mirror of
https://github.com/lua/lua
synced 2024-11-21 20:31:22 +03:00
1996 lines
56 KiB
C
1996 lines
56 KiB
C
/*
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** $Id: lparser.c $
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** Lua Parser
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** See Copyright Notice in lua.h
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*/
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#define lparser_c
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#define LUA_CORE
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#include "lprefix.h"
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#include <limits.h>
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#include <string.h>
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#include "lua.h"
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#include "lcode.h"
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#include "ldebug.h"
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#include "ldo.h"
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#include "lfunc.h"
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#include "llex.h"
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#include "lmem.h"
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#include "lobject.h"
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#include "lopcodes.h"
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#include "lparser.h"
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#include "lstate.h"
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#include "lstring.h"
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#include "ltable.h"
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/* maximum number of local variables per function (must be smaller
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than 250, due to the bytecode format) */
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#define MAXVARS 200
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#define hasmultret(k) ((k) == VCALL || (k) == VVARARG)
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/* because all strings are unified by the scanner, the parser
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can use pointer equality for string equality */
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#define eqstr(a,b) ((a) == (b))
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/*
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** nodes for block list (list of active blocks)
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*/
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typedef struct BlockCnt {
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struct BlockCnt *previous; /* chain */
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int firstlabel; /* index of first label in this block */
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int firstgoto; /* index of first pending goto in this block */
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lu_byte nactvar; /* # active locals outside the block */
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lu_byte upval; /* true if some variable in the block is an upvalue */
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lu_byte isloop; /* true if 'block' is a loop */
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lu_byte insidetbc; /* true if inside the scope of a to-be-closed var. */
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} BlockCnt;
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/*
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** prototypes for recursive non-terminal functions
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*/
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static void statement (LexState *ls);
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static void expr (LexState *ls, expdesc *v);
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static l_noret error_expected (LexState *ls, int token) {
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luaX_syntaxerror(ls,
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luaO_pushfstring(ls->L, "%s expected", luaX_token2str(ls, token)));
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}
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static l_noret errorlimit (FuncState *fs, int limit, const char *what) {
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lua_State *L = fs->ls->L;
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const char *msg;
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int line = fs->f->linedefined;
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const char *where = (line == 0)
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? "main function"
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: luaO_pushfstring(L, "function at line %d", line);
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msg = luaO_pushfstring(L, "too many %s (limit is %d) in %s",
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what, limit, where);
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luaX_syntaxerror(fs->ls, msg);
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}
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void luaY_checklimit (FuncState *fs, int v, int l, const char *what) {
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if (l_unlikely(v > l)) errorlimit(fs, l, what);
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}
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/*
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** Test whether next token is 'c'; if so, skip it.
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*/
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static int testnext (LexState *ls, int c) {
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if (ls->t.token == c) {
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luaX_next(ls);
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return 1;
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}
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else return 0;
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}
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/*
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** Check that next token is 'c'.
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*/
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static void check (LexState *ls, int c) {
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if (ls->t.token != c)
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error_expected(ls, c);
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}
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/*
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** Check that next token is 'c' and skip it.
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*/
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static void checknext (LexState *ls, int c) {
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check(ls, c);
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luaX_next(ls);
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}
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#define check_condition(ls,c,msg) { if (!(c)) luaX_syntaxerror(ls, msg); }
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/*
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** Check that next token is 'what' and skip it. In case of error,
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** raise an error that the expected 'what' should match a 'who'
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** in line 'where' (if that is not the current line).
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*/
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static void check_match (LexState *ls, int what, int who, int where) {
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if (l_unlikely(!testnext(ls, what))) {
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if (where == ls->linenumber) /* all in the same line? */
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error_expected(ls, what); /* do not need a complex message */
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else {
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luaX_syntaxerror(ls, luaO_pushfstring(ls->L,
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"%s expected (to close %s at line %d)",
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luaX_token2str(ls, what), luaX_token2str(ls, who), where));
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}
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}
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}
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static TString *str_checkname (LexState *ls) {
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TString *ts;
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check(ls, TK_NAME);
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ts = ls->t.seminfo.ts;
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luaX_next(ls);
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return ts;
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}
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static void init_exp (expdesc *e, expkind k, int i) {
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e->f = e->t = NO_JUMP;
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e->k = k;
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e->u.info = i;
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}
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static void codestring (expdesc *e, TString *s) {
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e->f = e->t = NO_JUMP;
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e->k = VKSTR;
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e->u.strval = s;
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}
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static void codename (LexState *ls, expdesc *e) {
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codestring(e, str_checkname(ls));
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}
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/*
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** Register a new local variable in the active 'Proto' (for debug
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** information).
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*/
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static short registerlocalvar (LexState *ls, FuncState *fs,
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TString *varname) {
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Proto *f = fs->f;
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int oldsize = f->sizelocvars;
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luaM_growvector(ls->L, f->locvars, fs->ndebugvars, f->sizelocvars,
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LocVar, SHRT_MAX, "local variables");
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while (oldsize < f->sizelocvars)
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f->locvars[oldsize++].varname = NULL;
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f->locvars[fs->ndebugvars].varname = varname;
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f->locvars[fs->ndebugvars].startpc = fs->pc;
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luaC_objbarrier(ls->L, f, varname);
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return fs->ndebugvars++;
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}
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/*
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** Create a new local variable with the given 'name' and given 'kind'.
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** Return its index in the function.
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*/
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static int new_localvarkind (LexState *ls, TString *name, lu_byte kind) {
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lua_State *L = ls->L;
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FuncState *fs = ls->fs;
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Dyndata *dyd = ls->dyd;
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Vardesc *var;
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luaY_checklimit(fs, dyd->actvar.n + 1 - fs->firstlocal,
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MAXVARS, "local variables");
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luaM_growvector(L, dyd->actvar.arr, dyd->actvar.n + 1,
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dyd->actvar.size, Vardesc, SHRT_MAX, "local variables");
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var = &dyd->actvar.arr[dyd->actvar.n++];
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var->vd.kind = kind; /* default */
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var->vd.name = name;
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return dyd->actvar.n - 1 - fs->firstlocal;
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}
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/*
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** Create a new local variable with the given 'name' and regular kind.
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*/
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static int new_localvar (LexState *ls, TString *name) {
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return new_localvarkind(ls, name, VDKREG);
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}
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#define new_localvarliteral(ls,v) \
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new_localvar(ls, \
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luaX_newstring(ls, "" v, (sizeof(v)/sizeof(char)) - 1));
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/*
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** Return the "variable description" (Vardesc) of a given variable.
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** (Unless noted otherwise, all variables are referred to by their
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** compiler indices.)
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*/
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static Vardesc *getlocalvardesc (FuncState *fs, int vidx) {
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return &fs->ls->dyd->actvar.arr[fs->firstlocal + vidx];
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}
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/*
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** Convert 'nvar', a compiler index level, to its corresponding
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** register. For that, search for the highest variable below that level
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** that is in a register and uses its register index ('ridx') plus one.
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*/
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static lu_byte reglevel (FuncState *fs, int nvar) {
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while (nvar-- > 0) {
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Vardesc *vd = getlocalvardesc(fs, nvar); /* get previous variable */
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if (vd->vd.kind != RDKCTC) /* is in a register? */
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return cast_byte(vd->vd.ridx + 1);
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}
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return 0; /* no variables in registers */
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}
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/*
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** Return the number of variables in the register stack for the given
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** function.
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*/
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lu_byte luaY_nvarstack (FuncState *fs) {
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return reglevel(fs, fs->nactvar);
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}
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/*
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** Get the debug-information entry for current variable 'vidx'.
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*/
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static LocVar *localdebuginfo (FuncState *fs, int vidx) {
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Vardesc *vd = getlocalvardesc(fs, vidx);
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if (vd->vd.kind == RDKCTC)
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return NULL; /* no debug info. for constants */
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else {
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int idx = vd->vd.pidx;
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lua_assert(idx < fs->ndebugvars);
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return &fs->f->locvars[idx];
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}
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}
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/*
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** Create an expression representing variable 'vidx'
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*/
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static void init_var (FuncState *fs, expdesc *e, int vidx) {
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e->f = e->t = NO_JUMP;
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e->k = VLOCAL;
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e->u.var.vidx = cast(unsigned short, vidx);
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e->u.var.ridx = getlocalvardesc(fs, vidx)->vd.ridx;
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}
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/*
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** Raises an error if variable described by 'e' is read only
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*/
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static void check_readonly (LexState *ls, expdesc *e) {
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FuncState *fs = ls->fs;
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TString *varname = NULL; /* to be set if variable is const */
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switch (e->k) {
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case VCONST: {
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varname = ls->dyd->actvar.arr[e->u.info].vd.name;
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break;
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}
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case VLOCAL: {
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Vardesc *vardesc = getlocalvardesc(fs, e->u.var.vidx);
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if (vardesc->vd.kind != VDKREG) /* not a regular variable? */
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varname = vardesc->vd.name;
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break;
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}
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case VUPVAL: {
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Upvaldesc *up = &fs->f->upvalues[e->u.info];
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if (up->kind != VDKREG)
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varname = up->name;
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break;
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}
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default:
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return; /* other cases cannot be read-only */
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}
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if (varname) {
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const char *msg = luaO_pushfstring(ls->L,
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"attempt to assign to const variable '%s'", getstr(varname));
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luaK_semerror(ls, msg); /* error */
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}
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}
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/*
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** Start the scope for the last 'nvars' created variables.
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*/
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static void adjustlocalvars (LexState *ls, int nvars) {
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FuncState *fs = ls->fs;
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int reglevel = luaY_nvarstack(fs);
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int i;
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for (i = 0; i < nvars; i++) {
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int vidx = fs->nactvar++;
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Vardesc *var = getlocalvardesc(fs, vidx);
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var->vd.ridx = cast_byte(reglevel++);
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var->vd.pidx = registerlocalvar(ls, fs, var->vd.name);
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}
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}
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/*
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** Close the scope for all variables up to level 'tolevel'.
