lua/lparser.c
2000-03-09 10:57:37 -03:00

1106 lines
28 KiB
C

/*
** $Id: lparser.c,v 1.64 2000/03/03 20:29:25 roberto Exp roberto $
** LL(1) Parser and code generator for Lua
** See Copyright Notice in lua.h
*/
#include <stdio.h>
#include <string.h>
#define LUA_REENTRANT
#include "lcode.h"
#include "ldo.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"
/*
** check whether arbitrary limits fit into respective opcode types
*/
#if MAXLOCALS > MAXARG_U || MAXUPVALUES > MAXARG_B || MAXVARSLH > MAXARG_B || \
MAXPARAMS > MAXLOCALS || MAXSTACK > MAXARG_A || \
LFIELDS_PER_FLUSH > MAXARG_B || MULT_RET > MAXARG_B
#error invalid limits
#endif
/*
** 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;
/*
** 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->token = luaX_lex(ls);
}
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 error_unexpected (LexState *ls) {
luaK_error(ls, "unexpected token");
}
static void error_unmatched (LexState *ls, int what, int who, int where) {
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);
}
}
static void check (LexState *ls, int c) {
if (ls->token != c)
error_expected(ls, c);
next(ls);
}
static int optional (LexState *ls, int c) {
if (ls->token == c) {
next(ls);
return 1;
}
else return 0;
}
static void checklimit (LexState *ls, int val, int limit, const char *msg) {
if (val > limit) {
char buff[100];
sprintf(buff, "too many %.50s (limit=%d)", msg, limit);
luaK_error(ls, buff);
}
}
static void check_debugline (LexState *ls) {
if (ls->L->debug && ls->linenumber != ls->fs->lastsetline) {
luaK_U(ls, SETLINE, ls->linenumber, 0);
ls->fs->lastsetline = ls->linenumber;
}
}
static void check_match (LexState *ls, int what, int who, int where) {
if (ls->token != what)
error_unmatched(ls, what, who, where);
check_debugline(ls); /* to `mark' the `what' */
next(ls);
}
static int string_constant (LexState *ls, FuncState *fs, TaggedString *s) {
TProtoFunc *f = fs->f;
int c = s->constindex;
if (c >= f->nkstr || f->kstr[c] != s) {
luaM_growvector(ls->L, f->kstr, f->nkstr, 1, TaggedString *,
constantEM, MAXARG_U);
c = f->nkstr++;
f->kstr[c] = s;
s->constindex = c; /* hint for next time */
}
return c;
}
static void code_string (LexState *ls, TaggedString *s) {
luaK_kstr(ls, string_constant(ls, ls->fs, s));
}
static int checkname (LexState *ls) {
int sc;
if (ls->token != NAME)
luaK_error(ls, "<name> expected");
sc = string_constant(ls, ls->fs, ls->seminfo.ts);
next(ls);
return sc;
}
static TaggedString *str_checkname (LexState *ls) {
int i = checkname(ls); /* this call may realloc `f->consts' */
return ls->fs->f->kstr[i];
}
static void luaI_registerlocalvar (LexState *ls, TaggedString *varname,
int line) {
FuncState *fs = ls->fs;
if (fs->nvars != -1) { /* debug information? */
TProtoFunc *f = fs->f;
luaM_growvector(ls->L, f->locvars, fs->nvars, 1, LocVar, "", MAX_INT);
f->locvars[fs->nvars].varname = varname;
f->locvars[fs->nvars].line = line;
fs->nvars++;
}
}
static void luaI_unregisterlocalvar (LexState *ls, int line) {
luaI_registerlocalvar(ls, NULL, line);
}
static void store_localvar (LexState *ls, TaggedString *name, int n) {
FuncState *fs = ls->fs;
checklimit(ls, fs->nlocalvar+n+1, MAXLOCALS, "local variables");
fs->localvar[fs->nlocalvar+n] = name;
}
static void adjustlocalvars (LexState *ls, int nvars, int line) {
FuncState *fs = ls->fs;
int i;
fs->nlocalvar += nvars;
for (i=fs->nlocalvar-nvars; i<fs->nlocalvar; i++)
