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   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                 c = getchar();
 160         return c;
 161 }
 162
 163 static inline void
 164 lex_unget(int c)
 165 {
 166         if (c != EOF)
 167                 lex_unget_c = c;
 168 }
 169
 170 static int
 171 lex_quoted (void)
 172 {
 173         int     c;
 174         int     v;
 175         int     count;
 176
 177         c = lex_get();
 178 //      if (jumping)
 179 //              return nil;
 180         if (c == EOF)
 181                 return EOF;
 182         c &= 0x7f;
 183         switch (c) {
 184         case 'n':
 185                 return '\n';
 186         case 'f':
 187                 return '\f';
 188         case 'b':
 189                 return '\b';
 190         case 'r':
 191                 return '\r';
 192         case 'v':
 193                 return '\v';
 194         case 't':
 195                 return '\t';
 196         case '0':
 197         case '1':
 198         case '2':
 199         case '3':
 200         case '4':
 201         case '5':
 202         case '6':
 203         case '7':
 204                 v = c - '0';
 205                 count = 1;
 206                 while (count <= 3) {
 207                         c = lex_get();
 208 //                      if (jumping)
 209 //                              return nil;
 210                         if (c == EOF)
 211                                 return EOF;
 212                         c &= 0x7f;
 213                         if (c < '0' || '7' < c) {
 214                                 lex_unget(c);
 215                                 break;
 216                         }
 217                         v = (v << 3) + c - '0';
 218                         ++count;
 219                 }
 220                 return v;
 221         default:
 222                 return c;
 223         }
 224 }
 225
 226 static uint16_t lex_class;
 227
 228 static int
 229 lexc(void)
 230 {
 231         int     c;
 232         do {
 233                 c = lex_get();
 234                 if (c == EOF) {
 235                         lex_class = ENDOFFILE;
 236                         c = 0;
 237                 } else {
 238                         c &= 0x7f;
 239                         lex_class = lex_classes[c];
 240                         if (lex_class & BACKSLASH) {
 241                                 c = lex_quoted();
 242                                 if (c == EOF)
 243                                         lex_class = ENDOFFILE;
 244                                 else
 245                                         lex_class = PRINTABLE;
 246                         }
 247                 }
 248         } while (lex_class & IGNORE);
 249         return c;
 250 }
 251
 252 #define AO_LISP_TOKEN_MAX       32
 253
 254 static char     token_string[AO_LISP_TOKEN_MAX];
 255 static int      token_int;
 256 static int      token_len;
 257
 258 static inline void add_token(int c) {
 259         if (c && token_len < AO_LISP_TOKEN_MAX - 1)
 260                 token_string[token_len++] = c;
 261 }
 262
 263 static inline void end_token(void) {
 264         token_string[token_len] = '\0';
 265 }
 266
 267 static int
 268 lex(void)
 269 {
 270         int     c;
 271
 272         token_len = 0;
 273         for (;;) {
 274                 c = lexc();
 275                 if (lex_class & ENDOFFILE)
 276                         return AO_LISP_NIL;
 277
 278 //              if (jumping)
 279 //                      return nil;
 280                 if (lex_class & WHITE)
 281                         continue;
 282
 283                 if (lex_class & (BRA|KET|QUOTEC)) {
 284                         add_token(c);
 285                         end_token();
 286                         switch (c) {
 287                         case '(':
 288                                 return OPEN;
 289                         case ')':
 290                                 return CLOSE;
 291                         case '\'':
 292                                 return QUOTE;
 293                         }
 294                 }
 295                 if (lex_class & TWIDDLE) {
 296                         token_int = lexc();
 297                         return NUM;
 298                 }
 299                 if (lex_class & STRINGC) {
 300                         for (;;) {
 301                                 c = lexc();
 302 //                              if (jumping)
 303 //                                      return nil;
 304                                 if (lex_class & (STRINGC|ENDOFFILE)) {
 305                                         end_token();
 306                                         return STRING;
 307                                 }
 308                                 add_token(c);
 309                         }
 310                 }
 311                 if (lex_class & PRINTABLE) {
 312                         int     isnum;
 313                         int     hasdigit;
 314                         int     isneg;
 315
 316                         isnum = 1;
 317                         hasdigit = 0;
 318                         token_int = 0;
 319                         isneg = 0;
 320                         for (;;) {
 321                                 if (!(lex_class & NUMBER)) {
 322                                         isnum = 0;
 323                                 } else {