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** (debug info.)
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*/
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static void removevars (FuncState *fs, int tolevel) {
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fs->ls->dyd->actvar.n -= (fs->nactvar - tolevel);
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while (fs->nactvar > tolevel) {
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LocVar *var = localdebuginfo(fs, --fs->nactvar);
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if (var) /* does it have debug information? */
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var->endpc = fs->pc;
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}
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}
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/*
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** Search the upvalues of the function 'fs' for one
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** with the given 'name'.
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*/
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static int searchupvalue (FuncState *fs, TString *name) {
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int i;
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Upvaldesc *up = fs->f->upvalues;
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for (i = 0; i < fs->nups; i++) {
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if (eqstr(up[i].name, name)) return i;
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}
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return -1; /* not found */
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}
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static Upvaldesc *allocupvalue (FuncState *fs) {
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Proto *f = fs->f;
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int oldsize = f->sizeupvalues;
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luaY_checklimit(fs, fs->nups + 1, MAXUPVAL, "upvalues");
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luaM_growvector(fs->ls->L, f->upvalues, fs->nups, f->sizeupvalues,
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Upvaldesc, MAXUPVAL, "upvalues");
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while (oldsize < f->sizeupvalues)
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f->upvalues[oldsize++].name = NULL;
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return &f->upvalues[fs->nups++];
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}
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static int newupvalue (FuncState *fs, TString *name, expdesc *v) {
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Upvaldesc *up = allocupvalue(fs);
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FuncState *prev = fs->prev;
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if (v->k == VLOCAL) {
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up->instack = 1;
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up->idx = v->u.var.ridx;
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up->kind = getlocalvardesc(prev, v->u.var.vidx)->vd.kind;
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lua_assert(eqstr(name, getlocalvardesc(prev, v->u.var.vidx)->vd.name));
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}
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else {
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up->instack = 0;
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up->idx = cast_byte(v->u.info);
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up->kind = prev->f->upvalues[v->u.info].kind;
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lua_assert(eqstr(name, prev->f->upvalues[v->u.info].name));
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}
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up->name = name;
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luaC_objbarrier(fs->ls->L, fs->f, name);
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return fs->nups - 1;
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}
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/*
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** Look for an active local variable with the name 'n' in the
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** function 'fs'. If found, initialize 'var' with it and return
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** its expression kind; otherwise return -1.
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*/
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static int searchvar (FuncState *fs, TString *n, expdesc *var) {
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int i;
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for (i = cast_int(fs->nactvar) - 1; i >= 0; i--) {
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Vardesc *vd = getlocalvardesc(fs, i);
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if (eqstr(n, vd->vd.name)) { /* found? */
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if (vd->vd.kind == RDKCTC) /* compile-time constant? */
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init_exp(var, VCONST, fs->firstlocal + i);
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else /* real variable */
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init_var(fs, var, i);
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return var->k;
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}
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}
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return -1; /* not found */
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}
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/*
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** Mark block where variable at given level was defined
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** (to emit close instructions later).
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*/
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static void markupval (FuncState *fs, int level) {
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BlockCnt *bl = fs->bl;
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while (bl->nactvar > level)
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bl = bl->previous;
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bl->upval = 1;
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fs->needclose = 1;
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}
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/*
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** Mark that current block has a to-be-closed variable.
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*/
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static void marktobeclosed (FuncState *fs) {
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BlockCnt *bl = fs->bl;
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bl->upval = 1;
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bl->insidetbc = 1;
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fs->needclose = 1;
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}
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/*
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** Find a variable with the given name 'n'. If it is an upvalue, add
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** this upvalue into all intermediate functions. If it is a global, set
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** 'var' as 'void' as a flag.
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*/
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static void singlevaraux (FuncState *fs, TString *n, expdesc *var, int base) {
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if (fs == NULL) /* no more levels? */
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init_exp(var, VVOID, 0); /* default is global */
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else {
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int v = searchvar(fs, n, var); /* look up locals at current level */
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if (v >= 0) { /* found? */
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if (v == VLOCAL && !base)
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markupval(fs, var->u.var.vidx); /* local will be used as an upval */
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}
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else { /* not found as local at current level; try upvalues */
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int idx = searchupvalue(fs, n); /* try existing upvalues */
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if (idx < 0) { /* not found? */
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singlevaraux(fs->prev, n, var, 0); /* try upper levels */
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if (var->k == VLOCAL || var->k == VUPVAL) /* local or upvalue? */
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idx = newupvalue(fs, n, var); /* will be a new upvalue */
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else /* it is a global or a constant */
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return; /* don't need to do anything at this level */
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}
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init_exp(var, VUPVAL, idx); /* new or old upvalue */
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}
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}
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}
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/*
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** Find a variable with the given name 'n', handling global variables
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** too.
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*/
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static void singlevar (LexState *ls, expdesc *var) {
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TString *varname = str_checkname(ls);
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FuncState *fs = ls->fs;
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singlevaraux(fs, varname, var, 1);
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if (var->k == VVOID) { /* global name? */
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expdesc key;
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singlevaraux(fs, ls->envn, var, 1); /* get environment variable */
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lua_assert(var->k != VVOID); /* this one must exist */
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luaK_exp2anyregup(fs, var); /* but could be a constant */
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codestring(&key, varname); /* key is variable name */
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luaK_indexed(fs, var, &key); /* env[varname] */
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}
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}
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/*
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** Adjust the number of results from an expression list 'e' with 'nexps'
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** expressions to 'nvars' values.
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*/
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static void adjust_assign (LexState *ls, int nvars, int nexps, expdesc *e) {
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FuncState *fs = ls->fs;
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int needed = nvars - nexps; /* extra values needed */
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if (hasmultret(e->k)) { /* last expression has multiple returns? */
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int extra = needed + 1; /* discount last expression itself */
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if (extra < 0)
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extra = 0;
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luaK_setreturns(fs, e, extra); /* last exp. provides the difference */
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}
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else {
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if (e->k != VVOID) /* at least one expression? */
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luaK_exp2nextreg(fs, e); /* close last expression */
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if (needed > 0) /* missing values? */
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luaK_nil(fs, fs->freereg, needed); /* complete with nils */
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}
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if (needed > 0)
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luaK_reserveregs(fs, needed); /* registers for extra values */
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else /* adding 'needed' is actually a subtraction */
|
|
fs->freereg = cast_byte(fs->freereg + needed); /* remove extra values */
|
|
}
|
|
|
|
|
|
#define enterlevel(ls) luaE_incCstack(ls->L)
|
|
|
|
|
|
#define leavelevel(ls) ((ls)->L->nCcalls--)
|
|
|
|
|
|
/*
|
|
** Generates an error that a goto jumps into the scope of some
|
|
** local variable.
|
|
*/
|
|
static l_noret jumpscopeerror (LexState *ls, Labeldesc *gt) {
|
|
TString *tsname = getlocalvardesc(ls->fs, gt->nactvar)->vd.name;
|
|
const char *varname = getstr(tsname);
|
|
const char *msg = "<goto %s> at line %d jumps into the scope of local '%s'";
|
|
msg = luaO_pushfstring(ls->L, msg, getstr(gt->name), gt->line, varname);
|
|
luaK_semerror(ls, msg); /* raise the error */
|
|
}
|
|
|
|
|
|
/*
|
|
** Solves the goto at index 'g' to given 'label' and removes it
|
|
** from the list of pending gotos.
|
|
** If it jumps into the scope of some variable, raises an error.
|
|
*/
|
|
static void solvegoto (LexState *ls, int g, Labeldesc *label) {
|
|
int i;
|
|
Labellist *gl = &ls->dyd->gt; /* list of gotos */
|
|
Labeldesc *gt = &gl->arr[g]; /* goto to be resolved */
|
|
lua_assert(eqstr(gt->name, label->name));
|
|
if (l_unlikely(gt->nactvar < label->nactvar)) /* enter some scope? */
|
|
jumpscopeerror(ls, gt);
|
|
luaK_patchlist(ls->fs, gt->pc, label->pc);
|
|
for (i = g; i < gl->n - 1; i++) /* remove goto from pending list */
|
|
gl->arr[i] = gl->arr[i + 1];
|
|
gl->n--;
|
|
}
|
|
|
|
|
|
/*
|
|
** Search for an active label with the given name.
|
|
*/
|
|
static Labeldesc *findlabel (LexState *ls, TString *name) {
|
|
int i;
|
|
Dyndata *dyd = ls->dyd;
|
|
/* check labels in current function for a match */
|
|
for (i = ls->fs->firstlabel; i < dyd->label.n; i++) {
|
|
Labeldesc *lb = &dyd->label.arr[i];
|
|
if (eqstr(lb->name, name)) /* correct label? */
|
|
return lb;
|
|
}
|
|
return NULL; /* label not found */
|
|
}
|
|
|
|
|
|
/*
|
|
** Adds a new label/goto in the corresponding list.
|
|
*/
|
|
static int newlabelentry (LexState *ls, Labellist *l, TString *name,
|
|
int line, int pc) {
|
|
int n = l->n;
|
|
luaM_growvector(ls->L, l->arr, n, l->size,
|
|
Labeldesc, SHRT_MAX, "labels/gotos");
|
|
l->arr[n].name = name;
|
|
l->arr[n].line = line;
|
|
l->arr[n].nactvar = ls->fs->nactvar;
|
|
l->arr[n].close = 0;
|
|
l->arr[n].pc = pc;
|
|
l->n = n + 1;
|
|
return n;
|
|
}
|
|
|
|
|
|
static int newgotoentry (LexState *ls, TString *name, int line, int pc) {
|
|
return newlabelentry(ls, &ls->dyd->gt, name, line, pc);