luaI_registerlocalvar(ls, fs->localvar[i], line);
}
static void add_localvar (LexState *ls, TaggedString *name) {
store_localvar(ls, name, 0);
adjustlocalvars(ls, 1, 0);
}
static int aux_localname (FuncState *fs, TaggedString *n) {
int i;
for (i=fs->nlocalvar-1; i >= 0; i--)
if (n == fs->localvar[i]) return i; /* local var index */
return -1; /* not found */
}
static void singlevar (LexState *ls, TaggedString *n, expdesc *var, int prev) {
FuncState *fs = prev ? ls->fs->prev : ls->fs;
int i = aux_localname(fs, n);
if (i >= 0) { /* local value? */
var->k = VLOCAL;
var->u.index = i;
}
else {
FuncState *level = fs;
while ((level = level->prev) != NULL) /* check shadowing */
if (aux_localname(level, n) >= 0)
luaX_syntaxerror(ls, "cannot access a variable in outer scope", n->str);
var->k = VGLOBAL;
var->u.index = string_constant(ls, fs, n);
}
}
static int indexupvalue (LexState *ls, TaggedString *n) {
FuncState *fs = ls->fs;
expdesc v;
int i;
singlevar(ls, n, &v, 1);
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 */
++(fs->nupvalues);
checklimit(ls, fs->nupvalues, MAXUPVALUES, "upvalues");
fs->upvalues[i] = v; /* i = fs->nupvalues - 1 */
return i;
}
static void pushupvalue (LexState *ls, TaggedString *n) {
if (ls->fs->prev == NULL)
luaX_syntaxerror(ls, "cannot access upvalue in main", n->str);
if (aux_localname(ls->fs, n) >= 0)
luaX_syntaxerror(ls, "cannot access an upvalue in current scope", n->str);
luaK_U(ls, PUSHUPVALUE, indexupvalue(ls, n), 1);
}
static void adjust_mult_assign (LexState *ls, int nvars, int nexps) {
int diff = nexps - nvars;
if (nexps == 0 || !luaK_lastisopen(ls)) { /* list is empty or closed */
/* push or pop eventual difference between list lengths */
luaK_adjuststack(ls, diff);
}
else { /* list ends in a function call; must correct it */
diff--; /* do not count function call itself */
if (diff <= 0) { /* more variables than values? */
/* function call must provide extra values */
luaK_setcallreturns(ls, -diff);
}
else { /* more values than variables */
luaK_setcallreturns(ls, 0); /* call should provide no value */
luaK_adjuststack(ls, diff); /* pop eventual extra values */
}
}
}
static void code_args (LexState *ls, int nparams, int dots) {
FuncState *fs = ls->fs;
adjustlocalvars(ls, nparams, 0);
checklimit(ls, fs->nlocalvar, MAXPARAMS, "parameters");
nparams = fs->nlocalvar; /* `self' could be there already */
fs->f->numparams = nparams;
fs->f->is_vararg = dots;
if (!dots)
luaK_deltastack(ls, nparams);
else {
luaK_deltastack(ls, nparams+1);
add_localvar(ls, luaS_newfixed(ls->L, "arg"));
}
}
static int getvarname (LexState *ls, expdesc *var) {
switch (var->k) {
case VGLOBAL:
return var->u.index;
case VLOCAL:
return string_constant(ls, ls->fs, ls->fs->localvar[var->u.index]);
break;
default:
error_unexpected(ls); /* there is no `var name' */
return 0; /* to avoid warnings */
}
}
static void func_onstack (LexState *ls, FuncState *func) {
TProtoFunc *f = ls->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, TProtoFunc *,
constantEM, MAXARG_A);
f->kproto[f->nkproto++] = func->f;
luaK_deltastack(ls, 1); /* CLOSURE puts one extra element before popping */
luaK_AB(ls, CLOSURE, f->nkproto-1, func->nupvalues, -func->nupvalues);
}
static void init_state (LexState *ls, FuncState *fs, TaggedString *source) {
lua_State *L = ls->L;
TProtoFunc *f = luaF_newproto(ls->L);
fs->prev = ls->fs; /* linked list of funcstates */
ls->fs = fs;
fs->stacksize = 0;