 324                                         if (token_len != 0 &&
 325                                             (lex_class & SIGN))
 326                                         {
 327                                                 isnum = 0;
 328                                         }
 329                                         if (c == '-')
 330                                                 isneg = 1;
 331                                         if (lex_class & DIGIT) {
 332                                                 hasdigit = 1;
 333                                                 if (isnum)
 334                                                         token_int = token_int * 10 + c - '0';
 335                                         }
 336                                 }
 337                                 add_token (c);
 338                                 c = lexc ();
 339 //                              if (jumping)
 340 //                                      return nil;
 341                                 if (lex_class & (NOTNAME)) {
 342 //                                      if (lex_class & ENDOFFILE)
 343 //                                              clearerr (f);
 344                                         lex_unget(c);
 345                                         end_token ();
 346                                         if (isnum && hasdigit) {
 347                                                 if (isneg)
 348                                                         token_int = -token_int;
 349                                                 return NUM;
 350                                         }
 351                                         return NAME;
 352                                 }
 353                         }
 354
 355                 }
 356         }
 357 }
 358
 359 static int parse_token;
 360 static uint8_t                  been_here;
 361 static struct ao_lisp_cons      *read_cons;
 362 static struct ao_lisp_cons      *read_cons_tail;
 363 static struct ao_lisp_cons      *read_stack;
 364
 365 static ao_lisp_poly
 366 read_item(void)
 367 {
 368         struct ao_lisp_atom     *atom;
 369         char                    *string;
 370         int                     cons;
 371         ao_lisp_poly            v;
 372
 373         if (!been_here) {
 374                 ao_lisp_root_add(&ao_lisp_cons_type, &read_cons);
 375                 ao_lisp_root_add(&ao_lisp_cons_type, &read_cons_tail);
 376                 ao_lisp_root_add(&ao_lisp_cons_type, &read_stack);
 377         }
 378
 379         cons = 0;
 380         read_cons = read_cons_tail = read_stack = 0;
 381         for (;;) {
 382                 while (parse_token == OPEN) {
 383                         if (cons++)
 384                                 read_stack = ao_lisp_cons(ao_lisp_cons_poly(read_cons), read_stack);
 385                         read_cons = NULL;
 386                         read_cons_tail = NULL;
 387                         parse_token = lex();
 388                 }
 389
 390                 switch (parse_token) {
 391                 case ENDOFFILE:
 392                 default:
 393                         v = AO_LISP_NIL;
 394                         break;
 395                 case NAME:
 396                         atom = ao_lisp_atom_intern(token_string);
 397                         if (atom)
 398                                 v = ao_lisp_atom_poly(atom);
 399                         else
 400                                 v = AO_LISP_NIL;
 401                         break;
 402                 case NUM:
 403                         v = ao_lisp_int_poly(token_int);
 404                         break;
 405                 case STRING:
 406                         string = ao_lisp_string_copy(token_string);
 407                         if (string)
 408                                 v = ao_lisp_string_poly(string);
 409                         else
 410                                 v = AO_LISP_NIL;
 411                         break;
 412                 case CLOSE:
 413                         if (cons)
 414                                 v = ao_lisp_cons_poly(read_cons);
 415                         else
 416                                 v = AO_LISP_NIL;
 417                         if (--cons) {
 418                                 read_cons = ao_lisp_poly_cons(read_stack->car);
 419                                 read_stack = read_stack->cdr;
 420                                 for (read_cons_tail = read_cons;
 421                                      read_cons_tail && read_cons_tail->cdr;
 422                                      read_cons_tail = read_cons_tail->cdr)
 423                                         ;
 424                         }
 425                         break;
 426                 }
 427
 428                 if (!cons)
 429                         break;
 430
 431                 struct ao_lisp_cons     *read = ao_lisp_cons(v, NULL);
 432                 if (read_cons_tail)
 433                         read_cons_tail->cdr = read;
 434                 else
 435                         read_cons = read;
 436                 read_cons_tail = read;
 437
 438                 parse_token = lex();
 439         }
 440         return v;
 441 }
 442
 443 ao_lisp_poly
 444 ao_lisp_read(void)
 445 {
 446         parse_token = lex();
 447         return read_item();
 448 }