lua/llex.c

454 lines
12 KiB
C

/*
** $Id: llex.c,v 1.57 2000/04/12 18:57:19 roberto Exp roberto $
** Lexical Analyzer
** See Copyright Notice in lua.h
*/
#include <ctype.h>
#include <stdio.h>
#include <string.h>
#define LUA_REENTRANT
#include "lauxlib.h"
#include "llex.h"
#include "lmem.h"
#include "lobject.h"
#include "lparser.h"
#include "lstate.h"
#include "lstring.h"
#include "ltable.h"
#include "luadebug.h"
#include "lzio.h"
#define next(LS) (LS->current = zgetc(LS->z))
#define save(L, c) luaL_addchar(L, c)
#define save_and_next(L, LS) (save(L, LS->current), next(LS))
/* ORDER RESERVED */
static const char *const token2string [] = {
"and", "break", "do", "else", "elseif", "end", "for",
"function", "if", "local", "nil", "not", "or", "repeat", "return", "then",
"until", "while", "", "..", "...", "==", ">=", "<=", "~=", "", "", "<eof>"};
void luaX_init (lua_State *L) {
int i;
for (i=0; i<NUM_RESERVED; i++) {
TString *ts = luaS_new(L, token2string[i]);
ts->marked = (unsigned char)(RESERVEDMARK+i); /* reserved word */
}
}
#define MAXSRC 80
void luaX_syntaxerror (LexState *ls, const char *s, const char *token) {
char buff[MAXSRC];
luaL_chunkid(buff, zname(ls->z), sizeof(buff));
luaL_verror(ls->L, "%.100s;\n last token read: `%.50s' at line %d in %.80s",
s, token, ls->linenumber, buff);
}
void luaX_error (LexState *ls, const char *s, int token) {
char buff[TOKEN_LEN];
luaX_token2str(token, buff);
if (buff[0] == '\0') {
save(ls->L, '\0');
luaX_syntaxerror(ls, s, luaL_buffer(ls->L));
}
else
luaX_syntaxerror(ls, s, buff);
}
void luaX_token2str (int token, char *s) {
if (token < 256) {
s[0] = (char)token;
s[1] = '\0';
}
else
strcpy(s, token2string[token-FIRST_RESERVED]);
}
static void luaX_invalidchar (LexState *ls, int c) {
char buff[8];
sprintf(buff, "0x%02X", c);
luaX_syntaxerror(ls, "invalid control char", buff);
}
static void firstline (LexState *LS)
{
int c = zgetc(LS->z);
if (c == '#')
while ((c=zgetc(LS->z)) != '\n' && c != EOZ) /* skip first line */;
zungetc(LS->z);
}
void luaX_setinput (lua_State *L, LexState *LS, ZIO *z) {
LS->L = L;
LS->current = '\n';
LS->linenumber = 0;
LS->iflevel = 0;
LS->ifstate[0].skip = 0;
LS->ifstate[0].elsepart = 1; /* to avoid a free $else */
LS->z = z;
LS->fs = NULL;
firstline(LS);
luaL_resetbuffer(L);
}
/*
** =======================================================
** PRAGMAS
** =======================================================
*/
static void skipspace (LexState *LS) {
while (LS->current == ' ' || LS->current == '\t' || LS->current == '\r')
next(LS);
}
static int globaldefined (lua_State *L, const char *name) {
const TObject *value = luaH_getglobal(L, name);
return ttype(value) != TAG_NIL;
}
static int checkcond (lua_State *L, LexState *LS, const char *buff) {
static const char *const opts[] = {"nil", "1", NULL};
int i = luaL_findstring(buff, opts);
if (i >= 0) return i;
else if (isalpha((unsigned char)buff[0]) || buff[0] == '_')
return globaldefined(L, buff);
else {
luaX_syntaxerror(LS, "invalid $if condition", buff);
return 0; /* to avoid warnings */
}
}
static void readname (LexState *LS, char *buff) {
int i = 0;
skipspace(LS);
while (isalnum(LS->current) || LS->current == '_') {
if (i >= PRAGMASIZE) {