fs->nlocalvar = 0;
fs->nupvalues = 0;
fs->lastsetline = 0;
fs->f = f;
f->source = source;
fs->pc = 0;
fs->lasttarget = 0;
f->code = NULL;
f->maxstacksize = 0;
f->numparams = 0; /* default for main chunk */
f->is_vararg = 0; /* default for main chunk */
fs->nvars = (L->debug) ? 0 : -1; /* flag no debug information? */
/* push function (to avoid GC) */
tfvalue(L->top) = f;
ttype(L->top) = LUA_T_LPROTO;
incr_top;
}
static void close_func (LexState *ls) {
FuncState *fs = ls->fs;
TProtoFunc *f = fs->f;
luaK_0(ls, ENDCODE, 0);
luaM_reallocvector(ls->L, f->code, fs->pc, Instruction);
luaM_reallocvector(ls->L, f->kstr, f->nkstr, TaggedString *);
luaM_reallocvector(ls->L, f->knum, f->nknum, real);
luaM_reallocvector(ls->L, f->kproto, f->nkproto, TProtoFunc *);
if (fs->nvars != -1) { /* debug information? */
luaI_registerlocalvar(ls, NULL, -1); /* flag end of vector */
luaM_reallocvector(ls->L, f->locvars, fs->nvars, LocVar);
}
ls->fs = fs->prev;
ls->L->top--; /* pop function */
}
TProtoFunc *luaY_parser (lua_State *L, ZIO *z) {
struct LexState lexstate;
struct FuncState funcstate;
luaX_setinput(L, &lexstate, z);
init_state(&lexstate, &funcstate, luaS_new(L, zname(z)));
next(&lexstate); /* read first token */
chunk(&lexstate);
if (lexstate.token != EOS)
luaK_error(&lexstate, "<eof> expected");
close_func(&lexstate);
return funcstate.f;
}
/*============================================================*/
/* GRAMAR RULES */
/*============================================================*/
static int explist1 (LexState *ls) {
/* explist1 -> expr { ',' expr } */
int n = 1; /* at least one expression */
expdesc v;
expr(ls, &v);
while (ls->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);
return n;
}
static int explist (LexState *ls) {
/* explist -> [ explist1 ] */
switch (ls->token) {
case ELSE: case ELSEIF: case END: case UNTIL:
case EOS: case ';': case ')':
return 0; /* empty list */
default:
return explist1(ls);
}
}
static void funcargs (LexState *ls, int slf) {
FuncState *fs = ls->fs;
int slevel = fs->stacksize - slf - 1; /* where is func in the stack */
switch (ls->token) {
case '(': { /* funcargs -> '(' explist ')' */
int line = ls->linenumber;
int nargs;
next(ls);
nargs = explist(ls);
check_match(ls, ')', '(', line);
#ifdef LUA_COMPAT_ARGRET
if (nargs > 0) /* arg list is not empty? */
luaK_setcallreturns(ls, 1); /* last call returns only 1 value */
#endif
break;
}
case '{': /* funcargs -> constructor */
constructor(ls);
break;
case STRING: /* funcargs -> STRING */
code_string(ls, ls->seminfo.ts); /* must use `seminfo' before `next' */
next(ls);
break;
default:
luaK_error(ls, "function arguments expected");
break;
}
fs->stacksize = slevel; /* call will remove function and arguments */
luaK_AB(ls, CALL, slevel, MULT_RET, 0);
}
static void var_or_func_tail (LexState *ls, expdesc *v) {
for (;;) {
switch (ls->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_U(ls, PUSHSELF, name, 1);
funcargs(ls, 1);
v->k = VEXP;
v->u.l.t = v->u.l.f = 0;
break;
}
case '(': case 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 = 0;
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 = 0;
}
else /* variable name */
singlevar(ls, str_checkname(ls), v, 0);
var_or_func_tail(ls, v);
}
/*
** {======================================================================
** Rules for Constructors
** =======================================================================
*/
