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|DOTC|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|HEX_LETTER,   /*  A */
  87         PRINTABLE|HEX_LETTER,   /*  B */
  88         PRINTABLE|HEX_LETTER,   /*  C */
  89         PRINTABLE|HEX_LETTER,   /*  D */
  90         PRINTABLE|FLOATC|HEX_LETTER,/*  E */
  91         PRINTABLE|HEX_LETTER,   /*  F */
  92         PRINTABLE,              /*  G */
  93         PRINTABLE,              /*  H */
  94         PRINTABLE,              /*  I */
  95         PRINTABLE,              /*  J */
  96         PRINTABLE,              /*  K */
  97         PRINTABLE,              /*  L */
  98         PRINTABLE,              /*  M */
  99         PRINTABLE,              /*  N */
 100         PRINTABLE,              /*  O */
 101         PRINTABLE,              /*  P */
 102         PRINTABLE,              /*  Q */
 103         PRINTABLE,              /*  R */
 104         PRINTABLE,              /*  S */
 105         PRINTABLE,              /*  T */
 106         PRINTABLE,              /*  U */
 107         PRINTABLE,              /*  V */
 108         PRINTABLE,              /*  W */
 109         PRINTABLE,              /*  X */
 110         PRINTABLE,              /*  Y */
 111         PRINTABLE,              /*  Z */
 112         PRINTABLE,              /*  [ */
 113         PRINTABLE,              /*  \ */
 114         PRINTABLE,              /*  ] */
 115         PRINTABLE,              /*  ^ */
 116         PRINTABLE,              /*  _ */
 117         PRINTABLE|SPECIAL_QUASI,        /*  ` */
 118         PRINTABLE|HEX_LETTER,   /*  a */
 119         PRINTABLE|HEX_LETTER,   /*  b */
 120         PRINTABLE|HEX_LETTER,   /*  c */
 121         PRINTABLE|HEX_LETTER,   /*  d */
 122         PRINTABLE|FLOATC|HEX_LETTER,/*  e */
 123         PRINTABLE|HEX_LETTER,   /*  f */
 124         PRINTABLE,              /*  g */
 125         PRINTABLE,              /*  h */
 126         PRINTABLE,              /*  i */
 127         PRINTABLE,              /*  j */
 128         PRINTABLE,              /*  k */
 129         PRINTABLE,              /*  l */
 130         PRINTABLE,              /*  m */
 131         PRINTABLE,              /*  n */
 132         PRINTABLE,              /*  o */
 133         PRINTABLE,              /*  p */
 134         PRINTABLE,              /*  q */
 135         PRINTABLE,              /*  r */
 136         PRINTABLE,              /*  s */
 137         PRINTABLE,              /*  t */
 138         PRINTABLE,              /*  u */
 139         PRINTABLE,              /*  v */
 140         PRINTABLE,              /*  w */
 141         PRINTABLE,              /*  x */
 142         PRINTABLE,              /*  y */
 143         PRINTABLE,              /*  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(void)
 155 {
 156         int     c;
 157         if (lex_unget_c) {
 158                 c = lex_unget_c;
 159                 lex_unget_c = 0;
 160         } else {
 161                 c = ao_scheme_getc();
 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(void)
 177 {
 178         int     c;
 179         do {
 180                 c = lex_get();
 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(void)
 194 {
 195         int     c;
 196         int     v;
 197         int     count;
 198
 199         c = lex_get();
 200         if (c == EOF) {
 201                 lex_class = ENDOFFILE;
 202                 return 0;
 203         }
 204         lex_class = 0;
 205         c &= 0x7f;
 206         switch (c) {
 207         case 'a':
 208                 return '\a';
 209         case 'b':
 210                 return '\b';
 211         case 't':
 212                 return '\t';
 213         case 'n':
 214                 return '\n';
 215         case 'r':
 216                 return '\r';
 217         case 'f':
 218                 return '\f';
 219         case 'v':
 220                 return '\v';
 221         case '0':
 222         case '1':
 223         case '2':
 224         case '3':
 225         case '4':
 226         case '5':
 227         case '6':
 228         case '7':
 229                 v = c - '0';
 230                 count = 1;
 231                 while (count <= 3) {
 232                         c = lex_get();
 233                         if (c == EOF)
 234                                 return EOF;
 235                         c &= 0x7f;
 236                         if (c < '0' || '7' < c) {
 237                                 lex_unget(c);
 238                                 break;
 239                         }
 240                         v = (v << 3) + c - '0';
 241                         ++count;
 242                 }
 243                 return v;
 244         default:
 245                 return c;
 246         }
 247 }
 248
 249 #ifndef AO_SCHEME_TOKEN_MAX
 250 #define AO_SCHEME_TOKEN_MAX     128
 251 #endif
 252
 253 static char     token_string[AO_SCHEME_TOKEN_MAX];
 254 static int32_t  token_int;
 255 static int      token_len;
 256
 257 static inline void add_token(int c) {
 258         if (c && token_len < AO_SCHEME_TOKEN_MAX - 1)
 259                 token_string[token_len++] = c;
 260 }
 261
