Re: dofile, loadfile, loadstring in a coroutine
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- Subject: Re: dofile, loadfile, loadstring in a coroutine
- From: lists@...
- Date: 2007年4月21日 21:40:51 -0400 (EDT)
First of all, thanks for the help (and the explanation of the
lua_yield/lua_pcall constraint... I think I might get it now)
On Apr 21, 2007, at 2:35 PM, Rici Lake wrote:
Perhaps you should try:
print ("f()", f, xpcall(f, debug.traceback))
f = loadstring("print('hello')")
print ("f()", f, xpcall(f, debug.traceback))
--> f() function: 0x1094250 true
i.e. no error, but no print('hello') either.
The only error I can think of is that 'print' isn't in the function
environment of the compiled chunk.
Shouldn't the xpcall return false and an error in this case?
I don't think you can resume the master state, although I could be wrong.
It works:
extern "C" {
#include "lua.h"
#include "lualib.h"
#include "lauxlib.h"
}
int main (int argc, char ** argv)
{
char * filename = "/test1.lua";
int result;
lua_State * L = luaL_newstate(); //lua_newstate(Lua :: alloc, 0);
if (L) {
luaL_openlibs(L);
// luaL_dofile(L, "/preload1.lua"); // *1*
if (luaL_loadfile (L, filename))
{
printf("luaL_loadfile error: %s", lua_tostring(L, -1));
printf("luaL_loadfile failed");
lua_pop(L, 1);
}
else
{
result = lua_resume(L, lua_gettop(L) - 1);
printf("lua_resume result %i\n", result);
}
} else {
printf("luaL_newstate failed\n");
}
return 0;
}
And if test1.lua contains this:
print("hello from test1.lua")
f = loadstring("print('hello from chunk')")
print ("f()", f, xpcall(f, debug.traceback)))
Then I correctly get:
hello from test1.lua
hello
f() function: 0x307730 true
lua_resume result 0
I isolated the offending element - it is a token filter applied to the
state before loading the file. If I remove the filter (*1* in the code
sample above), the function works as expected.
It looks like the line
loadstring("print('hello from chunk')")
is being trashed by the token FILTER, returning only <eof>. Is this
because I'm calling it by resuming a thread?
I'm using Lua 5.1.2, with the token filter patch applied and proxy.c
included.
Here is preload1.lua, based upon the example in the tokenf package:
print("hello from preload1.lua")
-- debug filter
local function IN(get,put)
put("IN init")
while true do
local line,token,value=get()
print(line,token,value)
put(line,token,value)
end
end
local function OUT(get,put)
put("OUT init")
while true do
local line,token,value=get()
print("",line,token,value)
put(line,token,value)
end
end
local function pipe(f,get,put)
put = put or coroutine.yield
local F=coroutine.wrap(f)
F(get,put)
return F
end
function FILTER(get,source) FILTER=pipe(OUT,pipe(IN,get)) end
And here is the output if line *1* is uncommented:
hello from preload1.lua
1 <name> print
1 <name> print
1 ( nil
1 ( nil
1 <string> hello from test1.lua
1 <string> hello from test1.lua
1 ) nil
1 ) nil
3 <name> f
3 <name> f
3 = nil
3 = nil
3 <name> loadstring
3 <name> loadstring
3 ( nil
3 ( nil
3 <string> print('hello from chunk')
3 <string> print('hello from chunk')
3 ) nil
3 ) nil
4 <name> print
4 <name> print
4 ( nil
4 ( nil
4 <string> f()
4 <string> f()
4 , nil
4 , nil
4 <name> f
4 <name> f
4 , nil
4 , nil
4 <name> xpcall
4 <name> xpcall
4 ( nil
4 ( nil
4 <name> f
4 <name> f
4 , nil
4 , nil
4 <name> debug
4 <name> debug
4 . nil
4 . nil
4 <name> traceback
4 <name> traceback
4 ) nil
4 ) nil
4 ) nil
4 ) nil
5 <eof> nil
5 <eof> nil
hello from test1.lua
0 <eof> nil
0 <eof> nil
0 <eof> nil
0 <eof> nil
f() function: 0x309410 true
lua_resume result 0
FWIW, I've included the patched llex.c at the end, in case there's
something there that might be the culprit.
