lparser.c
(4.0.1)
/*
** $Id: lparser.c,v 1.117 2000/11/29 11:57:42 roberto Exp $
** LL(1) Parser and code generator for Lua
** See Copyright Notice in lua.h
*/
#include <stdio.h>
#include <string.h>
#include "lua.h"
#include "lcode.h"
#include "lfunc.h"
#include "llex.h"
#include "lmem.h"
#include "lobject.h"
#include "lopcodes.h"
#include "lparser.h"
#include "lstate.h"
#include "lstring.h"
/*
** Constructors descriptor:
** `n' indicates number of elements, and `k' signals whether
** it is a list constructor (k = 0) or a record constructor (k = 1)
** or empty (k = ';' or '}')
*/
typedef struct Constdesc {
int n;
int k;
} Constdesc;
typedef struct Breaklabel {
struct Breaklabel *previous; /* chain */
int breaklist;
int stacklevel;
} Breaklabel;
/*
** prototypes for recursive non-terminal functions
*/
static void body (LexState *ls, int needself, int line);
static void chunk (LexState *ls);
static void constructor (LexState *ls);
static void expr (LexState *ls, expdesc *v);
static void exp1 (LexState *ls);
static void 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 = luaX_lex(ls, &ls->t.seminfo); /* read next token */
}
static void lookahead (LexState *ls) {
LUA_ASSERT(ls->lookahead.token == TK_EOS, "two look-aheads");
ls->lookahead.token = luaX_lex(ls, &ls->lookahead.seminfo);
}
static void error_expected (LexState *ls, int token) {
char buff[100], t[TOKEN_LEN];
luaX_token2str(token, t);
sprintf(buff, "`%.20s' expected", t);
luaK_error(ls, buff);
}
static void check (LexState *ls, int c) {
if (ls->t.token != c)
error_expected(ls, c);
next(ls);
}
static void check_condition (LexState *ls, int c, const char *msg) {
if (!c) luaK_error(ls, msg);
}
static int optional (LexState *ls, int c) {
if (ls->t.token == c) {
next(ls);
return 1;
}
else return 0;
}
static void check_match (LexState *ls, int what, int who, int where) {
if (ls->t.token != what) {
if (where == ls->linenumber)
error_expected(ls, what);
else {
char buff[100];
char t_what[TOKEN_LEN], t_who[TOKEN_LEN];
luaX_token2str(what, t_what);
luaX_token2str(who, t_who);
sprintf(buff, "`%.20s' expected (to close `%.20s' at line %d)",
t_what, t_who, where);
luaK_error(ls, buff);
}
}
next(ls);
}
static int string_constant (FuncState *fs, TString *s) {
Proto *f = fs->f;
int c = s->u.s.constindex;
if (c >= f->nkstr || f->kstr[c] != s) {
luaM_growvector(fs->L, f->kstr, f->nkstr, 1, TString *,
"constant table overflow", MAXARG_U);
c = f->nkstr++;
f->kstr[c] = s;
s->u.s.constindex = c; /* hint for next time */
}
return c;
}
static void code_string (LexState *ls, TString *s) {
luaK_kstr(ls, string_constant(ls->fs, s));
}
static TString *str_checkname (LexState *ls) {
TString *ts;
check_condition(ls, (ls->t.token == TK_NAME), "<name> expected");
ts = ls->t.seminfo.ts;
next(ls);
return ts;
}
static int checkname (LexState *ls) {
return string_constant(ls->fs, str_checkname(ls));
}
static int luaI_registerlocalvar (LexState *ls, TString *varname) {
Proto *f = ls->fs->f;
luaM_growvector(ls->L, f->locvars, f->nlocvars, 1, LocVar, "", MAX_INT);
f->locvars[f->nlocvars].varname = varname;
return f->nlocvars++;
}
static void new_localvar (LexState *ls, TString *name, int n) {
FuncState *fs = ls->fs;
luaX_checklimit(ls, fs->nactloc+n+1, MAXLOCALS, "local variables");
fs->actloc[fs->nactloc+n] = luaI_registerlocalvar(ls, name);
