lua/lua.stx

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%{
/*
** $Id: $
** Syntax analizer and code generator
** See Copyright Notice in lua.h
*/
#include <stdlib.h>
#include "lauxlib.h"
#include "ldo.h"
#include "lfunc.h"
#include "lglobal.h"
#include "llex.h"
#include "lmem.h"
#include "lopcodes.h"
#include "lparser.h"
#include "lstring.h"
#include "lua.h"
#include "luadebug.h"
#include "lzio.h"
/* to avoid warnings generated by yacc */
int luaY_parse (void);
#define malloc luaM_malloc
#define realloc luaM_realloc
#define free luaM_free
/* maximum number of local variables */
#define MAXLOCALS 32
/* maximum number of variables in a multiple assignment */
#define MAXVAR 32
/* maximum number of nested functions */
#define MAXSTATES 6
/* maximum number of upvalues */
#define MAXUPVALUES 8
/*
** Variable descriptor: if n>0, represents global variable indexed
** by (n-1); if n<0, represents local variable index (-n)-1;
** if n==0, represents an indexed variable (table and index on top of stack)
** Must be long to store negative Word values.
*/
typedef long vardesc;
/* state needed to generate code for a given function */
static struct State {
TProtoFunc *f; /* current function header */
int pc; /* next position to code */
TaggedString *localvar[MAXLOCALS]; /* store local variable names */
int stacksize; /* number of values on activation register */
int maxstacksize; /* maximum number of values on activation register */
int nlocalvar; /* number of active local variables */
int nvars; /* number of entries in f->locvars */
int maxcode; /* size of f->code */
int maxvars; /* size of f->locvars (-1 if no debug information) */
int maxconsts; /* size of f->consts */
vardesc varbuffer[MAXVAR]; /* variables in an assignment list */
vardesc upvalues[MAXUPVALUES]; /* upvalues */
} *mainState, *currState;
void luaY_syntaxerror (char *s, char *token)
{
if (token[0] == 0)
token = "<eof>";
luaL_verror("%.100s;\n> last token read: \"%.50s\" at line %d in file %.50s",
s, token, luaX_linenumber, mainState->f->fileName->str);
}
void luaY_error (char *s)
{
luaY_syntaxerror(s, luaX_lasttoken());
}
static void code_byte (Byte c)
{
if (currState->pc >= currState->maxcode)
currState->maxcode = luaM_growvector(&currState->f->code,
currState->maxcode, Byte, codeEM, MAX_INT);
currState->f->code[currState->pc++] = c;
}
static void deltastack (int delta)
{
currState->stacksize += delta;
if (currState->stacksize > currState->maxstacksize) {
if (currState->stacksize > 255)
luaY_error("expression too complex");
currState->maxstacksize = currState->stacksize;
}
}
static void code_opcode (OpCode op, int delta)
{
code_byte(op);
deltastack(delta);
}
static void code_word_at (int pc, int n)
{
Word w = n;
if (w != n)
luaY_error("block too big");
currState->f->code[pc] = n&0xFF;
currState->f->code[pc+1] = n>>8;
}
static void code_word (int n)
{
code_byte(n&0xFF);
code_byte(n>>8);
}
static void code_constant (int c)
{
if (c <= 255) {
code_opcode(PUSHCONSTANTB, 1);
code_byte(c);
}
else {
code_opcode(PUSHCONSTANT, 1);
code_word(c);
}
}
static int next_constant (void)
