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/*
** $Id: llex.c,v 1.81 2001/02/23 20:32:16 roberto Exp roberto $
** Lexical Analyzer
** See Copyright Notice in lua.h
*/
#include <ctype.h>
#include <stdio.h>
#include <string.h>
#include "lua.h"
#include "llex.h"
#include "lobject.h"
#include "lparser.h"
#include "lstate.h"
#include "lstring.h"
#include "lzio.h"
#define next(LS) (LS->current = zgetc(LS->z))
/* ORDER RESERVED */
static const l_char *const token2string [] = {
l_s("and"), l_s("break"), l_s("do"), l_s("else"), l_s("elseif"),
l_s("end"), l_s("for"), l_s("function"), l_s("if"), l_s("local"),
l_s("nil"), l_s("not"), l_s("or"), l_s("repeat"), l_s("return"),
l_s("then"), l_s("until"), l_s("while"), l_s(""), l_s(".."), l_s("..."),
l_s("=="), l_s(">="), l_s("<="), l_s("~="), l_s(""), l_s(""), l_s("<eof>")
};
void luaX_init (lua_State *L) {
int i;
for (i=0; i<NUM_RESERVED; i++) {
TString *ts = luaS_new(L, token2string[i]);
lua_assert(strlen(token2string[i])+1 <= TOKEN_LEN);
ts->marked = RESERVEDMARK+i; /* reserved word */
}
}
#define MAXSRC 80
void luaX_checklimit (LexState *ls, int val, int limit, const l_char *msg) {
if (val > limit) {
l_char buff[90];
sprintf(buff, l_s("too many %.40s (limit=%d)"), msg, limit);
luaX_error(ls, buff, ls->t.token);
}
}
void luaX_syntaxerror (LexState *ls, const l_char *s, const l_char *token) {
l_char buff[MAXSRC];
luaO_chunkid(buff, getstr(ls->source), MAXSRC);
luaO_verror(ls->L,
l_s("%.99s;\n last token read: `%.30s' at line %d in %.80s"),
s, token, ls->linenumber, buff);
}
void luaX_error (LexState *ls, const l_char *s, int token) {
l_char buff[TOKEN_LEN];
luaX_token2str(token, buff);
if (buff[0] == l_c('\0'))
luaX_syntaxerror(ls, s, (l_char *)G(ls->L)->Mbuffer);
else
luaX_syntaxerror(ls, s, buff);
}
void luaX_token2str (int token, l_char *s) {
if (token < 256) {
s[0] = (l_char)token;
s[1] = l_c('\0');
}
else
strcpy(s, token2string[token-FIRST_RESERVED]);
}
static void luaX_invalidchar (LexState *ls, int c) {
l_char buff[8];
sprintf(buff, l_s("0x%02X"), uchar(c));
luaX_syntaxerror(ls, l_s("invalid control char"), buff);
}
static void inclinenumber (LexState *LS) {
next(LS); /* skip `\n' */
++LS->linenumber;
luaX_checklimit(LS, LS->linenumber, MAX_INT, l_s("lines in a chunk"));
}
void luaX_setinput (lua_State *L, LexState *LS, ZIO *z, TString *source) {
LS->L = L;
LS->lookahead.token = TK_EOS; /* no look-ahead token */
LS->z = z;
LS->fs = NULL;
LS->linenumber = 1;
LS->lastline = 1;
LS->source = source;
next(LS); /* read first char */
if (LS->current == l_c('#')) {
do { /* skip first line */
next(LS);
} while (LS->current != l_c('\n') && LS->current != EOZ);
}
}
/*
** =======================================================
** LEXICAL ANALYZER
** =======================================================
*/
/* use Mbuffer to store names, literal strings and numbers */
#define EXTRABUFF 128
#define checkbuffer(L, n, len) \