}
static void adjustlocalvars (LexState *ls, int nvars) {
FuncState *fs = ls->fs;
while (nvars--)
fs->f->locvars[fs->actloc[fs->nactloc++]].startpc = fs->pc;
}
static void removelocalvars (LexState *ls, int nvars) {
FuncState *fs = ls->fs;
while (nvars--)
fs->f->locvars[fs->actloc[--fs->nactloc]].endpc = fs->pc;
}
static void new_localvarstr (LexState *ls, const char *name, int n) {
new_localvar(ls, luaS_newfixed(ls->L, name), n);
}
static int search_local (LexState *ls, TString *n, expdesc *var) {
FuncState *fs;
int level = 0;
for (fs=ls->fs; fs; fs=fs->prev) {
int i;
for (i=fs->nactloc-1; i >= 0; i--) {
if (n == fs->f->locvars[fs->actloc[i]].varname) {
var->k = VLOCAL;
var->u.index = i;
return level;
}
}
level++; /* `var' not found; check outer level */
}
var->k = VGLOBAL; /* not found in any level; must be global */
return -1;
}
static void singlevar (LexState *ls, TString *n, expdesc *var) {
int level = search_local(ls, n, var);
if (level >= 1) /* neither local (0) nor global (-1)? */
luaX_syntaxerror(ls, "cannot access a variable in outer scope", n->str);
else if (level == -1) /* global? */
var->u.index = string_constant(ls->fs, n);
}
static int indexupvalue (LexState *ls, expdesc *v) {
FuncState *fs = ls->fs;
int i;
for (i=0; i<fs->nupvalues; i++) {
if (fs->upvalues[i].k == v->k && fs->upvalues[i].u.index == v->u.index)
return i;
}
/* new one */
luaX_checklimit(ls, fs->nupvalues+1, MAXUPVALUES, "upvalues");
fs->upvalues[fs->nupvalues] = *v;
return fs->nupvalues++;
}
static void pushupvalue (LexState *ls, TString *n) {
FuncState *fs = ls->fs;
expdesc v;
int level = search_local(ls, n, &v);
if (level == -1) { /* global? */
if (fs->prev == NULL)
luaX_syntaxerror(ls, "cannot access upvalue in main", n->str);
v.u.index = string_constant(fs->prev, n);
}
else if (level != 1)
luaX_syntaxerror(ls,
"upvalue must be global or local to immediately outer scope", n->str);
luaK_code1(fs, OP_PUSHUPVALUE, indexupvalue(ls, &v));
}
static void adjust_mult_assign (LexState *ls, int nvars, int nexps) {
FuncState *fs = ls->fs;
int diff = nexps - nvars;
if (nexps > 0 && luaK_lastisopen(fs)) { /* list ends in a function call */
diff--; /* do not count function call itself */
if (diff <= 0) { /* more variables than values? */
luaK_setcallreturns(fs, -diff); /* function call provide extra values */
diff = 0; /* no more difference */
}
else /* more values than variables */
luaK_setcallreturns(fs, 0); /* call should provide no value */
}
/* push or pop eventual difference between list lengths */
luaK_adjuststack(fs, diff);
}
static void code_params (LexState *ls, int nparams, int dots) {
FuncState *fs = ls->fs;
adjustlocalvars(ls, nparams);
luaX_checklimit(ls, fs->nactloc, MAXPARAMS, "parameters");
fs->f->numparams = fs->nactloc; /* `self' could be there already */
fs->f->is_vararg = dots;
if (dots) {
new_localvarstr(ls, "arg", 0);
adjustlocalvars(ls, 1);
}
luaK_deltastack(fs, fs->nactloc); /* count parameters in the stack */
}
static void enterbreak (FuncState *fs, Breaklabel *bl) {
bl->stacklevel = fs->stacklevel;
bl->breaklist = NO_JUMP;
bl->previous = fs->bl;
fs->bl = bl;
}
static void leavebreak (FuncState *fs, Breaklabel *bl) {
fs->bl = bl->previous;
LUA_ASSERT(bl->stacklevel == fs->stacklevel, "wrong levels");
luaK_patchlist(fs, bl->breaklist, luaK_getlabel(fs));
