git.gag.com Git - fw/altos/blob - src/lisp/ao_lisp_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_lisp.h"
  16 #include "ao_lisp_read.h"
  17
  18 static const uint16_t   lex_classes[128] = {
  19         IGNORE,         /* ^@ */
  20         IGNORE,         /* ^A */
  21         IGNORE,         /* ^B */
  22         IGNORE,         /* ^C */
  23         IGNORE,         /* ^D */
  24         IGNORE,         /* ^E */
  25         IGNORE,         /* ^F */
  26         IGNORE,         /* ^G */
  27         IGNORE,         /* ^H */
  28         WHITE,          /* ^I */
  29         WHITE,          /* ^J */
  30         WHITE,          /* ^K */
  31         WHITE,          /* ^L */
  32         WHITE,          /* ^M */
  33         IGNORE,         /* ^N */
  34         IGNORE,         /* ^O */
  35         IGNORE,         /* ^P */
  36         IGNORE,         /* ^Q */
  37         IGNORE,         /* ^R */
  38         IGNORE,         /* ^S */
  39         IGNORE,         /* ^T */
  40         IGNORE,         /* ^U */
  41         IGNORE,         /* ^V */
  42         IGNORE,         /* ^W */
  43         IGNORE,         /* ^X */
  44         IGNORE,         /* ^Y */
  45         IGNORE,         /* ^Z */
  46         IGNORE,         /* ^[ */
  47         IGNORE,         /* ^\ */
  48         IGNORE,         /* ^] */
  49         IGNORE,         /* ^^ */
  50         IGNORE,         /* ^_ */
  51         PRINTABLE|WHITE,        /*    */
  52         PRINTABLE,              /* ! */
  53         PRINTABLE|STRINGC,      /* " */
  54         PRINTABLE|COMMENT,      /* # */
  55         PRINTABLE,              /* $ */
  56         PRINTABLE,              /* % */
  57         PRINTABLE,              /* & */
  58         PRINTABLE|QUOTEC,       /* ' */
  59         PRINTABLE|BRA,          /* ( */
  60         PRINTABLE|KET,          /* ) */
  61         PRINTABLE,              /* * */
  62         PRINTABLE|SIGN,         /* + */
  63         PRINTABLE,              /* , */
  64         PRINTABLE|SIGN,         /* - */
  65         PRINTABLE,              /* . */
  66         PRINTABLE,              /* / */
  67         PRINTABLE|DIGIT,        /* 0 */
  68         PRINTABLE|DIGIT,        /* 1 */
  69         PRINTABLE|DIGIT,        /* 2 */
  70         PRINTABLE|DIGIT,        /* 3 */
  71         PRINTABLE|DIGIT,        /* 4 */
  72         PRINTABLE|DIGIT,        /* 5 */
  73         PRINTABLE|DIGIT,        /* 6 */
  74         PRINTABLE|DIGIT,        /* 7 */
  75         PRINTABLE|DIGIT,        /* 8 */
  76         PRINTABLE|DIGIT,        /* 9 */
  77         PRINTABLE,              /* : */
  78         PRINTABLE|COMMENT,      /* ; */
  79         PRINTABLE,              /* < */
  80         PRINTABLE,              /* = */
  81         PRINTABLE,              /* > */
  82         PRINTABLE,              /* ? */
  83         PRINTABLE,              /*  @ */
  84         PRINTABLE,              /*  A */
  85         PRINTABLE,              /*  B */
  86         PRINTABLE,              /*  C */
  87         PRINTABLE,              /*  D */
  88         PRINTABLE,              /*  E */
  89         PRINTABLE,              /*  F */
  90         PRINTABLE,              /*  G */
  91         PRINTABLE,              /*  H */
  92         PRINTABLE,              /*  I */
  93         PRINTABLE,              /*  J */
  94         PRINTABLE,              /*  K */
  95         PRINTABLE,              /*  L */
  96         PRINTABLE,              /*  M */
  97         PRINTABLE,              /*  N */
  98         PRINTABLE,              /*  O */
  99         PRINTABLE,              /*  P */
 100         PRINTABLE,              /*  Q */
 101         PRINTABLE,              /*  R */
 102         PRINTABLE,              /*  S */
 103         PRINTABLE,              /*  T */
 104         PRINTABLE,              /*  U */
 105         PRINTABLE,              /*  V */
 106         PRINTABLE,              /*  W */
 107         PRINTABLE,              /*  X */
 108         PRINTABLE,              /*  Y */
 109         PRINTABLE,              /*  Z */
 110         PRINTABLE,              /*  [ */
 111         PRINTABLE|BACKSLASH,    /*  \ */
 112         PRINTABLE,              /*  ] */
 113         PRINTABLE,              /*  ^ */
 114         PRINTABLE,              /*  _ */
 115         PRINTABLE,              /*  ` */
 116         PRINTABLE,              /*  a */
 117         PRINTABLE,              /*  b */
 118         PRINTABLE,              /*  c */
 119         PRINTABLE,              /*  d */
 120         PRINTABLE,              /*  e */
 121         PRINTABLE,              /*  f */
 122         PRINTABLE,              /*  g */
 123         PRINTABLE,              /*  h */
