summaryrefslogtreecommitdiff
path: root/src/lua/lparser.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/lua/lparser.c')
-rw-r--r--src/lua/lparser.c1129
1 files changed, 1129 insertions, 0 deletions
diff --git a/src/lua/lparser.c b/src/lua/lparser.c
new file mode 100644
index 00000000..1ac1f37b
--- /dev/null
+++ b/src/lua/lparser.c
@@ -0,0 +1,1129 @@
+/*
+** $Id: lparser.c,v 1.8 2004/06/04 13:42:10 neil 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"
+
+#ifdef __MWERKS__
+/* To avoid name conflict resulting from the use of prefix header */
+#define stat lua_hack_stat
+#endif /* __MWERKS__ */
+
+
+/*
+** 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))
+ 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");
+ }
+}
+