}
static void pushclosure (LexState *ls, FuncState *func) {
FuncState *fs = ls->fs;
Proto *f = fs->f;
int i;
for (i=0; i<func->nupvalues; i++)
luaK_tostack(ls, &func->upvalues[i], 1);
luaM_growvector(ls->L, f->kproto, f->nkproto, 1, Proto *,
"constant table overflow", MAXARG_A);
f->kproto[f->nkproto++] = func->f;
luaK_code2(fs, OP_CLOSURE, f->nkproto-1, func->nupvalues);
}
static void open_func (LexState *ls, FuncState *fs) {
Proto *f = luaF_newproto(ls->L);
fs->prev = ls->fs; /* linked list of funcstates */
fs->ls = ls;
fs->L = ls->L;
ls->fs = fs;
fs->stacklevel = 0;
fs->nactloc = 0;
fs->nupvalues = 0;
fs->bl = NULL;
fs->f = f;
f->source = ls->source;
fs->pc = 0;
fs->lasttarget = 0;
fs->lastline = 0;
fs->jlt = NO_JUMP;
f->code = NULL;
f->maxstacksize = 0;
f->numparams = 0; /* default for main chunk */
f->is_vararg = 0; /* default for main chunk */
}
static void close_func (LexState *ls) {
lua_State *L = ls->L;
FuncState *fs = ls->fs;
Proto *f = fs->f;
luaK_code0(fs, OP_END);
luaK_getlabel(fs); /* close eventual list of pending jumps */
luaM_reallocvector(L, f->code, fs->pc, Instruction);
luaM_reallocvector(L, f->kstr, f->nkstr, TString *);
luaM_reallocvector(L, f->knum, f->nknum, Number);
luaM_reallocvector(L, f->kproto, f->nkproto, Proto *);
removelocalvars(ls, fs->nactloc);
luaM_reallocvector(L, f->locvars, f->nlocvars, LocVar);
luaM_reallocvector(L, f->lineinfo, f->nlineinfo+1, int);
f->lineinfo[f->nlineinfo++] = MAX_INT; /* end flag */
luaF_protook(L, f, fs->pc); /* proto is ok now */
ls->fs = fs->prev;
LUA_ASSERT(fs->bl == NULL, "wrong list end");
}
Proto *luaY_parser (lua_State *L, ZIO *z) {
struct LexState lexstate;
struct FuncState funcstate;
luaX_setinput(L, &lexstate, z, luaS_new(L, zname(z)));
open_func(&lexstate, &funcstate);
next(&lexstate); /* read first token */
chunk(&lexstate);
check_condition(&lexstate, (lexstate.t.token == TK_EOS), "<eof> expected");
close_func(&lexstate);
LUA_ASSERT(funcstate.prev == NULL, "wrong list end");
LUA_ASSERT(funcstate.nupvalues == 0, "no upvalues in main");
return funcstate.f;
}
/*============================================================*/
/* GRAMMAR RULES */
/*============================================================*/
static int explist1 (LexState *ls) {
/* explist1 -> expr { ',' expr } */
int n = 1; /* at least one expression */
expdesc v;
expr(ls, &v);
while (ls->t.token == ',') {
luaK_tostack(ls, &v, 1); /* gets only 1 value from previous expression */
next(ls); /* skip comma */
expr(ls, &v);
n++;
}
luaK_tostack(ls, &v, 0); /* keep open number of values of last expression */
return n;
}
static void funcargs (LexState *ls, int slf) {
FuncState *fs = ls->fs;
int slevel = fs->stacklevel - slf - 1; /* where is func in the stack */
switch (ls->t.token) {
case '(': { /* funcargs -> '(' [ explist1 ] ')' */
int line = ls->linenumber;
int nargs = 0;
next(ls);
if (ls->t.token != ')') /* arg list not empty? */
nargs = explist1(ls);
check_match(ls, ')', '(', line);
#ifdef LUA_COMPAT_ARGRET
if (nargs > 0) /* arg list is not empty? */
luaK_setcallreturns(fs, 1); /* last call returns only 1 value */
#else
UNUSED(nargs); /* to avoid warnings */
#endif
break;
}
case '{': { /* funcargs -> constructor */
constructor(ls);
break;
}
case TK_STRING: { /* funcargs -> STRING */
code_string(ls, ls->t.seminfo.ts); /* must use `seminfo' before `next' */
