lua/lparser.c
Roberto Ierusalimschy 7e59a8901d NEW LL(1) PARSER
1998-05-27 10:08:34 -03:00

1333 lines
33 KiB
C

/*
** $Id: $
** LL(1) Parser and code generator for Lua
** See Copyright Notice in lua.h
*/
#include <stdio.h>
#include "lauxlib.h"
#include "ldo.h"
#include "lfunc.h"
#include "llex.h"
#include "lmem.h"
#include "lopcodes.h"
#include "lparser.h"
#include "lstate.h"
#include "lstring.h"
#include "lua.h"
#include "luadebug.h"
#include "lzio.h"
/* for limit numbers in error messages */
#define MES_LIM(x) "(limit=" x ")"
/* size of a "normal" jump instruction: OpCode + 1 byte */
#define JMPSIZE 2
/* maximum number of local variables */
#define MAXLOCALS 32
#define SMAXLOCALS "32"
/* maximum number of upvalues */
#define MAXUPVALUES 16
#define SMAXUPVALUES "16"
/*
** Variable descriptor:
** must include a "exp" option because LL(1) cannot distinguish
** between variables, upvalues and function calls on first sight.
** VGLOBAL: info is constant index of global name
** VLOCAL: info is stack index
** VDOT: info is constant index of index name
** VEXP: info is pc index of "nparam" of function call (or 0 if exp is closed)
*/
typedef enum {VGLOBAL, VLOCAL, VDOT, VINDEXED, VEXP} varkind;
typedef struct {
varkind k;
int info;
} vardesc;
/*
** Expression List descriptor:
** tells number of expressions in the list,
** and, if last expression is open (a function call),
** where is its pc index of "nparam"
*/
typedef struct {
int n;
int pc; /* 0 if last expression is closed */
} listdesc;
/*
** 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 {
int n;
int k;
} constdesc;
/* state needed to generate code for a given function */
typedef struct FuncState {
TProtoFunc *f; /* current function header */
struct FuncState *prev; /* enclosuring function */
int pc; /* next position to code */
int stacksize; /* number of values on activation register */
int maxstacksize; /* maximum number of values on activation register */
int nlocalvar; /* number of active local variables */
int nupvalues; /* number of upvalues */
int nvars; /* number of entries in f->locvars */
int maxcode; /* size of f->code */
int maxvars; /* size of f->locvars (-1 if no debug information) */
int maxconsts; /* size of f->consts */
int lastsetline; /* line where last SETLINE was issued */
vardesc upvalues[MAXUPVALUES]; /* upvalues */
TaggedString *localvar[MAXLOCALS]; /* store local variable names */
} FuncState;
static int assignment (LexState *ls, vardesc *v, int nvars);
static int cond (LexState *ls);
static int funcname (LexState *ls, vardesc *v);
static int funcparams (LexState *ls, int slf);
static int listfields (LexState *ls);
static int localnamelist (LexState *ls);
static int optional (LexState *ls, int c);
static int recfields (LexState *ls);
static int stat (LexState *ls);
static void block (LexState *ls);
static void body (LexState *ls, int needself, int line);
static void chunk (LexState *ls);
static void constructor (LexState *ls);
static void decinit (LexState *ls, listdesc *d);
static void exp (LexState *ls, vardesc *v);
static void exp1 (LexState *ls);
static void exp2 (LexState *ls, vardesc *v);
static void explist (LexState *ls, listdesc *e);
static void explist1 (LexState *ls, listdesc *e);
static void ifpart (LexState *ls);
static void parlist (LexState *ls);
static void part (LexState *ls, constdesc *cd);
static void recfield (LexState *ls);
static void ret (LexState *ls);
static void simpleexp (LexState *ls, vardesc *v);
static void statlist (LexState *ls);
static void var_or_func (LexState *ls, vardesc *v);
