diff options
Diffstat (limited to 'source/luametatex/source/luacore/lua54/src/lparser.c')
-rw-r--r-- | source/luametatex/source/luacore/lua54/src/lparser.c | 1967 |
1 files changed, 1967 insertions, 0 deletions
diff --git a/source/luametatex/source/luacore/lua54/src/lparser.c b/source/luametatex/source/luacore/lua54/src/lparser.c new file mode 100644 index 000000000..fe693b571 --- /dev/null +++ b/source/luametatex/source/luacore/lua54/src/lparser.c @@ -0,0 +1,1967 @@ +/* +** $Id: lparser.c $ +** Lua Parser +** See Copyright Notice in lua.h +*/ + +#define lparser_c +#define LUA_CORE + +#include "lprefix.h" + + +#include <limits.h> +#include <string.h> + +#include "lua.h" + +#include "lcode.h" +#include "ldebug.h" +#include "ldo.h" +#include "lfunc.h" +#include "llex.h" +#include "lmem.h" +#include "lobject.h" +#include "lopcodes.h" +#include "lparser.h" +#include "lstate.h" +#include "lstring.h" +#include "ltable.h" + + + +/* maximum number of local variables per function (must be smaller + than 250, due to the bytecode format) */ +#define MAXVARS 200 + + +#define hasmultret(k) ((k) == VCALL || (k) == VVARARG) + + +/* because all strings are unified by the scanner, the parser + can use pointer equality for string equality */ +#define eqstr(a,b) ((a) == (b)) + + +/* +** nodes for block list (list of active blocks) +*/ +typedef struct BlockCnt { + struct BlockCnt *previous; /* chain */ + int firstlabel; /* index of first label in this block */ + int firstgoto; /* index of first pending goto in this block */ + lu_byte nactvar; /* # active locals outside the block */ + lu_byte upval; /* true if some variable in the block is an upvalue */ + lu_byte isloop; /* true if 'block' is a loop */ + lu_byte insidetbc; /* true if inside the scope of a to-be-closed var. */ +} BlockCnt; + + + +/* +** prototypes for recursive non-terminal functions +*/ +static void statement (LexState *ls); +static void expr (LexState *ls, expdesc *v); + + +static l_noret error_expected (LexState *ls, int token) { + luaX_syntaxerror(ls, + luaO_pushfstring(ls->L, "%s expected", luaX_token2str(ls, token))); +} + + +static l_noret errorlimit (FuncState *fs, int limit, const char *what) { + lua_State *L = fs->ls->L; + const char *msg; + int line = fs->f->linedefined; + const char *where = (line == 0) + ? "main function" + : luaO_pushfstring(L, "function at line %d", line); + msg = luaO_pushfstring(L, "too many %s (limit is %d) in %s", + what, limit, where); + luaX_syntaxerror(fs->ls, msg); +} + + +static void checklimit (FuncState *fs, int v, int l, const char *what) { + if (v > l) errorlimit(fs, l, what); +} + + +/* +** Test whether next token is 'c'; if so, skip it. +*/ +static int testnext (LexState *ls, int c) { + if (ls->t.token == c) { + luaX_next(ls); + return 1; + } + else return 0; +} + + +/* +** Check that next token is 'c'. +*/ +static void check (LexState *ls, int c) { + if (ls->t.token != c) + error_expected(ls, c); +} + + +/* +** Check that next token is 'c' and skip it. +*/ +static void checknext (LexState *ls, int c) { + check(ls, c); + luaX_next(ls); +} + + +#define check_condition(ls,c,msg) { if (!(c)) luaX_syntaxerror(ls, msg); } + + +/* +** Check that next token is 'what' and skip it. In case of error, +** raise an error that the expected 'what' should match a 'who' +** in line 'where' (if that is not the current line). +*/ +static void check_match (LexState *ls, int what, int who, int where) { + if (l_unlikely(!testnext(ls, what))) { + if (where == ls->linenumber) /* all in the same line? */ + error_expected(ls, what); /* do not need a complex message */ + else { + luaX_syntaxerror(ls, luaO_pushfstring(ls->L, + "%s expected (to close %s at line %d)", + luaX_token2str(ls, what), luaX_token2str(ls, who), where)); + } + } +} + + +static TString *str_checkname (LexState *ls) { + TString *ts; + check(ls, TK_NAME); + ts = ls->t.seminfo.ts; + luaX_next(ls); + return ts; +} + + +static void init_exp (expdesc *e, expkind k, int i) { + e->f = e->t = NO_JUMP; + e->k = k; + e->u.info = i; +} + + +static void codestring (expdesc *e, TString *s) { + e->f = e->t = NO_JUMP; + e->k = VKSTR; + e->u.strval = s; +} + + +static void