 124         PRINTABLE,              /*  i */
 125         PRINTABLE,              /*  j */
 126         PRINTABLE,              /*  k */
 127         PRINTABLE,              /*  l */
 128         PRINTABLE,              /*  m */
 129         PRINTABLE,              /*  n */
 130         PRINTABLE,              /*  o */
 131         PRINTABLE,              /*  p */
 132         PRINTABLE,              /*  q */
 133         PRINTABLE,              /*  r */
 134         PRINTABLE,              /*  s */
 135         PRINTABLE,              /*  t */
 136         PRINTABLE,              /*  u */
 137         PRINTABLE,              /*  v */
 138         PRINTABLE,              /*  w */
 139         PRINTABLE,              /*  x */
 140         PRINTABLE,              /*  y */
 141         PRINTABLE,              /*  z */
 142         PRINTABLE,              /*  { */
 143         PRINTABLE|VBAR,         /*  | */
 144         PRINTABLE,              /*  } */
 145         PRINTABLE|TWIDDLE,      /*  ~ */
 146         IGNORE,                 /*  ^? */
 147 };
 148
 149 static int lex_unget_c;
 150
 151 static inline int
 152 lex_get()
 153 {
 154         int     c;
 155         if (lex_unget_c) {
 156                 c = lex_unget_c;
 157                 lex_unget_c = 0;
 158         } else {
 159 #if AO_LISP_ALTOS
 160                 static uint8_t  at_eol;
 161
 162                 if (at_eol) {
 163                         ao_cmd_readline();
 164                         at_eol = 0;
 165                 }
 166                 c = ao_cmd_lex();
 167                 if (c == '\n')
 168                         at_eol = 1;
 169 #else
 170                 c = getchar();
 171 #endif
 172         }
 173         return c;
 174 }
 175
 176 static inline void
 177 lex_unget(int c)
 178 {
 179         if (c != EOF)
 180                 lex_unget_c = c;
 181 }
 182
 183 static int
 184 lex_quoted (void)
 185 {
 186         int     c;
 187         int     v;
 188         int     count;
 189
 190         c = lex_get();
 191         if (c == EOF)
 192                 return EOF;
 193         c &= 0x7f;
 194         switch (c) {
 195         case 'n':
 196                 return '\n';
 197         case 'f':
 198                 return '\f';
 199         case 'b':
 200                 return '\b';
 201         case 'r':
 202                 return '\r';
 203         case 'v':
 204                 return '\v';
 205         case 't':
 206                 return '\t';
 207         case '0':
 208         case '1':
 209         case '2':
 210         case '3':
 211         case '4':
 212         case '5':
 213         case '6':
 214         case '7':
 215                 v = c - '0';
 216                 count = 1;
 217                 while (count <= 3) {
 218                         c = lex_get();
 219                         if (c == EOF)
 220                                 return EOF;
 221                         c &= 0x7f;
 222                         if (c < '0' || '7' < c) {
 223                                 lex_unget(c);
 224                                 break;
 225                         }
 226                         v = (v << 3) + c - '0';
 227                         ++count;
 228                 }
 229                 return v;
 230         default:
 231                 return c;
 232         }
 233 }
 234
 235 static uint16_t lex_class;
 236
 237 static int
 238 lexc(void)
 239 {
 240         int     c;
 241         do {
 242                 c = lex_get();
 243                 if (c == EOF) {
 244                         lex_class = ENDOFFILE;
 245                         c = 0;
 246                 } else {
 247                         c &= 0x7f;
 248                         lex_class = lex_classes[c];
 249                         if (lex_class & BACKSLASH) {
 250                                 c = lex_quoted();
 251                                 if (c == EOF)
 252                                         lex_class = ENDOFFILE;
 253                                 else
 254                                         lex_class = PRINTABLE;
 255                         }
 256                 }
 257         } while (lex_class & IGNORE);
 258         return c;
 259 }
 260
 261 #define AO_LISP_TOKEN_MAX       32
 262
 263 static char     token_string[AO_LISP_TOKEN_MAX];
 264 static int      token_int;
 265 static int      token_len;
 266
 267 static inline void add_token(int c) {
 268         if (c && token_len < AO_LISP_TOKEN_MAX - 1)
 269                 token_string[token_len++] = c;
 270 }
 271
 272 static inline void end_token(void) {
 273         token_string[token_len] = '\0';
 274 }
 275
 276 static int
 277 lex(void)
 278 {
 279         int     c;
 280
 281         token_len = 0;