static void var_or_func_tail (LexState *ls, vardesc *v);
static void check_pc (FuncState *fs, int n) {
if (fs->pc+n > fs->maxcode)
fs->maxcode = luaM_growvector(&fs->f->code, fs->maxcode,
Byte, codeEM, MAX_INT);
}
static void code_byte (FuncState *fs, Byte c) {
check_pc(fs, 1);
fs->f->code[fs->pc++] = c;
}
static void deltastack (LexState *ls, int delta) {
FuncState *fs = ls->fs;
fs->stacksize += delta;
if (fs->stacksize > fs->maxstacksize) {
if (fs->stacksize > 255)
luaX_error(ls, "function/expression too complex");
fs->maxstacksize = fs->stacksize;
}
}
static int code_oparg_at (LexState *ls, int pc, OpCode op, int builtin,
int arg, int delta) {
Byte *code = ls->fs->f->code;
deltastack(ls, delta);
if (arg < builtin) {
code[pc] = op+1+arg;
return 1;
}
else if (arg <= 255) {
code[pc] = op;
code[pc+1] = arg;
return 2;
}
else if (arg <= MAX_WORD) {
code[pc] = op+1+builtin;
code[pc+1] = arg>>8;
code[pc+2] = arg&0xFF;
return 3;
}
else luaX_error(ls, "code too long " MES_LIM("64K"));
return 0; /* to avoid warnings */
}
static int fix_opcode (LexState *ls, int pc, OpCode op, int builtin, int arg) {
FuncState *fs = ls->fs;
TProtoFunc *f = fs->f;
if (arg < builtin) { /* close space */
luaO_memdown(f->code+pc+1, f->code+pc+2, fs->pc-(pc+2));
fs->pc--;
}
else if (arg > 255) { /* open space */
check_pc(fs, 1);
luaO_memup(f->code+pc+1, f->code+pc, fs->pc-pc);
fs->pc++;
}
return code_oparg_at(ls, pc, op, builtin, arg, 0) - 2;
}
static void code_oparg (LexState *ls, OpCode op, int builtin, int arg,
int delta) {
check_pc(ls->fs, 3); /* maximum code size */
ls->fs->pc += code_oparg_at(ls, ls->fs->pc, op, builtin, arg, delta);
}
static void code_opcode (LexState *ls, OpCode op, int delta) {
deltastack(ls, delta);
code_byte(ls->fs, op);
}
static void code_constant (LexState *ls, int c) {
code_oparg(ls, PUSHCONSTANT, 8, c, 1);
}
static int next_constant (FuncState *fs) {
TProtoFunc *f = fs->f;
if (f->nconsts >= fs->maxconsts) {
fs->maxconsts = luaM_growvector(&f->consts, fs->maxconsts, TObject,
constantEM, MAX_WORD);
}
return f->nconsts++;
}
static int string_constant (FuncState *fs, TaggedString *s) {
TProtoFunc *f = fs->f;
int c = s->constindex;
if (!(c < f->nconsts &&
ttype(&f->consts[c]) == LUA_T_STRING && tsvalue(&f->consts[c]) == s)) {
c = next_constant(fs);
ttype(&f->consts[c]) = LUA_T_STRING;
tsvalue(&f->consts[c]) = s;
s->constindex = c; /* hint for next time */
}
return c;
}
static void code_string (LexState *ls, TaggedString *s) {
code_constant(ls, string_constant(ls->fs, s));
}
#define LIM 20
static int real_constant (FuncState *fs, real r) {
/* check whether 'r' has appeared within the last LIM entries */
TObject *cnt = fs->f->consts;
int c = fs->f->nconsts;
int lim = c < LIM ? 0 : c-LIM;
while (--c >= lim) {
if (ttype(&cnt[c]) == LUA_T_NUMBER && nvalue(&cnt[c]) == r)
return c;
}
/* not found; create a luaM_new entry */
c = next_constant(fs);
cnt = fs->f->consts; /* 'next_constant' may reallocate this vector */
ttype(&cnt[c]) = LUA_T_NUMBER;
nvalue(&cnt[c]) = r;
return c;
}
static void code_number (LexState *ls, real f) {
int i;
if (f >= 0 && f <= (real)MAX_WORD && (real)(i=(int)f) == f)
code_oparg(ls, PUSHNUMBER, 3, i, 1); /* f has a short integer value */
else
code_constant(ls, real_constant(ls->fs, f));
}
static void flush_record (LexState *ls, int n) {
if (n > 0)
code_oparg(ls, SETMAP, 1, n-1, -2*n);
}
static void flush_list (LexState *ls, int m, int n) {
if (n == 0) return;
code_oparg(ls, SETLIST, 1, m, -n);
code_byte(ls->fs, n);
}
static void luaI_registerlocalvar (FuncState *fs, TaggedString *varname,