llex.c:
/*
** $Id: llex.c,v 2.20 2006年03月09日 18:14:31 roberto Exp $
** Lexical Analyzer
** See Copyright Notice in lua.h
*/
#include <ctype.h>
#include <locale.h>
#include <string.h>
#define llex_c
#define LUA_CORE
#include "lua.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 */
const char *const luaX_tokens [] = {
"and", "break", "do", "else", "elseif",
"end", "false", "for", "function", "if",
"in", "local", "nil", "not", "or", "repeat",
"return", "then", "true", "until", "while",
"..", "...", "==", ">=", "<=", "~=",
"<number>", "<name>", "<string>", "<eof>",
NULL
};
#define save_and_next(ls) (save(ls, ls->current), next(ls))
static void save (LexState *ls, int c) {
Mbuffer *b = ls->buff;
if (b->n + 1 > b->buffsize) {
size_t newsize;
if (b->buffsize >= MAX_SIZET/2)
luaX_lexerror(ls, "lexical element too long", 0);
newsize = b->buffsize * 2;
luaZ_resizebuffer(ls->L, b, newsize);
}
b->buffer[b->n++] = cast(char, c);
}
void luaX_init (lua_State *L) {
int i;
for (i=0; i<NUM_RESERVED; i++) {
TString *ts = luaS_new(L, luaX_tokens[i]);
luaS_fix(ts); /* reserved words are never collected */
lua_assert(strlen(luaX_tokens[i])+1 <= TOKEN_LEN);
ts->tsv.reserved = cast_byte(i+1); /* reserved word */
}
}
#define MAXSRC 80
const char *luaX_token2str (LexState *ls, int token) {
if (token < FIRST_RESERVED) {
lua_assert(token == cast(unsigned char, token));
return (iscntrl(token)) ? luaO_pushfstring(ls->L, "char(%d)", token) :
luaO_pushfstring(ls->L, "%c", token);
}
else
return luaX_tokens[token-FIRST_RESERVED];
}
static const char *txtToken (LexState *ls, int token) {
switch (token) {
case TK_NAME:
case TK_STRING:
case TK_NUMBER:
save(ls, '0円');
return luaZ_buffer(ls->buff);
default:
return luaX_token2str(ls, token);
}
}
void luaX_lexerror (LexState *ls, const char *msg, int token) {
char buff[MAXSRC];
luaO_chunkid(buff, getstr(ls->source), MAXSRC);
msg = luaO_pushfstring(ls->L, "%s:%d: %s", buff, ls->linenumber, msg);
if (token)
luaO_pushfstring(ls->L, "%s near " LUA_QS, msg, txtToken(ls, token));
luaD_throw(ls->L, LUA_ERRSYNTAX);
}
void luaX_syntaxerror (LexState *ls, const char *msg) {
luaX_lexerror(ls, msg, ls->t.token);
}
TString *luaX_newstring (LexState *ls, const char *str, size_t l) {
lua_State *L = ls->L;
TString *ts = luaS_newlstr(L, str, l);
TValue *o = luaH_setstr(L, ls->fs->h, ts); /* entry for `str' */
if (ttisnil(o))
setbvalue(o, 1); /* make sure `str' will not be collected */
return ts;
}
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)
luaX_syntaxerror(ls, "chunk has too many lines");
}
static void setinput (lua_State *L, LexState *ls, ZIO *z, TString *source) {
ls->decpoint = '.';
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;
luaZ_resizebuffer(ls->L, ls->buff, LUA_MINBUFFER); /* initialize buffer */
next(ls); /* read first char */
}
/*
** =======================================================
** LEXICAL ANALYZER
** =======================================================
*/
static int check_next (LexState *ls, const char *set) {
if (!strchr(set, ls->current))
return 0;
save_and_next(ls);
return 1;
}
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;
}
static void trydecpoint (LexState *ls, SemInfo *seminfo) {
/* format error: try to update decimal point separator */
struct lconv *cv = localeconv();
char old = ls->decpoint;
ls->decpoint = (cv ? cv->decimal_point[0] : '.');
buffreplace(ls, old, ls->decpoint); /* try updated decimal separator */
if (!luaO_str2d(luaZ_buffer(ls->buff), &seminfo->r)) {
/* format error with correct decimal point: no more options */