next(ls);
break;
}
default: {
luaK_error(ls, "function arguments expected");
break;
}
}
fs->stacklevel = slevel; /* call will remove function and arguments */
luaK_code2(fs, OP_CALL, slevel, MULT_RET);
}
static void var_or_func_tail (LexState *ls, expdesc *v) {
for (;;) {
switch (ls->t.token) {
case '.': { /* var_or_func_tail -> '.' NAME */
next(ls);
luaK_tostack(ls, v, 1); /* `v' must be on stack */
luaK_kstr(ls, checkname(ls));
v->k = VINDEXED;
break;
}
case '[': { /* var_or_func_tail -> '[' exp1 ']' */
next(ls);
luaK_tostack(ls, v, 1); /* `v' must be on stack */
v->k = VINDEXED;
exp1(ls);
check(ls, ']');
break;
}
case ':': { /* var_or_func_tail -> ':' NAME funcargs */
int name;
next(ls);
name = checkname(ls);
luaK_tostack(ls, v, 1); /* `v' must be on stack */
luaK_code1(ls->fs, OP_PUSHSELF, name);
funcargs(ls, 1);
v->k = VEXP;
v->u.l.t = v->u.l.f = NO_JUMP;
break;
}
case '(': case TK_STRING: case '{': { /* var_or_func_tail -> funcargs */
luaK_tostack(ls, v, 1); /* `v' must be on stack */
funcargs(ls, 0);
v->k = VEXP;
v->u.l.t = v->u.l.f = NO_JUMP;
break;
}
default: return; /* should be follow... */
}
}
}
static void var_or_func (LexState *ls, expdesc *v) {
/* var_or_func -> ['%'] NAME var_or_func_tail */
if (optional(ls, '%')) { /* upvalue? */
pushupvalue(ls, str_checkname(ls));
v->k = VEXP;
v->u.l.t = v->u.l.f = NO_JUMP;
}
else /* variable name */
singlevar(ls, str_checkname(ls), v);
var_or_func_tail(ls, v);
}
/*
** {======================================================================
** Rules for Constructors
** =======================================================================
*/
static void recfield (LexState *ls) {
/* recfield -> (NAME | '['exp1']') = exp1 */
switch (ls->t.token) {
case TK_NAME: {
luaK_kstr(ls, checkname(ls));
break;
}
case '[': {
next(ls);
exp1(ls);
check(ls, ']');
break;
}
default: luaK_error(ls, "<name> or `[' expected");
}
check(ls, '=');
exp1(ls);
}
static int recfields (LexState *ls) {
/* recfields -> recfield { ',' recfield } [','] */
FuncState *fs = ls->fs;
int n = 1; /* at least one element */
recfield(ls);
while (ls->t.token == ',') {
next(ls);
if (ls->t.token == ';' || ls->t.token == '}')
break;
recfield(ls);
n++;
if (n%RFIELDS_PER_FLUSH == 0)
luaK_code1(fs, OP_SETMAP, RFIELDS_PER_FLUSH);
}
luaK_code1(fs, OP_SETMAP, n%RFIELDS_PER_FLUSH);
return n;
}
static int listfields (LexState *ls) {
/* listfields -> exp1 { ',' exp1 } [','] */
FuncState *fs = ls->fs;
int n = 1; /* at least one element */
exp1(ls);
while (ls->t.token == ',') {
next(ls);
if (ls->t.token == ';' || ls->t.token == '}')
break;
exp1(ls);
n++;
luaX_checklimit(ls, n/LFIELDS_PER_FLUSH, MAXARG_A,
"`item groups' in a list initializer");
if (n%LFIELDS_PER_FLUSH == 0)
luaK_code2(fs, OP_SETLIST, n/LFIELDS_PER_FLUSH - 1, LFIELDS_PER_FLUSH);
}
luaK_code2(fs, OP_SETLIST, n/LFIELDS_PER_FLUSH, n%LFIELDS_PER_FLUSH);
return n;
}
static void constructor_part (LexState *ls, Constdesc *cd) {
switch (ls->t.token) {
case ';': case '}': { /* constructor_part -> empty */
cd->n = 0;
cd->k = ls->t.token;
break;
}
case TK_NAME: { /* may be listfields or recfields */
lookahead(ls);
if (ls->lookahead.token != '=') /* expression? */
goto case_default;
/* else go through to recfields */
}
case '[': { /* constructor_part -> recfields */
cd->n = recfields(ls);