int line) {
if (fs->maxvars != -1) { /* debug information? */
TProtoFunc *f = fs->f;
if (fs->nvars >= fs->maxvars)
fs->maxvars = luaM_growvector(&f->locvars, fs->maxvars,
LocVar, "", MAX_WORD);
f->locvars[fs->nvars].varname = varname;
f->locvars[fs->nvars].line = line;
fs->nvars++;
}
}
static void luaI_unregisterlocalvar (FuncState *fs, int line) {
luaI_registerlocalvar(fs, NULL, line);
}
static void store_localvar (LexState *ls, TaggedString *name, int n) {
FuncState *fs = ls->fs;
if (fs->nlocalvar+n < MAXLOCALS)
fs->localvar[fs->nlocalvar+n] = name;
else
luaX_error(ls, "too many local variables " MES_LIM(SMAXLOCALS));
luaI_registerlocalvar(fs, name, ls->linenumber);
}
static void add_localvar (LexState *ls, TaggedString *name) {
store_localvar(ls, name, 0);
ls->fs->nlocalvar++;
}
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, vardesc *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->info = i;
}
else { /* check shadowing */
FuncState *level = fs;
while ((level = level->prev) != NULL)
if (aux_localname(level, n) >= 0)
luaX_syntaxerror(ls, "cannot access a variable in outer scope", n->str);
var->k = VGLOBAL;
var->info = string_constant(fs, n);
}
}
static int indexupvalue (LexState *ls, TaggedString *n) {
FuncState *fs = ls->fs;
vardesc 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].info == v.info)
return i;
}
/* new one */
if (++(fs->nupvalues) > MAXUPVALUES)
luaX_error(ls, "too many upvalues in a single function "
MES_LIM(SMAXUPVALUES));
fs->upvalues[i] = v; /* i = fs->nupvalues - 1 */
return i;
}
static void pushupvalue (LexState *ls, TaggedString *n) {
int i;
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);
i = indexupvalue(ls, n);
code_oparg(ls, PUSHUPVALUE, 2, i, 1);
}
static void check_debugline (LexState *ls) {
if (lua_debug && ls->linenumber != ls->fs->lastsetline) {
code_oparg(ls, SETLINE, 0, ls->linenumber, 0);
ls->fs->lastsetline = ls->linenumber;
}
}
static void adjuststack (LexState *ls, int n) {
if (n > 0)
code_oparg(ls, POP, 2, n-1, -n);
else if (n < 0)
code_oparg(ls, PUSHNIL, 1, (-n)-1, -n);
}
static void close_exp (LexState *ls, int pc, int nresults) {
if (pc > 0) { /* expression is an open function call */
Byte *code = ls->fs->f->code;
int nparams = code[pc]; /* save nparams */
pc += fix_opcode(ls, pc-2, CALLFUNC, 2, nresults);
code[pc] = nparams; /* restore nparams */
if (nresults != MULT_RET)
deltastack(ls, nresults); /* "push" results */
deltastack(ls, -(nparams+1)); /* "pop" params and function */
}
}
static void adjust_mult_assign (LexState *ls, int nvars, listdesc *d) {
int diff = d->n - nvars;
if (d->pc == 0) { /* list is closed */
/* push or pop eventual difference between list lengths */
adjuststack(ls, diff);
}
else { /* must correct function call */
diff--; /* do not count function call itself */
if (diff < 0) { /* more variables than values */
/* function call must provide extra values */
close_exp(ls, d->pc, -diff);
}
else { /* more values than variables */
close_exp(ls, d->pc, 0); /* call should provide no value */
adjuststack(ls, diff); /* pop eventual extra values */
}
}
}
static void code_args (LexState *ls, int nparams, int dots) {
FuncState *fs = ls->fs;
fs->nlocalvar += nparams; /* "self" may already be there */
nparams = fs->nlocalvar;
if (!dots) {
fs->f->code[1] = nparams; /* fill-in arg information */
deltastack(ls, nparams);
}
else {
fs->f->code[1] = nparams+ZEROVARARG;
deltastack(ls, nparams+1);
add_localvar(ls, luaS_new("arg"));
}
}
static void lua_pushvar (LexState *ls, vardesc *var) {
switch (var->k) {
