Subversion Repositories NedoOS

Rev

Blame | Last modification | View Log | Download

  1. /*
  2. ** $Id: llex.c,v 2.63.1.3 2015/02/09 17:56:34 roberto Exp $
  3. ** Lexical Analyzer
  4. ** See Copyright Notice in lua.h
  5. */
  6.  
  7.  
  8. #include <locale.h>
  9. #include <string.h>
  10.  
  11. #define llex_c
  12. #define LUA_CORE
  13.  
  14. #include "lua.h"
  15.  
  16. #include "lctype.h"
  17. #include "ldo.h"
  18. #include "llex.h"
  19. #include "lobject.h"
  20. #include "lparser.h"
  21. #include "lstate.h"
  22. #include "lstring.h"
  23. #include "ltable.h"
  24. #include "lzio.h"
  25.  
  26.  
  27.  
  28. #define next(ls) (ls->current = zgetc(ls->z))
  29.  
  30.  
  31.  
  32. #define currIsNewline(ls)       (ls->current == '\n' || ls->current == '\r')
  33.  
  34.  
  35. /* ORDER RESERVED */
  36. static const char *const luaX_tokens [] = {
  37.     "and", "break", "do", "else", "elseif",
  38.     "end", "false", "for", "function", "goto", "if",
  39.     "in", "local", "nil", "not", "or", "repeat",
  40.     "return", "then", "true", "until", "while",
  41.     "..", "...", "==", ">=", "<=", "~=", "::", "<eof>",
  42.     "<number>", "<name>", "<string>"
  43. };
  44.  
  45.  
  46. #define save_and_next(ls) (save(ls, ls->current), next(ls))
  47.  
  48.  
  49. static l_noret lexerror (LexState *ls, const char *msg, int token);
  50.  
  51.  
  52. static void save (LexState *ls, int c) {
  53.   Mbuffer *b = ls->buff;
  54.   if (luaZ_bufflen(b) + 1 > luaZ_sizebuffer(b)) {
  55.     size_t newsize;
  56.     if (luaZ_sizebuffer(b) >= MAX_SIZET/2)
  57.       lexerror(ls, "lexical element too long", 0);
  58.     newsize = luaZ_sizebuffer(b) * 2;
  59.     luaZ_resizebuffer(ls->L, b, newsize);
  60.   }
  61.   b->buffer[luaZ_bufflen(b)++] = cast(char, c);
  62. }
  63.  
  64.  
  65. void luaX_init (lua_State *L) {
  66.   int i;
  67.   for (i=0; i<NUM_RESERVED; i++) {
  68.     TString *ts = luaS_new(L, luaX_tokens[i]);
  69.     luaS_fix(ts);  /* reserved words are never collected */
  70.     ts->tsv.extra = cast_byte(i+1);  /* reserved word */
  71.   }
  72. }
  73.  
  74.  
  75. const char *luaX_token2str (LexState *ls, int token) {
  76.   if (token < FIRST_RESERVED) {  /* single-byte symbols? */
  77.     lua_assert(token == cast(unsigned char, token));
  78.     return (lisprint(token)) ? luaO_pushfstring(ls->L, LUA_QL("%c"), token) :
  79.                               luaO_pushfstring(ls->L, "char(%d)", token);
  80.   }
  81.   else {
  82.     const char *s = luaX_tokens[token - FIRST_RESERVED];
  83.     if (token < TK_EOS)  /* fixed format (symbols and reserved words)? */
  84.       return luaO_pushfstring(ls->L, LUA_QS, s);
  85.     else  /* names, strings, and numerals */
  86.       return s;
  87.   }
  88. }
  89.  
  90.  
  91. static const char *txtToken (LexState *ls, int token) {
  92.   switch (token) {
  93.     case TK_NAME:
  94.     case TK_STRING:
  95.     case TK_NUMBER:
  96.       save(ls, '\0');
  97.       return luaO_pushfstring(ls->L, LUA_QS, luaZ_buffer(ls->buff));
  98.     default:
  99.       return luaX_token2str(ls, token);
  100.   }
  101. }
  102.  
  103.  
