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new semantics for "for" local variables

This commit is contained in:
Roberto Ierusalimschy 2003-05-13 17:15:59 -03:00
parent c767747191
commit 6d268b0b00
5 changed files with 61 additions and 52 deletions
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5
ldebug.c
View File

@ -1,5 +1,5 @@
/*
** $Id: ldebug.c,v 1.150 2003/03/19 21:24:04 roberto Exp roberto $
** $Id: ldebug.c,v 1.151 2003/04/28 13:31:06 roberto Exp roberto $
** Debug Interface
** See Copyright Notice in lua.h
*/
@ -374,10 +374,11 @@ static Instruction luaG_symbexec (const Proto *pt, int lastpc, int reg) {
break;
}
case OP_TFORLOOP:
checkreg(pt, a+c+5);
checkreg(pt, a+5);
if (reg >= a) last = pc; /* affect all registers above base */
/* go through */
case OP_FORLOOP:
case OP_FORPREP:
checkreg(pt, a+2);
/* go through */
case OP_JMP: {

4
lopcodes.c
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@ -1,5 +1,5 @@
/*
** $Id: lopcodes.c,v 1.21 2002/08/20 20:03:05 roberto Exp roberto $
** $Id: lopcodes.c,v 1.22 2002/12/04 17:38:31 roberto Exp roberto $
** extracted automatically from lopcodes.h by mkprint.lua
** DO NOT EDIT
** See Copyright Notice in lua.h
@ -46,6 +46,7 @@ const char *const luaP_opnames[] = {
"TAILCALL",
"RETURN",
"FORLOOP",
"FORPREP",
"TFORLOOP",
"TFORPREP",
"SETLIST",
@ -92,6 +93,7 @@ const lu_byte luaP_opmodes[NUM_OPCODES] = {
,opmode(0, 0, 0, 0, 0, 0, iABC) /* OP_TAILCALL */
,opmode(0, 0, 0, 0, 0, 0, iABC) /* OP_RETURN */
,opmode(0, 0, 0, 0, 0, 0, iAsBx) /* OP_FORLOOP */
,opmode(0, 0, 0, 0, 0, 0, iAsBx) /* OP_FORPREP */
,opmode(1, 0, 0, 0, 0, 0, iABC) /* OP_TFORLOOP */
,opmode(0, 0, 0, 0, 0, 0, iAsBx) /* OP_TFORPREP */
,opmode(0, 0, 0, 0, 0, 0, iABx) /* OP_SETLIST */

4
lopcodes.h
View File

@ -1,5 +1,5 @@
/*
** $Id: lopcodes.h,v 1.101 2002/08/20 20:03:05 roberto Exp roberto $
** $Id: lopcodes.h,v 1.102 2002/08/21 18:56:09 roberto Exp roberto $
** Opcodes for Lua virtual machine
** See Copyright Notice in lua.h
*/
@ -172,6 +172,7 @@ OP_TAILCALL,/* A B C return R(A)(R(A+1), ... ,R(A+B-1)) */
OP_RETURN,/* A B return R(A), ... ,R(A+B-2) (see note) */
OP_FORLOOP,/* A sBx R(A)+=R(A+2); if R(A) <?= R(A+1) then PC+= sBx */
OP_FORPREP,/* A sBx R(A)-=R(A+2); PC += sBx */
OP_TFORLOOP,/* A C R(A+2), ... ,R(A+2+C) := R(A)(R(A+1), R(A+2));
if R(A+2) ~= nil then pc++ */
@ -214,7 +215,6 @@ enum OpModeMask {
OpModesetA, /* instruction set register A */
OpModeK, /* Bx is a constant */
OpModeT /* operator is a test */
};