{
TProtoFunc *f = currState->f;
if (f->nconsts >= currState->maxconsts) {
currState->maxconsts =
luaM_growvector(&f->consts, currState->maxconsts, TObject,
constantEM, MAX_WORD);
}
return f->nconsts++;
}
static int string_constant (TaggedString *s)
{
TProtoFunc *f = currState->f;
int c = s->u.s.constindex;
if (!(0 <= c && c < f->nconsts &&
ttype(&f->consts[c]) == LUA_T_STRING && tsvalue(&f->consts[c]) == s)) {
c = next_constant();
ttype(&f->consts[c]) = LUA_T_STRING;
tsvalue(&f->consts[c]) = s;
s->u.s.constindex = c; /* hint for next time */
}
return c;
}
static void code_string (TaggedString *s)
{
code_constant(string_constant(s));
}
#define LIM 13
static int real_constant (real r)
{
/* check whether 'r' has appeared within the last LIM entries */
TObject *cnt = currState->f->consts;
int c = currState->f->nconsts;
int lim = c < LIM ? 0 : c-LIM;
while (--c >= lim) {
if (ttype(&cnt[c]) == LUA_T_NUMBER && nvalue(&cnt[c]) == r)
return c;
}
/* not found; create a luaM_new entry */
c = next_constant();
cnt = currState->f->consts; /* 'next_constant' may reallocate this vector */
ttype(&cnt[c]) = LUA_T_NUMBER;
nvalue(&cnt[c]) = r;
return c;
}
static void code_number (real f)
{
Word i;
if (f >= 0 && f <= (real)MAX_WORD && (real)(i=(Word)f) == f) {
/* f has an (short) integer value */
if (i <= 2) code_opcode(PUSH0 + i, 1);
else if (i <= 255) {
code_opcode(PUSHBYTE, 1);
code_byte(i);
}
else {
code_opcode(PUSHWORD, 1);
code_word(i);
}
}
else
code_constant(real_constant(f));
}
static void flush_record (int n)
{
if (n == 0) return;
code_opcode(SETMAP, -2*n);
code_byte(n);
}
static void flush_list (int m, int n)
{
if (n == 0) return;
if (m == 0)
code_opcode(SETLIST0, -n);
else if (m < 255) {
code_opcode(SETLIST, -n);
code_byte(m);
}
else
luaY_error("list constructor too long");
code_byte(n);
}
static void luaI_registerlocalvar (TaggedString *varname, int line)
{
if (currState->maxvars != -1) { /* debug information? */
if (currState->nvars >= currState->maxvars)
currState->maxvars = luaM_growvector(&currState->f->locvars,
currState->maxvars, LocVar, "", MAX_WORD);
currState->f->locvars[currState->nvars].varname = varname;
currState->f->locvars[currState->nvars].line = line;
currState->nvars++;
}
}
static void luaI_unregisterlocalvar (int line)
{
luaI_registerlocalvar(NULL, line);
}
static void store_localvar (TaggedString *name, int n)
{
if (currState->nlocalvar+n < MAXLOCALS)
currState->localvar[currState->nlocalvar+n] = name;
else
luaY_error("too many local variables");
luaI_registerlocalvar(name, luaX_linenumber);
}
static void add_localvar (TaggedString *name)
{
store_localvar(name, 0);
currState->nlocalvar++;
}
static void add_varbuffer (vardesc var, int n)
{
if (n >= MAXVAR)
luaY_error("variable buffer overflow");
currState->varbuffer[n] = var;
}
static int aux_localname (TaggedString *n, struct State *st)
{
int i;
for (i=st->nlocalvar-1; i >= 0; i--)
if (n == st->localvar[i]) return i; /* local var index */
return -1; /* not found */
}
static vardesc singlevar (TaggedString *n, struct State *st)
{
int i = aux_localname(n, st);