|
|
}
|
|
|
|
|
|
/*
|
|
** Solves forward jumps. Check whether new label 'lb' matches any
|
|
** pending gotos in current block and solves them. Return true
|
|
** if any of the gotos need to close upvalues.
|
|
*/
|
|
static int solvegotos (LexState *ls, Labeldesc *lb) {
|
|
Labellist *gl = &ls->dyd->gt;
|
|
int i = ls->fs->bl->firstgoto;
|
|
int needsclose = 0;
|
|
while (i < gl->n) {
|
|
if (eqstr(gl->arr[i].name, lb->name)) {
|
|
needsclose |= gl->arr[i].close;
|
|
solvegoto(ls, i, lb); /* will remove 'i' from the list */
|
|
}
|
|
else
|
|
i++;
|
|
}
|
|
return needsclose;
|
|
}
|
|
|
|
|
|
/*
|
|
** Create a new label with the given 'name' at the given 'line'.
|
|
** 'last' tells whether label is the last non-op statement in its
|
|
** block. Solves all pending gotos to this new label and adds
|
|
** a close instruction if necessary.
|
|
** Returns true iff it added a close instruction.
|
|
*/
|
|
static int createlabel (LexState *ls, TString *name, int line,
|
|
int last) {
|
|
FuncState *fs = ls->fs;
|
|
Labellist *ll = &ls->dyd->label;
|
|
int l = newlabelentry(ls, ll, name, line, luaK_getlabel(fs));
|
|
if (last) { /* label is last no-op statement in the block? */
|
|
/* assume that locals are already out of scope */
|
|
ll->arr[l].nactvar = fs->bl->nactvar;
|
|
}
|
|
if (solvegotos(ls, &ll->arr[l])) { /* need close? */
|
|
luaK_codeABC(fs, OP_CLOSE, luaY_nvarstack(fs), 0, 0);
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
|
|
/*
|
|
** Adjust pending gotos to outer level of a block.
|
|
*/
|
|
static void movegotosout (FuncState *fs, BlockCnt *bl) {
|
|
int i;
|
|
Labellist *gl = &fs->ls->dyd->gt;
|
|
/* correct pending gotos to current block */
|
|
for (i = bl->firstgoto; i < gl->n; i++) { /* for each pending goto */
|
|
Labeldesc *gt = &gl->arr[i];
|
|
/* leaving a variable scope? */
|
|
if (reglevel(fs, gt->nactvar) > reglevel(fs, bl->nactvar))
|
|
gt->close |= bl->upval; /* jump may need a close */
|
|
gt->nactvar = bl->nactvar; /* update goto level */
|
|
}
|
|
}
|
|
|
|
|
|
static void enterblock (FuncState *fs, BlockCnt *bl, lu_byte isloop) {
|
|
bl->isloop = isloop;
|
|
bl->nactvar = fs->nactvar;
|
|
bl->firstlabel = fs->ls->dyd->label.n;
|
|
bl->firstgoto = fs->ls->dyd->gt.n;
|
|
bl->upval = 0;
|
|
bl->insidetbc = (fs->bl != NULL && fs->bl->insidetbc);
|
|
bl->previous = fs->bl;
|
|
fs->bl = bl;
|
|
lua_assert(fs->freereg == luaY_nvarstack(fs));
|
|
}
|
|
|
|
|
|
/*
|
|
** generates an error for an undefined 'goto'.
|
|
*/
|
|
static l_noret undefgoto (LexState *ls, Labeldesc *gt) {
|
|
const char *msg;
|
|
if (eqstr(gt->name, luaS_newliteral(ls->L, "break"))) {
|
|
msg = "break outside loop at line %d";
|
|
msg = luaO_pushfstring(ls->L, msg, gt->line);
|
|
}
|
|
else {
|
|
msg = "no visible label '%s' for <goto> at line %d";
|
|
msg = luaO_pushfstring(ls->L, msg, getstr(gt->name), gt->line);
|
|
}
|
|
luaK_semerror(ls, msg);
|
|
}
|
|
|
|
|
|
static void leaveblock (FuncState *fs) {
|
|
BlockCnt *bl = fs->bl;
|
|
LexState *ls = fs->ls;
|
|
int hasclose = 0;
|
|
lu_byte stklevel = reglevel(fs, bl->nactvar); /* level outside the block */
|
|
removevars(fs, bl->nactvar); /* remove block locals */
|
|
lua_assert(bl->nactvar == fs->nactvar); /* back to level on entry */
|
|
if (bl->isloop) /* has to fix pending breaks? */
|
|
hasclose = createlabel(ls, luaS_newliteral(ls->L, "break"), 0, 0);
|
|
if (!hasclose && bl->previous && bl->upval) /* still need a 'close'? */
|
|
luaK_codeABC(fs, OP_CLOSE, stklevel, 0, 0);
|
|
fs->freereg = stklevel; /* free registers */
|
|
ls->dyd->label.n = bl->firstlabel; /* remove local labels */
|
|
fs->bl = bl->previous; /* current block now is previous one */
|
|
if (bl->previous) /* was it a nested block? */
|
|
movegotosout(fs, bl); /* update pending gotos to enclosing block */
|
|
else {
|
|
if (bl->firstgoto < ls->dyd->gt.n) /* still pending gotos? */
|
|
undefgoto(ls, &ls->dyd->gt.arr[bl->firstgoto]); /* error */
|
|
}
|
|
}
|
|
|
|
|
|
/*
|
|
** adds a new prototype into list of prototypes
|
|
*/
|
|
static Proto *addprototype (LexState *ls) {
|
|
Proto *clp;
|
|
lua_State *L = ls->L;
|
|
FuncState *fs = ls->fs;
|
|
Proto *f = fs->f; /* prototype of current function */
|
|
if (fs->np >= f->sizep) {
|
|
int oldsize = f->sizep;
|
|
luaM_growvector(L, f->p, fs->np, f->sizep, Proto *, MAXARG_Bx, "functions");
|
|
while (oldsize < f->sizep)
|
|
f->p[oldsize++] = NULL;
|
|
}
|
|
f->p[fs->np++] = clp = luaF_newproto(L);
|
|
luaC_objbarrier(L, f, clp);
|
|
return clp;
|
|
}
|
|
|
|
|
|
/*
|
|
** codes instruction to create new closure in parent function.
|
|
** The OP_CLOSURE instruction uses the last available register,
|
|
** so that, if it invokes the GC, the GC knows which registers
|
|
** are in use at that time.
|
|
|
|
*/
|
|
static void codeclosure (LexState *ls, expdesc *v) {
|
|
FuncState *fs = ls->fs->prev;
|
|
init_exp(v, VRELOC, luaK_codeABx(fs, OP_CLOSURE, 0, fs->np - 1));
|
|
luaK_exp2nextreg(fs, v); /* fix it at the last register */
|
|
}
|
|
|
|
|
|
static void open_func (LexState *ls, FuncState *fs, BlockCnt *bl) {
|
|
Proto *f = fs->f;
|
|
fs->prev = ls->fs; /* linked list of funcstates */
|
|
fs->ls = ls;
|
|
ls->fs = fs;
|
|
fs->pc = 0;
|
|
fs->previousline = f->linedefined;
|
|
fs->iwthabs = 0;
|
|
fs->lasttarget = 0;
|
|
fs->freereg = 0;
|
|
fs->nk = 0;
|
|
fs->nabslineinfo = 0;
|
|
fs->np = 0;
|
|
fs->nups = 0;
|
|
fs->ndebugvars = 0;
|
|
fs->nactvar = 0;
|
|
fs->needclose = 0;
|
|
fs->firstlocal = ls->dyd->actvar.n;
|
|
fs->firstlabel = ls->dyd->label.n;
|
|
fs->bl = NULL;
|
|
f->source = ls->source;
|
|
luaC_objbarrier(ls->L, f, f->source);
|
|
f->maxstacksize = 2; /* registers 0/1 are always valid */
|
|
enterblock(fs, bl, 0);
|
|
}
|
|
|
|
|
|
static void close_func (LexState *ls) {
|
|
lua_State *L = ls->L;
|
|
FuncState *fs = ls->fs;
|
|
Proto *f = fs->f;
|
|
luaK_ret(fs, luaY_nvarstack(fs), 0); /* final return */
|
|
leaveblock(fs);
|
|
lua_assert(fs->bl == NULL);
|
|
luaK_finish(fs);
|
|
luaM_shrinkvector(L, f->code, f->sizecode, fs->pc, Instruction);
|
|
luaM_shrinkvector(L, f->lineinfo, f->sizelineinfo, fs->pc, ls_byte);
|
|
luaM_shrinkvector(L, f->abslineinfo, f->sizeabslineinfo,
|
|
fs->nabslineinfo, AbsLineInfo);
|
|
luaM_shrinkvector(L, f->k, f->sizek, fs->nk, TValue);
|
|
luaM_shrinkvector(L, f->p, f->sizep, fs->np, Proto *);
|
|
luaM_shrinkvector(L, f->locvars, f->sizelocvars, fs->ndebugvars, LocVar);
|
|
luaM_shrinkvector(L, f->upvalues, f->sizeupvalues, fs->nups, Upvaldesc);
|
|
ls->fs = fs->prev;
|
|
luaC_checkGC(L);