 262 static inline void del_token(void) {
 263         if (token_len > 0)
 264                 token_len--;
 265 }
 266
 267 static inline 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(int base)
 291 {
 292         int     cval;
 293         int     c;
 294
 295         token_int = 0;
 296         for (;;) {
 297                 c = lexc();
 298                 if ((lex_class & HEX_DIGIT) == 0) {
 299                         lex_unget(c);
 300                         end_token();
 301                         return NUM;
 302                 }
 303                 add_token(c);
 304                 if ('0' <= c && c <= '9')
 305                         cval = c - '0';
 306                 else
 307                         cval = (c | ('a' - 'A')) - 'a' + 10;
 308                 token_int = token_int * base + cval;
 309         }
 310         return NUM;
 311 }
 312
 313 static int
 314 _lex(void)
 315 {
 316         int     c;
 317
 318         token_len = 0;
 319         for (;;) {
 320                 c = lexc();
 321                 if (lex_class & ENDOFFILE)
 322                         return END;
 323
 324                 if (lex_class & WHITE)
 325                         continue;
 326
 327                 if (lex_class & COMMENT) {
 328                         while ((c = lexc()) != '\n') {
 329                                 if (lex_class & ENDOFFILE)
 330                                         return END;
 331                         }
 332                         continue;
 333                 }
 334
 335                 if (lex_class & (SPECIAL|DOTC)) {
 336                         add_token(c);
 337                         end_token();
 338                         switch (c) {
 339                         case '(':
 340                         case '[':
 341                                 return OPEN;
 342                         case ')':
 343                         case ']':
 344                                 return CLOSE;
 345                         case '\'':
 346                                 return QUOTE;
 347                         case '.':
 348                                 return DOT;
 349 #ifdef AO_SCHEME_FEATURE_QUASI
 350                         case '`':
 351                                 return QUASIQUOTE;
 352                         case ',':
 353                                 c = lexc();
 354                                 if (c == '@') {
 355                                         add_token(c);
 356                                         end_token();
 357                                         return UNQUOTE_SPLICING;
 358                                 } else {
 359                                         lex_unget(c);
 360                                         return UNQUOTE;
 361                                 }
 362 #endif
 363                         }
 364                 }
 365                 if (c == '#') {
 366                         c = lexc();
 367                         switch (c) {
 368                         case 't':
 369                                 add_token(c);
 370                                 end_token();
 371                                 return BOOL;
 372                         case 'f':
 373                                 add_token(c);
 374                                 end_token();
 375                                 return BOOL;
 376 #ifdef AO_SCHEME_FEATURE_VECTOR
 377                         case '(':
 378                                 return OPEN_VECTOR;
 379 #endif
 380                         case '\\':
 381                                 for (;;) {
 382                                         int alphabetic;
 383                                         c = lexc();
 384                                         alphabetic = (('a' <= c && c <= 'z') || ('A' <= c && c <= 'Z'));
 385                                         if (token_len == 0) {
 386                                                 add_token(c);
 387                                                 if (!alphabetic)
 388                                                         break;
 389                                         } else {
 390                                                 if (alphabetic)
 391                                                         add_token(c);
 392                                                 else {
 393                                                         lex_unget(c);
 394                                                         break;
 395                                                 }
 396                                         }
 397                                 }
 398                                 end_token();
 399                                 if (token_len == 1)
 400                                         token_int = token_string[0];
 401                                 else if (!strcmp(token_string, "space"))
 402                                         token_int = ' ';
 403                                 else if (!strcmp(token_string, "newline"))
 404                                         token_int = '\n';
 405                                 else if (!strcmp(token_string, "tab"))
 406                                         token_int = '\t';