buff[PRAGMASIZE] = 0;
luaX_syntaxerror(LS, "pragma too long", buff);
}
buff[i++] = (char)LS->current;
next(LS);
}
buff[i] = 0;
}
static void inclinenumber (lua_State *L, LexState *LS);
static void ifskip (lua_State *L, LexState *LS) {
while (LS->ifstate[LS->iflevel].skip) {
if (LS->current == '\n')
inclinenumber(L, LS);
else if (LS->current == EOZ)
luaX_error(LS, "input ends inside a $if", TK_EOS);
else next(LS);
}
}
static void inclinenumber (lua_State *L, LexState *LS) {
static const char *const pragmas [] =
{"debug", "nodebug", "endinput", "end", "ifnot", "if", "else", NULL};
next(LS); /* skip '\n' */
++LS->linenumber;
if (LS->current == '$') { /* is a pragma? */
char buff[PRAGMASIZE+1];
int ifnot = 0;
int skip = LS->ifstate[LS->iflevel].skip;
next(LS); /* skip $ */
readname(LS, buff);
switch (luaL_findstring(buff, pragmas)) {
case 0: /* debug */
if (!skip) L->debug = 1;
break;
case 1: /* nodebug */
if (!skip) L->debug = 0;
break;
case 2: /* endinput */
if (!skip) {
LS->current = EOZ;
LS->iflevel = 0; /* to allow $endinput inside a $if */
}
break;
case 3: /* end */
if (LS->iflevel-- == 0)
luaX_syntaxerror(LS, "unmatched $end", "$end");
break;
case 4: /* ifnot */
ifnot = 1;
/* go through */
case 5: /* if */
if (LS->iflevel == MAX_IFS-1)
luaX_syntaxerror(LS, "too many nested $ifs", "$if");
readname(LS, buff);
LS->iflevel++;
LS->ifstate[LS->iflevel].elsepart = 0;
LS->ifstate[LS->iflevel].condition = checkcond(L, LS, buff) ? !ifnot : ifnot;
LS->ifstate[LS->iflevel].skip = skip || !LS->ifstate[LS->iflevel].condition;
break;
case 6: /* else */
if (LS->ifstate[LS->iflevel].elsepart)
luaX_syntaxerror(LS, "unmatched $else", "$else");
LS->ifstate[LS->iflevel].elsepart = 1;
LS->ifstate[LS->iflevel].skip = LS->ifstate[LS->iflevel-1].skip ||
LS->ifstate[LS->iflevel].condition;
break;
default:
luaX_syntaxerror(LS, "unknown pragma", buff);
}
skipspace(LS);
if (LS->current == '\n') /* pragma must end with a '\n' ... */
inclinenumber(L, LS);
else if (LS->current != EOZ) /* or eof */
luaX_syntaxerror(LS, "invalid pragma format", buff);
ifskip(L, LS);
}
}
/*
** =======================================================
** LEXICAL ANALYZER
** =======================================================
*/
static void read_long_string (lua_State *L, LexState *LS) {
int cont = 0;
for (;;) {
switch (LS->current) {
case EOZ:
luaX_error(LS, "unfinished long string", TK_STRING);
break; /* to avoid warnings */
case '[':
save_and_next(L, LS);
if (LS->current == '[') {
cont++;
save_and_next(L, LS);
}
continue;
case ']':
save_and_next(L, LS);
if (LS->current == ']') {
if (cont == 0) goto endloop;
cont--;
save_and_next(L, LS);
}
continue;
case '\n':
save(L, '\n');
inclinenumber(L, LS);
continue;
default:
save_and_next(L, LS);
}
} endloop:
save_and_next(L, LS); /* skip the second ']' */
LS->seminfo.ts = luaS_newlstr(L, L->Mbuffer+(L->Mbuffbase+2),
L->Mbuffnext-L->Mbuffbase-4);
}
static void read_string (lua_State *L, LexState *LS, int del) {
save_and_next(L, LS);
while (LS->current != del) {
switch (LS->current) {
case EOZ: case '\n':
luaX_error(LS, "unfinished string", TK_STRING);
break; /* to avoid warnings */
case '\\':
next(LS); /* do not save the '\' */
switch (LS->current) {