case VLOCAL:
code_oparg(ls, PUSHLOCAL, 8, var->info, 1);
break;
case VGLOBAL:
code_oparg(ls, GETGLOBAL, 8, var->info, 1);
break;
case VDOT:
code_oparg(ls, GETDOTTED, 8, var->info, 0);
break;
case VINDEXED:
code_opcode(ls, GETTABLE, -1);
break;
case VEXP:
close_exp(ls, var->info, 1); /* function must return 1 value */
break;
}
var->k = VEXP;
var->info = 0; /* now this is a closed expression */
}
static void storevar (LexState *ls, vardesc *var) {
switch (var->k) {
case VLOCAL:
code_oparg(ls, SETLOCAL, 8, var->info, -1);
break;
case VGLOBAL:
code_oparg(ls, SETGLOBAL, 8, var->info, -1);
break;
case VINDEXED:
code_opcode(ls, SETTABLE0, -3);
break;
default:
LUA_INTERNALERROR("invalid var kind to store");
}
}
static int fix_jump (LexState *ls, int pc, OpCode op, int n) {
/* jump is relative to position following jump instruction */
return fix_opcode(ls, pc, op, 0, n-(pc+JMPSIZE));
}
static void fix_upjmp (LexState *ls, OpCode op, int pos) {
int delta = ls->fs->pc+JMPSIZE - pos; /* jump is relative */
if (delta > 255) delta++;
code_oparg(ls, op, 0, delta, 0);
}
static void codeIf (LexState *ls, int thenAdd, int elseAdd) {
FuncState *fs = ls->fs;
int elseinit = elseAdd+JMPSIZE;
if (fs->pc == elseinit) { /* no else part */
fs->pc -= JMPSIZE;
elseinit = fs->pc;
}
else
elseinit += fix_jump(ls, elseAdd, JMP, fs->pc);
fix_jump(ls, thenAdd, IFFJMP, elseinit);
}
static void func_onstack (LexState *ls, FuncState *func) {
FuncState *fs = ls->fs;
int i;
int c = next_constant(fs);
ttype(&fs->f->consts[c]) = LUA_T_PROTO;
fs->f->consts[c].value.tf = func->f;
if (func->nupvalues == 0)
code_constant(ls, c);
else {
for (i=0; i<func->nupvalues; i++)
lua_pushvar(ls, &func->upvalues[i]);
code_oparg(ls, CLOSURE, 0, c, -func->nupvalues+1);
code_byte(fs, func->nupvalues);
}
}
static void init_state (LexState *ls, FuncState *fs, TaggedString *filename) {
TProtoFunc *f = luaF_newproto();
fs->prev = ls->fs; /* linked list of funcstates */
ls->fs = fs;
fs->stacksize = 0;
fs->maxstacksize = 0;
fs->nlocalvar = 0;
fs->nupvalues = 0;
fs->lastsetline = 0;
fs->f = f;
f->fileName = filename;
fs->pc = 0;
fs->maxcode = 0;
f->code = NULL;
fs->maxconsts = 0;
if (lua_debug)
fs->nvars = fs->maxvars = 0;
else
fs->maxvars = -1; /* flag no debug information */
code_byte(fs, 0); /* to be filled with stacksize */
code_byte(fs, 0); /* to be filled with arg information */
}
static void close_func (LexState *ls) {
FuncState *fs = ls->fs;
TProtoFunc *f = fs->f;
code_opcode(ls, ENDCODE, 0);
f->code[0] = fs->maxstacksize;
f->code = luaM_reallocvector(f->code, fs->pc, Byte);
f->consts = luaM_reallocvector(f->consts, f->nconsts, TObject);
if (fs->maxvars != -1) { /* debug information? */
luaI_registerlocalvar(fs, NULL, -1); /* flag end of vector */
f->locvars = luaM_reallocvector(f->locvars, fs->nvars, LocVar);
}
ls->fs = fs->prev;
}
static int expfollow [] = {ELSE, ELSEIF, THEN, IF, WHILE, REPEAT, DO, NAME,
LOCAL, FUNCTION, END, UNTIL, RETURN, ')', ']', '}', ';', EOS, ',', 0};
static int is_in (int tok, int *toks) {
int *t = toks;
while (*t) {
if (*t == tok)
return t-toks;
t++;
}
return -1;
}
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(ls, token, t);
sprintf(buff, "`%s' expected", t);
luaX_error(ls, buff);
}
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(ls, what, t_what);
luaX_token2str(ls, who, t_who);
sprintf(buff, "`%s' expected (to close `%s' at line %d)",
t_what, t_who, where);
luaX_error(ls, buff);
}
}
static void check (LexState *ls, int c) {
if (ls->token != c)
error_expected(ls, c);
next(ls);
}