if (i == -1) { /* check shadowing */
int l;
for (l=1; l<=(st-mainState); l++)
if (aux_localname(n, st-l) >= 0)
luaY_syntaxerror("cannot access a variable in outer scope", n->str);
return luaG_findsymbol(n)+1; /* positive value */
}
else return -(i+1); /* negative value */
}
static int indexupvalue (TaggedString *n)
{
vardesc v = singlevar(n, currState-1);
int i;
for (i=0; i<currState->f->nupvalues; i++) {
if (currState->upvalues[i] == v)
return i;
}
/* new one */
if (++currState->f->nupvalues > MAXUPVALUES)
luaY_error("too many upvalues in a single function");
currState->upvalues[i] = v; /* i = currState->f->nupvalues - 1 */
return i;
}
static void pushupvalue (TaggedString *n)
{
int i;
if (currState == mainState)
luaY_error("cannot access upvalue in main");
if (aux_localname(n, currState) >= 0)
luaY_syntaxerror("cannot access an upvalue in current scope", n->str);
i = indexupvalue(n);
if (i == 0)
code_opcode(PUSHUPVALUE0, 1);
else {
code_opcode(PUSHUPVALUE, 1);
code_byte(i);
}
}
void luaY_codedebugline (int line)
{
static int lastline = 0;
if (lua_debug && line != lastline) {
code_opcode(SETLINE, 0);
code_word(line);
lastline = line;
}
}
static void adjuststack (int n)
{
if (n > 0) {
code_opcode(POPS, -n);
code_byte(n);
}
else if (n < 0) {
if (n == -1)
code_opcode(PUSHNIL, 1);
else {
code_opcode(PUSHNILS, -n);
code_byte(-n);
}
}
}
static long adjust_functioncall (long exp, int i)
{
if (exp <= 0)
return -exp; /* exp is -list length */
else {
int temp = currState->f->code[exp];
currState->f->code[exp] = i;
if (i != MULT_RET)
deltastack(i);
return temp+i;
}
}
static void adjust_mult_assign (int vars, long exps)
{
if (exps > 0) { /* must correct function call */
int diff = currState->f->code[exps] - vars;
if (diff < 0)
adjust_functioncall(exps, -diff);
else {
adjust_functioncall(exps, 0);
adjuststack(diff);
}
}
else adjuststack((-exps)-vars);
}
static void code_args (int dots)
{
if (!dots) {
code_opcode(ARGS, currState->nlocalvar);
code_byte(currState->nlocalvar);
}
else {
code_opcode(VARARGS, currState->nlocalvar+1);
code_byte(currState->nlocalvar);
add_localvar(luaS_new("arg"));
}
}
static void lua_pushvar (vardesc number)
{
if (number > 0) { /* global var */
code_opcode(PUSHGLOBAL, 1);
code_word(number-1);
}
else if (number < 0) { /* local var */
number = (-number) - 1;
if (number < 10)
code_opcode(PUSHLOCAL0 + number, 1);
else {
code_opcode(PUSHLOCAL, 1);
code_byte(number);
}
}
else {
code_opcode(PUSHTABLE, -1);
}
}
static void storevar (vardesc number)
{
if (number == 0) /* indexed var */
code_opcode(SETTABLE0, -3);
else if (number > 0) { /* global var */
code_opcode(SETGLOBAL, -1);
code_word(number-1);
}
else { /* number < 0 - local var */
number = (-number) - 1;
if (number < 10)
code_opcode(SETLOCAL0 + number, -1);
else {
code_opcode(SETLOCAL, -1);
code_byte(number);
}
}
}
/* returns how many elements are left as 'garbage' on the stack */
static int lua_codestore (int i, int left)
{
if (currState->varbuffer[i] != 0 || /* global or local var or */
left+i == 0) { /* indexed var without values in between */
storevar(currState->varbuffer[i]);