|
|
}
|
|
|
|
|
|
|
|
/*============================================================*/
|
|
/* GRAMMAR RULES */
|
|
/*============================================================*/
|
|
|
|
|
|
/*
|
|
** check whether current token is in the follow set of a block.
|
|
** 'until' closes syntactical blocks, but do not close scope,
|
|
** so it is handled in separate.
|
|
*/
|
|
static int block_follow (LexState *ls, int withuntil) {
|
|
switch (ls->t.token) {
|
|
case TK_ELSE: case TK_ELSEIF:
|
|
case TK_END: case TK_EOS:
|
|
return 1;
|
|
case TK_UNTIL: return withuntil;
|
|
default: return 0;
|
|
}
|
|
}
|
|
|
|
|
|
static void statlist (LexState *ls) {
|
|
/* statlist -> { stat [';'] } */
|
|
while (!block_follow(ls, 1)) {
|
|
if (ls->t.token == TK_RETURN) {
|
|
statement(ls);
|
|
return; /* 'return' must be last statement */
|
|
}
|
|
statement(ls);
|
|
}
|
|
}
|
|
|
|
|
|
static void fieldsel (LexState *ls, expdesc *v) {
|
|
/* fieldsel -> ['.' | ':'] NAME */
|
|
FuncState *fs = ls->fs;
|
|
expdesc key;
|
|
luaK_exp2anyregup(fs, v);
|
|
luaX_next(ls); /* skip the dot or colon */
|
|
codename(ls, &key);
|
|
luaK_indexed(fs, v, &key);
|
|
}
|
|
|
|
|
|
static void yindex (LexState *ls, expdesc *v) {
|
|
/* index -> '[' expr ']' */
|
|
luaX_next(ls); /* skip the '[' */
|
|
expr(ls, v);
|
|
luaK_exp2val(ls->fs, v);
|
|
checknext(ls, ']');
|
|
}
|
|
|
|
|
|
/*
|
|
** {======================================================================
|
|
** Rules for Constructors
|
|
** =======================================================================
|
|
*/
|
|
|
|
typedef struct ConsControl {
|
|
expdesc v; /* last list item read */
|
|
expdesc *t; /* table descriptor */
|
|
int nh; /* total number of 'record' elements */
|
|
int na; /* number of array elements already stored */
|
|
int tostore; /* number of array elements pending to be stored */
|
|
int maxtostore; /* maximum number of pending elements */
|
|
} ConsControl;
|
|
|
|
|
|
static void recfield (LexState *ls, ConsControl *cc) {
|
|
/* recfield -> (NAME | '['exp']') = exp */
|
|
FuncState *fs = ls->fs;
|
|
lu_byte reg = ls->fs->freereg;
|
|
expdesc tab, key, val;
|
|
if (ls->t.token == TK_NAME) {
|
|
luaY_checklimit(fs, cc->nh, INT_MAX / 2, "items in a constructor");
|
|
codename(ls, &key);
|
|
}
|
|
else /* ls->t.token == '[' */
|
|
yindex(ls, &key);
|
|
cc->nh++;
|
|
checknext(ls, '=');
|
|
tab = *cc->t;
|
|
luaK_indexed(fs, &tab, &key);
|
|
expr(ls, &val);
|
|
luaK_storevar(fs, &tab, &val);
|
|
fs->freereg = reg; /* free registers */
|
|
}
|
|
|
|
|
|
static void closelistfield (FuncState *fs, ConsControl *cc) {
|
|
if (cc->v.k == VVOID) return; /* there is no list item */
|
|
luaK_exp2nextreg(fs, &cc->v);
|
|
cc->v.k = VVOID;
|
|
if (cc->tostore >= cc->maxtostore) {
|
|
luaK_setlist(fs, cc->t->u.info, cc->na, cc->tostore); /* flush */
|
|
cc->na += cc->tostore;
|
|
cc->tostore = 0; /* no more items pending */
|
|
}
|
|
}
|
|
|
|
|
|
static void lastlistfield (FuncState *fs, ConsControl *cc) {
|
|
if (cc->tostore == 0) return;
|
|
if (hasmultret(cc->v.k)) {
|
|
luaK_setmultret(fs, &cc->v);
|
|
luaK_setlist(fs, cc->t->u.info, cc->na, LUA_MULTRET);
|
|
cc->na--; /* do not count last expression (unknown number of elements) */
|
|
}
|
|
else {
|
|
if (cc->v.k != VVOID)
|
|
luaK_exp2nextreg(fs, &cc->v);
|
|
luaK_setlist(fs, cc->t->u.info, cc->na, cc->tostore);
|
|
}
|
|
cc->na += cc->tostore;
|
|
}
|
|
|
|
|
|
static void listfield (LexState *ls, ConsControl *cc) {
|
|
/* listfield -> exp */
|
|
expr(ls, &cc->v);
|
|
cc->tostore++;
|
|
}
|
|
|
|
|
|
static void field (LexState *ls, ConsControl *cc) {
|
|
/* field -> listfield | recfield */
|
|
switch(ls->t.token) {
|
|
case TK_NAME: { /* may be 'listfield' or 'recfield' */
|
|
if (luaX_lookahead(ls) != '=') /* expression? */
|
|
listfield(ls, cc);
|
|
else
|
|
recfield(ls, cc);
|
|
break;
|
|
}
|
|
case '[': {
|
|
recfield(ls, cc);
|
|
break;
|
|
}
|
|
default: {
|
|
listfield(ls, cc);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
/*
|
|
** Compute a limit for how many registers a constructor can use before
|
|
** emitting a 'SETLIST' instruction, based on how many registers are
|
|
** available.
|
|
*/
|
|
static int maxtostore (FuncState *fs) {
|
|
int numfreeregs = MAX_FSTACK - fs->freereg;
|
|
if (numfreeregs >= 160) /* "lots" of registers? */
|
|
return numfreeregs / 5; /* use up to 1/5 of them */
|
|
else if (numfreeregs >= 80) /* still "enough" registers? */
|
|
return 10; /* one 'SETLIST' instruction for each 10 values */
|
|
else /* save registers for potential more nesting */
|
|
return 1;
|
|
}
|
|
|
|
|
|
static void constructor (LexState *ls, expdesc *t) {
|
|
/* constructor -> '{' [ field { sep field } [sep] ] '}'
|
|
sep -> ',' | ';' */
|
|
FuncState *fs = ls->fs;
|
|
int line = ls->linenumber;
|
|
int pc = luaK_codevABCk(fs, OP_NEWTABLE, 0, 0, 0, 0);
|
|
ConsControl cc;
|
|
luaK_code(fs, 0); /* space for extra arg. */
|
|
cc.na = cc.nh = cc.tostore = 0;
|
|
cc.t = t;
|
|
init_exp(t, VNONRELOC, fs->freereg); /* table will be at stack top */
|
|
luaK_reserveregs(fs, 1);
|
|
init_exp(&cc.v, VVOID, 0); /* no value (yet) */
|
|
checknext(ls, '{');
|
|
cc.maxtostore = maxtostore(fs);
|
|
do {
|
|
lua_assert(cc.v.k == VVOID || cc.tostore > 0);
|
|
if (ls->t.token == '}') break;
|
|
closelistfield(fs, &cc);
|
|
field(ls, &cc);
|
|
} while (testnext(ls, ',') || testnext(ls, ';'));
|
|
check_match(ls, '}', '{', line);
|
|
lastlistfield(fs, &cc);
|
|
luaK_settablesize(fs, pc, t->u.info, cc.na, cc.nh);
|
|
}
|
|
|
|
/* }====================================================================== */
|
|
|
|
|
|
static void setvararg (FuncState *fs, int nparams) {
|
|
fs->f->flag |= PF_ISVARARG;
|
|
luaK_codeABC(fs, OP_VARARGPREP, nparams, 0, 0);
|
|
}
|
|
|
|
|
|
static void parlist (LexState *ls) {
|
|
/* parlist -> [ {NAME ','} (NAME | '...') ] */
|
|
FuncState *fs = ls->fs;
|
|
Proto *f = fs->f;
|
|
int nparams = 0;
|
|
int isvararg = 0;
|
|
if (ls->t.token != ')') { /* is 'parlist' not empty? */
|
|
do {
|
|
switch (ls->t.token) {
|
|
case TK_NAME: {
|
|
new_localvar(ls, str_checkname(ls));
|
|
nparams++;
|
|
break;
|
|
}
|
|
case TK_DOTS: {
|
|
luaX_next(ls);
|
|
isvararg = 1;
|
|
break;
|
|
}
|
|
default: luaX_syntaxerror(ls, "<name> or '...' expected");
|
|
}
|
|
} while (!isvararg && testnext(ls, ','));
|
|
}
|
|
adjustlocalvars(ls, nparams);
|
|
f->numparams = cast_byte(fs->nactvar);
|
|
if (isvararg)
|
|
setvararg(fs, f->numparams); /* declared vararg */
|
|
luaK_reserveregs(fs, fs->nactvar); /* reserve registers for parameters */
|
|
}
|
|
|
|
|
|
static void body (LexState *ls, expdesc *e, int ismethod, int line) {
|
|
/* body -> '(' parlist ')' block END */
|
|
FuncState new_fs;
|
|
BlockCnt bl;
|
|
new_fs.f = addprototype(ls);
|
|
new_fs.f->linedefined = line;
|
|
open_func(ls, &new_fs, &bl);
|
|
checknext(ls, '(');
|
|
if (ismethod) {
|
|
new_localvarliteral(ls, "self"); /* create 'self' parameter */
|
|
adjustlocalvars(ls, 1);
|
|
}
|
|
parlist(ls);
|
|
checknext(ls, ')');
|
|
statlist(ls);
|
|
new_fs.f->lastlinedefined = ls->linenumber;
|
|
check_match(ls, TK_END, TK_FUNCTION, line);
|
|
codeclosure(ls, e);
|
|
close_func(ls);
|
|
}
|
|
|
|
|
|
static int explist (LexState *ls, expdesc *v) {
|
|
/* explist -> expr { ',' expr } */