buffreplace(ls, ls->decpoint, '.'); /* undo change (for error
message) */
luaX_lexerror(ls, "malformed number", TK_NUMBER);
}
}
/* LUA_NUMBER */
static void read_numeral (LexState *ls, SemInfo *seminfo) {
lua_assert(isdigit(ls->current));
do {
save_and_next(ls);
} while (isdigit(ls->current) || ls->current == '.');
if (check_next(ls, "Ee")) /* `E'? */
check_next(ls, "+-"); /* optional exponent sign */
while (isalnum(ls->current) || ls->current == '_')
save_and_next(ls);
save(ls, '0円');
buffreplace(ls, '.', ls->decpoint); /* follow locale for decimal point */
if (!luaO_str2d(luaZ_buffer(ls->buff), &seminfo->r)) /* format error? */
trydecpoint(ls, seminfo); /* try to update decimal point separator */
}
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 cont = 0;
(void)(cont); /* avoid warnings when `cont' is not used */
save_and_next(ls); /* skip 2nd `[' */
if (currIsNewline(ls)) /* string starts with a newline? */
inclinenumber(ls); /* skip it */
for (;;) {
switch (ls->current) {
case EOZ:
luaX_lexerror(ls, (seminfo) ? "unfinished long string" :
"unfinished long comment", TK_EOS);
break; /* to avoid warnings */
#if defined(LUA_COMPAT_LSTR)
case '[': {
if (skip_sep(ls) == sep) {
save_and_next(ls); /* skip 2nd `[' */
cont++;
#if LUA_COMPAT_LSTR == 1
if (sep == 0)
luaX_lexerror(ls, "nesting of [[...]] is deprecated", '[');
#endif
}
break;
}
#endif
case ']': {
if (skip_sep(ls) == sep) {
save_and_next(ls); /* skip 2nd `]' */
#if defined(LUA_COMPAT_LSTR) && LUA_COMPAT_LSTR == 2
cont--;
if (sep == 0 && cont >= 0) break;
#endif
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 read_string (LexState *ls, int del, SemInfo *seminfo) {
save_and_next(ls);
while (ls->current != del) {
switch (ls->current) {
case EOZ:
luaX_lexerror(ls, "unfinished string", TK_EOS);
continue; /* to avoid warnings */
case '\n':
case '\r':
luaX_lexerror(ls, "unfinished string", TK_STRING);
continue; /* to avoid warnings */
case '\\': {
int c;
next(ls); /* do not save the `\' */
switch (ls->current) {
case 'a': c = '\a'; break;
case 'b': c = '\b'; break;
case 'f': c = '\f'; break;
case 'n': c = '\n'; break;
case 'r': c = '\r'; break;
case 't': c = '\t'; break;
case 'v': c = '\v'; break;
case '\n': /* go through */
case '\r': save(ls, '\n'); inclinenumber(ls); continue;
case EOZ: continue; /* will raise an error next loop */
default: {
if (!isdigit(ls->current))
save_and_next(ls); /* handles \,円 \", \', and \? */
else { /* \xxx */
int i = 0;
c = 0;
do {
c = 10*c + (ls->current-'0');
next(ls);
} while (++i<3 && isdigit(ls->current));
if (c > UCHAR_MAX)
luaX_lexerror(ls, "escape sequence too large", TK_STRING);
save(ls, c);
}
continue;
}
}
save(ls, c);
next(ls);
continue;
}
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': {
inclinenumber(ls);
continue;
}
case '-': {
next(ls);
if (ls->current != '-') return '-';
/* else is a comment */
next(ls);
if (ls->current == '[') {
int sep = skip_sep(ls);
luaZ_resetbuffer(ls->buff); /* `skip_sep' may dirty the buffer */
if (sep >= 0) {
read_long_string(ls, NULL, sep); /* long comment */
luaZ_resetbuffer(ls->buff);
continue;
}
}
/* else short comment */
while (!currIsNewline(ls) && ls->current != EOZ)
next(ls);
continue;
}
case '[': {
int sep = skip_sep(ls);
if (sep >= 0) {
read_long_string(ls, seminfo, sep);
return TK_STRING;
}
else if (sep == -1) return '[';
else luaX_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 '"':
case '\'': {
read_string(ls, ls->current, seminfo);
return TK_STRING;
}
case '.': {
save_and_next(ls);
if (check_next(ls, ".")) {
if (check_next(ls, "."))