return left;
}
else { /* indexed var with values in between*/
code_opcode(SETTABLE, -1);
code_byte(left+i); /* number of elements between table/index and value */
return left+2; /* table/index are not poped, since they are not on top */
}
}
static void codeIf (int thenAdd, int elseAdd)
{
int elseinit = elseAdd+sizeof(Word)+1;
if (currState->pc == elseinit) { /* no else part */
currState->pc -= sizeof(Word)+1;
elseinit = currState->pc;
}
else {
currState->f->code[elseAdd] = JMP;
code_word_at(elseAdd+1, currState->pc-elseinit);
}
currState->f->code[thenAdd] = IFFJMP;
code_word_at(thenAdd+1, elseinit-(thenAdd+sizeof(Word)+1));
}
static void code_shortcircuit (int pc, Byte jmp)
{
currState->f->code[pc] = jmp;
code_word_at(pc+1, currState->pc - (pc + sizeof(Word)+1));
}
static void codereturn (void)
{
code_opcode(RETCODE, 0);
code_byte(currState->nlocalvar);
currState->stacksize = currState->nlocalvar;
}
static void func_onstack (TProtoFunc *f)
{
int i;
int nupvalues = (currState+1)->f->nupvalues;
int c = next_constant();
ttype(&currState->f->consts[c]) = LUA_T_PROTO;
currState->f->consts[c].value.tf = (currState+1)->f;
for (i=0; i<nupvalues; i++)
lua_pushvar((currState+1)->upvalues[i]);
code_constant(c);
code_opcode(CLOSURE, -nupvalues);
}
static void init_state (TaggedString *filename)
{
TProtoFunc *f = luaF_newproto();
currState->stacksize = 0;
currState->maxstacksize = 0;
currState->nlocalvar = 0;
currState->f = f;
f->fileName = filename;
currState->pc = 0;
currState->maxcode = 0;
f->code = NULL;
currState->maxconsts = 0;
if (lua_debug) {
currState->nvars = 0;
currState->maxvars = 0;
}
else
currState->maxvars = -1; /* flag no debug information */
code_byte(0); /* to be filled with stacksize */
}
static void init_func (void)
{
if (currState-mainState >= MAXSTATES-1)
luaY_error("too many nested functions");
currState++;
init_state(mainState->f->fileName);
luaY_codedebugline(luaX_linenumber);
currState->f->lineDefined = luaX_linenumber;
}
static TProtoFunc *close_func (void)
{
TProtoFunc *f = currState->f;
code_opcode(ENDCODE, 0);
f->code[0] = currState->maxstacksize;
f->code = luaM_reallocvector(f->code, currState->pc, Byte);
f->consts = luaM_reallocvector(f->consts, f->nconsts, TObject);
if (currState->maxvars != -1) { /* debug information? */
luaI_registerlocalvar(NULL, -1); /* flag end of vector */
f->locvars = luaM_reallocvector(f->locvars, currState->nvars, LocVar);
}
currState--;
return f;
}
/*
** Parse LUA code.
*/
TProtoFunc *luaY_parser (ZIO *z, char *chunkname)
{
struct State state[MAXSTATES];
currState = mainState = &state[0];
luaX_setinput(z);
init_state(luaS_new(chunkname));
if (luaY_parse ()) lua_error("parse error");
return close_func();
}
%}
%union
{
int vInt;
real vReal;
char *pChar;
long vLong;
TaggedString *pTStr;
TProtoFunc *pFunc;
}
%start chunk
%token WRONGTOKEN
%token NIL
%token IF THEN ELSE ELSEIF WHILE DO REPEAT UNTIL END
%token RETURN
%token LOCAL
%token FUNCTION
%token DOTS
%token <vReal> NUMBER
%token <pTStr> NAME STRING
%type <vInt> PrepJump, PrepJumpPop
%type <vLong> exprlist, exprlist1 /* if > 0, points to function return