static void recfield (LexState *ls) {
/* recfield -> (NAME | '['exp1']') = exp1 */
switch (ls->token) {
case 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 } [','] */
int n = 1; /* one has been read before */
int mod_n = 1; /* mod_n == n%RFIELDS_PER_FLUSH */
while (ls->token == ',') {
next(ls);
if (ls->token == ';' || ls->token == '}')
break;
recfield(ls);
n++;
if (++mod_n == RFIELDS_PER_FLUSH) {
luaK_U(ls, SETMAP, RFIELDS_PER_FLUSH-1, -2*RFIELDS_PER_FLUSH);
mod_n = 0;
}
}
if (mod_n)
luaK_U(ls, SETMAP, mod_n-1, -2*mod_n);
return n;
}
static int listfields (LexState *ls) {
/* listfields -> { ',' exp1 } [','] */
int n = 1; /* one has been read before */
int mod_n = 1; /* mod_n == n%LFIELDS_PER_FLUSH */
while (ls->token == ',') {
next(ls);
if (ls->token == ';' || ls->token == '}')
break;
exp1(ls);
n++;
checklimit(ls, n, MAXARG_A*LFIELDS_PER_FLUSH,
"items in a list initializer");
if (++mod_n == LFIELDS_PER_FLUSH) {
luaK_AB(ls, SETLIST, n/LFIELDS_PER_FLUSH - 1, LFIELDS_PER_FLUSH-1,
-LFIELDS_PER_FLUSH);
mod_n = 0;
}
}
if (mod_n > 0)
luaK_AB(ls, SETLIST, n/LFIELDS_PER_FLUSH, mod_n-1, -mod_n);
return n;
}
static void constructor_part (LexState *ls, constdesc *cd) {
switch (ls->token) {
case ';': case '}': /* constructor_part -> empty */
cd->n = 0;
cd->k = ls->token;
return;
case NAME: {
expdesc v;
expr(ls, &v);
if (ls->token == '=') {
luaK_kstr(ls, getvarname(ls, &v));
next(ls); /* skip '=' */
exp1(ls);
cd->n = recfields(ls);
cd->k = 1; /* record */
}
else {
luaK_tostack(ls, &v, 0);
cd->n = listfields(ls);
cd->k = 0; /* list */
}
break;
}
case '[': /* constructor_part -> recfield recfields */
recfield(ls);
cd->n = recfields(ls);
cd->k = 1; /* record */
break;
default: /* constructor_part -> exp1 listfields */
exp1(ls);
cd->n = listfields(ls);
cd->k = 0; /* list */
break;
}
}
static void constructor (LexState *ls) {
/* constructor -> '{' constructor_part [';' constructor_part] '}' */
int line = ls->linenumber;
int pc = luaK_U(ls, CREATETABLE, 0, 1);
int nelems;
constdesc cd;
check(ls, '{');
constructor_part(ls, &cd);
nelems = cd.n;
if (ls->token == ';') {
constdesc other_cd;
next(ls);
constructor_part(ls, &other_cd);
if (cd.k == other_cd.k) /* repeated parts? */
luaK_error(ls, "invalid constructor syntax");
nelems += other_cd.n;
}
check_match(ls, '}', '{', line);
/* set initial table size */
SETARG_U(ls->fs->f->code[pc], nelems);
}
/* }====================================================================== */
/*
** {======================================================================
** Expression parsing
** =======================================================================
*/
static void simpleexp (LexState *ls, expdesc *v) {
check_debugline(ls);
switch (ls->token) {
case NUMBER: { /* simpleexp -> NUMBER */
real r = ls->seminfo.r;
next(ls);
luaK_number(ls, r);
break;
}
case STRING: /* simpleexp -> STRING */
code_string(ls, ls->seminfo.ts); /* must use `seminfo' before `next' */
next(ls);
break;
case NIL: /* simpleexp -> NIL */
luaK_adjuststack(ls, -1);
next(ls);
break;
case '{': /* simpleexp -> constructor */
constructor(ls);
break;
case FUNCTION: /* simpleexp -> FUNCTION body */
next(ls);
body(ls, 0, ls->linenumber);
break;
case '(': /* simpleexp -> '(' expr ')' */
next(ls);
expr(ls, v);
check(ls, ')');
return;
case 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 = 0;
}
static void exp1 (LexState *ls) {
expdesc v;
expr(ls, &v);
luaK_tostack(ls, &v, 1);