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 TaggedString *checkname (LexState *ls) {
TaggedString *ts;
if (ls->token != NAME)
luaX_error(ls, "`NAME' expected");
ts = ls->seminfo.ts;
next(ls);
return ts;
}
static int optional (LexState *ls, int c) {
if (ls->token == c) {
next(ls);
return 1;
}
else return 0;
}
TProtoFunc *luaY_parser (ZIO *z) {
struct LexState lexstate;
struct FuncState funcstate;
luaX_setinput(&lexstate, z);
init_state(&lexstate, &funcstate, luaS_new(zname(z)));
next(&lexstate); /* read first token */
chunk(&lexstate);
if (lexstate.token != EOS)
luaX_error(&lexstate, "<eof> expected");
close_func(&lexstate);
return funcstate.f;
}
/*============================================================*/
/* GRAMAR RULES */
/*============================================================*/
static void chunk (LexState *ls) {
/* chunk -> statlist ret */
statlist(ls);
ret(ls);
}
static void statlist (LexState *ls) {
/* statlist -> { stat [;] } */
while (stat(ls)) {
LUA_ASSERT(ls->fs->stacksize == ls->fs->nlocalvar,
"stack size != # local vars");
optional(ls, ';');
}
}
static int stat (LexState *ls) {
int line = ls->linenumber; /* may be needed for error messages */
FuncState *fs = ls->fs;
switch (ls->token) {
case IF: { /* stat -> IF ifpart END */
next(ls);
ifpart(ls);
check_match(ls, END, IF, line);
return 1;
}
case WHILE: { /* stat -> WHILE cond DO block END */
TProtoFunc *f = fs->f;
int while_init = fs->pc;
int cond_end, cond_size;
next(ls);
cond_end = cond(ls);
check(ls, DO);
block(ls);
check_match(ls, END, WHILE, line);
cond_size = cond_end-while_init;
check_pc(fs, cond_size);
memcpy(f->code+fs->pc, f->code+while_init, cond_size);
luaO_memdown(f->code+while_init, f->code+cond_end, fs->pc-while_init);
while_init += JMPSIZE + fix_jump(ls, while_init, JMP, fs->pc-cond_size);
fix_upjmp(ls, IFTUPJMP, while_init);
return 1;
}
case DO: { /* stat -> DO block END */
next(ls);
block(ls);
check_match(ls, END, DO, line);
return 1;
}
case REPEAT: { /* stat -> REPEAT block UNTIL exp1 */
int repeat_init = fs->pc;
next(ls);
block(ls);
check_match(ls, UNTIL, REPEAT, line);
exp1(ls);
fix_upjmp(ls, IFFUPJMP, repeat_init);
deltastack(ls, -1); /* pops condition */
return 1;
}
case FUNCTION: { /* stat -> FUNCTION funcname body */
int needself;
vardesc v;
if (ls->fs->prev) /* inside other function? */
return 0;
check_debugline(ls);
next(ls);
needself = funcname(ls, &v);
body(ls, needself, line);
storevar(ls, &v);
return 1;
}
case LOCAL: { /* stat -> LOCAL localnamelist decinit */
listdesc d;
int nvars;
check_debugline(ls);
next(ls);
nvars = localnamelist(ls);
decinit(ls, &d);
ls->fs->nlocalvar += nvars;
adjust_mult_assign(ls, nvars, &d);
return 1;
}
case NAME: case '%': { /* stat -> func | ['%'] NAME assignment */
vardesc v;
check_debugline(ls);
var_or_func(ls, &v);
if (v.k == VEXP) { /* stat -> func */
if (v.info == 0) /* is just an upper value? */
luaX_error(ls, "syntax error");
close_exp(ls, v.info, 0);
}
else {
int left = assignment(ls, &v, 1); /* stat -> ['%'] NAME assignment */
adjuststack(ls, left); /* remove eventual 'garbage' left on stack */
}
return 1;
}
case RETURN: case ';': case ELSE: case ELSEIF:
case END: case UNTIL: case EOS: /* 'stat' follow */
return 0;
default:
luaX_error(ls, "<statement> expected");
return 0; /* to avoid warnings */
}
}
static int SaveWord (LexState *ls) {
int res = ls->fs->pc;
check_pc(ls->fs, JMPSIZE);
ls->fs->pc += JMPSIZE; /* open space */
return res;
}
static int SaveWordPop (LexState *ls) {
deltastack(ls, -1); /* pop condition */
return SaveWord(ls);
}
static int cond (LexState *ls) {