return TK_DOTS; /* ... */
else return TK_CONCAT; /* .. */
}
else if (!isdigit(ls->current)) return '.';
else {
read_numeral(ls, seminfo);
return TK_NUMBER;
}
}
case EOZ: {
return TK_EOS;
}
default: {
if (isspace(ls->current)) {
lua_assert(!currIsNewline(ls));
next(ls);
continue;
}
else if (isdigit(ls->current)) {
read_numeral(ls, seminfo);
return TK_NUMBER;
}
else if (isalpha(ls->current) || ls->current == '_') {
/* identifier or reserved word */
TString *ts;
do {
save_and_next(ls);
} while (isalnum(ls->current) || ls->current == '_');
ts = luaX_newstring(ls, luaZ_buffer(ls->buff),
luaZ_bufflen(ls->buff));
if (ts->tsv.reserved > 0) /* reserved word? */
return ts->tsv.reserved - 1 + FIRST_RESERVED;
else {
seminfo->ts = ts;
return TK_NAME;
}
}
else {
int c = ls->current;
next(ls);
return c; /* single-char tokens (+ - / ...) */
}
}
}
}
}
//#include "proxy.c"
/* TOKEN FILTERS: */
#define USE_TOKEN_FILTERS
#ifdef USE_TOKEN_FILTERS
#define FILTER "FILTER"
static int gettoken(lua_State *L)
{
LexState *ls=lua_touserdata(L,lua_upvalueindex(1));
SemInfo seminfo;
int c;
if (ls!=NULL && ls->fs==NULL) return0;
if (ls==NULL)
{
c=TK_EOS;
lua_pushinteger(L,0);
}
else
{
c=llex(ls,&seminfo);
lua_pushinteger(L,ls->linenumber);
}
if (c<FIRST_RESERVED)
{
char s=c;
lua_pushlstring(L,&s,1);
}
else
lua_pushstring(L,luaX_tokens[c-FIRST_RESERVED]);
if (c==TK_NAME || c==TK_STRING)
lua_pushlstring(L,getstr(seminfo.ts),seminfo.ts->tsv.len);
elseif (c==TK_NUMBER)
lua_pushnumber(L,seminfo.r);
else
lua_pushnil(L);
if (c==TK_EOS && ls!=NULL)
{
lua_pushnil(L);
lua_replace(L,lua_upvalueindex(1));
}
return3;
}
void luaX_setinput(lua_State *L, LexState *ls, ZIO *z, TString *source)
{
setinput(L,ls,z,source);
lua_getglobal(L,FILTER);
if (lua_isnil(L,-1))
lua_pop(L,1);
else
{
lua_pushlightuserdata(L,ls);
lua_pushcclosure(L,gettoken,1);
lua_pushlstring(L,getstr(source),source->tsv.len);
lua_call(L,2,0);
}
}
static int nexttoken(LexState *ls, SemInfo *seminfo)
{
lua_State *L=ls->L;
lua_getglobal(L,FILTER);
if (lua_isnil(L,-1))
{
lua_pop(L,1);
return llex(ls,seminfo);
}
else
{
int c;
const char *token;
lua_call(L,0,3);
token=lua_tostring(L,-2);
if (token==NULL)
c=TK_EOS;
else
{
int i;
c=-1;
for (i=0; luaX_tokens[i]; i++)
{
if (strcmp(token,luaX_tokens[i])==0)
{
c=i+FIRST_RESERVED;
break;
}
}
if (c==-1)
c=token[0];
elseif (c==TK_NAME || c==TK_STRING)
{
if (lua_tostring(L,-1)==NULL)
seminfo->ts=luaS_newliteral(L,"?");
else
seminfo->ts=luaS_newlstr(L,lua_tostring(L,-1),lua_strlen(L,-1));
}
elseif (c==TK_NUMBER)
seminfo->r=lua_tonumber(L,-1);
}
ls->linenumber=lua_tointeger(L,-3);
lua_pop(L,3);
return c;
}
}
#define llex nexttoken
#endif
/* TOKEN FILTERS END */
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 */
}
void luaX_lookahead (LexState *ls) {
lua_assert(ls->lookahead.token == TK_EOS);
ls->lookahead.token = llex(ls, &ls->lookahead.seminfo);
}