if (((len)+(n))*sizeof(l_char) > G(L)->Mbuffsize) \
luaO_openspace(L, (len)+(n)+EXTRABUFF, l_char)
#define save(L, c, l) (((l_char *)G(L)->Mbuffer)[l++] = (l_char)c)
#define save_and_next(L, LS, l) (save(L, LS->current, l), next(LS))
static size_t readname (LexState *LS) {
lua_State *L = LS->L;
size_t l = 0;
checkbuffer(L, 10, l);
do {
checkbuffer(L, 10, l);
save_and_next(L, LS, l);
} while (isalnum(LS->current) || LS->current == l_c('_'));
save(L, l_c('\0'), l);
return l-1;
}
/* LUA_NUMBER */
static void read_number (LexState *LS, int comma, SemInfo *seminfo) {
lua_State *L = LS->L;
size_t l = 0;
checkbuffer(L, 10, l);
if (comma) save(L, l_c('.'), l);
while (isdigit(LS->current)) {
checkbuffer(L, 10, l);
save_and_next(L, LS, l);
}
if (LS->current == l_c('.')) {
save_and_next(L, LS, l);
if (LS->current == l_c('.')) {
save_and_next(L, LS, l);
save(L, l_c('\0'), l);
luaX_error(LS,
l_s("ambiguous syntax (decimal point x string concatenation)"),
TK_NUMBER);
}
}
while (isdigit(LS->current)) {
checkbuffer(L, 10, l);
save_and_next(L, LS, l);
}
if (LS->current == l_c('e') || LS->current == l_c('E')) {
save_and_next(L, LS, l); /* read `E' */
if (LS->current == l_c('+') || LS->current == l_c('-'))
save_and_next(L, LS, l); /* optional exponent sign */
while (isdigit(LS->current)) {
checkbuffer(L, 10, l);
save_and_next(L, LS, l);
}
}
save(L, l_c('\0'), l);
if (!luaO_str2d((l_char *)G(L)->Mbuffer, &seminfo->r))
luaX_error(LS, l_s("malformed number"), TK_NUMBER);
}
static void read_long_string (LexState *LS, SemInfo *seminfo) {
lua_State *L = LS->L;
int cont = 0;
size_t l = 0;
checkbuffer(L, 10, l);
save(L, l_c('['), l); /* save first `[' */
save_and_next(L, LS, l); /* pass the second `[' */
for (;;) {
checkbuffer(L, 10, l);
switch (LS->current) {
case EOZ:
save(L, l_c('\0'), l);
luaX_error(LS, l_s("unfinished long string"), TK_STRING);
break; /* to avoid warnings */
case l_c('['):
save_and_next(L, LS, l);
if (LS->current == l_c('[')) {
cont++;
save_and_next(L, LS, l);
}
continue;
case l_c(']'):
save_and_next(L, LS, l);
if (LS->current == l_c(']')) {
if (cont == 0) goto endloop;
cont--;
save_and_next(L, LS, l);
}
continue;
case l_c('\n'):
save(L, l_c('\n'), l);
inclinenumber(LS);
continue;
default:
save_and_next(L, LS, l);
}
} endloop:
save_and_next(L, LS, l); /* skip the second `]' */
save(L, l_c('\0'), l);
seminfo->ts = luaS_newlstr(L, (l_char *)G(L)->Mbuffer+2, l-5);
}
static void read_string (LexState *LS, int del, SemInfo *seminfo) {
lua_State *L = LS->L;
size_t l = 0;
checkbuffer(L, 10, l);
save_and_next(L, LS, l);
while (LS->current != del) {
checkbuffer(L, 10, l);
switch (LS->current) {
case EOZ: case l_c('\n'):
save(L, l_c('\0'), l);
luaX_error(LS, l_s("unfinished string"), TK_STRING);
break; /* to avoid warnings */
case l_c('\\'):
next(LS); /* do not save the `\' */
switch (LS->current) {
case l_c('a'): save(L, l_c('\a'), l); next(LS); break;
case l_c('b'): save(L, l_c('\b'), l); next(LS); break;