/* cond -> exp1 */
exp1(ls);
return SaveWordPop(ls);
}
static void block (LexState *ls) {
/* block -> chunk */
FuncState *fs = ls->fs;
int nlocalvar = fs->nlocalvar;
chunk(ls);
adjuststack(ls, fs->nlocalvar - nlocalvar);
for (; fs->nlocalvar > nlocalvar; fs->nlocalvar--)
luaI_unregisterlocalvar(fs, ls->linenumber);
}
static int funcname (LexState *ls, vardesc *v) {
/* funcname -> NAME [':' NAME | '.' NAME] */
int needself = 0;
singlevar(ls, checkname(ls), v, 0);
if (ls->token == ':' || ls->token == '.') {
needself = (ls->token == ':');
next(ls);
lua_pushvar(ls, v);
code_string(ls, checkname(ls));
v->k = VINDEXED;
}
return needself;
}
static void body (LexState *ls, int needself, int line) {
/* body -> '(' parlist ')' chunk END */
FuncState newfs;
init_state(ls, &newfs, ls->fs->f->fileName);
newfs.f->lineDefined = line;
check(ls, '(');
if (needself)
add_localvar(ls, luaS_new("self"));
parlist(ls);
check(ls, ')');
chunk(ls);
check_match(ls, END, FUNCTION, line);
close_func(ls);
func_onstack(ls, &newfs);
}
static void ifpart (LexState *ls) {
/* ifpart -> cond THEN block [ELSE block | ELSEIF ifpart] */
int c = cond(ls);
int e;
check(ls, THEN);
block(ls);
e = SaveWord(ls);
switch (ls->token) {
case ELSE:
next(ls);
block(ls);
break;
case ELSEIF:
next(ls);
ifpart(ls);
break;
}
codeIf(ls, c, e);
}
static void ret (LexState *ls) {
/* ret -> [RETURN explist sc] */
if (ls->token == RETURN) {
listdesc e;
check_debugline(ls);
next(ls);
explist(ls, &e);
close_exp(ls, e.pc, MULT_RET);
code_oparg(ls, RETCODE, 0, ls->fs->nlocalvar, 0);
ls->fs->stacksize = ls->fs->nlocalvar; /* removes all temp values */
optional(ls, ';');
}
}
/*
** For parsing expressions, we use a classic stack with priorities.
** Each binary operator is represented by its index in "binop" + FIRSTBIN
** (EQ=2, NE=3, ... '^'=13). The unary NOT is 0 and UNMINUS is 1.
*/
/* code of first binary operator */
#define FIRSTBIN 2
/* code for power operator (last operator)
** '^' needs special treatment because it is right associative
*/
#define POW 13
static int binop [] = {EQ, NE, '>', '<', LE, GE, CONC,
'+', '-', '*', '/', '^', 0};
static int priority [POW+1] = {5, 5, 1, 1, 1, 1, 1, 1, 2, 3, 3, 4, 4, 6};
static OpCode opcodes [POW+1] = {NOTOP, MINUSOP, EQOP, NEQOP, GTOP, LTOP,
LEOP, GEOP, CONCOP, ADDOP, SUBOP, MULTOP, DIVOP, POWOP};
#define MAXOPS 20
typedef struct {
int ops[MAXOPS];
int top;
} stack_op;
static void exp1 (LexState *ls) {
vardesc v;
exp(ls, &v);
lua_pushvar(ls, &v);
if (is_in(ls->token, expfollow) < 0)
luaX_error(ls, "ill formed expression");
}
static void exp (LexState *ls, vardesc *v) {
exp2(ls, v);
while (ls->token == AND || ls->token == OR) {
int is_and = (ls->token == AND);
int pc;
lua_pushvar(ls, v);
next(ls);
pc = SaveWordPop(ls);
exp2(ls, v);
lua_pushvar(ls, v);
fix_jump(ls, pc, (is_and?ONFJMP:ONTJMP), ls->fs->pc);
}
}
static void push (LexState *ls, stack_op *s, int op) {
if (s->top == MAXOPS)
luaX_error(ls, "expression too complex");
s->ops[s->top++] = op;
}
static void prefix (LexState *ls, stack_op *s) {
while (ls->token == NOT || ls->token == '-') {
push(ls, s, ls->token==NOT?0:1);
next(ls);
}
}
static void pop_to (LexState *ls, stack_op *s, int prio) {
int op;
while (s->top > 0 && priority[(op=s->ops[s->top-1])] >= prio) {
code_opcode(ls, opcodes[op], op<FIRSTBIN?0:-1);
s->top--;
}
}
static void exp2 (LexState *ls, vardesc *v) {
stack_op s;
int op;
s.top = 0;
prefix(ls, &s);
simpleexp(ls, v);
while ((op = is_in(ls->token, binop)) >= 0) {
op += FIRSTBIN;
lua_pushvar(ls, v);