 407                                 else if (!strcmp(token_string, "return"))
 408                                         token_int = '\r';
 409                                 else if (!strcmp(token_string, "formfeed"))
 410                                         token_int = '\f';
 411                                 else {
 412                                         ao_scheme_error(AO_SCHEME_INVALID, "invalid character token #\\%s", token_string);
 413                                         continue;
 414                                 }
 415                                 return NUM;
 416                         case 'x':
 417                                 return parse_int(16);
 418                         case 'o':
 419                                 return parse_int(8);
 420                         case 'b':
 421                                 return parse_int(2);
 422                         }
 423                 }
 424                 if (lex_class & STRINGC) {
 425                         for (;;) {
 426                                 c = lexc();
 427                                 if (c == '\\')
 428                                         c = lex_quoted();
 429                                 if (lex_class & (STRINGC|ENDOFFILE)) {
 430                                         end_token();
 431                                         return STRING;
 432                                 }
 433                                 add_token(c);
 434                         }
 435                 }
 436                 if (lex_class & PRINTABLE) {
 437 #ifdef AO_SCHEME_FEATURE_FLOAT
 438                         int     isfloat = 1;
 439                         int     epos = 0;
 440 #endif
 441                         int     hasdigit = 0;
 442                         int     isneg = 0;
 443                         int     isint = 1;
 444
 445                         token_int = 0;
 446                         for (;;) {
 447                                 if (!(lex_class & NUMBER)) {
 448                                         isint = 0;
 449 #ifdef AO_SCHEME_FEATURE_FLOAT
 450                                         isfloat = 0;
 451 #endif
 452                                 } else {
 453 #ifdef AO_SCHEME_FEATURE_FLOAT
 454                                         if (!(lex_class & INTEGER))
 455                                                 isint = 0;
 456                                         if (token_len != epos &&
 457                                             (lex_class & SIGN))
 458                                         {
 459                                                 isint = 0;
 460                                                 isfloat = 0;
 461                                         }
 462 #endif
 463                                         if (c == '-')
 464                                                 isneg = 1;
 465 #ifdef AO_SCHEME_FEATURE_FLOAT
 466                                         if (c == '.' && epos != 0)
 467                                                 isfloat = 0;
 468                                         if (c == 'e' || c == 'E') {
 469                                                 if (token_len == 0)
 470                                                         isfloat = 0;
 471                                                 else
 472                                                         epos = token_len + 1;
 473                                         }
 474 #endif
 475                                         if (lex_class & DIGIT) {
 476                                                 hasdigit = 1;
 477                                                 if (isint)
 478                                                         token_int = token_int * 10 + c - '0';
 479                                         }
 480                                 }
 481                                 add_token (c);
 482                                 c = lexc ();
 483                                 if ((lex_class & (NOTNAME))
 484 #ifdef AO_SCHEME_FEATURE_FLOAT
 485                                     && (c != '.' || !isfloat)
 486 #endif
 487                                         ) {
 488 #ifdef AO_SCHEME_FEATURE_FLOAT
 489                                         unsigned int u;
 490 #endif
 491 //                                      if (lex_class & ENDOFFILE)
 492 //                                              clearerr (f);
 493                                         lex_unget(c);
 494                                         end_token ();
 495                                         if (isint && hasdigit) {
 496                                                 if (isneg)
 497                                                         token_int = -token_int;
 498                                                 return NUM;
 499                                         }
 500 #ifdef AO_SCHEME_FEATURE_FLOAT
 501                                         if (isfloat && hasdigit) {
 502                                                 token_float = strtof(token_string, NULL);
 503                                                 return FLOAT;
