/* ** $Id: llex.c,v 2.63.1.3 2015/02/09 17:56:34 roberto Exp $ ** Lexical Analyzer ** See Copyright Notice in lua.h */ #include #define llex_c #define LUA_CORE #include "lua.h" #include "lctype.h" #include "ldo.h" #include "llex.h" #include "lobject.h" #include "lparser.h" #include "lstate.h" #include "lstring.h" #include "ltable.h" #include "lzio.h" #define next(ls) (ls->current = zgetc(ls->z)) #define currIsNewline(ls) (ls->current == '\n' || ls->current == '\r') /* ORDER RESERVED */ static const char *const luaX_tokens [] = { "and", "break", "do", "else", "elseif", "end", "false", "for", "function", "goto", "if", "in", "local", "nil", "not", "or", "repeat", "return", "then", "true", "until", "while", "..", "...", "==", ">=", "<=", "~=", "::", "", "", "", "" }; #define save_and_next(ls) (save(ls, ls->current), next(ls)) static l_noret lexerror (LexState *ls, const char *msg, int token); static void save (LexState *ls, int c) { Mbuffer *b = ls->buff; if (luaZ_bufflen(b) + 1 > luaZ_sizebuffer(b)) { size_t newsize; if (luaZ_sizebuffer(b) >= MAX_SIZET/2) lexerror(ls, "lexical element too long", 0); newsize = luaZ_sizebuffer(b) * 2; luaZ_resizebuffer(ls->L, b, newsize); } b->buffer[luaZ_bufflen(b)++] = cast(char, c); } void luaX_init (lua_State *L) { int i; for (i=0; itsv.extra = cast_byte(i+1); /* reserved word */ } } const char *luaX_token2str (LexState *ls, int token) { if (token < FIRST_RESERVED) { /* single-byte symbols? */ lua_assert(token == cast(unsigned char, token)); return (lisprint(token)) ? luaO_pushfstring(ls->L, LUA_QL("%c"), token) : luaO_pushfstring(ls->L, "char(%d)", token); } else { const char *s = luaX_tokens[token - FIRST_RESERVED]; if (token < TK_EOS) /* fixed format (symbols and reserved words)? */ return luaO_pushfstring(ls->L, LUA_QS, s); else /* names, strings, and numerals */ return s; } } static const char *txtToken (LexState *ls, int token) { switch (token) { case TK_NAME: case TK_STRING: case TK_NUMBER: save(ls, '\0'); return luaO_pushfstring(ls->L, LUA_QS, luaZ_buffer(ls->buff)); default: return luaX_token2str(ls, token); } } static l_noret lexerror (LexState *ls, const char *msg, int token) { char buff[LUA_IDSIZE]; luaO_chunkid(buff, getstr(ls->source), LUA_IDSIZE); msg = luaO_pushfstring(ls->L, "%s:%d: %s", buff, ls->linenumber, msg); if (token) luaO_pushfstring(ls->L, "%s near %s", msg, txtToken(ls, token)); luaD_throw(ls->L, LUA_ERRSYNTAX); } l_noret luaX_syntaxerror (LexState *ls, const char *msg) { lexerror(ls, msg, ls->t.token); } /* ** creates a new string and anchors it in function's table so that ** it will not be collected until the end of the function's compilation ** (by that time it should be anchored in function's prototype) */ TString *luaX_newstring (LexState *ls, const char *str, size_t l) { lua_State *L = ls->L; TValue *o; /* entry for `str' */ TString *ts = luaS_newlstr(L, str, l); /* create new string */ setsvalue2s(L, L->top++, ts); /* temporarily anchor it in stack */ o = luaH_set(L, ls->fs->h, L->top - 1); if (ttisnil(o)) { /* not in use yet? (see 'addK') */ /* boolean value does not need GC barrier; table has no metatable, so it does not need to invalidate cache */ setbvalue(o, 1); /* t[string] = true */ luaC_checkGC(L); } else { /* string already present */ ts = rawtsvalue(keyfromval(o)); /* re-use value previously stored */ } L->top--; /* remove string from stack */ return ts; } /* ** increment line number and skips newline sequence (any of ** \n, \r, \n\r, or \r\n) */ static void inclinenumber (LexState *ls) { int old = ls->current; lua_assert(currIsNewline(ls)); next(ls); /* skip `\n' or `\r' */ if (currIsNewline(ls) && ls->current != old) next(ls); /* skip `\n\r' or `\r\n' */ if (++ls->linenumber >= MAX_INT) lexerror(ls, "chunk has too many lines", 0); } void luaX_setinput (lua_State *L, LexState *ls, ZIO *z, TString *source, int firstchar) { ls->decpoint = '.'; ls->L = L; ls->current = firstchar; ls->lookahead.token = TK_EOS; /* no look-ahead token */ ls->z = z; ls->fs = NULL; ls->linenumber = 1; ls->lastline = 1; ls->source = source; ls->envn = luaS_new(L, LUA_ENV); /* create env name */ luaS_fix(ls->envn); /* never collect this name */ luaZ_resizebuffer(ls->L, ls->buff, LUA_MINBUFFER); /* initialize buffer */ } /* ** ======================================================= ** LEXICAL ANALYZER ** ======================================================= */ static int check_next (LexState *ls, const char *set) { if (ls->current == '\0' || !strchr(set, ls->current)) return 0; save_and_next(ls); return 1; } /* ** change all characters 'from' in buffer to 'to' */ static void buffreplace (LexState *ls, char from, char to) { size_t n = luaZ_bufflen(ls->buff); char *p = luaZ_buffer(ls->buff); while (n--) if (p[n] == from) p[n] = to; } #if !defined(getlocaledecpoint) #define getlocaledecpoint() (localeconv()->decimal_point[0]) #endif #define buff2d(b,e) luaO_str2d(luaZ_buffer(b), luaZ_bufflen(b) - 1, e) /* ** in case of format error, try to change decimal point separator to ** the one defined in the current locale and check again */ static void trydecpoint (LexState *ls, SemInfo *seminfo) { char old = ls->decpoint; ls->decpoint = getlocaledecpoint(); buffreplace(ls, old, ls->decpoint); /* try new decimal separator */ if (!buff2d(ls->buff, &seminfo->r)) { /* format error with correct decimal point: no more options */ buffreplace(ls, ls->decpoint, '.'); /* undo change (for error message) */ lexerror(ls, "malformed number", TK_NUMBER); } } /* LUA_NUMBER */ /* ** this function is quite liberal in what it accepts, as 'luaO_str2d' ** will reject ill-formed numerals. */ static void read_numeral (LexState *ls, SemInfo *seminfo) { const char *expo = "Ee"; int first = ls->current; lua_assert(lisdigit(ls->current)); save_and_next(ls); if (first == '0' && check_next(ls, "Xx")) /* hexadecimal? */ expo = "Pp"; for (;;) { if (check_next(ls, expo)) /* exponent part? */ check_next(ls, "+-"); /* optional exponent sign */ if (lisxdigit(ls->current) || ls->current == '.') save_and_next(ls); else break; } save(ls, '\0'); buffreplace(ls, '.', ls->decpoint); /* follow locale for decimal point */ if (!buff2d(ls->buff, &seminfo->r)) /* format error? */ trydecpoint(ls, seminfo); /* try to update decimal point separator */ } /* ** skip a sequence '[=*[' or ']=*]' and return its number of '='s or ** -1 if sequence is malformed */ static int skip_sep (LexState *ls) { int count = 0; int s = ls->current; lua_assert(s == '[' || s == ']'); save_and_next(ls); while (ls->current == '=') { save_and_next(ls); count++; } return (ls->current == s) ? count : (-count) - 1; } static void read_long_string (LexState *ls, SemInfo *seminfo, int sep) { save_and_next(ls); /* skip 2nd `[' */ if (currIsNewline(ls)) /* string starts with a newline? */ inclinenumber(ls); /* skip it */ for (;;) { switch (ls->current) { case EOZ: lexerror(ls, (seminfo) ? "unfinished long string" : "unfinished long comment", TK_EOS); break; /* to avoid warnings */ case ']': { if (skip_sep(ls) == sep) { save_and_next(ls); /* skip 2nd `]' */ goto endloop; } break; } case '\n': case '\r': { save(ls, '\n'); inclinenumber(ls); if (!seminfo) luaZ_resetbuffer(ls->buff); /* avoid wasting space */ break; } default: { if (seminfo) save_and_next(ls); else next(ls); } } } endloop: if (seminfo) seminfo->ts = luaX_newstring(ls, luaZ_buffer(ls->buff) + (2 + sep), luaZ_bufflen(ls->buff) - 2*(2 + sep)); } static void escerror (LexState *ls, int *c, int n, const char *msg) { int i; luaZ_resetbuffer(ls->buff); /* prepare error message */ save(ls, '\\'); for (i = 0; i < n && c[i] != EOZ; i++) save(ls, c[i]); lexerror(ls, msg, TK_STRING); } static int readhexaesc (LexState *ls) { int c[3], i; /* keep input for error message */ int r = 0; /* result accumulator */ c[0] = 'x'; /* for error message */ for (i = 1; i < 3; i++) { /* read two hexadecimal digits */ c[i] = next(ls); if (!lisxdigit(c[i])) escerror(ls, c, i + 1, "hexadecimal digit expected"); r = (r << 4) + luaO_hexavalue(c[i]); } return r; } static int readdecesc (LexState *ls) { int c[3], i; int r = 0; /* result accumulator */ for (i = 0; i < 3 && lisdigit(ls->current); i++) { /* read up to 3 digits */ c[i] = ls->current; r = 10*r + c[i] - '0'; next(ls); } if (r > UCHAR_MAX) escerror(ls, c, i, "decimal escape too large"); return r; } static void read_string (LexState *ls, int del, SemInfo *seminfo) { save_and_next(ls); /* keep delimiter (for error messages) */ while (ls->current != del) { switch (ls->current) { case EOZ: lexerror(ls, "unfinished string", TK_EOS); break; /* to avoid warnings */ case '\n': case '\r': lexerror(ls, "unfinished string", TK_STRING); break; /* to avoid warnings */ case '\\': { /* escape sequences */ int c; /* final character to be saved */ next(ls); /* do not save the `\' */ switch (ls->current) { case 'a': c = '\a'; goto read_save; case 'b': c = '\b'; goto read_save; case 'f': c = '\f'; goto read_save; case 'n': c = '\n'; goto read_save; case 'r': c = '\r'; goto read_save; case 't': c = '\t'; goto read_save; case 'v': c = '\v'; goto read_save; case 'x': c = readhexaesc(ls); goto read_save; case '\n': case '\r': inclinenumber(ls); c = '\n'; goto only_save; case '\\': case '\"': case '\'': c = ls->current; goto read_save; case EOZ: goto no_save; /* will raise an error next loop */ case 'z': { /* zap following span of spaces */ next(ls); /* skip the 'z' */ while (lisspace(ls->current)) { if (currIsNewline(ls)) inclinenumber(ls); else next(ls); } goto no_save; } default: { if (!lisdigit(ls->current)) escerror(ls, &ls->current, 1, "invalid escape sequence"); /* digital escape \ddd */ c = readdecesc(ls); goto only_save; } } read_save: next(ls); /* read next character */ only_save: save(ls, c); /* save 'c' */ no_save: break; } default: save_and_next(ls); } } save_and_next(ls); /* skip delimiter */ seminfo->ts = luaX_newstring(ls, luaZ_buffer(ls->buff) + 1, luaZ_bufflen(ls->buff) - 2); } static int llex (LexState *ls, SemInfo *seminfo) { luaZ_resetbuffer(ls->buff); for (;;) { switch (ls->current) { case '\n': case '\r': { /* line breaks */ inclinenumber(ls); break; } case ' ': case '\f': case '\t': case '\v': { /* spaces */ next(ls); break; } case '-': { /* '-' or '--' (comment) */ next(ls); if (ls->current != '-') return '-'; /* else is a comment */ next(ls); if (ls->current == '[') { /* long comment? */ int sep = skip_sep(ls); luaZ_resetbuffer(ls->buff); /* `skip_sep' may dirty the buffer */ if (sep >= 0) { read_long_string(ls, NULL, sep); /* skip long comment */ luaZ_resetbuffer(ls->buff); /* previous call may dirty the buff. */ break; } } /* else short comment */ while (!currIsNewline(ls) && ls->current != EOZ) next(ls); /* skip until end of line (or end of file) */ break; } case '[': { /* long string or simply '[' */ int sep = skip_sep(ls); if (sep >= 0) { read_long_string(ls, seminfo, sep); return TK_STRING; } else if (sep == -1) return '['; else lexerror(ls, "invalid long string delimiter", TK_STRING); } case '=': { next(ls); if (ls->current != '=') return '='; else { next(ls); return TK_EQ; } } case '<': { next(ls); if (ls->current != '=') return '<'; else { next(ls); return TK_LE; } } case '>': { next(ls); if (ls->current != '=') return '>'; else { next(ls); return TK_GE; } } case '~': { next(ls); if (ls->current != '=') return '~'; else { next(ls); return TK_NE; } } case ':': { next(ls); if (ls->current != ':') return ':'; else { next(ls); return TK_DBCOLON; } } case '"': case '\'': { /* short literal strings */ read_string(ls, ls->current, seminfo); return TK_STRING; } case '.': { /* '.', '..', '...', or number */ save_and_next(ls); if (check_next(ls, ".")) { if (check_next(ls, ".")) return TK_DOTS; /* '...' */ else return TK_CONCAT; /* '..' */ } else if (!lisdigit(ls->current)) return '.'; /* else go through */ } /* FALLTHROUGH */ case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9': { read_numeral(ls, seminfo); return TK_NUMBER; } case EOZ: { return TK_EOS; } default: { if (lislalpha(ls->current)) { /* identifier or reserved word? */ TString *ts; do { save_and_next(ls); } while (lislalnum(ls->current)); ts = luaX_newstring(ls, luaZ_buffer(ls->buff), luaZ_bufflen(ls->buff)); seminfo->ts = ts; if (isreserved(ts)) /* reserved word? */ return ts->tsv.extra - 1 + FIRST_RESERVED; else { return TK_NAME; } } else { /* single-char tokens (+ - / ...) */ int c = ls->current; next(ls); return c; } } } } } void luaX_next (LexState *ls) { ls->lastline = ls->linenumber; if (ls->lookahead.token != TK_EOS) { /* is there a look-ahead token? */ ls->t = ls->lookahead; /* use this one */ ls->lookahead.token = TK_EOS; /* and discharge it */ } else ls->t.token = llex(ls, &ls->t.seminfo); /* read next token */ } int luaX_lookahead (LexState *ls) { lua_assert(ls->lookahead.token == TK_EOS); ls->lookahead.token = llex(ls, &ls->lookahead.seminfo); return ls->lookahead.token; }