 282         for (;;) {
 283                 c = lexc();
 284                 if (lex_class & ENDOFFILE)
 285                         return AO_LISP_NIL;
 286
 287                 if (lex_class & WHITE)
 288                         continue;
 289
 290                 if (lex_class & COMMENT) {
 291                         while ((c = lexc()) != '\n') {
 292                                 if (lex_class & ENDOFFILE)
 293                                         return AO_LISP_NIL;
 294                         }
 295                         continue;
 296                 }
 297
 298                 if (lex_class & (BRA|KET|QUOTEC)) {
 299                         add_token(c);
 300                         end_token();
 301                         switch (c) {
 302                         case '(':
 303                                 return OPEN;
 304                         case ')':
 305                                 return CLOSE;
 306                         case '\'':
 307                                 return QUOTE;
 308                         }
 309                 }
 310                 if (lex_class & TWIDDLE) {
 311                         token_int = lexc();
 312                         return NUM;
 313                 }
 314                 if (lex_class & STRINGC) {
 315                         for (;;) {
 316                                 c = lexc();
 317                                 if (lex_class & (STRINGC|ENDOFFILE)) {
 318                                         end_token();
 319                                         return STRING;
 320                                 }
 321                                 add_token(c);
 322                         }
 323                 }
 324                 if (lex_class & PRINTABLE) {
 325                         int     isnum;
 326                         int     hasdigit;
 327                         int     isneg;
 328
 329                         isnum = 1;
 330                         hasdigit = 0;
 331                         token_int = 0;
 332                         isneg = 0;
 333                         for (;;) {
 334                                 if (!(lex_class & NUMBER)) {
 335                                         isnum = 0;
 336                                 } else {
 337                                         if (token_len != 0 &&
 338                                             (lex_class & SIGN))
 339                                         {
 340                                                 isnum = 0;
 341                                         }
 342                                         if (c == '-')
 343                                                 isneg = 1;
 344                                         if (lex_class & DIGIT) {
 345                                                 hasdigit = 1;
 346                                                 if (isnum)
 347                                                         token_int = token_int * 10 + c - '0';
 348                                         }
 349                                 }
 350                                 add_token (c);
 351                                 c = lexc ();
 352                                 if (lex_class & (NOTNAME)) {
 353 //                                      if (lex_class & ENDOFFILE)
 354 //                                              clearerr (f);
 355                                         lex_unget(c);
 356                                         end_token ();
 357                                         if (isnum && hasdigit) {
 358                                                 if (isneg)
 359                                                         token_int = -token_int;
 360                                                 return NUM;
 361                                         }
 362                                         return NAME;
 363                                 }
 364                         }
 365
 366                 }
 367         }
 368 }
 369
 370 static int parse_token;
 371 static uint8_t                  been_here;
 372 static struct ao_lisp_cons      *read_cons;
 373 static struct ao_lisp_cons      *read_cons_tail;
 374 static struct ao_lisp_cons      *read_stack;
 375
 376 static int
 377 push_read_stack(int cons, int in_quote)
 378 {
 379         if (cons) {
 380                 read_stack = ao_lisp_cons_cons(ao_lisp_cons_poly(read_cons),
 381                                                ao_lisp_cons_cons(ao_lisp_int_poly(in_quote),
 382                                                                  read_stack));
 383                 if (!read_stack)
 384                         return 0;
 385         }
 386         read_cons = NULL;