  104. static l_noret lexerror (LexState *ls, const char *msg, int token) {
  105.   char buff[LUA_IDSIZE];
  106.   luaO_chunkid(buff, getstr(ls->source), LUA_IDSIZE);
  107.   msg = luaO_pushfstring(ls->L, "%s:%d: %s", buff, ls->linenumber, msg);
  108.   if (token)
  109.     luaO_pushfstring(ls->L, "%s near %s", msg, txtToken(ls, token));
  110.   luaD_throw(ls->L, LUA_ERRSYNTAX);
  111. }
  112.  
  113.  
  114. l_noret luaX_syntaxerror (LexState *ls, const char *msg) {
  115.   lexerror(ls, msg, ls->t.token);
  116. }
  117.  
  118.  
  119. /*
  120. ** creates a new string and anchors it in function's table so that
  121. ** it will not be collected until the end of the function's compilation
  122. ** (by that time it should be anchored in function's prototype)
  123. */
  124. TString *luaX_newstring (LexState *ls, const char *str, size_t l) {
  125.   lua_State *L = ls->L;
  126.   TValue *o;  /* entry for `str' */
  127.   TString *ts = luaS_newlstr(L, str, l);  /* create new string */
  128.   setsvalue2s(L, L->top++, ts);  /* temporarily anchor it in stack */
  129.   o = luaH_set(L, ls->fs->h, L->top - 1);
  130.   if (ttisnil(o)) {  /* not in use yet? (see 'addK') */
  131.     /* boolean value does not need GC barrier;
  132.        table has no metatable, so it does not need to invalidate cache */
  133.     setbvalue(o, 1);  /* t[string] = true */
  134.     luaC_checkGC(L);
  135.   }
  136.   else {  /* string already present */
  137.     ts = rawtsvalue(keyfromval(o));  /* re-use value previously stored */
  138.   }
  139.   L->top--;  /* remove string from stack */
  140.   return ts;
  141. }
  142.  
  143.  
  144. /*
  145. ** increment line number and skips newline sequence (any of
  146. ** \n, \r, \n\r, or \r\n)
  147. */
  148. static void inclinenumber (LexState *ls) {
  149.   int old = ls->current;
  150.   lua_assert(currIsNewline(ls));
  151.   next(ls);  /* skip `\n' or `\r' */
  152.   if (currIsNewline(ls) && ls->current != old)
  153.     next(ls);  /* skip `\n\r' or `\r\n' */
  154.   if (++ls->linenumber >= MAX_INT)
  155.     lexerror(ls, "chunk has too many lines", 0);
  156. }
  157.  
  158.  
  159. void luaX_setinput (lua_State *L, LexState *ls, ZIO *z, TString *source,
  160.                     int firstchar) {
  161.   ls->decpoint = '.';
  162.   ls->L = L;
  163.   ls->current = firstchar;
  164.   ls->lookahead.token = TK_EOS;  /* no look-ahead token */
  165.   ls->z = z;
  166.   ls->fs = NULL;
  167.   ls->linenumber = 1;
  168.   ls->lastline = 1;
  169.   ls->source = source;
  170.   ls->envn = luaS_new(L, LUA_ENV);  /* create env name */
  171.   luaS_fix(ls->envn);  /* never collect this name */
  172.   luaZ_resizebuffer(ls->L, ls->buff, LUA_MINBUFFER);  /* initialize buffer */
  173. }
  174.  
  175.  
  176.  
  177. /*
  178. ** =======================================================
  179. ** LEXICAL ANALYZER
  180. ** =======================================================
  181. */
  182.  
  183.  
  184.  
  185. static int check_next (LexState *ls, const char *set) {
  186.   if (ls->current == '\0' || !strchr(set, ls->current))
  187.     return 0;
  188.   save_and_next(ls);
  189.   return 1;
  190. }
  191.  
  192.  
  193. /*
  194. ** change all characters 'from' in buffer to 'to'
  195. */
  196. static void buffreplace (LexState *ls, char from, char to) {
  197.   size_t n = luaZ_bufflen(ls->buff);
  198.   char *p = luaZ_buffer(ls->buff);
  199.   while (n--)
  200.     if (p[n] == from) p[n] = to;
  201. }
  202.  
  203.  
  204. #if !defined(getlocaledecpoint)
  205. #define getlocaledecpoint()     (localeconv()->decimal_point[0])
  206. #endif
  207.  
  208.  
  209. #define buff2d(b,e)     luaO_str2d(luaZ_buffer(b), luaZ_bufflen(b) - 1, e)
  210.  
