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389 lines
10 KiB
389 lines
10 KiB
/*
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** $Id: llex.c,v 1.83 2001/03/07 12:49:37 roberto Exp roberto $
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** Lexical Analyzer
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** See Copyright Notice in lua.h
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*/
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#include <ctype.h>
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#include <stdio.h>
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#include <string.h>
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#define LUA_PRIVATE
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#include "lua.h"
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#include "llex.h"
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#include "lobject.h"
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#include "lparser.h"
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#include "lstate.h"
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#include "lstring.h"
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#include "lzio.h"
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#define next(LS) (LS->current = zgetc(LS->z))
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/* ORDER RESERVED */
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static const l_char *const token2string [] = {
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l_s("and"), l_s("break"), l_s("do"), l_s("else"), l_s("elseif"),
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l_s("end"), l_s("for"), l_s("function"), l_s("if"), l_s("local"),
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l_s("nil"), l_s("not"), l_s("or"), l_s("repeat"), l_s("return"),
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l_s("then"), l_s("until"), l_s("while"), l_s(""), l_s(".."), l_s("..."),
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l_s("=="), l_s(">="), l_s("<="), l_s("~="), l_s(""), l_s(""), l_s("<eof>")
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};
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void luaX_init (lua_State *L) {
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int i;
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for (i=0; i<NUM_RESERVED; i++) {
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TString *ts = luaS_new(L, token2string[i]);
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lua_assert(strlen(token2string[i])+1 <= TOKEN_LEN);
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ts->marked = RESERVEDMARK+i; /* reserved word */
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}
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}
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#define MAXSRC 80
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void luaX_checklimit (LexState *ls, int val, int limit, const l_char *msg) {
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if (val > limit) {
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l_char buff[90];
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sprintf(buff, l_s("too many %.40s (limit=%d)"), msg, limit);
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luaX_error(ls, buff, ls->t.token);
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}
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}
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void luaX_syntaxerror (LexState *ls, const l_char *s, const l_char *token) {
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l_char buff[MAXSRC];
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luaO_chunkid(buff, getstr(ls->source), MAXSRC);
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luaO_verror(ls->L,
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l_s("%.99s;\n last token read: `%.30s' at line %d in %.80s"),
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s, token, ls->linenumber, buff);
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}
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void luaX_error (LexState *ls, const l_char *s, int token) {
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l_char buff[TOKEN_LEN];
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luaX_token2str(token, buff);
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if (buff[0] == l_c('\0'))
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luaX_syntaxerror(ls, s, (l_char *)G(ls->L)->Mbuffer);
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else
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luaX_syntaxerror(ls, s, buff);
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}
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void luaX_token2str (int token, l_char *s) {
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if (token < 256) {
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s[0] = (l_char)token;
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s[1] = l_c('\0');
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}
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else
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strcpy(s, token2string[token-FIRST_RESERVED]);
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}
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static void luaX_invalidchar (LexState *ls, int c) {
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l_char buff[8];
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sprintf(buff, l_s("0x%02X"), uchar(c));
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luaX_syntaxerror(ls, l_s("invalid control char"), buff);
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}
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static void inclinenumber (LexState *LS) {
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next(LS); /* skip `\n' */
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++LS->linenumber;
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luaX_checklimit(LS, LS->linenumber, MAX_INT, l_s("lines in a chunk"));
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}
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void luaX_setinput (lua_State *L, LexState *LS, ZIO *z, TString *source) {
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LS->L = L;
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LS->lookahead.token = TK_EOS; /* no look-ahead token */
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LS->z = z;
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LS->fs = NULL;
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LS->linenumber = 1;
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LS->lastline = 1;
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LS->source = source;
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next(LS); /* read first char */
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if (LS->current == l_c('#')) {
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do { /* skip first line */
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next(LS);
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} while (LS->current != l_c('\n') && LS->current != EOZ);
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}
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}
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/*
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** =======================================================
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** LEXICAL ANALYZER
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** =======================================================
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*/
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/* use Mbuffer to store names, literal strings and numbers */
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#define EXTRABUFF 128
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#define checkbuffer(L, n, len) \
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if (((len)+(n))*sizeof(l_char) > G(L)->Mbuffsize) \
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luaO_openspace(L, (len)+(n)+EXTRABUFF, l_char)
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#define save(L, c, l) (((l_char *)G(L)->Mbuffer)[l++] = (l_char)c)
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#define save_and_next(L, LS, l) (save(L, LS->current, l), next(LS))
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static size_t readname (LexState *LS) {
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lua_State *L = LS->L;
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size_t l = 0;
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checkbuffer(L, 10, l);