|
|
int n = 1; /* at least one expression */
|
|
expr(ls, v);
|
|
while (testnext(ls, ',')) {
|
|
luaK_exp2nextreg(ls->fs, v);
|
|
expr(ls, v);
|
|
n++;
|
|
}
|
|
return n;
|
|
}
|
|
|
|
|
|
static void funcargs (LexState *ls, expdesc *f) {
|
|
FuncState *fs = ls->fs;
|
|
expdesc args;
|
|
int base, nparams;
|
|
int line = ls->linenumber;
|
|
switch (ls->t.token) {
|
|
case '(': { /* funcargs -> '(' [ explist ] ')' */
|
|
luaX_next(ls);
|
|
if (ls->t.token == ')') /* arg list is empty? */
|
|
args.k = VVOID;
|
|
else {
|
|
explist(ls, &args);
|
|
if (hasmultret(args.k))
|
|
luaK_setmultret(fs, &args);
|
|
}
|
|
check_match(ls, ')', '(', line);
|
|
break;
|
|
}
|
|
case '{': { /* funcargs -> constructor */
|
|
constructor(ls, &args);
|
|
break;
|
|
}
|
|
case TK_STRING: { /* funcargs -> STRING */
|
|
codestring(&args, ls->t.seminfo.ts);
|
|
luaX_next(ls); /* must use 'seminfo' before 'next' */
|
|
break;
|
|
}
|
|
default: {
|
|
luaX_syntaxerror(ls, "function arguments expected");
|
|
}
|
|
}
|
|
lua_assert(f->k == VNONRELOC);
|
|
base = f->u.info; /* base register for call */
|
|
if (hasmultret(args.k))
|
|
nparams = LUA_MULTRET; /* open call */
|
|
else {
|
|
if (args.k != VVOID)
|
|
luaK_exp2nextreg(fs, &args); /* close last argument */
|
|
nparams = fs->freereg - (base+1);
|
|
}
|
|
init_exp(f, VCALL, luaK_codeABC(fs, OP_CALL, base, nparams+1, 2));
|
|
luaK_fixline(fs, line);
|
|
/* call removes function and arguments and leaves one result (unless
|
|
changed later) */
|
|
fs->freereg = cast_byte(base + 1);
|
|
}
|
|
|
|
|
|
|
|
|
|
/*
|
|
** {======================================================================
|
|
** Expression parsing
|
|
** =======================================================================
|
|
*/
|
|
|
|
|
|
static void primaryexp (LexState *ls, expdesc *v) {
|
|
/* primaryexp -> NAME | '(' expr ')' */
|
|
switch (ls->t.token) {
|
|
case '(': {
|
|
int line = ls->linenumber;
|
|
luaX_next(ls);
|
|
expr(ls, v);
|
|
check_match(ls, ')', '(', line);
|
|
luaK_dischargevars(ls->fs, v);
|
|
return;
|
|
}
|
|
case TK_NAME: {
|
|
singlevar(ls, v);
|
|
return;
|
|
}
|
|
default: {
|
|
luaX_syntaxerror(ls, "unexpected symbol");
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
static void suffixedexp (LexState *ls, expdesc *v) {
|
|
/* suffixedexp ->
|
|
primaryexp { '.' NAME | '[' exp ']' | ':' NAME funcargs | funcargs } */
|
|
FuncState *fs = ls->fs;
|
|
primaryexp(ls, v);
|
|
for (;;) {
|
|
switch (ls->t.token) {
|
|
case '.': { /* fieldsel */
|
|
fieldsel(ls, v);
|
|
break;
|
|
}
|
|
case '[': { /* '[' exp ']' */
|
|
expdesc key;
|
|
luaK_exp2anyregup(fs, v);
|
|
yindex(ls, &key);
|
|
luaK_indexed(fs, v, &key);
|
|
break;
|
|
}
|
|
case ':': { /* ':' NAME funcargs */
|
|
expdesc key;
|
|
luaX_next(ls);
|
|
codename(ls, &key);
|
|
luaK_self(fs, v, &key);
|
|
funcargs(ls, v);
|
|
break;
|
|
}
|
|
case '(': case TK_STRING: case '{': { /* funcargs */
|
|
luaK_exp2nextreg(fs, v);
|
|
funcargs(ls, v);
|
|
break;
|
|
}
|
|
default: return;
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
static void simpleexp (LexState *ls, expdesc *v) {
|
|
/* simpleexp -> FLT | INT | STRING | NIL | TRUE | FALSE | ... |
|
|
constructor | FUNCTION body | suffixedexp */
|
|
switch (ls->t.token) {
|
|
case TK_FLT: {
|
|
init_exp(v, VKFLT, 0);
|
|
v->u.nval = ls->t.seminfo.r;
|
|
break;
|
|
}
|
|
case TK_INT: {
|
|
init_exp(v, VKINT, 0);
|
|
v->u.ival = ls->t.seminfo.i;
|
|
break;
|
|
}
|
|
case TK_STRING: {
|
|
codestring(v, ls->t.seminfo.ts);
|
|
break;
|
|
}
|
|
case TK_NIL: {
|
|
init_exp(v, VNIL, 0);
|
|
break;
|
|
}
|
|
case TK_TRUE: {
|
|
init_exp(v, VTRUE, 0);
|
|
break;
|
|
}
|
|
case TK_FALSE: {
|
|
init_exp(v, VFALSE, 0);
|
|
break;
|
|
}
|
|
case TK_DOTS: { /* vararg */
|
|
FuncState *fs = ls->fs;
|
|
check_condition(ls, fs->f->flag & PF_ISVARARG,
|
|
"cannot use '...' outside a vararg function");
|
|
init_exp(v, VVARARG, luaK_codeABC(fs, OP_VARARG, 0, 0, 1));
|
|
break;
|
|
}
|
|
case '{': { /* constructor */
|
|
constructor(ls, v);
|
|
return;
|
|
}
|
|
case TK_FUNCTION: {
|
|
luaX_next(ls);
|
|
body(ls, v, 0, ls->linenumber);
|
|
return;
|
|
}
|
|
default: {
|
|
suffixedexp(ls, v);
|
|
return;
|
|
}
|
|
}
|
|
luaX_next(ls);
|
|
}
|
|
|
|
|
|
static UnOpr getunopr (int op) {
|
|
switch (op) {
|
|
case TK_NOT: return OPR_NOT;
|
|
case '-': return OPR_MINUS;
|
|
case '~': return OPR_BNOT;
|
|
case '#': return OPR_LEN;
|
|
default: return OPR_NOUNOPR;
|
|
}
|
|
}
|
|
|
|
|
|
static BinOpr getbinopr (int op) {
|
|
switch (op) {
|
|
case '+': return OPR_ADD;
|
|
case '-': return OPR_SUB;
|
|
case '*': return OPR_MUL;
|
|
case '%': return OPR_MOD;
|
|
case '^': return OPR_POW;
|
|
case '/': return OPR_DIV;
|
|
case TK_IDIV: return OPR_IDIV;
|
|
case '&': return OPR_BAND;
|
|
case '|': return OPR_BOR;
|
|
case '~': return OPR_BXOR;
|
|
case TK_SHL: return OPR_SHL;
|
|
case TK_SHR: return OPR_SHR;
|
|
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;
|
|
}
|
|
}
|
|
|
|
|
|
/*
|
|
** Priority table for binary operators.
|
|
*/
|
|
static const struct {
|
|
lu_byte left; /* left priority for each binary operator */
|
|
lu_byte right; /* right priority */
|
|
} priority[] = { /* ORDER OPR */
|
|
{10, 10}, {10, 10}, /* '+' '-' */
|
|
{11, 11}, {11, 11}, /* '*' '%' */
|
|
{14, 13}, /* '^' (right associative) */
|
|
{11, 11}, {11, 11}, /* '/' '//' */
|
|
{6, 6}, {4, 4}, {5, 5}, /* '&' '|' '~' */
|
|
{7, 7}, {7, 7}, /* '<<' '>>' */
|
|
{9, 8}, /* '..' (right associative) */
|
|
{3, 3}, {3, 3}, {3, 3}, /* ==, <, <= */
|
|
{3, 3}, {3, 3}, {3, 3}, /* ~=, >, >= */
|
|
{2, 2}, {1, 1} /* and, or */
|
|
};
|
|
|
|
#define UNARY_PRIORITY 12 /* priority for unary operators */
|
|
|
|
|
|
/*
|
|
** subexpr -> (simpleexp | 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;
|
|
enterlevel(ls);
|
|
uop = getunopr(ls->t.token);
|
|
if (uop != OPR_NOUNOPR) { /* prefix (unary) operator? */
|
|
int line = ls->linenumber;
|
|
luaX_next(ls); /* skip operator */
|
|
subexpr(ls, v, UNARY_PRIORITY);
|
|
luaK_prefix(ls->fs, uop, v, line);
|
|
}
|
|
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;
|
|
int line = ls->linenumber;
|
|
luaX_next(ls); /* skip operator */
|
|
luaK_infix(ls->fs, op, v);
|
|
/* read sub-expression with higher priority */
|
|
nextop = subexpr(ls, &v2, priority[op].right);
|
|
luaK_posfix(ls->fs, op, v, &v2, line);
|
|
op = nextop;
|
|
}
|
|
leavelevel(ls);
|
|
return op; /* return first untreated operator */
|
|
}
|
|
|
|
|
|
static void expr (LexState *ls, expdesc *v) {
|
|
subexpr(ls, v, 0);
|
|
}
|
|
|
|
/* }==================================================================== */
|
|
|
|
|
|
|
|
/*
|
|
** {======================================================================
|
|
** Rules for Statements
|
|
** =======================================================================
|
|
*/
|
|
|
|
|
|
static void block (LexState *ls) {
|
|
/* block -> statlist */
|
|
FuncState *fs = ls->fs;
|
|
BlockCnt bl;
|
|
enterblock(fs, &bl, 0);
|
|
statlist(ls);
|
|
leaveblock(fs);
|
|
}
|
|
|
|
|
|
/*
|
|
** structure to chain all variables in the left-hand side of an
|
|
** assignment
|
|
*/
|
|
struct LHS_assign {
|
|
struct LHS_assign *prev;
|
|
expdesc v; /* variable (global, local, upvalue, or indexed) */
|
|
};