  211. /*
  212. ** in case of format error, try to change decimal point separator to
  213. ** the one defined in the current locale and check again
  214. */
  215. static void trydecpoint (LexState *ls, SemInfo *seminfo) {
  216.   char old = ls->decpoint;
  217.   ls->decpoint = getlocaledecpoint();
  218.   buffreplace(ls, old, ls->decpoint);  /* try new decimal separator */
  219.   if (!buff2d(ls->buff, &seminfo->r)) {
  220.     /* format error with correct decimal point: no more options */
  221.     buffreplace(ls, ls->decpoint, '.');  /* undo change (for error message) */
  222.     lexerror(ls, "malformed number", TK_NUMBER);
  223.   }
  224. }
  225.  
  226.  
  227. /* LUA_NUMBER */
  228. /*
  229. ** this function is quite liberal in what it accepts, as 'luaO_str2d'
  230. ** will reject ill-formed numerals.
  231. */
  232. static void read_numeral (LexState *ls, SemInfo *seminfo) {
  233.   const char *expo = "Ee";
  234.   int first = ls->current;
  235.   lua_assert(lisdigit(ls->current));
  236.   save_and_next(ls);
  237.   if (first == '0' && check_next(ls, "Xx"))  /* hexadecimal? */
  238.     expo = "Pp";
  239.   for (;;) {
  240.     if (check_next(ls, expo))  /* exponent part? */
  241.       check_next(ls, "+-");  /* optional exponent sign */
  242.     if (lisxdigit(ls->current) || ls->current == '.')
  243.       save_and_next(ls);
  244.     else  break;
  245.   }
  246.   save(ls, '\0');
  247.   buffreplace(ls, '.', ls->decpoint);  /* follow locale for decimal point */
  248.   if (!buff2d(ls->buff, &seminfo->r))  /* format error? */
  249.     trydecpoint(ls, seminfo); /* try to update decimal point separator */
  250. }
  251.  
  252.  
  253. /*
  254. ** skip a sequence '[=*[' or ']=*]' and return its number of '='s or
  255. ** -1 if sequence is malformed
  256. */
  257. static int skip_sep (LexState *ls) {
  258.   int count = 0;
  259.   int s = ls->current;
  260.   lua_assert(s == '[' || s == ']');
  261.   save_and_next(ls);
  262.   while (ls->current == '=') {
  263.     save_and_next(ls);
  264.     count++;
  265.   }
  266.   return (ls->current == s) ? count : (-count) - 1;
  267. }
  268.  
  269.  
  270. static void read_long_string (LexState *ls, SemInfo *seminfo, int sep) {
  271.   save_and_next(ls);  /* skip 2nd `[' */
  272.   if (currIsNewline(ls))  /* string starts with a newline? */
  273.     inclinenumber(ls);  /* skip it */
  274.   for (;;) {
  275.     switch (ls->current) {
  276.       case EOZ:
  277.         lexerror(ls, (seminfo) ? "unfinished long string" :
  278.                                  "unfinished long comment", TK_EOS);
  279.         break;  /* to avoid warnings */
  280.       case ']': {
  281.         if (skip_sep(ls) == sep) {
  282.           save_and_next(ls);  /* skip 2nd `]' */
  283.           goto endloop;
  284.         }
  285.         break;
  286.       }
  287.       case '\n': case '\r': {
  288.         save(ls, '\n');
  289.         inclinenumber(ls);
  290.         if (!seminfo) luaZ_resetbuffer(ls->buff);  /* avoid wasting space */
  291.         break;
  292.       }
  293.       default: {
  294.         if (seminfo) save_and_next(ls);
  295.         else next(ls);
  296.       }
  297.     }
  298.   } endloop:
  299.   if (seminfo)
  300.     seminfo->ts = luaX_newstring(ls, luaZ_buffer(ls->buff) + (2 + sep),
  301.                                      luaZ_bufflen(ls->buff) - 2*(2 + sep));
  302. }
  303.  
  304.  
  305. static void escerror (LexState *ls, int *c, int n, const char *msg) {
  306.   int i;
  307.   luaZ_resetbuffer(ls->buff);  /* prepare error message */
  308.   save(ls, '\\');
  309.   for (i = 0; i < n && c[i] != EOZ; i++)
  310.     save(ls, c[i]);
  311.   lexerror(ls, msg, TK_STRING);
  312. }
  313.  
  314.  