/* '^' is right associative, so must 'simulate' a higher priority */
pop_to(ls, &s, (op == POW)?priority[op]+1:priority[op]);
push(ls, &s, op);
next(ls);
prefix(ls, &s);
simpleexp(ls, v);
lua_pushvar(ls, v);
}
if (s.top > 0) {
lua_pushvar(ls, v);
pop_to(ls, &s, 0);
}
}
static void simpleexp (LexState *ls, vardesc *v) {
check_debugline(ls);
switch (ls->token) {
case '(': /* simpleexp -> '(' exp ')' */
next(ls);
exp(ls, v);
check(ls, ')');
break;
case NUMBER: /* simpleexp -> NUMBER */
code_number(ls, ls->seminfo.r);
next(ls);
v->k = VEXP; v->info = 0;
break;
case STRING: /* simpleexp -> STRING */
code_string(ls, ls->seminfo.ts);
next(ls);
v->k = VEXP; v->info = 0;
break;
case NIL: /* simpleexp -> NIL */
adjuststack(ls, -1);
next(ls);
v->k = VEXP; v->info = 0;
break;
case '{': /* simpleexp -> constructor */
constructor(ls);
v->k = VEXP; v->info = 0;
break;
case FUNCTION: { /* simpleexp -> FUNCTION body */
int line = ls->linenumber;
next(ls);
body(ls, 0, line);
v->k = VEXP; v->info = 0;
break;
}
case NAME: case '%':
var_or_func(ls, v);
break;
default:
luaX_error(ls, "<expression> expected");
break;
}
}
static void var_or_func (LexState *ls, vardesc *v) {
/* var_or_func -> ['%'] NAME var_or_func_tail */
if (optional(ls, '%')) { /* upvalue? */
pushupvalue(ls, checkname(ls));
v->k = VEXP;
v->info = 0; /* closed expression */
}
else /* variable name */
singlevar(ls, checkname(ls), v, 0);
var_or_func_tail(ls, v);
}
static void var_or_func_tail (LexState *ls, vardesc *v) {
for (;;) {
switch (ls->token) {
case '.': /* var_or_func_tail -> '.' NAME */
next(ls);
lua_pushvar(ls, v); /* 'v' must be on stack */
v->k = VDOT;
v->info = string_constant(ls->fs, checkname(ls));
break;
case '[': /* var_or_func_tail -> '[' exp1 ']' */
next(ls);
lua_pushvar(ls, v); /* 'v' must be on stack */
exp1(ls);
check(ls, ']');
v->k = VINDEXED;
break;
case ':': /* var_or_func_tail -> ':' NAME funcparams */
next(ls);
lua_pushvar(ls, v); /* 'v' must be on stack */
code_oparg(ls, PUSHSELF, 8, string_constant(ls->fs, checkname(ls)), 1);
v->k = VEXP;
v->info = funcparams(ls, 1);
break;
case '(': case STRING: case '{': /* var_or_func_tail -> funcparams */
lua_pushvar(ls, v); /* 'v' must be on stack */
v->k = VEXP;
v->info = funcparams(ls, 0);
break;
default: return; /* should be follow... */
}
}
}
static int funcparams (LexState *ls, int slf) {
FuncState *fs = ls->fs;
int nparams = 1; /* default value */
switch (ls->token) {
case '(': { /* funcparams -> '(' explist ')' */
listdesc e;
next(ls);
explist(ls, &e);
check(ls, ')');
close_exp(ls, e.pc, 1);
nparams = e.n;
break;
}
case '{': /* funcparams -> constructor */
constructor(ls);
break;
case STRING: /* funcparams -> STRING */
next(ls);
break;
default:
luaX_error(ls, "function arguments expected");
break;
}
code_byte(fs, 0); /* save space for opcode */
code_byte(fs, 0); /* and nresult */
code_byte(fs, nparams+slf);
return fs->pc-1;
}
static void explist (LexState *ls, listdesc *d) {
switch (ls->token) {
case ELSE: case ELSEIF: case END: case UNTIL:
case EOS: case ';': case ')':
d->pc = 0;
d->n = 0;
break;
default:
explist1(ls, d);
}
}
static void explist1 (LexState *ls, listdesc *d) {
vardesc v;
exp(ls, &v);
d->n = 1;
while (ls->token == ',') {
d->n++;
lua_pushvar(ls, &v);
next(ls);
exp(ls, &v);
}
if (v.k == VEXP)
d->pc = v.info;
else {
lua_pushvar(ls, &v);
d->pc = 0;
}
}
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, 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: luaX_error(ls, "NAME or `...' expected");
}
}
break;
case ')': break; /* parlist -> empty */
default: luaX_error(ls, "NAME or `...' expected");