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do {
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checkbuffer(L, 10, l);
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save_and_next(L, LS, l);
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} while (isalnum(LS->current) || LS->current == l_c('_'));
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save(L, l_c('\0'), l);
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return l-1;
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}
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/* LUA_NUMBER */
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static void read_number (LexState *LS, int comma, SemInfo *seminfo) {
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lua_State *L = LS->L;
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size_t l = 0;
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checkbuffer(L, 10, l);
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if (comma) save(L, l_c('.'), l);
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while (isdigit(LS->current)) {
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checkbuffer(L, 10, l);
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save_and_next(L, LS, l);
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}
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if (LS->current == l_c('.')) {
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save_and_next(L, LS, l);
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if (LS->current == l_c('.')) {
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save_and_next(L, LS, l);
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save(L, l_c('\0'), l);
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luaX_error(LS,
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l_s("ambiguous syntax (decimal point x string concatenation)"),
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TK_NUMBER);
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}
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}
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while (isdigit(LS->current)) {
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checkbuffer(L, 10, l);
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save_and_next(L, LS, l);
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}
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if (LS->current == l_c('e') || LS->current == l_c('E')) {
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save_and_next(L, LS, l); /* read `E' */
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if (LS->current == l_c('+') || LS->current == l_c('-'))
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save_and_next(L, LS, l); /* optional exponent sign */
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while (isdigit(LS->current)) {
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checkbuffer(L, 10, l);
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save_and_next(L, LS, l);
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}
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}
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save(L, l_c('\0'), l);
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if (!luaO_str2d((l_char *)G(L)->Mbuffer, &seminfo->r))
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luaX_error(LS, l_s("malformed number"), TK_NUMBER);
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}
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static void read_long_string (LexState *LS, SemInfo *seminfo) {
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lua_State *L = LS->L;
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int cont = 0;
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size_t l = 0;
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checkbuffer(L, 10, l);
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save(L, l_c('['), l); /* save first `[' */
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save_and_next(L, LS, l); /* pass the second `[' */
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if (LS->current == l_c('\n')) /* string starts with a newline? */
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inclinenumber(LS); /* skip it */
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for (;;) {
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checkbuffer(L, 10, l);
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switch (LS->current) {
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case EOZ:
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save(L, l_c('\0'), l);
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luaX_error(LS, l_s("unfinished long string"), TK_STRING);
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break; /* to avoid warnings */
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case l_c('['):
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save_and_next(L, LS, l);
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if (LS->current == l_c('[')) {
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cont++;
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save_and_next(L, LS, l);
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}
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continue;
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case l_c(']'):
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save_and_next(L, LS, l);
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if (LS->current == l_c(']')) {
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if (cont == 0) goto endloop;
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cont--;
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save_and_next(L, LS, l);
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}
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continue;
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case l_c('\n'):
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save(L, l_c('\n'), l);
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inclinenumber(LS);
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continue;
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default:
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save_and_next(L, LS, l);
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}
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} endloop:
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save_and_next(L, LS, l); /* skip the second `]' */
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save(L, l_c('\0'), l);
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seminfo->ts = luaS_newlstr(L, (l_char *)G(L)->Mbuffer+2, l-5);
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}
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static void read_string (LexState *LS, int del, SemInfo *seminfo) {
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lua_State *L = LS->L;
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size_t l = 0;
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checkbuffer(L, 10, l);
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save_and_next(L, LS, l);
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while (LS->current != del) {
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checkbuffer(L, 10, l);
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switch (LS->current) {
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case EOZ: case l_c('\n'):
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save(L, l_c('\0'), l);
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luaX_error(LS, l_s("unfinished string"), TK_STRING);
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break; /* to avoid warnings */
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case l_c('\\'):
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next(LS); /* do not save the `\' */
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switch (LS->current) {
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case l_c('a'): save(L, l_c('\a'), l); next(LS); break;
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case l_c('b'): save(L, l_c('\b'), l); next(LS); break;
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case l_c('f'): save(L, l_c('\f'), l); next(LS); break;
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case l_c('n'): save(L, l_c('\n'), l); next(LS); break;
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case l_c('r'): save(L, l_c('\r'), l); next(LS); break;
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case l_c('t'): save(L, l_c('\t'), l); next(LS); break;
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case l_c('v'): save(L, l_c('\v'), l); next(LS); break;
