_stack(read_state))
 640                                 return AO_SCHEME_NIL;
 641                         ao_scheme_read_list++;
 642                         read_state = READ_IN_QUOTE;
 643                         switch (parse_token) {
 644                         case QUOTE:
 645                                 v = _ao_scheme_atom_quote;
 646                                 break;
 647 #ifdef AO_SCHEME_FEATURE_QUASI
 648                         case QUASIQUOTE:
 649                                 v = _ao_scheme_atom_quasiquote;
 650                                 break;
 651                         case UNQUOTE:
 652                                 v = _ao_scheme_atom_unquote;
 653                                 break;
 654                         case UNQUOTE_SPLICING:
 655                                 v = _ao_scheme_atom_unquote2dsplicing;
 656                                 break;
 657 #endif
 658                         }
 659                         break;
 660                 case CLOSE:
 661                         if (!ao_scheme_read_list) {
 662                                 v = AO_SCHEME_NIL;
 663                                 break;
 664                         }
 665                         v = ao_scheme_cons_poly(ao_scheme_read_cons);
 666                         --ao_scheme_read_list;
 667                         read_state = pop_read_stack();
 668 #ifdef AO_SCHEME_FEATURE_VECTOR
 669                         if (read_state & READ_SAW_VECTOR) {
 670                                 v = ao_scheme_vector_poly(ao_scheme_list_to_vector(ao_scheme_poly_cons(v)));
 671                                 read_state &= ~READ_SAW_VECTOR;
 672                         }
 673 #endif
 674                         break;
 675                 case DOT:
 676                         if (!ao_scheme_read_list) {
 677                                 ao_scheme_error(AO_SCHEME_INVALID, ". outside of cons");
 678                                 return AO_SCHEME_NIL;
 679                         }
 680                         if (!ao_scheme_read_cons) {
 681                                 ao_scheme_error(AO_SCHEME_INVALID, ". first in cons");
 682                                 return AO_SCHEME_NIL;
 683                         }
 684                         read_state |= READ_SAW_DOT;
 685                         continue;
 686                 }
 687
 688                 /* loop over QUOTE ends */
 689                 for (;;) {
 690                         if (!ao_scheme_read_list)
 691                                 return v;
 692
 693                         if (read_state & READ_DONE_DOT) {
 694                                 ao_scheme_error(AO_SCHEME_INVALID, ". not last in cons");
 695                                 return AO_SCHEME_NIL;
 696                         }
 697
 698                         if (read_state & READ_SAW_DOT) {
 699                                 read_state |= READ_DONE_DOT;
 700                                 ao_scheme_read_cons_tail->cdr = v;
 701                         } else {
 702                                 struct ao_scheme_cons   *read = ao_scheme_cons_cons(v, AO_SCHEME_NIL);
 703                                 if (!read)
 704                                         return AO_SCHEME_NIL;
 705
 706                                 if (ao_scheme_read_cons_tail)
 707                                         ao_scheme_read_cons_tail->cdr = ao_scheme_cons_poly(read);
 708                                 else
 709                                         ao_scheme_read_cons = read;
 710                                 ao_scheme_read_cons_tail = read;
 711                         }
 712
 713                         if (!(read_state & READ_IN_QUOTE) || !ao_scheme_read_cons->cdr)
 714                                 break;
 715
 716                         v = ao_scheme_cons_poly(ao_scheme_read_cons);
 717                         --ao_scheme_read_list;
 718                         read_state = pop_read_stack();
 719                 }
 720         }
 721         return v;
 722 }