}
code_args(ls, nparams, dots);
}
static int localnamelist (LexState *ls) {
/* localnamelist -> NAME {',' NAME} */
int i = 1;
store_localvar(ls, checkname(ls), 0);
while (ls->token == ',') {
next(ls);
store_localvar(ls, checkname(ls), i++);
}
return i;
}
static void decinit (LexState *ls, listdesc *d) {
/* decinit -> ['=' explist1] */
if (ls->token == '=') {
next(ls);
explist1(ls, d);
}
else {
d->n = 0;
d->pc = 0;
}
}
static int assignment (LexState *ls, vardesc *v, int nvars) {
int left = 0;
/* dotted variables <a.x> must be stored like regular indexed vars <a["x"]> */
if (v->k == VDOT) {
code_constant(ls, v->info);
v->k = VINDEXED;
}
if (ls->token == ',') { /* assignment -> ',' NAME assignment */
vardesc nv;
next(ls);
var_or_func(ls, &nv);
if (nv.k == VEXP)
luaX_error(ls, "syntax error");
left = assignment(ls, &nv, nvars+1);
}
else { /* assignment -> '=' explist1 */
listdesc d;
check(ls, '=');
explist1(ls, &d);
adjust_mult_assign(ls, nvars, &d);
}
if (v->k != VINDEXED || left+(nvars-1) == 0) {
/* global/local var or indexed var without values in between */
storevar(ls, v);
}
else { /* indexed var with values in between*/
code_oparg(ls, SETTABLE, 0, left+(nvars-1), -1);
left += 2; /* table/index are not popped, because they aren't on top */
}
return left;
}
static void constructor (LexState *ls) {
/* constructor -> '{' part [';' part] '}' */
int line = ls->linenumber;
int pc = SaveWord(ls);
int nelems;
constdesc cd;
deltastack(ls, 1);
check(ls, '{');
part(ls, &cd);
nelems = cd.n;
if (ls->token == ';') {
constdesc other_cd;
next(ls);
part(ls, &other_cd);
if (cd.k == other_cd.k) /* repeated parts? */
luaX_error(ls, "invalid constructor syntax");
nelems += other_cd.n;
}
check_match(ls, '}', '{', line);
fix_opcode(ls, pc, CREATEARRAY, 2, nelems);
}
static void part (LexState *ls, constdesc *cd) {
switch (ls->token) {
case ';': case '}': /* part -> empty */
cd->n = 0;
cd->k = ls->token;
return;
case NAME: {
vardesc v;
exp(ls, &v);
if (ls->token == '=') {
switch (v.k) {
case VGLOBAL:
code_constant(ls, v.info);
break;
case VLOCAL:
code_string(ls, ls->fs->localvar[v.info]);
break;
default:
luaX_error(ls, "`=' unexpected");
}
next(ls);
exp1(ls);
cd->n = recfields(ls);
cd->k = 1; /* record */
}
else {
lua_pushvar(ls, &v);
cd->n = listfields(ls);
cd->k = 0; /* list */
}
break;
}
case '[': /* part -> recfield recfields */
recfield(ls);
cd->n = recfields(ls);
cd->k = 1; /* record */
break;
default: /* part -> exp1 listfields */
exp1(ls);
cd->n = listfields(ls);
cd->k = 0; /* list */
break;
}
}
static int recfields (LexState *ls) {
/* recfields -> { ',' recfield } [','] */
int n = 1; /* one has been read before */
while (ls->token == ',') {
next(ls);
if (ls->token == ';' || ls->token == '}')
break;
recfield(ls);
n++;
if (n%RFIELDS_PER_FLUSH == 0)
flush_record(ls, RFIELDS_PER_FLUSH);
}
flush_record(ls, n%RFIELDS_PER_FLUSH);
return n;
}
static int listfields (LexState *ls) {
/* listfields -> { ',' exp1 } [','] */
int n = 1; /* one has been read before */
while (ls->token == ',') {
next(ls);
if (ls->token == ';' || ls->token == '}')
break;
exp1(ls);
n++;
if (n%LFIELDS_PER_FLUSH == 0)
flush_list(ls, n/LFIELDS_PER_FLUSH - 1, LFIELDS_PER_FLUSH);
}
flush_list(ls, n/LFIELDS_PER_FLUSH, n%LFIELDS_PER_FLUSH);
return n;
}
static void recfield (LexState *ls) {
/* recfield -> (NAME | '['exp1']') = exp1 */
switch (ls->token) {
case NAME:
code_string(ls, checkname(ls));
break;
case '[':
next(ls);
exp1(ls);
check(ls, ']');
break;
default: luaX_error(ls, "NAME or `[' expected");
}
check(ls, '=');
exp1(ls);
}