cd->k = 1; /* record */
break;
}
default: { /* constructor_part -> listfields */
case_default:
cd->n = listfields(ls);
cd->k = 0; /* list */
break;
}
}
}
static void constructor (LexState *ls) {
/* constructor -> '{' constructor_part [';' constructor_part] '}' */
FuncState *fs = ls->fs;
int line = ls->linenumber;
int pc = luaK_code1(fs, OP_CREATETABLE, 0);
int nelems;
Constdesc cd;
check(ls, '{');
constructor_part(ls, &cd);
nelems = cd.n;
if (optional(ls, ';')) {
Constdesc other_cd;
constructor_part(ls, &other_cd);
check_condition(ls, (cd.k != other_cd.k), "invalid constructor syntax");
nelems += other_cd.n;
}
check_match(ls, '}', '{', line);
luaX_checklimit(ls, nelems, MAXARG_U, "elements in a table constructor");
SETARG_U(fs->f->code[pc], nelems); /* set initial table size */
}
/* }====================================================================== */
/*
** {======================================================================
** Expression parsing
** =======================================================================
*/
static void simpleexp (LexState *ls, expdesc *v) {
FuncState *fs = ls->fs;
switch (ls->t.token) {
case TK_NUMBER: { /* simpleexp -> NUMBER */
Number r = ls->t.seminfo.r;
next(ls);
luaK_number(fs, r);
break;
}
case TK_STRING: { /* simpleexp -> STRING */
code_string(ls, ls->t.seminfo.ts); /* must use `seminfo' before `next' */
next(ls);
break;
}
case TK_NIL: { /* simpleexp -> NIL */
luaK_adjuststack(fs, -1);
next(ls);
break;
}
case '{': { /* simpleexp -> constructor */
constructor(ls);
break;
}
case TK_FUNCTION: { /* simpleexp -> FUNCTION body */
next(ls);
body(ls, 0, ls->linenumber);
break;
}
case '(': { /* simpleexp -> '(' expr ')' */
next(ls);
expr(ls, v);
check(ls, ')');
return;
}
case TK_NAME: case '%': {
var_or_func(ls, v);
return;
}
default: {
luaK_error(ls, "<expression> expected");
return;
}
}
v->k = VEXP;
v->u.l.t = v->u.l.f = NO_JUMP;
}
static void exp1 (LexState *ls) {
expdesc v;
expr(ls, &v);
luaK_tostack(ls, &v, 1);
}
static UnOpr getunopr (int op) {
switch (op) {
case TK_NOT: return OPR_NOT;
case '-': return OPR_MINUS;
default: return OPR_NOUNOPR;
}
}
static BinOpr getbinopr (int op) {
switch (op) {
case '+': return OPR_ADD;
case '-': return OPR_SUB;
case '*': return OPR_MULT;
case '/': return OPR_DIV;
case '^': return OPR_POW;
case TK_CONCAT: return OPR_CONCAT;
case TK_NE: return OPR_NE;
case TK_EQ: return OPR_EQ;
case '<': return OPR_LT;
case TK_LE: return OPR_LE;
case '>': return OPR_GT;
case TK_GE: return OPR_GE;
case TK_AND: return OPR_AND;
case TK_OR: return OPR_OR;
default: return OPR_NOBINOPR;
}
}
static const struct {
char left; /* left priority for each binary operator */
char right; /* right priority */
} priority[] = { /* ORDER OPR */
{5, 5}, {5, 5}, {6, 6}, {6, 6}, /* arithmetic */
{9, 8}, {4, 3}, /* power and concat (right associative) */
{2, 2}, {2, 2}, /* equality */
{2, 2}, {2, 2}, {2, 2}, {2, 2}, /* order */
{1, 1}, {1, 1} /* logical */
};
#define UNARY_PRIORITY 7 /* priority for unary operators */
/*
** subexpr -> (simplexep | unop subexpr) { binop subexpr }
** where `binop' is any binary operator with a priority higher than `limit'
*/
static BinOpr subexpr (LexState *ls, expdesc *v, int limit) {
BinOpr op;
UnOpr uop = getunopr(ls->t.token);
if (uop != OPR_NOUNOPR) {
next(ls);