counter (which has list length); if <= 0, -list lenght */
%type <vLong> functioncall, expr /* if != 0, points to function return
counter */
%type <vInt> varlist1, funcParams, funcvalue
%type <vInt> fieldlist, localdeclist, decinit
%type <vInt> ffieldlist, ffieldlist1, semicolonpart
%type <vInt> lfieldlist, lfieldlist1
%type <vInt> parlist1, par
%type <vLong> var, singlevar, funcname /* vardesc */
%type <pFunc> body
%left AND OR
%left EQ NE '>' '<' LE GE
%left CONC
%left '+' '-'
%left '*' '/'
%left UNARY NOT
%right '^'
%% /* beginning of rules section */
chunk : statlist ret
;
statlist : /* empty */
| statlist stat sc { if (currState->stacksize != currState->nlocalvar)
{ luaY_error("contagem"); exit(1); }}
;
sc : /* empty */ | ';' ;
stat : IF expr1 THEN PrepJumpPop block PrepJump elsepart END
{ codeIf($4, $6); }
| WHILE {$<vInt>$=currState->pc;} expr1 DO PrepJumpPop block PrepJump END
{
currState->f->code[$5] = IFFJMP;
code_word_at($5+1, currState->pc - ($5+sizeof(Word)+1));
currState->f->code[$7] = UPJMP;
code_word_at($7+1, currState->pc - ($<vInt>2));
}
| REPEAT {$<vInt>$=currState->pc;} block UNTIL expr1 PrepJumpPop
{
currState->f->code[$6] = IFFUPJMP;
code_word_at($6+1, currState->pc - ($<vInt>2));
}
| varlist1 '=' exprlist1
{{
int i;
int left = 0;
adjust_mult_assign($1, $3);
for (i=$1-1; i>=0; i--)
left = lua_codestore(i, left);
adjuststack(left); /* remove eventual 'garbage' left on stack */
}}
| functioncall
| LOCAL localdeclist decinit
{
currState->nlocalvar += $2;
adjust_mult_assign($2, $3);
}
| FUNCTION funcname body
{
func_onstack($3);
storevar($2);
}
;
block : {$<vInt>$ = currState->nlocalvar;} chunk
{
adjuststack(currState->nlocalvar - $<vInt>1);
for (; currState->nlocalvar > $<vInt>1; currState->nlocalvar--)
luaI_unregisterlocalvar(luaX_linenumber);
}
;
funcname : var { init_func(); $$ = $1; }
| varexp ':' NAME
{
code_string($3);
$$ = 0; /* indexed variable */
init_func();
add_localvar(luaS_new("self"));
}
;
body : '(' parlist ')' chunk END { $$ = close_func(); }
;
elsepart : /* empty */
| ELSE block
| ELSEIF expr1 THEN PrepJumpPop block PrepJump elsepart
{ codeIf($4, $6); }
;
ret : /* empty */
| RETURN exprlist sc
{
adjust_functioncall($2, MULT_RET);
codereturn();
}
;
PrepJump : /* empty */
{
$$ = currState->pc;
code_opcode(0, 0); /* open space */
code_word(0);
}
;
PrepJumpPop : PrepJump { $$ = $1; deltastack(-1); /* pop condition */ }
;
expr1 : expr { adjust_functioncall($1, 1); }
;
expr : '(' expr ')' { $$ = $2; }
| expr1 EQ expr1 { code_opcode(EQOP, -1); $$ = 0; }
| expr1 '<' expr1 { code_opcode(LTOP, -1); $$ = 0; }
| expr1 '>' expr1 { code_opcode(GTOP, -1); $$ = 0; }
| expr1 NE expr1 { code_opcode(NEQOP, -1); $$ = 0; }
| expr1 LE expr1 { code_opcode(LEOP, -1); $$ = 0; }
| expr1 GE expr1 { code_opcode(GEOP, -1); $$ = 0; }
| expr1 '+' expr1 { code_opcode(ADDOP, -1); $$ = 0; }
| expr1 '-' expr1 { code_opcode(SUBOP, -1); $$ = 0; }
| expr1 '*' expr1 { code_opcode(MULTOP, -1); $$ = 0; }
| expr1 '/' expr1 { code_opcode(DIVOP, -1); $$ = 0; }
| expr1 '^' expr1 { code_opcode(POWOP, -1); $$ = 0; }