 504                                         }
 505                                         for (u = 0; u < NUM_NAMED_FLOATS; u++)
 506                                                 if (!strcmp(namedfloats[u].name, token_string)) {
 507                                                         token_float = namedfloats[u].value;
 508                                                         return FLOAT;
 509                                                 }
 510 #endif
 511                                         return NAME;
 512                                 }
 513                         }
 514                 }
 515         }
 516 }
 517
 518 static inline int lex(void)
 519 {
 520         int     parse_token = _lex();
 521         RDBGI("token %d \"%s\"\n", parse_token, token_string);
 522         return parse_token;
 523 }
 524
 525 static int parse_token;
 526
 527 int                     ao_scheme_read_list;
 528 struct ao_scheme_cons   *ao_scheme_read_cons;
 529 struct ao_scheme_cons   *ao_scheme_read_cons_tail;
 530 struct ao_scheme_cons   *ao_scheme_read_stack;
 531 static int              ao_scheme_read_state;
 532
 533 #define READ_IN_QUOTE   0x01
 534 #define READ_SAW_DOT    0x02
 535 #define READ_DONE_DOT   0x04
 536 #define READ_SAW_VECTOR 0x08
 537
 538 static int
 539 push_read_stack(int read_state)
 540 {
 541         RDBGI("push read stack %p 0x%x\n", ao_scheme_read_cons, read_state);
 542         RDBG_IN();
 543         if (ao_scheme_read_list) {
 544                 ao_scheme_read_stack = ao_scheme_cons_cons(ao_scheme_cons_poly(ao_scheme_read_cons),
 545                                                        ao_scheme_cons(ao_scheme_int_poly(read_state),
 546                                                                      ao_scheme_cons_poly(ao_scheme_read_stack)));
 547                 if (!ao_scheme_read_stack)
 548                         return 0;
 549         } else
 550                 ao_scheme_read_state = read_state;
 551         ao_scheme_read_cons = NULL;
 552         ao_scheme_read_cons_tail = NULL;
 553         return 1;
 554 }
 555
 556 static int
 557 pop_read_stack(void)
 558 {
 559         int     read_state = 0;
 560         if (ao_scheme_read_list) {
 561                 ao_scheme_read_cons = ao_scheme_poly_cons(ao_scheme_read_stack->car);
 562                 ao_scheme_read_stack = ao_scheme_poly_cons(ao_scheme_read_stack->cdr);
 563                 read_state = ao_scheme_poly_int(ao_scheme_read_stack->car);
 564                 ao_scheme_read_stack = ao_scheme_poly_cons(ao_scheme_read_stack->cdr);
 565                 for (ao_scheme_read_cons_tail = ao_scheme_read_cons;
 566                      ao_scheme_read_cons_tail && ao_scheme_read_cons_tail->cdr;
 567                      ao_scheme_read_cons_tail = ao_scheme_poly_cons(ao_scheme_read_cons_tail->cdr))
 568                         ;
 569         } else {
 570                 read_state = ao_scheme_read_state;
 571                 ao_scheme_read_cons = NULL;
 572                 ao_scheme_read_cons_tail = NULL;
 573                 ao_scheme_read_stack = NULL;
 574                 ao_scheme_read_state = 0;
 575         }
 576         RDBG_OUT();
 577         RDBGI("pop read stack %p %d\n", ao_scheme_read_cons, read_state);
 578         return read_state;
 579 }
 580
 581 #ifdef AO_SCHEME_FEATURE_VECTOR
 582 #define is_open(t) ((t) == OPEN || (t) == OPEN_VECTOR)
 583 #else
 584 #define is_open(t) ((t) == OPEN)
 585 #endif
 586
 587 ao_poly
 588 ao_scheme_read(void)
 589 {
 590         struct ao_scheme_atom   *atom;
 591         struct ao_scheme_string *string;
 592         int                     read_state;
 593         ao_poly                 v = AO_SCHEME_NIL;
 594
 595         ao_scheme_read_list = 0;
 596         read_state = 0;
 597         ao_scheme_read_cons = ao_scheme_read_cons_tail = ao_scheme_read_stack = NULL;
 598         for (;;) {
 599                 parse_token = lex();
 600                 while (is_open(parse_token)) {
 601 #ifdef AO_SCHEME_FEATURE_VECTOR
 602                         if (parse_token == OPEN_VECTOR)
 603                                 read_state |= READ_SAW_VECTOR;
 604 #endif
 605                         if (!push_read_stack(read_state))
 606                                 return AO_SCHEME_NIL;
 607                         ao_scheme_read_list++;
 608                         read_state = 0;
 609                         parse_token = lex();
 610                 }
 611
 612                 switch (parse_token) {
 613                 case END:
 614                 default:
 615                         if (ao_scheme_read_list)
 616                                 ao_scheme_error(AO_SCHEME_EOF, "unexpected end of file");
 617                         return _ao_scheme_atom_eof;
 618                         break;
 619                 case NAME:
 620                         atom = ao_scheme_atom_intern(token_string);
 621                         if (atom)
 622                                 v = ao_scheme_atom_poly(atom);
 623                         else
 624                                 v = AO_SCHEME_NIL;
 625                         break;
 626                 case NUM:
 627                         v = ao_scheme_integer_poly(token_int);
 628                         break;
 629 #ifdef AO_SCHEME_FEATURE_FLOAT
 630                 case FLOAT:
 631                         v = ao_scheme_float_get(token_float);
 632                         break;
 633 #endif
 634                 case BOOL:
 635                         if (token_string[0] == 't')
 636                                 v = _ao_scheme_bool_true;
 637                         else
 638                                 v = _ao_scheme_bool_false;
 639                         break;
 640                 case STRING:
 641                         string = ao_scheme_string_new(token_string);
 642                         if (string)
 643                                 v = ao_scheme_string_poly(string);
 644                         else
 645                                 v = AO_SCHEME_NIL;
 646                         break;
 647                 case QUOTE:
 648 #ifdef AO_SCHEME_FEATURE_QUASI
 649                 case QUASIQUOTE:
 650                 case UNQUOTE:
 651                 case UNQUOTE_SPLICING:
 652 #endif
 653                         if (!push_read_stack(read_state))
 654                                 return AO_SCHEME_NIL;
 655                         ao_scheme_read_list++;
 656                         read_state = READ_IN_QUOTE;
 657                         switch (parse_token) {
 658                         case QUOTE:
 659                                 v = _ao_scheme_atom_quote;
 660                                 break;
 661 #ifdef AO_SCHEME_FEATURE_QUASI
 662                         case QUASIQUOTE:
 663                                 v = _ao_scheme_atom_quasiquote;
 664                                 break;
 665                         case UNQUOTE:
 666                                 v = _ao_scheme_atom_unquote;
 667                                 break;
 668                         case UNQUOTE_SPLICING:
 669                                 v = _ao_scheme_atom_unquote2dsplicing;
 670                                 break;
 671 #endif
 672                         }
 673                         break;
 674                 case CLOSE:
 675                         if (!ao_scheme_read_list) {
 676                                 v = AO_SCHEME_NIL;
 677                                 break;
 678                         }
 679                         v = ao_scheme_cons_poly(ao_scheme_read_cons);
 680                         --ao_scheme_read_list;
 681                         read_state = pop_read_stack();
 682 #ifdef AO_SCHEME_FEATURE_VECTOR
 683                         if (read_state & READ_SAW_VECTOR) {
 684                                 v = ao_scheme_vector_poly(ao_scheme_list_to_vector(ao_scheme_poly_cons(v)));
 685                                 read_state &= ~READ_SAW_VECTOR;
 686                         }
 687 #endif
 688                         break;
 689                 case DOT:
 690                         if (!ao_scheme_read_list) {
 691                                 ao_scheme_error(AO_SCHEME_INVALID, ". outside of cons");
 692                                 return AO_SCHEME_NIL;
 693                         }
 694                         if (!ao_scheme_read_cons) {
 695                                 ao_scheme_error(AO_SCHEME_INVALID, ". first in cons");
 696                                 return AO_SCHEME_NIL;
 697                         }
 698                         read_state |= READ_SAW_DOT;
 699                         continue;
 700                 }
 701
 702                 /* loop over QUOTE ends */
 703                 for (;;) {
 704                         if (!ao_scheme_read_list)
 705                                 return v;
 706
 707                         if (read_state & READ_DONE_DOT) {
 708                                 ao_scheme_error(AO_SCHEME_INVALID, ". not last in cons");
 709                                 return AO_SCHEME_NIL;
 710                         }
 711
 712                         if (read_state & READ_SAW_DOT) {
 713                                 read_state |= READ_DONE_DOT;
 714                                 ao_scheme_read_cons_tail->cdr = v;
 715                         } else {
 716                                 struct ao_scheme_cons   *read = ao_scheme_cons_cons(v, AO_SCHEME_NIL);
 717                                 if (!read)
 718                                         return AO_SCHEME_NIL;
 719
 720                                 if (ao_scheme_read_cons_tail)
 721                                         ao_scheme_read_cons_tail->cdr = ao_scheme_cons_poly(read);
 722                                 else
 723                                         ao_scheme_read_cons = read;
 724                                 ao_scheme_read_cons_tail = read;
 725                         }
 726
 727                         if (!(read_state & READ_IN_QUOTE) || !ao_scheme_read_cons->cdr)
 728                                 break;
 729
 730                         v = ao_scheme_cons_poly(ao_scheme_read_cons);
 731                         --ao_scheme_read_list;
 732                         read_state = pop_read_stack();
 733                 }
 734         }
 735         return v;
 736 }