subexpr(ls, v, UNARY_PRIORITY);
luaK_prefix(ls, uop, v);
}
else simpleexp(ls, v);
/* expand while operators have priorities higher than `limit' */
op = getbinopr(ls->t.token);
while (op != OPR_NOBINOPR && priority[op].left > limit) {
expdesc v2;
BinOpr nextop;
next(ls);
luaK_infix(ls, op, v);
/* read sub-expression with higher priority */
nextop = subexpr(ls, &v2, priority[op].right);
luaK_posfix(ls, op, v, &v2);
op = nextop;
}
return op; /* return first untreated operator */
}
static void expr (LexState *ls, expdesc *v) {
subexpr(ls, v, -1);
}
/* }==================================================================== */
/*
** {======================================================================
** Rules for Statements
** =======================================================================
*/
static int block_follow (int token) {
switch (token) {
case TK_ELSE: case TK_ELSEIF: case TK_END:
case TK_UNTIL: case TK_EOS:
return 1;
default: return 0;
}
}
static void block (LexState *ls) {
/* block -> chunk */
FuncState *fs = ls->fs;
int nactloc = fs->nactloc;
chunk(ls);
luaK_adjuststack(fs, fs->nactloc - nactloc); /* remove local variables */
removelocalvars(ls, fs->nactloc - nactloc);
}
static int assignment (LexState *ls, expdesc *v, int nvars) {
int left = 0; /* number of values left in the stack after assignment */
luaX_checklimit(ls, nvars, MAXVARSLH, "variables in a multiple assignment");
if (ls->t.token == ',') { /* assignment -> ',' NAME assignment */
expdesc nv;
next(ls);
var_or_func(ls, &nv);
check_condition(ls, (nv.k != VEXP), "syntax error");
left = assignment(ls, &nv, nvars+1);
}
else { /* assignment -> '=' explist1 */
int nexps;
check(ls, '=');
nexps = explist1(ls);
adjust_mult_assign(ls, nvars, nexps);
}
if (v->k != VINDEXED)
luaK_storevar(ls, v);
else { /* there may be garbage between table-index and value */
luaK_code2(ls->fs, OP_SETTABLE, left+nvars+2, 1);
left += 2;
}
return left;
}
static void cond (LexState *ls, expdesc *v) {
/* cond -> exp */
expr(ls, v); /* read condition */
luaK_goiftrue(ls->fs, v, 0);
}
static void whilestat (LexState *ls, int line) {
/* whilestat -> WHILE cond DO block END */
FuncState *fs = ls->fs;
int while_init = luaK_getlabel(fs);
expdesc v;
Breaklabel bl;
enterbreak(fs, &bl);
next(ls);
cond(ls, &v);
check(ls, TK_DO);
block(ls);
luaK_patchlist(fs, luaK_jump(fs), while_init);
luaK_patchlist(fs, v.u.l.f, luaK_getlabel(fs));
check_match(ls, TK_END, TK_WHILE, line);
leavebreak(fs, &bl);
}
static void repeatstat (LexState *ls, int line) {
/* repeatstat -> REPEAT block UNTIL cond */
FuncState *fs = ls->fs;
int repeat_init = luaK_getlabel(fs);
expdesc v;
Breaklabel bl;
enterbreak(fs, &bl);
next(ls);
block(ls);
check_match(ls, TK_UNTIL, TK_REPEAT, line);
cond(ls, &v);
luaK_patchlist(fs, v.u.l.f, repeat_init);
leavebreak(fs, &bl);
}
static void forbody (LexState *ls, int nvar, OpCode prepfor, OpCode loopfor) {
/* forbody -> DO block END */
FuncState *fs = ls->fs;
int prep = luaK_code1(fs, prepfor, NO_JUMP);
int blockinit = luaK_getlabel(fs);
check(ls, TK_DO);
adjustlocalvars(ls, nvar); /* scope for control variables */
block(ls);
luaK_patchlist(fs, luaK_code1(fs, loopfor, NO_JUMP), blockinit);
luaK_patchlist(fs, prep, luaK_getlabel(fs));
removelocalvars(ls, nvar);
}
static void fornum (LexState *ls, TString *varname) {