 387         read_cons_tail = NULL;
 388         return 1;
 389 }
 390
 391 static int
 392 pop_read_stack(int cons)
 393 {
 394         int     in_quote = 0;
 395         if (cons) {
 396                 read_cons = ao_lisp_poly_cons(read_stack->car);
 397                 read_stack = ao_lisp_poly_cons(read_stack->cdr);
 398                 in_quote = ao_lisp_poly_int(read_stack->car);
 399                 read_stack = ao_lisp_poly_cons(read_stack->cdr);
 400                 for (read_cons_tail = read_cons;
 401                      read_cons_tail && read_cons_tail->cdr;
 402                      read_cons_tail = ao_lisp_poly_cons(read_cons_tail->cdr))
 403                         ;
 404         } else {
 405                 read_cons = 0;
 406                 read_cons_tail = 0;
 407                 read_stack = 0;
 408         }
 409         return in_quote;
 410 }
 411
 412 ao_poly
 413 ao_lisp_read(void)
 414 {
 415         struct ao_lisp_atom     *atom;
 416         char                    *string;
 417         int                     cons;
 418         int                     in_quote;
 419         ao_poly                 v;
 420
 421         if (!been_here) {
 422                 ao_lisp_root_add(&ao_lisp_cons_type, &read_cons);
 423                 ao_lisp_root_add(&ao_lisp_cons_type, &read_cons_tail);
 424                 ao_lisp_root_add(&ao_lisp_cons_type, &read_stack);
 425                 been_here = 1;
 426         }
 427         parse_token = lex();
 428
 429         cons = 0;
 430         in_quote = 0;
 431         read_cons = read_cons_tail = read_stack = 0;
 432         for (;;) {
 433                 while (parse_token == OPEN) {
 434                         if (!push_read_stack(cons, in_quote))
 435                                 return AO_LISP_NIL;
 436                         cons++;
 437                         in_quote = 0;
 438                         parse_token = lex();
 439                 }
 440
 441                 switch (parse_token) {
 442                 case ENDOFFILE:
 443                 default:
 444                         v = AO_LISP_NIL;
 445                         break;
 446                 case NAME:
 447                         atom = ao_lisp_atom_intern(token_string);
 448                         if (atom)
 449                                 v = ao_lisp_atom_poly(atom);
 450                         else
 451                                 v = AO_LISP_NIL;
 452                         break;
 453                 case NUM:
 454                         v = ao_lisp_int_poly(token_int);
 455                         break;
 456                 case STRING:
 457                         string = ao_lisp_string_copy(token_string);
 458                         if (string)
 459                                 v = ao_lisp_string_poly(string);
 460                         else
 461                                 v = AO_LISP_NIL;
 462                         break;
 463                 case QUOTE:
 464                         if (!push_read_stack(cons, in_quote))
 465                                 return AO_LISP_NIL;
 466                         cons++;
 467                         in_quote = 1;
 468                         v = _ao_lisp_atom_quote;
 469                         break;
 470                 case CLOSE:
 471                         if (!cons) {
 472                                 v = AO_LISP_NIL;
 473                                 break;
 474                         }
 475                         v = ao_lisp_cons_poly(read_cons);
 476                         --cons;
 477                         in_quote = pop_read_stack(cons);
 478                         break;
 479                 }
 480
 481                 /* loop over QUOTE ends */
 482                 for (;;) {
 483                         if (!cons)
 484                                 return v;
 485
 486                         struct ao_lisp_cons     *read = ao_lisp_cons_cons(v, NULL);
 487                         if (!read)
 488                                 return AO_LISP_NIL;
 489
 490                         if (read_cons_tail)
 491                                 read_cons_tail->cdr = ao_lisp_cons_poly(read);
 492                         else
 493                                 read_cons = read;
 494                         read_cons_tail = read;
 495
 496                         if (!in_quote || !read_cons->cdr)
 497                                 break;
 498
 499                         v = ao_lisp_cons_poly(read_cons);
 500                         --cons;
 501                         in_quote = pop_read_stack(cons);
 502                 }
 503
 504                 parse_token = lex();
 505         }
 506         return v;
 507 }