|
|
|
|
|
|
/*
|
|
** check whether, in an assignment to an upvalue/local variable, the
|
|
** upvalue/local variable is begin used in a previous assignment to a
|
|
** table. If so, save original upvalue/local value in a safe place and
|
|
** use this safe copy in the previous assignment.
|
|
*/
|
|
static void check_conflict (LexState *ls, struct LHS_assign *lh, expdesc *v) {
|
|
FuncState *fs = ls->fs;
|
|
lu_byte extra = fs->freereg; /* eventual position to save local variable */
|
|
int conflict = 0;
|
|
for (; lh; lh = lh->prev) { /* check all previous assignments */
|
|
if (vkisindexed(lh->v.k)) { /* assignment to table field? */
|
|
if (lh->v.k == VINDEXUP) { /* is table an upvalue? */
|
|
if (v->k == VUPVAL && lh->v.u.ind.t == v->u.info) {
|
|
conflict = 1; /* table is the upvalue being assigned now */
|
|
lh->v.k = VINDEXSTR;
|
|
lh->v.u.ind.t = extra; /* assignment will use safe copy */
|
|
}
|
|
}
|
|
else { /* table is a register */
|
|
if (v->k == VLOCAL && lh->v.u.ind.t == v->u.var.ridx) {
|
|
conflict = 1; /* table is the local being assigned now */
|
|
lh->v.u.ind.t = extra; /* assignment will use safe copy */
|
|
}
|
|
/* is index the local being assigned? */
|
|
if (lh->v.k == VINDEXED && v->k == VLOCAL &&
|
|
lh->v.u.ind.idx == v->u.var.ridx) {
|
|
conflict = 1;
|
|
lh->v.u.ind.idx = extra; /* previous assignment will use safe copy */
|
|
}
|
|
}
|
|
}
|
|
}
|
|
if (conflict) {
|
|
/* copy upvalue/local value to a temporary (in position 'extra') */
|
|
if (v->k == VLOCAL)
|
|
luaK_codeABC(fs, OP_MOVE, extra, v->u.var.ridx, 0);
|
|
else
|
|
luaK_codeABC(fs, OP_GETUPVAL, extra, v->u.info, 0);
|
|
luaK_reserveregs(fs, 1);
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Parse and compile a multiple assignment. The first "variable"
|
|
** (a 'suffixedexp') was already read by the caller.
|
|
**
|
|
** assignment -> suffixedexp restassign
|
|
** restassign -> ',' suffixedexp restassign | '=' explist
|
|
*/
|
|
static void restassign (LexState *ls, struct LHS_assign *lh, int nvars) {
|
|
expdesc e;
|
|
check_condition(ls, vkisvar(lh->v.k), "syntax error");
|
|
check_readonly(ls, &lh->v);
|
|
if (testnext(ls, ',')) { /* restassign -> ',' suffixedexp restassign */
|
|
struct LHS_assign nv;
|
|
nv.prev = lh;
|
|
suffixedexp(ls, &nv.v);
|
|
if (!vkisindexed(nv.v.k))
|
|
check_conflict(ls, lh, &nv.v);
|
|
enterlevel(ls); /* control recursion depth */
|
|
restassign(ls, &nv, nvars+1);
|
|
leavelevel(ls);
|
|
}
|
|
else { /* restassign -> '=' explist */
|
|
int nexps;
|
|
checknext(ls, '=');
|
|
nexps = explist(ls, &e);
|
|
if (nexps != nvars)
|
|
adjust_assign(ls, nvars, nexps, &e);
|
|
else {
|
|
luaK_setoneret(ls->fs, &e); /* close last expression */
|
|
luaK_storevar(ls->fs, &lh->v, &e);
|
|
return; /* avoid default */
|
|
}
|
|
}
|
|
init_exp(&e, VNONRELOC, ls->fs->freereg-1); /* default assignment */
|
|
luaK_storevar(ls->fs, &lh->v, &e);
|
|
}
|
|
|
|
|
|
static int cond (LexState *ls) {
|
|
/* cond -> exp */
|
|
expdesc v;
|
|
expr(ls, &v); /* read condition */
|
|
if (v.k == VNIL) v.k = VFALSE; /* 'falses' are all equal here */
|
|
luaK_goiftrue(ls->fs, &v);
|
|
return v.f;
|
|
}
|
|
|
|
|
|
static void gotostat (LexState *ls) {
|
|
FuncState *fs = ls->fs;
|
|
int line = ls->linenumber;
|
|
TString *name = str_checkname(ls); /* label's name */
|
|
Labeldesc *lb = findlabel(ls, name);
|
|
if (lb == NULL) /* no label? */
|
|
/* forward jump; will be resolved when the label is declared */
|
|
newgotoentry(ls, name, line, luaK_jump(fs));
|
|
else { /* found a label */
|
|
/* backward jump; will be resolved here */
|
|
int lblevel = reglevel(fs, lb->nactvar); /* label level */
|
|
if (luaY_nvarstack(fs) > lblevel) /* leaving the scope of a variable? */
|
|
luaK_codeABC(fs, OP_CLOSE, lblevel, 0, 0);
|
|
/* create jump and link it to the label */
|
|
luaK_patchlist(fs, luaK_jump(fs), lb->pc);
|
|
}
|
|
}
|
|
|
|
|
|
/*
|
|
** Break statement. Semantically equivalent to "goto break".
|
|
*/
|
|
static void breakstat (LexState *ls) {
|
|
int line = ls->linenumber;
|
|
luaX_next(ls); /* skip break */
|
|
newgotoentry(ls, luaS_newliteral(ls->L, "break"), line, luaK_jump(ls->fs));
|
|
}
|
|
|
|
|
|
/*
|
|
** Check whether there is already a label with the given 'name'.
|
|
*/
|
|
static void checkrepeated (LexState *ls, TString *name) {
|
|
Labeldesc *lb = findlabel(ls, name);
|
|
if (l_unlikely(lb != NULL)) { /* already defined? */
|
|
const char *msg = "label '%s' already defined on line %d";
|
|
msg = luaO_pushfstring(ls->L, msg, getstr(name), lb->line);
|
|
luaK_semerror(ls, msg); /* error */
|
|
}
|
|
}
|
|
|
|
|
|
static void labelstat (LexState *ls, TString *name, int line) {
|
|
/* label -> '::' NAME '::' */
|
|
checknext(ls, TK_DBCOLON); /* skip double colon */
|
|
while (ls->t.token == ';' || ls->t.token == TK_DBCOLON)
|
|
statement(ls); /* skip other no-op statements */
|
|
checkrepeated(ls, name); /* check for repeated labels */
|
|
createlabel(ls, name, line, block_follow(ls, 0));
|
|
}
|
|
|
|
|
|
static void whilestat (LexState *ls, int line) {
|
|
/* whilestat -> WHILE cond DO block END */
|
|
FuncState *fs = ls->fs;
|
|
int whileinit;
|
|
int condexit;
|
|
BlockCnt bl;
|
|
luaX_next(ls); /* skip WHILE */
|
|
whileinit = luaK_getlabel(fs);
|
|
condexit = cond(ls);
|
|
enterblock(fs, &bl, 1);
|
|
checknext(ls, TK_DO);
|
|
block(ls);
|
|
luaK_jumpto(fs, whileinit);
|
|
check_match(ls, TK_END, TK_WHILE, line);
|
|
leaveblock(fs);
|
|
luaK_patchtohere(fs, condexit); /* false conditions finish the loop */
|
|
}
|
|
|
|
|
|
static void repeatstat (LexState *ls, int line) {
|
|
/* repeatstat -> REPEAT block UNTIL cond */
|
|
int condexit;
|
|
FuncState *fs = ls->fs;
|
|
int repeat_init = luaK_getlabel(fs);
|
|
BlockCnt bl1, bl2;
|
|
enterblock(fs, &bl1, 1); /* loop block */
|
|
enterblock(fs, &bl2, 0); /* scope block */
|
|
luaX_next(ls); /* skip REPEAT */
|
|
statlist(ls);
|
|
check_match(ls, TK_UNTIL, TK_REPEAT, line);
|
|
condexit = cond(ls); /* read condition (inside scope block) */
|
|
leaveblock(fs); /* finish scope */
|
|
if (bl2.upval) { /* upvalues? */
|
|
int exit = luaK_jump(fs); /* normal exit must jump over fix */
|
|
luaK_patchtohere(fs, condexit); /* repetition must close upvalues */
|
|
luaK_codeABC(fs, OP_CLOSE, reglevel(fs, bl2.nactvar), 0, 0);
|
|
condexit = luaK_jump(fs); /* repeat after closing upvalues */
|
|
luaK_patchtohere(fs, exit); /* normal exit comes to here */
|
|
}
|
|
luaK_patchlist(fs, condexit, repeat_init); /* close the loop */
|
|
leaveblock(fs); /* finish loop */
|
|
}
|
|
|
|
|
|
/*
|
|
** Read an expression and generate code to put its results in next
|
|
** stack slot.
|
|
**
|
|
*/
|
|
static void exp1 (LexState *ls) {
|
|
expdesc e;
|
|
expr(ls, &e);
|
|
luaK_exp2nextreg(ls->fs, &e);
|
|
lua_assert(e.k == VNONRELOC);
|
|
}
|
|
|
|
|
|
/*
|
|
** Fix for instruction at position 'pc' to jump to 'dest'.
|
|
** (Jump addresses are relative in Lua). 'back' true means
|
|
** a back jump.
|
|
*/
|
|
static void fixforjump (FuncState *fs, int pc, int dest, int back) {
|
|
Instruction *jmp = &fs->f->code[pc];
|
|
int offset = dest - (pc + 1);
|
|
if (back)
|
|
offset = -offset;
|
|
if (l_unlikely(offset > MAXARG_Bx))
|
|
luaX_syntaxerror(fs->ls, "control structure too long");
|
|
SETARG_Bx(*jmp, offset);