| expr1 CONC expr1 { code_opcode(CONCOP, -1); $$ = 0; }
| '-' expr1 %prec UNARY { code_opcode(MINUSOP, 0); $$ = 0;}
| table { $$ = 0; }
| varexp { $$ = 0;}
| NUMBER { code_number($1); $$ = 0; }
| STRING
{
code_string($1);
$$ = 0;
}
| NIL {code_opcode(PUSHNIL, 1); $$ = 0; }
| functioncall { $$ = $1; }
| NOT expr1 { code_opcode(NOTOP, 0); $$ = 0;}
| expr1 AND PrepJumpPop expr1
{
code_shortcircuit($3, ONFJMP);
$$ = 0;
}
| expr1 OR PrepJumpPop expr1
{
code_shortcircuit($3, ONTJMP);
$$ = 0;
}
| FUNCTION { init_func(); } body { func_onstack($3); $$ = 0; }
;
table :
{
code_opcode(CREATEARRAY, 1);
$<vInt>$ = currState->pc; code_word(0);
}
'{' fieldlist '}'
{
code_word_at($<vInt>1, $3);
}
;
functioncall : funcvalue funcParams
{
code_opcode(CALLFUNC, -($1+$2+1)); /* ajdust counts results */
code_byte($1+$2);
$$ = currState->pc;
code_byte(0); /* may be adjusted by other rules */
}
;
funcvalue : varexp { $$ = 0; }
| varexp ':' NAME
{
code_opcode(PUSHSELF, 1);
code_word(string_constant($3));
$$ = 1;
}
;
funcParams : '(' exprlist ')'
{ $$ = adjust_functioncall($2, 1); }
| table { $$ = 1; }
;
exprlist : /* empty */ { $$ = 0; }
| exprlist1 { $$ = $1; }
;
exprlist1 : expr { if ($1 != 0) $$ = $1; else $$ = -1; }
| exprlist1 ',' { $<vLong>$ = adjust_functioncall($1, 1); } expr
{
if ($4 == 0) $$ = -($<vLong>3 + 1); /* -length */
else
{
currState->f->code[$4] = $<vLong>3; /* store list length */
$$ = $4;
}
}
;
parlist : /* empty */ { code_args(0); }
| parlist1 { code_args($1); }
;
parlist1 : par { $$ = $1; }
| parlist1 ',' par
{
if ($1)
luaY_error("invalid parameter list");
$$ = $3;
}
;
par : NAME { add_localvar($1); $$ = 0; }
| DOTS { $$ = 1; }
;
fieldlist : lfieldlist
{ flush_list($1/LFIELDS_PER_FLUSH, $1%LFIELDS_PER_FLUSH); }
semicolonpart
{ $$ = $1+$3; }
| ffieldlist1 lastcomma
{ $$ = $1; flush_record($1%RFIELDS_PER_FLUSH); }
;
semicolonpart : /* empty */
{ $$ = 0; }
| ';' ffieldlist
{ $$ = $2; flush_record($2%RFIELDS_PER_FLUSH); }
;
lastcomma : /* empty */
| ','
;
ffieldlist : /* empty */ { $$ = 0; }
| ffieldlist1 lastcomma { $$ = $1; }
;
ffieldlist1 : ffield {$$=1;}
| ffieldlist1 ',' ffield
{
$$=$1+1;
if ($$%RFIELDS_PER_FLUSH == 0)
flush_record(RFIELDS_PER_FLUSH);
}
;
ffield : ffieldkey '=' expr1
;
ffieldkey : '[' expr1 ']'
| NAME { code_string($1); }
;
lfieldlist : /* empty */ { $$ = 0; }
| lfieldlist1 lastcomma { $$ = $1; }
;
lfieldlist1 : expr1 {$$=1;}
| lfieldlist1 ',' expr1
{
$$=$1+1;
if ($$%LFIELDS_PER_FLUSH == 0)
flush_list($$/LFIELDS_PER_FLUSH - 1, LFIELDS_PER_FLUSH);
}
;
varlist1 : var
{
$$ = 1;
add_varbuffer($1, 0);
}
| varlist1 ',' var
{
add_varbuffer($3, $1);
$$ = $1+1;
}
;
var : singlevar { $$ = $1; }
| varexp '[' expr1 ']'
{
$$ = 0; /* indexed variable */
}
| varexp '.' NAME
{
code_string($3);
$$ = 0; /* indexed variable */
}
;
singlevar : NAME { $$ = singlevar($1, currState); }
;
varexp : var { lua_pushvar($1); }
| '%' NAME { pushupvalue($2); }
;
localdeclist : NAME {store_localvar($1, 0); $$ = 1;}
| localdeclist ',' NAME
{
store_localvar($3, $1);
$$ = $1+1;
}
;
decinit : /* empty */ { $$ = 0; }
| '=' exprlist1 { $$ = $2; }
;
%%