case l_c('f'): save(L, l_c('\f'), l); next(LS); break;
case l_c('n'): save(L, l_c('\n'), l); next(LS); break;
case l_c('r'): save(L, l_c('\r'), l); next(LS); break;
case l_c('t'): save(L, l_c('\t'), l); next(LS); break;
case l_c('v'): save(L, l_c('\v'), l); next(LS); break;
case l_c('\n'): save(L, l_c('\n'), l); inclinenumber(LS); break;
default: {
if (!isdigit(LS->current))
save_and_next(L, LS, l); /* handles \\, \", \', and \? */
else { /* \xxx */
int c = 0;
int i = 0;
do {
c = 10*c + (LS->current-l_c('0'));
next(LS);
} while (++i<3 && isdigit(LS->current));
if (c > UCHAR_MAX) {
save(L, l_c('\0'), l);
luaX_error(LS, l_s("escape sequence too large"), TK_STRING);
}
save(L, c, l);
}
}
}
break;
default:
save_and_next(L, LS, l);
}
}
save_and_next(L, LS, l); /* skip delimiter */
save(L, l_c('\0'), l);
seminfo->ts = luaS_newlstr(L, (l_char *)G(L)->Mbuffer+1, l-3);
}
int luaX_lex (LexState *LS, SemInfo *seminfo) {
for (;;) {
switch (LS->current) {
case l_c(' '): case l_c('\t'): case l_c('\r'): /* `\r' to avoid problems with DOS */
next(LS);
continue;
case l_c('\n'):
inclinenumber(LS);
continue;
case l_c('$'):
luaX_error(LS,
l_s("unexpected `$' (pragmas are no longer supported)"),
LS->current);
break;
case l_c('-'):
next(LS);
if (LS->current != l_c('-')) return l_c('-');
do { next(LS); } while (LS->current != l_c('\n') && LS->current != EOZ);
continue;
case l_c('['):
next(LS);
if (LS->current != l_c('[')) return l_c('[');
else {
read_long_string(LS, seminfo);
return TK_STRING;
}
case l_c('='):
next(LS);
if (LS->current != l_c('=')) return l_c('=');
else { next(LS); return TK_EQ; }
case l_c('<'):
next(LS);
if (LS->current != l_c('=')) return l_c('<');
else { next(LS); return TK_LE; }
case l_c('>'):
next(LS);
if (LS->current != l_c('=')) return l_c('>');
else { next(LS); return TK_GE; }
case l_c('~'):
next(LS);
if (LS->current != l_c('=')) return l_c('~');
else { next(LS); return TK_NE; }
case l_c('"'):
case l_c('\''):
read_string(LS, LS->current, seminfo);
return TK_STRING;
case l_c('.'):
next(LS);
if (LS->current == l_c('.')) {
next(LS);
if (LS->current == l_c('.')) {
next(LS);
return TK_DOTS; /* ... */
}
else return TK_CONCAT; /* .. */
}
else if (!isdigit(LS->current)) return l_c('.');
else {
read_number(LS, 1, seminfo);
return TK_NUMBER;
}
case EOZ:
return TK_EOS;
default: {
if (isdigit(LS->current)) {
read_number(LS, 0, seminfo);
return TK_NUMBER;
}
else if (isalpha(LS->current) || LS->current == l_c('_')) {
/* identifier or reserved word */
size_t l = readname(LS);
TString *ts = luaS_newlstr(LS->L, (l_char *)G(LS->L)->Mbuffer, l);
if (ts->marked >= RESERVEDMARK) /* reserved word? */
return ts->marked-RESERVEDMARK+FIRST_RESERVED;
seminfo->ts = ts;
return TK_NAME;
}
else {
int c = LS->current;
if (iscntrl(c))
luaX_invalidchar(LS, c);
next(LS);
return c; /* single-char tokens (+ - / ...) */
}
}
}
}
}
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