|
|
}
|
|
|
|
|
|
/*
|
|
** Generate code for a 'for' loop.
|
|
*/
|
|
static void forbody (LexState *ls, int base, int line, int nvars, int isgen) {
|
|
/* forbody -> DO block */
|
|
static const OpCode forprep[2] = {OP_FORPREP, OP_TFORPREP};
|
|
static const OpCode forloop[2] = {OP_FORLOOP, OP_TFORLOOP};
|
|
BlockCnt bl;
|
|
FuncState *fs = ls->fs;
|
|
int prep, endfor;
|
|
checknext(ls, TK_DO);
|
|
prep = luaK_codeABx(fs, forprep[isgen], base, 0);
|
|
fs->freereg--; /* both 'forprep' remove one register from the stack */
|
|
enterblock(fs, &bl, 0); /* scope for declared variables */
|
|
adjustlocalvars(ls, nvars);
|
|
luaK_reserveregs(fs, nvars);
|
|
block(ls);
|
|
leaveblock(fs); /* end of scope for declared variables */
|
|
fixforjump(fs, prep, luaK_getlabel(fs), 0);
|
|
if (isgen) { /* generic for? */
|
|
luaK_codeABC(fs, OP_TFORCALL, base, 0, nvars);
|
|
luaK_fixline(fs, line);
|
|
}
|
|
endfor = luaK_codeABx(fs, forloop[isgen], base, 0);
|
|
fixforjump(fs, endfor, prep + 1, 1);
|
|
luaK_fixline(fs, line);
|
|
}
|
|
|
|
|
|
static void fornum (LexState *ls, TString *varname, int line) {
|
|
/* fornum -> NAME = exp,exp[,exp] forbody */
|
|
FuncState *fs = ls->fs;
|
|
int base = fs->freereg;
|
|
new_localvarliteral(ls, "(for state)");
|
|
new_localvarliteral(ls, "(for state)");
|
|
new_localvarkind(ls, varname, RDKCONST); /* control variable */
|
|
checknext(ls, '=');
|
|
exp1(ls); /* initial value */
|
|
checknext(ls, ',');
|
|
exp1(ls); /* limit */
|
|
if (testnext(ls, ','))
|
|
exp1(ls); /* optional step */
|
|
else { /* default step = 1 */
|
|
luaK_int(fs, fs->freereg, 1);
|
|
luaK_reserveregs(fs, 1);
|
|
}
|
|
adjustlocalvars(ls, 2); /* start scope for internal variables */
|
|
forbody(ls, base, line, 1, 0);
|
|
}
|
|
|
|
|
|
static void forlist (LexState *ls, TString *indexname) {
|
|
/* forlist -> NAME {,NAME} IN explist forbody */
|
|
FuncState *fs = ls->fs;
|
|
expdesc e;
|
|
int nvars = 4; /* function, state, closing, control */
|
|
int line;
|
|
int base = fs->freereg;
|
|
/* create internal variables */
|
|
new_localvarliteral(ls, "(for state)"); /* iterator function */
|
|
new_localvarliteral(ls, "(for state)"); /* state */
|
|
new_localvarliteral(ls, "(for state)"); /* closing var. (after swap) */
|
|
new_localvarkind(ls, indexname, RDKCONST); /* control variable */
|
|
/* other declared variables */
|
|
while (testnext(ls, ',')) {
|
|
new_localvar(ls, str_checkname(ls));
|
|
nvars++;
|
|
}
|
|
checknext(ls, TK_IN);
|
|
line = ls->linenumber;
|
|
adjust_assign(ls, 4, explist(ls, &e), &e);
|
|
adjustlocalvars(ls, 3); /* start scope for internal variables */
|
|
marktobeclosed(fs); /* last internal var. must be closed */
|
|
luaK_checkstack(fs, 2); /* extra space to call iterator */
|
|
forbody(ls, base, line, nvars - 3, 1);
|
|
}
|
|
|
|
|
|
static void forstat (LexState *ls, int line) {
|
|
/* forstat -> FOR (fornum | forlist) END */
|
|
FuncState *fs = ls->fs;
|
|
TString *varname;
|
|
BlockCnt bl;
|
|
enterblock(fs, &bl, 1); /* scope for loop and control variables */
|
|
luaX_next(ls); /* skip 'for' */
|
|
varname = str_checkname(ls); /* first variable name */
|
|
switch (ls->t.token) {
|
|
case '=': fornum(ls, varname, line); break;
|
|
case ',': case TK_IN: forlist(ls, varname); break;
|
|
default: luaX_syntaxerror(ls, "'=' or 'in' expected");
|
|
}
|
|
check_match(ls, TK_END, TK_FOR, line);
|
|
leaveblock(fs); /* loop scope ('break' jumps to this point) */
|
|
}
|
|
|
|
|
|
static void test_then_block (LexState *ls, int *escapelist) {
|
|
/* test_then_block -> [IF | ELSEIF] cond THEN block */
|
|
BlockCnt bl;
|
|
FuncState *fs = ls->fs;
|
|
expdesc v;
|
|
int jf; /* instruction to skip 'then' code (if condition is false) */
|
|
luaX_next(ls); /* skip IF or ELSEIF */
|
|
expr(ls, &v); /* read condition */
|
|
checknext(ls, TK_THEN);
|
|
if (ls->t.token == TK_BREAK) { /* 'if x then break' ? */
|
|
int line = ls->linenumber;
|
|
luaK_goiffalse(ls->fs, &v); /* will jump if condition is true */
|
|
luaX_next(ls); /* skip 'break' */
|
|
enterblock(fs, &bl, 0); /* must enter block before 'goto' */
|
|
newgotoentry(ls, luaS_newliteral(ls->L, "break"), line, v.t);
|
|
while (testnext(ls, ';')) {} /* skip semicolons */
|
|
if (block_follow(ls, 0)) { /* jump is the entire block? */
|
|
leaveblock(fs);
|
|
return; /* and that is it */
|
|
}
|
|
else /* must skip over 'then' part if condition is false */
|
|
jf = luaK_jump(fs);
|
|
}
|
|
else { /* regular case (not a break) */
|
|
luaK_goiftrue(ls->fs, &v); /* skip over block if condition is false */
|
|
enterblock(fs, &bl, 0);
|
|
jf = v.f;
|
|
}
|
|
statlist(ls); /* 'then' part */
|
|
leaveblock(fs);
|
|
if (ls->t.token == TK_ELSE ||
|
|
ls->t.token == TK_ELSEIF) /* followed by 'else'/'elseif'? */
|
|
luaK_concat(fs, escapelist, luaK_jump(fs)); /* must jump over it */
|
|
luaK_patchtohere(fs, jf);
|
|
}
|
|
|
|
|
|
static void ifstat (LexState *ls, int line) {
|
|
/* ifstat -> IF cond THEN block {ELSEIF cond THEN block} [ELSE block] END */
|
|
FuncState *fs = ls->fs;
|
|
int escapelist = NO_JUMP; /* exit list for finished parts */
|
|
test_then_block(ls, &escapelist); /* IF cond THEN block */
|
|
while (ls->t.token == TK_ELSEIF)
|
|
test_then_block(ls, &escapelist); /* ELSEIF cond THEN block */
|
|
if (testnext(ls, TK_ELSE))
|
|
block(ls); /* 'else' part */
|
|
check_match(ls, TK_END, TK_IF, line);
|
|
luaK_patchtohere(fs, escapelist); /* patch escape list to 'if' end */
|
|
}
|
|
|
|
|
|
static void localfunc (LexState *ls) {
|
|
expdesc b;
|
|
FuncState *fs = ls->fs;
|
|
int fvar = fs->nactvar; /* function's variable index */
|
|
new_localvar(ls, str_checkname(ls)); /* new local variable */
|
|
adjustlocalvars(ls, 1); /* enter its scope */
|
|
body(ls, &b, 0, ls->linenumber); /* function created in next register */
|
|
/* debug information will only see the variable after this point! */
|
|
localdebuginfo(fs, fvar)->startpc = fs->pc;
|
|
}
|
|
|
|
|
|
static lu_byte getlocalattribute (LexState *ls) {
|
|
/* ATTRIB -> ['<' Name '>'] */
|
|
if (testnext(ls, '<')) {
|
|
TString *ts = str_checkname(ls);
|
|
const char *attr = getstr(ts);
|
|
checknext(ls, '>');
|
|
if (strcmp(attr, "const") == 0)
|
|
return RDKCONST; /* read-only variable */
|
|
else if (strcmp(attr, "close") == 0)
|
|
return RDKTOCLOSE; /* to-be-closed variable */
|
|
else
|
|
luaK_semerror(ls,
|
|
luaO_pushfstring(ls->L, "unknown attribute '%s'", attr));
|
|
}
|
|
return VDKREG; /* regular variable */
|
|
}
|
|
|
|
|
|
static void checktoclose (FuncState *fs, int level) {
|
|
if (level != -1) { /* is there a to-be-closed variable? */
|
|
marktobeclosed(fs);
|
|
luaK_codeABC(fs, OP_TBC, reglevel(fs, level), 0, 0);
|
|
}
|
|
}
|
|
|
|
|
|
static void localstat (LexState *ls) {
|
|
/* stat -> LOCAL NAME ATTRIB { ',' NAME ATTRIB } ['=' explist] */
|
|
FuncState *fs = ls->fs;
|
|
int toclose = -1; /* index of to-be-closed variable (if any) */
|
|
Vardesc *var; /* last variable */
|
|
int vidx; /* index of last variable */
|
|
int nvars = 0;
|
|
int nexps;
|
|
expdesc e;
|
|
do {
|
|
TString *vname = str_checkname(ls);
|
|
lu_byte kind = getlocalattribute(ls);
|
|
vidx = new_localvarkind(ls, vname, kind);
|
|
if (kind == RDKTOCLOSE) { /* to-be-closed? */
|
|
if (toclose != -1) /* one already present? */
|
|
luaK_semerror(ls, "multiple to-be-closed variables in local list");
|
|
toclose = fs->nactvar + nvars;
|
|
}
|
|
nvars++;
|
|
} while (testnext(ls, ','));
|
|
if (testnext(ls, '='))
|
|
nexps = explist(ls, &e);
|
|
else {
|
|
e.k = VVOID;
|
|
nexps = 0;
|
|
}
|
|
var = getlocalvardesc(fs, vidx); /* get last variable */
|
|
if (nvars == nexps && /* no adjustments? */
|
|
var->vd.kind == RDKCONST && /* last variable is const? */
|
|
luaK_exp2const(fs, &e, &var->k)) { /* compile-time constant? */
|
|
var->vd.kind = RDKCTC; /* variable is a compile-time constant */
|
|
adjustlocalvars(ls, nvars - 1); /* exclude last variable */
|
|
fs->nactvar++; /* but count it */
|
|
}
|
|
else {
|
|
adjust_assign(ls, nvars, nexps, &e);
|
|
adjustlocalvars(ls, nvars);
|
|
}
|
|
checktoclose(fs, toclose);
|
|
}
|
|
|
|
|
|
static int funcname (LexState *ls, expdesc *v) {
|
|
/* funcname -> NAME {fieldsel} [':' NAME] */
|
|
int ismethod = 0;
|
|
singlevar(ls, v);
|
|
while (ls->t.token == '.')