/* fornum -> NAME = exp1,exp1[,exp1] forbody */
FuncState *fs = ls->fs;
check(ls, '=');
exp1(ls); /* initial value */
check(ls, ',');
exp1(ls); /* limit */
if (optional(ls, ','))
exp1(ls); /* optional step */
else
luaK_code1(fs, OP_PUSHINT, 1); /* default step */
new_localvar(ls, varname, 0);
new_localvarstr(ls, "(limit)", 1);
new_localvarstr(ls, "(step)", 2);
forbody(ls, 3, OP_FORPREP, OP_FORLOOP);
}
static void forlist (LexState *ls, TString *indexname) {
/* forlist -> NAME,NAME IN exp1 forbody */
TString *valname;
check(ls, ',');
valname = str_checkname(ls);
/* next test is dirty, but avoids `in' being a reserved word */
check_condition(ls,
(ls->t.token == TK_NAME && ls->t.seminfo.ts == luaS_new(ls->L, "in")),
"`in' expected");
next(ls); /* skip `in' */
exp1(ls); /* table */
new_localvarstr(ls, "(table)", 0);
new_localvar(ls, indexname, 1);
new_localvar(ls, valname, 2);
forbody(ls, 3, OP_LFORPREP, OP_LFORLOOP);
}
static void forstat (LexState *ls, int line) {
/* forstat -> fornum | forlist */
FuncState *fs = ls->fs;
TString *varname;
Breaklabel bl;
enterbreak(fs, &bl);
next(ls); /* skip `for' */
varname = str_checkname(ls); /* first variable name */
switch (ls->t.token) {
case '=': fornum(ls, varname); break;
case ',': forlist(ls, varname); break;
default: luaK_error(ls, "`=' or `,' expected");
}
check_match(ls, TK_END, TK_FOR, line);
leavebreak(fs, &bl);
}
static void test_then_block (LexState *ls, expdesc *v) {
/* test_then_block -> [IF | ELSEIF] cond THEN block */
next(ls); /* skip IF or ELSEIF */
cond(ls, v);
check(ls, TK_THEN);
block(ls); /* `then' part */
}
static void ifstat (LexState *ls, int line) {
/* ifstat -> IF cond THEN block {ELSEIF cond THEN block} [ELSE block] END */
FuncState *fs = ls->fs;
expdesc v;
int escapelist = NO_JUMP;
test_then_block(ls, &v); /* IF cond THEN block */
while (ls->t.token == TK_ELSEIF) {
luaK_concat(fs, &escapelist, luaK_jump(fs));
luaK_patchlist(fs, v.u.l.f, luaK_getlabel(fs));
test_then_block(ls, &v); /* ELSEIF cond THEN block */
}
if (ls->t.token == TK_ELSE) {
luaK_concat(fs, &escapelist, luaK_jump(fs));
luaK_patchlist(fs, v.u.l.f, luaK_getlabel(fs));
next(ls); /* skip ELSE */
block(ls); /* `else' part */
}
else
luaK_concat(fs, &escapelist, v.u.l.f);
luaK_patchlist(fs, escapelist, luaK_getlabel(fs));
check_match(ls, TK_END, TK_IF, line);
}
static void localstat (LexState *ls) {
/* stat -> LOCAL NAME {',' NAME} ['=' explist1] */
int nvars = 0;
int nexps;
do {
next(ls); /* skip LOCAL or ',' */
new_localvar(ls, str_checkname(ls), nvars++);
} while (ls->t.token == ',');
if (optional(ls, '='))
nexps = explist1(ls);
else
nexps = 0;
adjust_mult_assign(ls, nvars, nexps);
adjustlocalvars(ls, nvars);
}
static int funcname (LexState *ls, expdesc *v) {
/* funcname -> NAME [':' NAME | '.' NAME] */
int needself = 0;
singlevar(ls, str_checkname(ls), v);
if (ls->t.token == ':' || ls->t.token == '.') {
needself = (ls->t.token == ':');
next(ls);
luaK_tostack(ls, v, 1);
luaK_kstr(ls, checkname(ls));
v->k = VINDEXED;
}
return needself;
}
static void funcstat (LexState *ls, int line) {
/* funcstat -> FUNCTION funcname body */
int needself;
expdesc v;
next(ls); /* skip FUNCTION */
needself = funcname(ls, &v);
body(ls, needself, line);
luaK_storevar(ls, &v);
}
static void namestat (LexState *ls) {
/* stat -> func | ['%'] NAME assignment */