44
lparser.c
View File

@ -1,5 +1,5 @@
/*
** $Id: lparser.c,v 1.207 2003/02/28 17:19:47 roberto Exp roberto $
** $Id: lparser.c,v 1.208 2003/04/03 13:35:34 roberto Exp roberto $
** Lua Parser
** See Copyright Notice in lua.h
*/
@ -1027,30 +1027,34 @@ static int exp1 (LexState *ls) {
static void forbody (LexState *ls, int base, int line, int nvars, int isnum) {
/* forbody -> DO block */
BlockCnt bl;
FuncState *fs = ls->fs;
int prep, endfor;
adjustlocalvars(ls, nvars); /* scope for all variables */
adjustlocalvars(ls, 3); /* control variables */
check(ls, TK_DO);
enterblock(fs, &bl, 1); /* loop block */
prep = luaK_getlabel(fs);
prep = luaK_codeAsBx(fs, (isnum ? OP_FORPREP : OP_TFORPREP), base, NO_JUMP);
enterblock(fs, &bl, 0); /* scope for declared variables */
adjustlocalvars(ls, nvars);
luaK_reserveregs(fs, nvars);
block(ls);
luaK_patchtohere(fs, prep-1);
leaveblock(fs); /* end of scope for declared variables */
luaK_patchtohere(fs, prep);
endfor = (isnum) ? luaK_codeAsBx(fs, OP_FORLOOP, base, NO_JUMP) :
luaK_codeABC(fs, OP_TFORLOOP, base, 0, nvars - 3);
luaK_codeABC(fs, OP_TFORLOOP, base, 0, nvars);
luaK_fixline(fs, line); /* pretend that `OP_FOR' starts the loop */
luaK_patchlist(fs, (isnum) ? endfor : luaK_jump(fs), prep);
leaveblock(fs);
luaK_patchlist(fs, (isnum ? endfor : luaK_jump(fs)), prep + 1);
}
static void fornum (LexState *ls, TString *varname, int line) {
/* fornum -> NAME = exp1,exp1[,exp1] DO body */
/* fornum -> NAME = exp1,exp1[,exp1] forbody */
FuncState *fs = ls->fs;
int base = fs->freereg;
new_localvar(ls, varname, 0);
new_localvarstr(ls, "(for index)", 0);
new_localvarstr(ls, "(for limit)", 1);
new_localvarstr(ls, "(for step)", 2);
new_localvar(ls, varname, 3);
check(ls, '=');
exp1(ls); /* initial value */
check(ls, ',');
@ -1061,39 +1065,39 @@ static void fornum (LexState *ls, TString *varname, int line) {
luaK_codeABx(fs, OP_LOADK, fs->freereg, luaK_numberK(fs, 1));
luaK_reserveregs(fs, 1);
}
luaK_codeABC(fs, OP_SUB, fs->freereg - 3, fs->freereg - 3, fs->freereg - 1);
luaK_jump(fs);
forbody(ls, base, line, 3, 1);
forbody(ls, base, line, 1, 1);
}
static void forlist (LexState *ls, TString *indexname) {
/* forlist -> NAME {,NAME} IN explist1 DO body */
/* forlist -> NAME {,NAME} IN explist1 forbody */
FuncState *fs = ls->fs;
expdesc e;
int nvars = 0;
int line;
int base = fs->freereg;
/* create control variables */
new_localvarstr(ls, "(for generator)", nvars++);
new_localvarstr(ls, "(for state)", nvars++);
new_localvarstr(ls, "(for control)", nvars++);
/* create declared variables */
new_localvar(ls, indexname, nvars++);
while (testnext(ls, ','))
new_localvar(ls, str_checkname(ls), nvars++);
check(ls, TK_IN);
line = ls->linenumber;
adjust_assign(ls, nvars, explist1(ls, &e), &e);
adjust_assign(ls, 3, explist1(ls, &e), &e);
luaK_checkstack(fs, 3); /* extra space to call generator */
luaK_codeAsBx(fs, OP_TFORPREP, base, NO_JUMP);
forbody(ls, base, line, nvars, 0);
forbody(ls, base, line, nvars - 3, 0);
}
static void forstat (LexState *ls, int line) {
/* forstat -> fornum | forlist */
/* forstat -> FOR (fornum | forlist) END */
FuncState *fs = ls->fs;
TString *varname;
BlockCnt bl;
enterblock(fs, &bl, 0); /* block to control variable scope */
enterblock(fs, &bl, 1); /* scope for loop and control variables */
next(ls); /* skip `for' */
varname = str_checkname(ls); /* first variable name */
switch (ls->t.token) {
@ -1102,7 +1106,7 @@ static void forstat (LexState *ls, int line) {
default: luaX_syntaxerror(ls, "`=' or `in' expected");
}
check_match(ls, TK_END, TK_FOR, line);
leaveblock(fs);
leaveblock(fs); /* loop scope (`break' jumps to this point) */
}

