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First implementation of global declarations

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This commit is contained in:
Roberto Ierusalimschy
2025-05-05 16:24:59 -03:00
parent e055905914
commit be81209063
10 changed files with 272 additions and 117 deletions
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111
lparser.c
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@@ -30,8 +30,8 @@
/* maximum number of local variables per function (must be smaller
than 250, due to the bytecode format) */
/* maximum number of variable declarationss per function (must be
smaller than 250, due to the bytecode format) */
#define MAXVARS 200
@@ -54,6 +54,7 @@ typedef struct BlockCnt {
lu_byte upval; /* true if some variable in the block is an upvalue */
lu_byte isloop; /* 1 if 'block' is a loop; 2 if it has pending breaks */
lu_byte insidetbc; /* true if inside the scope of a to-be-closed var. */
lu_byte globdec; /* true if inside the scope of any global declaration */
} BlockCnt;
@@ -188,10 +189,10 @@ static short registerlocalvar (LexState *ls, FuncState *fs,
/*
** Create a new local variable with the given 'name' and given 'kind'.
** Create a new variable with the given 'name' and given 'kind'.
** Return its index in the function.
*/
static int new_localvarkind (LexState *ls, TString *name, lu_byte kind) {
static int new_varkind (LexState *ls, TString *name, lu_byte kind) {
lua_State *L = ls->L;
FuncState *fs = ls->fs;
Dyndata *dyd = ls->dyd;
@@ -211,7 +212,7 @@ static int new_localvarkind (LexState *ls, TString *name, lu_byte kind) {
** Create a new local variable with the given 'name' and regular kind.
*/
static int new_localvar (LexState *ls, TString *name) {
return new_localvarkind(ls, name, VDKREG);
return new_varkind(ls, name, VDKREG);
}
#define new_localvarliteral(ls,v) \
@@ -238,7 +239,7 @@ static Vardesc *getlocalvardesc (FuncState *fs, int vidx) {
static lu_byte reglevel (FuncState *fs, int nvar) {
while (nvar-- > 0) {
Vardesc *vd = getlocalvardesc(fs, nvar); /* get previous variable */
if (vd->vd.kind != RDKCTC) /* is in a register? */
if (varinreg(vd)) /* is in a register? */
return cast_byte(vd->vd.ridx + 1);
}
return 0; /* no variables in registers */
@@ -259,7 +260,7 @@ lu_byte luaY_nvarstack (FuncState *fs) {
*/
static LocVar *localdebuginfo (FuncState *fs, int vidx) {
Vardesc *vd = getlocalvardesc(fs, vidx);
if (vd->vd.kind == RDKCTC)
if (!varinreg(vd))
return NULL; /* no debug info. for constants */
else {
int idx = vd->vd.pidx;
@@ -401,7 +402,9 @@ static int searchvar (FuncState *fs, TString *n, expdesc *var) {
if (eqstr(n, vd->vd.name)) { /* found? */
if (vd->vd.kind == RDKCTC) /* compile-time constant? */
init_exp(var, VCONST, fs->firstlocal + i);
else /* real variable */
else if (vd->vd.kind == GDKREG || vd->vd.kind == GDKCONST)
init_exp(var, VGLOBAL, i);
else /* local variable */
init_var(fs, var, i);
return cast_int(var->k);
}
@@ -440,25 +443,24 @@ static void marktobeclosed (FuncState *fs) {
** 'var' as 'void' as a flag.
*/
static void singlevaraux (FuncState *fs, TString *n, expdesc *var, int base) {
if (fs == NULL) /* no more levels? */
init_exp(var, VVOID, 0); /* default is global */
else {
int v = searchvar(fs, n, var); /* look up locals at current level */
if (v >= 0) { /* found? */
if (v == VLOCAL && !base)
markupval(fs, var->u.var.vidx); /* local will be used as an upval */
}
else { /* not found as local at current level; try upvalues */
int idx = searchupvalue(fs, n); /* try existing upvalues */
if (idx < 0) { /* not found? */
int v = searchvar(fs, n, var); /* look up locals at current level */
if (v >= 0) { /* found? */
if (v == VLOCAL && !base)
markupval(fs, var->u.var.vidx); /* local will be used as an upval */
}
else { /* not found as local at current level; try upvalues */
int idx = searchupvalue(fs, n); /* try existing upvalues */
if (idx < 0) { /* not found? */
if (fs->prev != NULL) /* more levels? */
singlevaraux(fs->prev, n, var, 0); /* try upper levels */
if (var->k == VLOCAL || var->k == VUPVAL) /* local or upvalue? */
idx = newupvalue(fs, n, var); /* will be a new upvalue */
else /* it is a global or a constant */
return; /* don't need to do anything at this level */
}
init_exp(var, VUPVAL, idx); /* new or old upvalue */
else /* no more levels */
init_exp(var, VGLOBAL, -1); /* global by default */
if (var->k == VLOCAL || var->k == VUPVAL) /* local or upvalue? */
idx = newupvalue(fs, n, var); /* will be a new upvalue */
else /* it is a global or a constant */