}
/*
** gets priorities of an operator. Returns the priority to the left, and
** sets `rp' to the priority to the right.
*/
static int get_priority (int op, int *rp) {
switch (op) {
case '^': *rp = 8; return 9; /* right associative */
#define UNARY_PRIORITY 7
case '*': case '/': *rp = 6; return 6;
case '+': case '-': *rp = 5; return 5;
case CONC: *rp = 3; return 4; /* right associative (?) */
case EQ: case NE: case '>': case '<': case LE: case GE:
*rp = 2; return 2;
case AND: case OR: *rp = 1; return 1;
default: *rp = -1; return -1;
}
}
/*
** subexpr -> (simplexep | (NOT | '-') subexpr) { binop subexpr }
** where `binop' is any binary operator with a priority higher than `limit'
*/
static void subexpr (LexState *ls, expdesc *v, int limit) {
int rp;
if (ls->token == '-' || ls->token == NOT) {
int op = ls->token; /* operator */
next(ls);
subexpr(ls, v, UNARY_PRIORITY);
luaK_prefix(ls, op, v);
}
else simpleexp(ls, v);
/* expand while operators have priorities higher than `limit' */
while (get_priority(ls->token, &rp) > limit) {
expdesc v2;
int op = ls->token; /* current operator (with priority == `rp') */
next(ls);
luaK_infix(ls, op, v);
subexpr(ls, &v2, rp); /* read sub-expression with priority > `rp' */
luaK_posfix(ls, op, v, &v2);
}
}
static void expr (LexState *ls, expdesc *v) {
subexpr(ls, v, -1);
}
/* }==================================================================== */
/*
** {======================================================================
** Rules for Statements
** =======================================================================
*/
static void block (LexState *ls) {
/* block -> chunk */
FuncState *fs = ls->fs;
int nlocalvar = fs->nlocalvar;
chunk(ls);
luaK_adjuststack(ls, fs->nlocalvar - nlocalvar); /* remove local variables */
for (; fs->nlocalvar > nlocalvar; fs->nlocalvar--)
luaI_unregisterlocalvar(ls, fs->lastsetline);
}
static int assignment (LexState *ls, expdesc *v, int nvars) {
int left = 0;
checklimit(ls, nvars, MAXVARSLH, "variables in a multiple assignment");
if (ls->token == ',') { /* assignment -> ',' NAME assignment */
expdesc nv;
next(ls);
var_or_func(ls, &nv);
if (nv.k == VEXP)
luaK_error(ls, "syntax error");
left = assignment(ls, &nv, nvars+1);
}
else { /* assignment -> '=' explist1 */
int nexps;;
if (ls->token != '=')
error_unexpected(ls);
next(ls);
nexps = explist1(ls);
adjust_mult_assign(ls, nvars, nexps);
}
if (v->k != VINDEXED || left+(nvars-1) == 0) {
/* global/local var or indexed var without values in between */
luaK_storevar(ls, v);
}
else { /* indexed var with values in between*/
luaK_U(ls, SETTABLE, left+(nvars-1), -1);
left += 2; /* table&index are not popped, because they aren't on top */
}
return left;
}
/* maximum size of a while condition */
#ifndef MAX_WHILE_EXP
#define MAX_WHILE_EXP 200 /* arbitrary limit */
#endif
static void whilestat (LexState *ls, int line) {
/* whilestat -> WHILE exp1 DO block END */
Instruction buffer[MAX_WHILE_EXP];
FuncState *fs = ls->fs;
int while_init = luaK_getlabel(ls);
int loopentry; /* point to jump to repeat the loop */
int cond_init; /* init of condition, after the move */
int cond_size;
expdesc v;