|
|
fieldsel(ls, v);
|
|
if (ls->t.token == ':') {
|
|
ismethod = 1;
|
|
fieldsel(ls, v);
|
|
}
|
|
return ismethod;
|
|
}
|
|
|
|
|
|
static void funcstat (LexState *ls, int line) {
|
|
/* funcstat -> FUNCTION funcname body */
|
|
int ismethod;
|
|
expdesc v, b;
|
|
luaX_next(ls); /* skip FUNCTION */
|
|
ismethod = funcname(ls, &v);
|
|
body(ls, &b, ismethod, line);
|
|
check_readonly(ls, &v);
|
|
luaK_storevar(ls->fs, &v, &b);
|
|
luaK_fixline(ls->fs, line); /* definition "happens" in the first line */
|
|
}
|
|
|
|
|
|
static void exprstat (LexState *ls) {
|
|
/* stat -> func | assignment */
|
|
FuncState *fs = ls->fs;
|
|
struct LHS_assign v;
|
|
suffixedexp(ls, &v.v);
|
|
if (ls->t.token == '=' || ls->t.token == ',') { /* stat -> assignment ? */
|
|
v.prev = NULL;
|
|
restassign(ls, &v, 1);
|
|
}
|
|
else { /* stat -> func */
|
|
Instruction *inst;
|
|
check_condition(ls, v.v.k == VCALL, "syntax error");
|
|
inst = &getinstruction(fs, &v.v);
|
|
SETARG_C(*inst, 1); /* call statement uses no results */
|
|
}
|
|
}
|
|
|
|
|
|
static void retstat (LexState *ls) {
|
|
/* stat -> RETURN [explist] [';'] */
|
|
FuncState *fs = ls->fs;
|
|
expdesc e;
|
|
int nret; /* number of values being returned */
|
|
int first = luaY_nvarstack(fs); /* first slot to be returned */
|
|
if (block_follow(ls, 1) || ls->t.token == ';')
|
|
nret = 0; /* return no values */
|
|
else {
|
|
nret = explist(ls, &e); /* optional return values */
|
|
if (hasmultret(e.k)) {
|
|
luaK_setmultret(fs, &e);
|
|
if (e.k == VCALL && nret == 1 && !fs->bl->insidetbc) { /* tail call? */
|
|
SET_OPCODE(getinstruction(fs,&e), OP_TAILCALL);
|
|
lua_assert(GETARG_A(getinstruction(fs,&e)) == luaY_nvarstack(fs));
|
|
}
|
|
nret = LUA_MULTRET; /* return all values */
|
|
}
|
|
else {
|
|
if (nret == 1) /* only one single value? */
|
|
first = luaK_exp2anyreg(fs, &e); /* can use original slot */
|
|
else { /* values must go to the top of the stack */
|
|
luaK_exp2nextreg(fs, &e);
|
|
lua_assert(nret == fs->freereg - first);
|
|
}
|
|
}
|
|
}
|
|
luaK_ret(fs, first, nret);
|
|
testnext(ls, ';'); /* skip optional semicolon */
|
|
}
|
|
|
|
|
|
static void statement (LexState *ls) {
|
|
int line = ls->linenumber; /* may be needed for error messages */
|
|
enterlevel(ls);
|
|
switch (ls->t.token) {
|
|
case ';': { /* stat -> ';' (empty statement) */
|
|
luaX_next(ls); /* skip ';' */
|
|
break;
|
|
}
|
|
case TK_IF: { /* stat -> ifstat */
|
|
ifstat(ls, line);
|
|
break;
|
|
}
|
|
case TK_WHILE: { /* stat -> whilestat */
|
|
whilestat(ls, line);
|
|
break;
|
|
}
|
|
case TK_DO: { /* stat -> DO block END */
|
|
luaX_next(ls); /* skip DO */
|
|
block(ls);
|
|
check_match(ls, TK_END, TK_DO, line);
|
|
break;
|
|
}
|
|
case TK_FOR: { /* stat -> forstat */
|
|
forstat(ls, line);
|
|
break;
|
|
}
|
|
case TK_REPEAT: { /* stat -> repeatstat */
|
|
repeatstat(ls, line);
|
|
break;
|
|
}
|
|
case TK_FUNCTION: { /* stat -> funcstat */
|
|
funcstat(ls, line);
|
|
break;
|
|
}
|
|
case TK_LOCAL: { /* stat -> localstat */
|
|
luaX_next(ls); /* skip LOCAL */
|
|
if (testnext(ls, TK_FUNCTION)) /* local function? */
|
|
localfunc(ls);
|
|
else
|
|
localstat(ls);
|
|
break;
|
|
}
|
|
case TK_DBCOLON: { /* stat -> label */
|
|
luaX_next(ls); /* skip double colon */
|
|
labelstat(ls, str_checkname(ls), line);
|
|
break;
|
|
}
|
|
case TK_RETURN: { /* stat -> retstat */
|
|
luaX_next(ls); /* skip RETURN */
|
|
retstat(ls);
|
|
break;
|
|
}
|
|
case TK_BREAK: { /* stat -> breakstat */
|
|
breakstat(ls);
|
|
break;
|
|
}
|
|
case TK_GOTO: { /* stat -> 'goto' NAME */
|
|
luaX_next(ls); /* skip 'goto' */
|
|
gotostat(ls);
|
|
break;
|
|
}
|
|
default: { /* stat -> func | assignment */
|
|
exprstat(ls);
|
|
break;
|
|
}
|
|
}
|
|
lua_assert(ls->fs->f->maxstacksize >= ls->fs->freereg &&
|
|
ls->fs->freereg >= luaY_nvarstack(ls->fs));
|
|
ls->fs->freereg = luaY_nvarstack(ls->fs); /* free registers */
|
|
leavelevel(ls);
|
|
}
|
|
|
|
/* }====================================================================== */
|
|
|
|
|
|
/*
|
|
** compiles the main function, which is a regular vararg function with an
|
|
** upvalue named LUA_ENV
|
|
*/
|
|
static void mainfunc (LexState *ls, FuncState *fs) {
|
|
BlockCnt bl;
|
|
Upvaldesc *env;
|
|
open_func(ls, fs, &bl);
|
|
setvararg(fs, 0); /* main function is always declared vararg */
|
|
env = allocupvalue(fs); /* ...set environment upvalue */
|
|
env->instack = 1;
|
|
env->idx = 0;
|
|
env->kind = VDKREG;
|
|
env->name = ls->envn;
|
|
luaC_objbarrier(ls->L, fs->f, env->name);
|
|
luaX_next(ls); /* read first token */
|
|
statlist(ls); /* parse main body */
|
|
check(ls, TK_EOS);
|
|
close_func(ls);
|
|
}
|
|
|
|
|
|
LClosure *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff,
|
|
Dyndata *dyd, const char *name, int firstchar) {
|
|
LexState lexstate;
|
|
FuncState funcstate;
|
|
LClosure *cl = luaF_newLclosure(L, 1); /* create main closure */
|
|
setclLvalue2s(L, L->top.p, cl); /* anchor it (to avoid being collected) */
|
|
luaD_inctop(L);
|
|
lexstate.h = luaH_new(L); /* create table for scanner */
|
|
sethvalue2s(L, L->top.p, lexstate.h); /* anchor it */
|
|
luaD_inctop(L);
|
|
funcstate.f = cl->p = luaF_newproto(L);
|
|
luaC_objbarrier(L, cl, cl->p);
|
|
funcstate.f->source = luaS_new(L, name); /* create and anchor TString */
|
|
luaC_objbarrier(L, funcstate.f, funcstate.f->source);
|
|
lexstate.buff = buff;
|
|
lexstate.dyd = dyd;
|
|
dyd->actvar.n = dyd->gt.n = dyd->label.n = 0;
|
|
luaX_setinput(L, &lexstate, z, funcstate.f->source, firstchar);
|
|
mainfunc(&lexstate, &funcstate);
|
|
lua_assert(!funcstate.prev && funcstate.nups == 1 && !lexstate.fs);
|
|
/* all scopes should be correctly finished */
|
|
lua_assert(dyd->actvar.n == 0 && dyd->gt.n == 0 && dyd->label.n == 0);
|
|
L->top.p--; /* remove scanner's table */
|
|
return cl; /* closure is on the stack, too */
|
|
}
|
|
|