return; /* don't need to do anything at this level */
}
init_exp(var, VUPVAL, idx); /* new or old upvalue */
}
}
@@ -471,10 +473,15 @@ static void singlevar (LexState *ls, expdesc *var) {
TString *varname = str_checkname(ls);
FuncState *fs = ls->fs;
singlevaraux(fs, varname, var, 1);
if (var->k == VVOID) { /* global name? */
if (var->k == VGLOBAL) { /* global name? */
expdesc key;
/* global by default in the scope of a global declaration? */
if (var->u.info == -1 && fs->bl->globdec)
luaK_semerror(ls, "variable '%s' not declared", getstr(varname));
singlevaraux(fs, ls->envn, var, 1); /* get environment variable */
lua_assert(var->k != VVOID); /* this one must exist */
if (var->k == VGLOBAL)
luaK_semerror(ls, "_ENV is global when accessing variable '%s'",
getstr(varname));
luaK_exp2anyregup(fs, var); /* but could be a constant */
codestring(&key, varname); /* key is variable name */
luaK_indexed(fs, var, &key); /* env[varname] */
@@ -664,8 +671,13 @@ static void enterblock (FuncState *fs, BlockCnt *bl, lu_byte isloop) {
bl->firstlabel = fs->ls->dyd->label.n;
bl->firstgoto = fs->ls->dyd->gt.n;
bl->upval = 0;
/* inherit 'insidetbc' from enclosing block */
bl->insidetbc = (fs->bl != NULL && fs->bl->insidetbc);
bl->previous = fs->bl;
/* inherit 'globdec' from enclosing block or enclosing function */
bl->globdec = fs->bl != NULL ? fs->bl->globdec
: fs->prev != NULL ? fs->prev->bl->globdec
: 0; /* chunk's first block */
bl->previous = fs->bl; /* link block in function's block list */
fs->bl = bl;
lua_assert(fs->freereg == luaY_nvarstack(fs));
}
@@ -1600,7 +1612,7 @@ static void fornum (LexState *ls, TString *varname, int line) {
int base = fs->freereg;
new_localvarliteral(ls, "(for state)");
new_localvarliteral(ls, "(for state)");
new_localvarkind(ls, varname, RDKCONST); /* control variable */
new_varkind(ls, varname, RDKCONST); /* control variable */
checknext(ls, '=');
exp1(ls); /* initial value */
checknext(ls, ',');
@@ -1627,7 +1639,7 @@ static void forlist (LexState *ls, TString *indexname) {
new_localvarliteral(ls, "(for state)"); /* iterator function */
new_localvarliteral(ls, "(for state)"); /* state */
new_localvarliteral(ls, "(for state)"); /* closing var. (after swap) */
new_localvarkind(ls, indexname, RDKCONST); /* control variable */
new_varkind(ls, indexname, RDKCONST); /* control variable */
/* other declared variables */
while (testnext(ls, ',')) {
new_localvar(ls, str_checkname(ls));
@@ -1702,7 +1714,7 @@ static void localfunc (LexState *ls) {
}
static lu_byte getlocalattribute (LexState *ls) {
static lu_byte getvarattribute (LexState *ls) {
/* ATTRIB -> ['<' Name '>'] */
if (testnext(ls, '<')) {
TString *ts = str_checkname(ls);
@@ -1738,8 +1750,8 @@ static void localstat (LexState *ls) {
expdesc e;
do {
TString *vname = str_checkname(ls);
lu_byte kind = getlocalattribute(ls);
vidx = new_localvarkind(ls, vname, kind);
lu_byte kind = getvarattribute(ls);
vidx = new_varkind(ls, vname, kind);
if (kind == RDKTOCLOSE) { /* to-be-closed? */
if (toclose != -1) /* one already present? */
luaK_semerror(ls, "multiple to-be-closed variables in local list");
@@ -1769,6 +1781,24 @@ static void localstat (LexState *ls) {
}
static void globalstat (LexState *ls) {
FuncState *fs = ls->fs;
luaX_next(ls); /* skip 'global' */
do {
TString *vname = str_checkname(ls);
lu_byte kind = getvarattribute(ls);
if (kind == RDKTOCLOSE)
luaK_semerror(ls, "global variable ('%s') cannot be to-be-closed",
getstr(vname));
/* adjust kind for global variable */
kind = (kind == VDKREG) ? GDKREG : GDKCONST;
new_varkind(ls, vname, kind);
fs->nactvar++; /* activate declaration */
} while (testnext(ls, ','));
fs->bl->globdec = 1; /* code is in the scope of a global declaration */
}
static int funcname (LexState *ls, expdesc *v) {
/* funcname -> NAME {fieldsel} [':' NAME] */
int ismethod = 0;
@@ -1888,6 +1918,10 @@ static void statement (LexState *ls) {
localstat(ls);
break;
}
case TK_GLOBAL: { /* stat -> globalstat */
globalstat(ls);
break;
}
case TK_DBCOLON: { /* stat -> label */
luaX_next(ls); /* skip double colon */
labelstat(ls, str_checkname(ls), line);
@@ -1907,6 +1941,17 @@ static void statement (LexState *ls) {
gotostat(ls, line);
break;
}
case TK_NAME: {
/* compatibility code to parse global keyword when "global"
is not reserved */
if (eqstr(ls->t.seminfo.ts, luaS_newliteral(ls->L, "global"))) {
int lk = luaX_lookahead(ls);
if (lk == TK_NAME) { /* 'global name'? */
globalstat(ls);
break;
}
} /* else... */
} /* FALLTHROUGH */
default: { /* stat -> func | assignment */
exprstat(ls);
break;