int i;
next(ls); /* skip WHILE */
expr(ls, &v); /* read condition */
luaK_goiffalse(ls, &v, 0);
cond_size = fs->pc - while_init;
/* save condition (to move it to after body) */
if (cond_size > MAX_WHILE_EXP)
luaK_error(ls, "while condition too complex");
for (i=0; i<cond_size; i++) buffer[i] = fs->f->code[while_init+i];
/* go back to state prior condition */
fs->pc = while_init;
luaK_S(ls, JMP, 0, 0); /* initial jump to condition */
check(ls, DO);
loopentry = luaK_getlabel(ls);
block(ls);
check_match(ls, END, WHILE, line);
cond_init = luaK_getlabel(ls);
luaK_fixjump(ls, while_init, cond_init);
/* correct `v' and copy condition to new position */
if (v.u.l.t != 0) v.u.l.t += cond_init-while_init;
for (i=0; i<cond_size; i++) luaK_primitivecode(ls, buffer[i]);
luaK_patchlist(ls, v.u.l.t, loopentry);
luaK_getlabel(ls); /* mark possible jump to this point */
}
static void repeatstat (LexState *ls, int line) {
/* repeatstat -> REPEAT block UNTIL exp1 */
int repeat_init = luaK_getlabel(ls);
expdesc v;
next(ls);
block(ls);
check_match(ls, UNTIL, REPEAT, line);
expr(ls, &v);
luaK_goiftrue(ls, &v, 0);
luaK_patchlist(ls, v.u.l.f, repeat_init);
}
static int localnamelist (LexState *ls) {
/* localnamelist -> NAME {',' NAME} */
int i = 1;
store_localvar(ls, str_checkname(ls), 0);
while (ls->token == ',') {
next(ls);
store_localvar(ls, str_checkname(ls), i++);
}
return i;
}
static int decinit (LexState *ls) {
/* decinit -> ['=' explist1] */
if (ls->token == '=') {
next(ls);
return explist1(ls);
}
else
return 0; /* no initializations */
}
static void localstat (LexState *ls) {
/* stat -> LOCAL localnamelist decinit */
FuncState *fs = ls->fs;
int nvars;
int nexps;
check_debugline(ls);
next(ls);
nvars = localnamelist(ls);
nexps = decinit(ls);
adjustlocalvars(ls, nvars, fs->lastsetline);
adjust_mult_assign(ls, nvars, nexps);
}
static int funcname (LexState *ls, expdesc *v) {
/* funcname -> NAME [':' NAME | '.' NAME] */
int needself = 0;
singlevar(ls, str_checkname(ls), v, 0);
if (ls->token == ':' || ls->token == '.') {
needself = (ls->token == ':');
next(ls);
luaK_tostack(ls, v, 1);
luaK_kstr(ls, checkname(ls));
v->k = VINDEXED;
}
return needself;
}
static int funcstat (LexState *ls, int line) {
/* funcstat -> FUNCTION funcname body */
int needself;
expdesc v;
if (ls->fs->prev) /* inside other function? */
return 0;
check_debugline(ls);
next(ls);
needself = funcname(ls, &v);
body(ls, needself, line);
luaK_storevar(ls, &v);
return 1;
}
static void namestat (LexState *ls) {
/* stat -> func | ['%'] NAME assignment */
expdesc v;
check_debugline(ls);
var_or_func(ls, &v);
if (v.k == VEXP) { /* stat -> func */
if (!luaK_lastisopen(ls)) /* is just an upvalue? */
luaK_error(ls, "syntax error");
luaK_setcallreturns(ls, 0); /* call statement uses no results */
}
else { /* stat -> ['%'] NAME assignment */
int left = assignment(ls, &v, 1);
luaK_adjuststack(ls, left); /* remove eventual garbage left on stack */
}
}
static void ifpart (LexState *ls, int line) {
/* ifpart -> cond THEN block (ELSEIF ifpart | [ELSE block] END) */
FuncState *fs = ls->fs;
expdesc v;
int elseinit;
next(ls); /* skip IF or ELSEIF */