  315. static int readhexaesc (LexState *ls) {
  316.   int c[3], i;  /* keep input for error message */
  317.   int r = 0;  /* result accumulator */
  318.   c[0] = 'x';  /* for error message */
  319.   for (i = 1; i < 3; i++) {  /* read two hexadecimal digits */
  320.     c[i] = next(ls);
  321.     if (!lisxdigit(c[i]))
  322.       escerror(ls, c, i + 1, "hexadecimal digit expected");
  323.     r = (r << 4) + luaO_hexavalue(c[i]);
  324.   }
  325.   return r;
  326. }
  327.  
  328.  
  329. static int readdecesc (LexState *ls) {
  330.   int c[3], i;
  331.   int r = 0;  /* result accumulator */
  332.   for (i = 0; i < 3 && lisdigit(ls->current); i++) {  /* read up to 3 digits */
  333.     c[i] = ls->current;
  334.     r = 10*r + c[i] - '0';
  335.     next(ls);
  336.   }
  337.   if (r > UCHAR_MAX)
  338.     escerror(ls, c, i, "decimal escape too large");
  339.   return r;
  340. }
  341.  
  342.  
  343. static void read_string (LexState *ls, int del, SemInfo *seminfo) {
  344.   save_and_next(ls);  /* keep delimiter (for error messages) */
  345.   while (ls->current != del) {
  346.     switch (ls->current) {
  347.       case EOZ:
  348.         lexerror(ls, "unfinished string", TK_EOS);
  349.         break;  /* to avoid warnings */
  350.       case '\n':
  351.       case '\r':
  352.         lexerror(ls, "unfinished string", TK_STRING);
  353.         break;  /* to avoid warnings */
  354.       case '\\': {  /* escape sequences */
  355.         int c;  /* final character to be saved */
  356.         next(ls);  /* do not save the `\' */
  357.         switch (ls->current) {
  358.           case 'a': c = '\a'; goto read_save;
  359.           case 'b': c = '\b'; goto read_save;
  360.           case 'f': c = '\f'; goto read_save;
  361.           case 'n': c = '\n'; goto read_save;
  362.           case 'r': c = '\r'; goto read_save;
  363.           case 't': c = '\t'; goto read_save;
  364.           case 'v': c = '\v'; goto read_save;
  365.           case 'x': c = readhexaesc(ls); goto read_save;
  366.           case '\n': case '\r':
  367.             inclinenumber(ls); c = '\n'; goto only_save;
  368.           case '\\': case '\"': case '\'':
  369.             c = ls->current; goto read_save;
  370.           case EOZ: goto no_save;  /* will raise an error next loop */
  371.           case 'z': {  /* zap following span of spaces */
  372.             next(ls);  /* skip the 'z' */
  373.             while (lisspace(ls->current)) {
  374.               if (currIsNewline(ls)) inclinenumber(ls);
  375.               else next(ls);
  376.             }
  377.             goto no_save;
  378.           }
  379.           default: {
  380.             if (!lisdigit(ls->current))
  381.               escerror(ls, &ls->current, 1, "invalid escape sequence");
  382.             /* digital escape \ddd */
  383.             c = readdecesc(ls);
  384.             goto only_save;
  385.           }
  386.         }
  387.        read_save: next(ls);  /* read next character */
  388.        only_save: save(ls, c);  /* save 'c' */
  389.        no_save: break;
  390.       }
  391.       default:
  392.         save_and_next(ls);
  393.     }
  394.   }
  395.   save_and_next(ls);  /* skip delimiter */
  396.   seminfo->ts = luaX_newstring(ls, luaZ_buffer(ls->buff) + 1,
  397.                                    luaZ_bufflen(ls->buff) - 2);
  398. }
  399.  
  400.  
