/* ** $Id: llex.c,v 2.96.1.1 2017/04/19 17:20:42 roberto Exp $ ** Lexical Analyzer ** See Copyright Notice in lua.h */ #define llex_c #define LUA_CORE #include "lprefix.h" #include #include #include "lua.h" #include "lctype.h" #include "ldebug.h" #include "ldo.h" #include "lgc.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_SIZE/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; TString *e = luaS_newliteral(L, LUA_ENV); /* create env name */ luaC_fix(L, obj2gco(e)); /* never collect this name */ for (i=0; iextra = 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_uchar(token)); return luaO_pushfstring(ls->L, "'%c'", 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, "'%s'", 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_FLT: case TK_INT: save(ls, '\0'); return luaO_pushfstring(ls->L, "'%s'", luaZ_buffer(ls->buff)); default: return luaX_token2str(ls, token); } } static l_noret lexerror (LexState *ls, const char *msg, int token) { msg = luaG_addinfo(ls->L, msg, ls->source, ls->linenumber); 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 scanner's table so that ** it will not be collected until the end of the compilation ** (by that time it should be anchored somewhere) */ 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->h, L->top - 1); if (ttisnil(o)) { /* not in use yet? */ /* 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 = tsvalue(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->t.token = 0; 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_newliteral(L, LUA_ENV); /* get env name */ luaZ_resizebuffer(ls->L, ls->buff, LUA_MINBUFFER); /* initialize buffer */ } /* ** ======================================================= ** LEXICAL ANALYZER ** ======================================================= */ static int check_next1 (LexState *ls, int c) { if (ls->current == c) { next(ls); return 1; } else return 0; } /* ** Check whether current char is in set 'set' (with two chars) and ** saves it */ static int check_next2 (LexState *ls, const char *set) { lua_assert(set[2] == '\0'); if (ls->current == set[0] || ls->current == set[1]) { save_and_next(ls); return 1; } else return 0; } /* LUA_NUMBER */ /* ** this function is quite liberal in what it accepts, as 'luaO_str2num' ** will reject ill-formed numerals. */ static int read_numeral (LexState *ls, SemInfo *seminfo) { TValue obj; const char *expo = "Ee"; int first = ls->current; lua_assert(lisdigit(ls->current)); save_and_next(ls); if (first == '0' && check_next2(ls, "xX")) /* hexadecimal? */ expo = "Pp"; for (;;) { if (check_next2(ls, expo)) /* exponent part? */ check_next2(ls, "-+"); /* optional exponent sign */ if (lisxdigit(ls->current)) save_and_next(ls); else if (ls->current == '.') save_and_next(ls); else break; } save(ls, '\0'); if (luaO_str2num(luaZ_buffer(ls->buff), &obj) == 0) /* format error? */ lexerror(ls, "malformed number", TK_FLT); if (ttisinteger(&obj)) { seminfo->i = ivalue(&obj); return TK_INT; } else { lua_assert(ttisfloat(&obj)); seminfo->r = fltvalue(&obj); return TK_FLT; } } /* ** skip a sequence '[=*[' or ']=*]'; if sequence is well formed, return ** its number of '='s; otherwise, return a negative number (-1 iff there ** are no '='s after initial bracket) */ 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) { int line = ls->linenumber; /* initial line (for error message) */ save_and_next(ls); /* skip 2nd '[' */ if (currIsNewline(ls)) /* string starts with a newline? */ inclinenumber(ls); /* skip it */ for (;;) { switch (ls->current) { case EOZ: { /* error */ const char *what = (seminfo ? "string" : "comment"); const char *msg = luaO_pushfstring(ls->L, "unfinished long %s (starting at line %d)", what, line); lexerror(ls, msg, 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 esccheck (LexState *ls, int c, const char *msg) { if (!c) { if (ls->current != EOZ) save_and_next(ls); /* add current to buffer for error message */ lexerror(ls, msg, TK_STRING); } } static int gethexa (LexState *ls) { save_and_next(ls); esccheck (ls, lisxdigit(ls->current), "hexadecimal digit expected"); return luaO_hexavalue(ls->current); } static int readhexaesc (LexState *ls) { int r = gethexa(ls); r = (r << 4) + gethexa(ls); luaZ_buffremove(ls->buff, 2); /* remove saved chars from buffer */ return r; } static unsigned long readutf8esc (LexState *ls) { unsigned long r; int i = 4; /* chars to be removed: '\', 'u', '{', and first digit */ save_and_next(ls); /* skip 'u' */ esccheck(ls, ls->current == '{', "missing '{'"); r = gethexa(ls); /* must have at least one digit */ while ((save_and_next(ls), lisxdigit(ls->current))) { i++; r = (r << 4) + luaO_hexavalue(ls->current); esccheck(ls, r <= 0x10FFFF, "UTF-8 value too large"); } esccheck(ls, ls->current == '}', "missing '}'"); next(ls); /* skip '}' */ luaZ_buffremove(ls->buff, i); /* remove saved chars from buffer */ return r; } static void utf8esc (LexState *ls) { char buff[UTF8BUFFSZ]; int n = luaO_utf8esc(buff, readutf8esc(ls)); for (; n > 0; n--) /* add 'buff' to string */ save(ls, buff[UTF8BUFFSZ - n]); } static int readdecesc (LexState *ls) { int i; int r = 0; /* result accumulator */ for (i = 0; i < 3 && lisdigit(ls->current); i++) { /* read up to 3 digits */ r = 10*r + ls->current - '0'; save_and_next(ls); } esccheck(ls, r <= UCHAR_MAX, "decimal escape too large"); luaZ_buffremove(ls->buff, i); /* remove read digits from buffer */ 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 */ save_and_next(ls); /* keep '\\' for error messages */ 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 'u': utf8esc(ls); goto no_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 */ luaZ_buffremove(ls->buff, 1); /* remove '\\' */ next(ls); /* skip the 'z' */ while (lisspace(ls->current)) { if (currIsNewline(ls)) inclinenumber(ls); else next(ls); } goto no_save; } default: { esccheck(ls, lisdigit(ls->current), "invalid escape sequence"); c = readdecesc(ls); /* digital escape '\ddd' */ goto only_save; } } read_save: next(ls); /* go through */ only_save: luaZ_buffremove(ls->buff, 1); /* remove '\\' */ save(ls, c); /* go through */ 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) /* '[=...' missing second bracket */ lexerror(ls, "invalid long string delimiter", TK_STRING); return '['; } case '=': { next(ls); if (check_next1(ls, '=')) return TK_EQ; else return '='; } case '<': { next(ls); if (check_next1(ls, '=')) return TK_LE; else if (check_next1(ls, '<')) return TK_SHL; else return '<'; } case '>': { next(ls); if (check_next1(ls, '=')) return TK_GE; else if (check_next1(ls, '>')) return TK_SHR; else return '>'; } case '/': { next(ls); if (check_next1(ls, '/')) return TK_IDIV; else return '/'; } case '~': { next(ls); if (check_next1(ls, '=')) return TK_NE; else return '~'; } case ':': { next(ls); if (check_next1(ls, ':')) return TK_DBCOLON; else return ':'; } case '"': case '\'': { /* short literal strings */ read_string(ls, ls->current, seminfo); return TK_STRING; } case '.': { /* '.', '..', '...', or number */ save_and_next(ls); if (check_next1(ls, '.')) { if (check_next1(ls, '.')) return TK_DOTS; /* '...' */ else return TK_CONCAT; /* '..' */ } else if (!lisdigit(ls->current)) return '.'; else return read_numeral(ls, seminfo); } case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9': { return read_numeral(ls, seminfo); } 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->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; }