expr(ls, &v); /* cond */
luaK_goiftrue(ls, &v, 0);
check(ls, THEN);
block(ls); /* `then' part */
luaK_S(ls, JMP, 0, 0); /* 2nd jump: over `else' part */
elseinit = luaK_getlabel(ls); /* address of 2nd jump == elseinit-1 */
if (ls->token == ELSEIF)
ifpart(ls, line);
else {
if (optional(ls, ELSE))
block(ls); /* `else' part */
check_match(ls, END, IF, line);
}
if (fs->pc > elseinit) { /* is there an `else' part? */
luaK_fixjump(ls, elseinit-1, luaK_getlabel(ls)); /* fix 2nd jump */
}
else { /* no else part */
fs->pc--; /* remove 2nd jump */
elseinit = luaK_getlabel(ls); /* `elseinit' points to end */
}
luaK_patchlist(ls, v.u.l.f, elseinit); /* fix 1st jump to `else' part */
}
static int stat (LexState *ls) {
int line = ls->linenumber; /* may be needed for error messages */
switch (ls->token) {
case IF: /* stat -> IF ifpart END */
ifpart(ls, line);
return 1;
case WHILE: /* stat -> whilestat */
whilestat(ls, line);
return 1;
case DO: { /* stat -> DO block END */
next(ls);
block(ls);
check_match(ls, END, DO, line);
return 1;
}
case REPEAT: /* stat -> repeatstat */
repeatstat(ls, line);
return 1;
case FUNCTION: /* stat -> funcstat */
return funcstat(ls, line);
case LOCAL: /* stat -> localstat */
localstat(ls);
return 1;
case NAME: case '%': /* stat -> namestat */
namestat(ls);
return 1;
case RETURN: case ';': case ELSE: case ELSEIF:
case END: case UNTIL: case EOS: /* `stat' follow */
return 0;
default:
error_unexpected(ls);
return 0; /* to avoid warnings */
}
}
static void parlist (LexState *ls) {
int nparams = 0;
int dots = 0;
switch (ls->token) {
case DOTS: /* parlist -> DOTS */
next(ls);
dots = 1;
break;
case NAME: /* parlist, tailparlist -> NAME [',' tailparlist] */
init:
store_localvar(ls, str_checkname(ls), nparams++);
if (ls->token == ',') {
next(ls);
switch (ls->token) {
case DOTS: /* tailparlist -> DOTS */
next(ls);
dots = 1;
break;
case NAME: /* tailparlist -> NAME [',' tailparlist] */
goto init;
default: luaK_error(ls, "<name> or `...' expected");
}
}
break;
case ')': break; /* parlist -> empty */
default: luaK_error(ls, "<name> or `...' expected");
}
code_args(ls, nparams, dots);
}
static void body (LexState *ls, int needself, int line) {
/* body -> '(' parlist ')' chunk END */
FuncState new_fs;
init_state(ls, &new_fs, ls->fs->f->source);
new_fs.f->lineDefined = line;
check(ls, '(');
if (needself)
add_localvar(ls, luaS_newfixed(ls->L, "self"));
parlist(ls);
check(ls, ')');
chunk(ls);
check_match(ls, END, FUNCTION, line);
close_func(ls);
func_onstack(ls, &new_fs);
}
static void ret (LexState *ls) {
/* ret -> [RETURN explist sc] */
if (ls->token == RETURN) {
int nexps; /* number of expressions returned */
check_debugline(ls);
next(ls);
nexps = explist(ls);
luaK_retcode(ls, ls->fs->nlocalvar, nexps);
ls->fs->stacksize = ls->fs->nlocalvar; /* removes all temp values */
optional(ls, ';');
}
}
/* }====================================================================== */
static void chunk (LexState *ls) {
/* chunk -> { stat [;] } ret */
while (stat(ls)) {
LUA_ASSERT(ls->L, ls->fs->stacksize == ls->fs->nlocalvar,
"stack size != # local vars");
optional(ls, ';');
}
ret(ls); /* optional return */
}