case 'a': save(L, '\a'); next(LS); break;
case 'b': save(L, '\b'); next(LS); break;
case 'f': save(L, '\f'); next(LS); break;
case 'n': save(L, '\n'); next(LS); break;
case 'r': save(L, '\r'); next(LS); break;
case 't': save(L, '\t'); next(LS); break;
case 'v': save(L, '\v'); next(LS); break;
case '\n': save(L, '\n'); inclinenumber(L, LS); break;
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9': {
int c = 0;
int i = 0;
do {
c = 10*c + (LS->current-'0');
next(LS);
} while (++i<3 && isdigit(LS->current));
if (c != (unsigned char)c)
luaX_error(LS, "escape sequence too large", TK_STRING);
save(L, c);
break;
}
default: /* handles \\, \", \', and \? */
save(L, LS->current);
next(LS);
}
break;
default:
save_and_next(L, LS);
}
}
save_and_next(L, LS); /* skip delimiter */
LS->seminfo.ts = luaS_newlstr(L, L->Mbuffer+(L->Mbuffbase+1),
L->Mbuffnext-L->Mbuffbase-2);
}
int luaX_lex (LexState *LS) {
lua_State *L = LS->L;
for (;;) {
switch (LS->current) {
case ' ': case '\t': case '\r': /* `\r' to avoid problems with DOS */
next(LS);
continue;
case '\n':
inclinenumber(L, LS);
continue;
case '-':
next(LS);
if (LS->current != '-') return '-';
do { next(LS); } while (LS->current != '\n' && LS->current != EOZ);
continue;
case '[':
luaL_resetbuffer(L);
save_and_next(L, LS);
if (LS->current != '[') return '[';
else {
save_and_next(L, LS); /* pass the second '[' */
read_long_string(L, LS);
return 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 '"':
case '\'':
luaL_resetbuffer(L);
read_string(L, LS, LS->current);
return TK_STRING;
case '.':
luaL_resetbuffer(L);
save_and_next(L, LS);
if (LS->current == '.') {
next(LS);
if (LS->current == '.') {
next(LS);
return TK_DOTS; /* ... */
}
else return TK_CONCAT; /* .. */
}
else if (!isdigit(LS->current)) return '.';
else goto fraction; /* LS->current is a digit */
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
luaL_resetbuffer(L);
do {
save_and_next(L, LS);
} while (isdigit(LS->current));
if (LS->current == '.') {
save_and_next(L, LS);
if (LS->current == '.') {
save(L, '.');
luaX_error(LS, "ambiguous syntax"
" (decimal point x string concatenation)", TK_NUMBER);
}
}
fraction: /* LUA_NUMBER */
while (isdigit(LS->current))
save_and_next(L, LS);
if (LS->current == 'e' || LS->current == 'E') {
save_and_next(L, LS); /* read 'E' */
if (LS->current == '+' || LS->current == '-')
save_and_next(L, LS); /* optional exponent sign */
while (isdigit(LS->current))
save_and_next(L, LS);
}
save(L, '\0');
if (!luaO_str2d(L->Mbuffer+L->Mbuffbase, &LS->seminfo.r))
luaX_error(LS, "malformed number", TK_NUMBER);
return TK_NUMBER;
case EOZ:
if (LS->iflevel > 0)
luaX_error(LS, "input ends inside a $if", TK_EOS);
return TK_EOS;
case '_': goto tname;
default:
if (!isalpha(LS->current)) {
int c = LS->current;
if (iscntrl(c))
luaX_invalidchar(LS, c);
next(LS);
return c;
}
tname: { /* identifier or reserved word */
TString *ts;
luaL_resetbuffer(L);
do {
save_and_next(L, LS);
} while (isalnum(LS->current) || LS->current == '_');
save(L, '\0');
ts = luaS_new(L, L->Mbuffer+L->Mbuffbase);
if (ts->marked >= RESERVEDMARK) /* reserved word? */
return ts->marked-RESERVEDMARK+FIRST_RESERVED;
LS->seminfo.ts = ts;
return TK_NAME;
}
}
}
}