FuncState *fs = ls->fs;
expdesc v;
var_or_func(ls, &v);
if (v.k == VEXP) { /* stat -> func */
check_condition(ls, luaK_lastisopen(fs), "syntax error"); /* an upvalue? */
luaK_setcallreturns(fs, 0); /* call statement uses no results */
}
else { /* stat -> ['%'] NAME assignment */
int left = assignment(ls, &v, 1);
luaK_adjuststack(fs, left); /* remove eventual garbage left on stack */
}
}
static void retstat (LexState *ls) {
/* stat -> RETURN explist */
FuncState *fs = ls->fs;
next(ls); /* skip RETURN */
if (!block_follow(ls->t.token) && ls->t.token != ';')
explist1(ls); /* optional return values */
luaK_code1(fs, OP_RETURN, ls->fs->nactloc);
fs->stacklevel = fs->nactloc; /* removes all temp values */
}
static void breakstat (LexState *ls) {
/* stat -> BREAK [NAME] */
FuncState *fs = ls->fs;
int currentlevel = fs->stacklevel;
Breaklabel *bl = fs->bl;
if (!bl)
luaK_error(ls, "no loop to break");
next(ls); /* skip BREAK */
luaK_adjuststack(fs, currentlevel - bl->stacklevel);
luaK_concat(fs, &bl->breaklist, luaK_jump(fs));
/* correct stack for compiler and symbolic execution */
luaK_adjuststack(fs, bl->stacklevel - currentlevel);
}
static int stat (LexState *ls) {
int line = ls->linenumber; /* may be needed for error messages */
switch (ls->t.token) {
case TK_IF: { /* stat -> ifstat */
ifstat(ls, line);
return 0;
}
case TK_WHILE: { /* stat -> whilestat */
whilestat(ls, line);
return 0;
}
case TK_DO: { /* stat -> DO block END */
next(ls); /* skip DO */
block(ls);
check_match(ls, TK_END, TK_DO, line);
return 0;
}
case TK_FOR: { /* stat -> forstat */
forstat(ls, line);
return 0;
}
case TK_REPEAT: { /* stat -> repeatstat */
repeatstat(ls, line);
return 0;
}
case TK_FUNCTION: { /* stat -> funcstat */
funcstat(ls, line);
return 0;
}
case TK_LOCAL: { /* stat -> localstat */
localstat(ls);
return 0;
}
case TK_NAME: case '%': { /* stat -> namestat */
namestat(ls);
return 0;
}
case TK_RETURN: { /* stat -> retstat */
retstat(ls);
return 1; /* must be last statement */
}
case TK_BREAK: { /* stat -> breakstat */
breakstat(ls);
return 1; /* must be last statement */
}
default: {
luaK_error(ls, "<statement> expected");
return 0; /* to avoid warnings */
}
}
}
static void parlist (LexState *ls) {
/* parlist -> [ param { ',' param } ] */
int nparams = 0;
int dots = 0;
if (ls->t.token != ')') { /* is `parlist' not empty? */
do {
switch (ls->t.token) {
case TK_DOTS: next(ls); dots = 1; break;
case TK_NAME: new_localvar(ls, str_checkname(ls), nparams++); break;
default: luaK_error(ls, "<name> or `...' expected");
}
} while (!dots && optional(ls, ','));
}
code_params(ls, nparams, dots);
}
static void body (LexState *ls, int needself, int line) {
/* body -> '(' parlist ')' chunk END */
FuncState new_fs;
open_func(ls, &new_fs);
new_fs.f->lineDefined = line;
check(ls, '(');
if (needself) {
new_localvarstr(ls, "self", 0);
adjustlocalvars(ls, 1);
}
parlist(ls);
check(ls, ')');
chunk(ls);
check_match(ls, TK_END, TK_FUNCTION, line);
close_func(ls);
pushclosure(ls, &new_fs);
}
/* }====================================================================== */
static void chunk (LexState *ls) {
/* chunk -> { stat [';'] } */
int islast = 0;
while (!islast && !block_follow(ls->t.token)) {
islast = stat(ls);
optional(ls, ';');
LUA_ASSERT(ls->fs->stacklevel == ls->fs->nactloc,
"stack size != # local vars");
}
}