56
lvm.c
View File

@ -1,5 +1,5 @@
/*
** $Id: lvm.c,v 1.284 2003/04/03 13:35:34 roberto Exp roberto $
** $Id: lvm.c,v 1.285 2003/05/05 18:39:57 roberto Exp roberto $
** Lua virtual machine
** See Copyright Notice in lua.h
*/
@ -639,43 +639,45 @@ StkId luaV_execute (lua_State *L) {
}
}
case OP_FORLOOP: {
lua_Number step, idx, limit;
const TObject *plimit = ra+1;
const TObject *pstep = ra+2;
if (!ttisnumber(ra))
luaG_runerror(L, "`for' initial value must be a number");
if (!tonumber(plimit, ra+1))
luaG_runerror(L, "`for' limit must be a number");
if (!tonumber(pstep, ra+2))
luaG_runerror(L, "`for' step must be a number");
step = nvalue(pstep);
idx = nvalue(ra) + step; /* increment index */
limit = nvalue(plimit);
lua_Number step = nvalue(ra+2);
lua_Number idx = nvalue(ra) + step; /* increment index */
lua_Number limit = nvalue(ra+1);
if (step > 0 ? idx <= limit : idx >= limit) {
dojump(pc, GETARG_sBx(i)); /* jump back */
chgnvalue(ra, idx); /* update index */
setnvalue(ra, idx); /* update internal index... */
setnvalue(ra+3, idx); /* ...and external index */
}
break;
}
case OP_FORPREP: {
const TObject *init = ra;
const TObject *plimit = ra+1;
const TObject *pstep = ra+2;
if (!tonumber(init, ra))
luaG_runerror(L, "`for' initial value must be a number");
else if (!tonumber(plimit, ra+1))
luaG_runerror(L, "`for' limit must be a number");
else if (!tonumber(pstep, ra+2))
luaG_runerror(L, "`for' step must be a number");
setnvalue(ra, nvalue(ra) - nvalue(pstep));
dojump(pc, GETARG_sBx(i));
break;
}
case OP_TFORLOOP: {
int nvar = GETARG_C(i) + 1;
StkId cb = ra + nvar + 2; /* call base */
setobjs2s(cb, ra);
setobjs2s(cb+1, ra+1);
StkId cb = ra + 3; /* call base */
setobjs2s(cb+2, ra+2);
setobjs2s(cb+1, ra+1);
setobjs2s(cb, ra);
L->top = cb+3; /* func. + 2 args (state and index) */
luaD_call(L, cb, nvar);
luaD_call(L, cb, GETARG_C(i));
L->top = L->ci->top;
ra = XRA(i) + 2; /* final position of first result */
cb = ra + nvar;
do { /* move results to proper positions */
nvar--;
setobjs2s(ra+nvar, cb+nvar);
} while (nvar > 0);
if (ttisnil(ra)) /* break loop? */
cb = XRA(i) + 3; /* previous call may change the stack */
if (ttisnil(cb)) /* break loop? */
pc++; /* skip jump (break loop) */
else
else {
setobjs2s(cb-1, cb); /* save control variable */
dojump(pc, GETARG_sBx(*pc) + 1); /* jump back */
}
break;
}
case OP_TFORPREP: { /* for compatibility only */