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case l_c('\n'): save(L, l_c('\n'), l); inclinenumber(LS); break;
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default: {
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if (!isdigit(LS->current))
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save_and_next(L, LS, l); /* handles \\, \", \', and \? */
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else { /* \xxx */
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int c = 0;
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int i = 0;
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do {
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c = 10*c + (LS->current-l_c('0'));
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next(LS);
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} while (++i<3 && isdigit(LS->current));
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if (c > UCHAR_MAX) {
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save(L, l_c('\0'), l);
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luaX_error(LS, l_s("escape sequence too large"), TK_STRING);
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}
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save(L, c, l);
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}
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}
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}
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break;
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default:
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save_and_next(L, LS, l);
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}
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}
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save_and_next(L, LS, l); /* skip delimiter */
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save(L, l_c('\0'), l);
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seminfo->ts = luaS_newlstr(L, (l_char *)G(L)->Mbuffer+1, l-3);
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}
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int luaX_lex (LexState *LS, SemInfo *seminfo) {
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for (;;) {
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switch (LS->current) {
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case l_c(' '): case l_c('\t'): case l_c('\r'): /* `\r' to avoid problems with DOS */
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next(LS);
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continue;
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case l_c('\n'):
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inclinenumber(LS);
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continue;
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case l_c('$'):
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luaX_error(LS,
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l_s("unexpected `$' (pragmas are no longer supported)"),
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LS->current);
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break;
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case l_c('-'):
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next(LS);
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if (LS->current != l_c('-')) return l_c('-');
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do { next(LS); } while (LS->current != l_c('\n') && LS->current != EOZ);
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continue;
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case l_c('['):
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next(LS);
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if (LS->current != l_c('[')) return l_c('[');
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else {
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read_long_string(LS, seminfo);
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return TK_STRING;
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}
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case l_c('='):
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next(LS);
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if (LS->current != l_c('=')) return l_c('=');
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else { next(LS); return TK_EQ; }
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case l_c('<'):
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next(LS);
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if (LS->current != l_c('=')) return l_c('<');
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else { next(LS); return TK_LE; }
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case l_c('>'):
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next(LS);
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if (LS->current != l_c('=')) return l_c('>');
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else { next(LS); return TK_GE; }
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case l_c('~'):
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next(LS);
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if (LS->current != l_c('=')) return l_c('~');
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else { next(LS); return TK_NE; }
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case l_c('"'):
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case l_c('\''):
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read_string(LS, LS->current, seminfo);
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return TK_STRING;
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case l_c('.'):
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next(LS);
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if (LS->current == l_c('.')) {
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next(LS);
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if (LS->current == l_c('.')) {
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next(LS);
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return TK_DOTS; /* ... */
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}
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else return TK_CONCAT; /* .. */
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}
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else if (!isdigit(LS->current)) return l_c('.');
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else {
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read_number(LS, 1, seminfo);
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return TK_NUMBER;
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}
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case EOZ:
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return TK_EOS;
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default: {
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if (isdigit(LS->current)) {
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read_number(LS, 0, seminfo);
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return TK_NUMBER;
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}
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else if (isalpha(LS->current) || LS->current == l_c('_')) {
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/* identifier or reserved word */
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size_t l = readname(LS);
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TString *ts = luaS_newlstr(LS->L, (l_char *)G(LS->L)->Mbuffer, l);
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if (ts->marked >= RESERVEDMARK) /* reserved word? */
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return ts->marked-RESERVEDMARK+FIRST_RESERVED;
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seminfo->ts = ts;
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return TK_NAME;
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}
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else {
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int c = LS->current;
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if (iscntrl(c))
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luaX_invalidchar(LS, c);
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next(LS);
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return c; /* single-char tokens (+ - / ...) */
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}
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}
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}
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}
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}
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