  401. static int llex (LexState *ls, SemInfo *seminfo) {
  402.   luaZ_resetbuffer(ls->buff);
  403.   for (;;) {
  404.     switch (ls->current) {
  405.       case '\n': case '\r': {  /* line breaks */
  406.         inclinenumber(ls);
  407.         break;
  408.       }
  409.       case ' ': case '\f': case '\t': case '\v': {  /* spaces */
  410.         next(ls);
  411.         break;
  412.       }
  413.       case '-': {  /* '-' or '--' (comment) */
  414.         next(ls);
  415.         if (ls->current != '-') return '-';
  416.         /* else is a comment */
  417.         next(ls);
  418.         if (ls->current == '[') {  /* long comment? */
  419.           int sep = skip_sep(ls);
  420.           luaZ_resetbuffer(ls->buff);  /* `skip_sep' may dirty the buffer */
  421.           if (sep >= 0) {
  422.             read_long_string(ls, NULL, sep);  /* skip long comment */
  423.             luaZ_resetbuffer(ls->buff);  /* previous call may dirty the buff. */
  424.             break;
  425.           }
  426.         }
  427.         /* else short comment */
  428.         while (!currIsNewline(ls) && ls->current != EOZ)
  429.           next(ls);  /* skip until end of line (or end of file) */
  430.         break;
  431.       }
  432.       case '[': {  /* long string or simply '[' */
  433.         int sep = skip_sep(ls);
  434.         if (sep >= 0) {
  435.           read_long_string(ls, seminfo, sep);
  436.           return TK_STRING;
  437.         }
  438.         else if (sep == -1) return '[';
  439.         else lexerror(ls, "invalid long string delimiter", TK_STRING);
  440.       }
  441.       case '=': {
  442.         next(ls);
  443.         if (ls->current != '=') return '=';
  444.         else { next(ls); return TK_EQ; }
  445.       }
  446.       case '<': {
  447.         next(ls);
  448.         if (ls->current != '=') return '<';
  449.         else { next(ls); return TK_LE; }
  450.       }
  451.       case '>': {
  452.         next(ls);
  453.         if (ls->current != '=') return '>';
  454.         else { next(ls); return TK_GE; }
  455.       }
  456.       case '~': {
  457.         next(ls);
  458.         if (ls->current != '=') return '~';
  459.         else { next(ls); return TK_NE; }
  460.       }
  461.       case ':': {
  462.         next(ls);
  463.         if (ls->current != ':') return ':';
  464.         else { next(ls); return TK_DBCOLON; }
  465.       }
  466.       case '"': case '\'': {  /* short literal strings */
  467.         read_string(ls, ls->current, seminfo);
  468.         return TK_STRING;
  469.       }
  470.       case '.': {  /* '.', '..', '...', or number */
  471.         save_and_next(ls);
  472.         if (check_next(ls, ".")) {
  473.           if (check_next(ls, "."))
  474.             return TK_DOTS;   /* '...' */
  475.           else return TK_CONCAT;   /* '..' */
  476.         }
  477.         else if (!lisdigit(ls->current)) return '.';
  478.         /* else go through */
  479.       }
  480.       case '0': case '1': case '2': case '3': case '4':
  481.       case '5': case '6': case '7': case '8': case '9': {
  482.         read_numeral(ls, seminfo);
  483.         return TK_NUMBER;
  484.       }
  485.       case EOZ: {
  486.         return TK_EOS;
  487.       }
  488.       default: {
  489.         if (lislalpha(ls->current)) {  /* identifier or reserved word? */
  490.           TString *ts;
  491.           do {
  492.             save_and_next(ls);
  493.           } while (lislalnum(ls->current));
  494.           ts = luaX_newstring(ls, luaZ_buffer(ls->buff),
  495.                                   luaZ_bufflen(ls->buff));
  496.           seminfo->ts = ts;
  497.           if (isreserved(ts))  /* reserved word? */
  498.             return ts->tsv.extra - 1 + FIRST_RESERVED;
  499.           else {
  500.             return TK_NAME;
  501.           }
  502.         }
  503.         else {  /* single-char tokens (+ - / ...) */
  504.           int c = ls->current;
  505.           next(ls);
  506.           return c;
  507.         }
  508.       }
  509.     }
  510.   }
  511. }
  512.  
  513.  
  514. void luaX_next (LexState *ls) {
  515.   ls->lastline = ls->linenumber;
  516.   if (ls->lookahead.token != TK_EOS) {  /* is there a look-ahead token? */
  517.     ls->t = ls->lookahead;  /* use this one */
  518.     ls->lookahead.token = TK_EOS;  /* and discharge it */
  519.   }
  520.   else
  521.     ls->t.token = llex(ls, &ls->t.seminfo);  /* read next token */
  522. }
  523.  
  524.  
  525. int luaX_lookahead (LexState *ls) {
  526.   lua_assert(ls->lookahead.token == TK_EOS);
  527.   ls->lookahead.token = llex(ls, &ls->lookahead.seminfo);
  528.   return ls->lookahead.token;
  529. }
  530.  
  531.