opensources
/
lua
mirror of https://github.com/lua/lua.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity
Browse Source

new semantics for "for" local variables

v5-2
Roberto Ierusalimschy 22 years ago
parent
c767747191
commit
6d268b0b00
5 changed files with 59 additions and 50 deletions
Whitespace
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
Split View
Diff Options
Show Stats Download Patch File Download Diff File
  1. 5
      ldebug.c
  2. 4
      lopcodes.c
  3. 4
      lopcodes.h
  4. 44
      lparser.c
  5. 52
      lvm.c

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
View File

@ -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) */
}

52
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;
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 */
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 (!ttisnumber(ra))
if (!tonumber(init, ra))
luaG_runerror(L, "`for' initial value must be a number");
if (!tonumber(plimit, ra+1))
else if (!tonumber(plimit, ra+1))
luaG_runerror(L, "`for' limit must be a number");
if (!tonumber(pstep, ra+2))
else 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);
if (step > 0 ? idx <= limit : idx >= limit) {
dojump(pc, GETARG_sBx(i)); /* jump back */
chgnvalue(ra, idx); /* update index */
}
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 */

Write Preview
Loading…
Cancel
Save