codename (LexState *ls, expdesc *e) { + codestring(e, str_checkname(ls)); +} + + +/* +** Register a new local variable in the active 'Proto' (for debug +** information). +*/ +static int registerlocalvar (LexState *ls, FuncState *fs, TString *varname) { + Proto *f = fs->f; + int oldsize = f->sizelocvars; + luaM_growvector(ls->L, f->locvars, fs->ndebugvars, f->sizelocvars, + LocVar, SHRT_MAX, "local variables"); + while (oldsize < f->sizelocvars) + f->locvars[oldsize++].varname = NULL; + f->locvars[fs->ndebugvars].varname = varname; + f->locvars[fs->ndebugvars].startpc = fs->pc; + luaC_objbarrier(ls->L, f, varname); + return fs->ndebugvars++; +} + + +/* +** Create a new local variable with the given 'name'. Return its index +** in the function. +*/ +static int new_localvar (LexState *ls, TString *name) { + lua_State *L = ls->L; + FuncState *fs = ls->fs; + Dyndata *dyd = ls->dyd; + Vardesc *var; + checklimit(fs, dyd->actvar.n + 1 - fs->firstlocal, + MAXVARS, "local variables"); + luaM_growvector(L, dyd->actvar.arr, dyd->actvar.n + 1, + dyd->actvar.size, Vardesc, USHRT_MAX, "local variables"); + var = &dyd->actvar.arr[dyd->actvar.n++]; + var->vd.kind = VDKREG; /* default */ + var->vd.name = name; + return dyd->actvar.n - 1 - fs->firstlocal; +} + +#define new_localvarliteral(ls,v) \ + new_localvar(ls, \ + luaX_newstring(ls, "" v, (sizeof(v)/sizeof(char)) - 1)); + + + +/* +** Return the "variable description" (Vardesc) of a given variable. +** (Unless noted otherwise, all variables are referred to by their +** compiler indices.) +*/ +static Vardesc *getlocalvardesc (FuncState *fs, int vidx) { + return &fs->ls->dyd->actvar.arr[fs->firstlocal + vidx]; +} + + +/* +** Convert 'nvar', a compiler index level, to its corresponding +** register. For that, search for the highest variable below that level +** that is in a register and uses its register index ('ridx') plus one. +*/ +static int reglevel (FuncState *fs, int nvar) { + while (nvar-- > 0) { + Vardesc *vd = getlocalvardesc(fs, nvar); /* get previous variable */ + if (vd->vd.kind != RDKCTC) /* is in a register? */ + return vd->vd.ridx + 1; + } + return 0; /* no variables in registers */ +} + + +/* +** Return the number of variables in the register stack for the given +** function. +*/ +int luaY_nvarstack (FuncState *fs) { + return reglevel(fs, fs->nactvar); +} + + +/* +** Get the debug-information entry for current variable 'vidx'. +*/ +static LocVar *localdebuginfo (FuncState *fs, int vidx) { + Vardesc *vd = getlocalvardesc(fs, vidx); + if (vd->vd.kind == RDKCTC) + return NULL; /* no debug info. for constants */ + else { + int idx = vd->vd.pidx; + lua_assert(idx < fs->ndebugvars); + return &fs->f->locvars[idx]; + } +} + + +/* +** Create an expression representing variable 'vidx' +*/ +static void init_var (FuncState *fs, expdesc *e, int vidx) { + e->f = e->t = NO_JUMP; + e->k = VLOCAL; + e->u.var.vidx = vidx; + e->u.var.ridx = getlocalvardesc(fs, vidx)->vd.ridx; +} + + +/* +** Raises an error if variable described by 'e' is read only +*/ +static void check_readonly (LexState *ls, expdesc *e) { + FuncState *fs = ls->fs; + TString *varname = NULL; /* to be set if variable is const */ + switch (e->k) { + case VCONST: { + varname = ls->dyd->actvar.arr[e->u.info].vd.name; + break; + } + case VLOCAL: { + Vardesc *vardesc = getlocalvardesc(fs, e->u.var.vidx); + if (vardesc->vd.kind != VDKREG) /* not a regular variable? */ + varname = vardesc->vd.name; + break; + } + case VUPVAL: { + Upvaldesc *up = &fs->f->upvalues[e->u.info]; + if (up->kind != VDKREG) + varname = up->name; + break; + } + default: + return; /* other cases cannot be read-only */ + } + if (varname) { + const char *msg = luaO_pushfstring(ls->L, + "attempt to assign to const variable '%s'", getstr(varname)); + luaK_semerror(ls, msg); /* error */ + } +} + + +/* +** Start the scope for the last 'nvars' created variables. +*/ +static void adjustlocalvars (LexState *ls, int nvars) { + FuncState *fs = ls->fs; + int reglevel = luaY_nvarstack(fs); + int i; + for (i = 0; i < nvars; i++) { + int vidx = fs->nactvar++; + Vardesc *var = getlocalvardesc(fs, vidx); + var->vd.ridx = reglevel++; + var->vd.pidx = registerlocalvar(ls, fs, var->vd.name); + } +} + + +/* +** Close the scope for all variables up to level 'tolevel'. +** (debug info.) +*/ +static void removevars (FuncState *fs, int tolevel) { + fs->ls->dyd->actvar.n -= (fs->nactvar - tolevel); + while (fs->nactvar > tolevel) { + LocVar *var = localdebuginfo(fs, --fs->nactvar); + if (var) /* does it have debug information? */ + var->endpc = fs->pc; + } +} + + +/* +** Search the upvalues of the function 'fs' for one +** with the given 'name'. +*/ +static int searchupvalue (FuncState *fs, TString *name) { + int i; + Upvaldesc *up = fs->f->upvalues; + for (i = 0; i < fs->nups; i++) { + if (eqstr(up[i].name, name)) return i; + } + return -1; /* not found */ +} + + +static Upvaldesc *allocupvalue (FuncState *fs) { + Proto *f = fs->f; + int oldsize = f->sizeupvalues; + checklimit(fs, fs->nups + 1, MAXUPVAL, "upvalues"); + luaM_growvector(fs->ls->L, f->upvalues, fs->nups, f->sizeupvalues, + Upvaldesc, MAXUPVAL, "upvalues"); + while (oldsize < f->sizeupvalues) + f->upvalues[oldsize++].name = NULL; + return &f->upvalues[fs->nups++]; +} + + +static int newupvalue (FuncState *fs, TString *name, expdesc *v) { + Upvaldesc *up = allocupvalue(fs); + FuncState *prev = fs->prev; + if (v->k == VLOCAL) { + up->instack = 1; + up->idx = v->u.var.ridx; + up->kind = getlocalvardesc(prev, v->u.var.vidx)->vd.kind; + lua_assert(eqstr(name, getlocalvardesc(prev, v->u.var.vidx)->vd.name)); + } + else { + up->instack = 0; + up->idx = cast_byte(v->u.info); + up->kind = prev->f->upvalues[v->u.info].kind; + lua_assert(eqstr(name, prev->f->upvalues[v->u.info].name)); + } + up->name = name; + luaC_objbarrier(fs->ls->L, fs->f, name); + return fs->nups - 1; +} + + +/* +** Look for an active local variable with the name 'n' in the +** function 'fs'. If found, initialize 'var' with it and return +** its expression kind; otherwise return -1. +*/ +static int searchvar (FuncState *fs, TString *n, expdesc *var) { + int i; + for (i = cast_int(fs->nactvar) - 1; i >= 0; i--) { + Vardesc *vd = getlocalvardesc(fs, i); + if (eqstr(n, vd->vd.name)) { /* found? */ + if (vd->vd.kind == RDKCTC) /* compile-time constant? */ + init_exp(var, VCONST, fs->firstlocal + i); + else /* real variable */ + init_var(fs, var, i); + return var->k; + } + } + return -1; /* not found */ +} + + +/* +** Mark block where variable at given level was defined +** (to emit close instructions later). +*/ +static void markupval (FuncState *fs, int level) { + BlockCnt *bl = fs->bl; + while (bl->nactvar > level) + bl = bl->previous; + bl->upval = 1; + fs->needclose = 1; +} + + +/* +** Mark that current block has a to-be-closed variable. +*/ +static void marktobeclosed (FuncState *fs) { + BlockCnt *bl = fs->bl; + bl->upval = 1; + bl->insidetbc = 1; + fs->needclose = 1; +} + + +/* +** Find a variable with the given name 'n'. If it is an upvalue, add +** this upvalue into all intermediate functions. If it is a global, set +** 'var' as 'void' as a flag. +*/ +static void singlevaraux (FuncState *fs, TString *n, expdesc *var, int base) { + if (fs == NULL) /* no more levels? */ + init_exp(var, VVOID, 0); /* default is global */ + else { + int v = searchvar(fs, n, var); /* look up locals at current level */ + if (v >= 0) { /* found? */ + if (v == VLOCAL && !base) + markupval(fs, var->u.var.vidx); /* local will be used as an upval */ + } + else { /* not found as local at current level; try upvalues */ + int idx = searchupvalue(fs, n); /* try existing upvalues */ + if (idx < 0) { /* not found? */ + singlevaraux(fs->prev, n, var, 0); /* try upper levels */ + if (var->k == VLOCAL || var->k == VUPVAL) /* local or upvalue? */ + idx = newupvalue(fs, n, var); /* will be a new upvalue */ + else /* it is a global or a constant */ + return; /* don't need to do anything at this level */ + } + init_exp(var, VUPVAL, idx); /* new or old upvalue */ + } + } +} + + +/* +** Find a variable with the given name 'n', handling global variables +** too. +*/ +static void singlevar (LexState *ls, expdesc *var) { + TString *varname = str_checkname(ls); + FuncState *fs = ls->fs; + singlevaraux(fs, varname, var, 1); + if (var->k == VVOID) { /* global name? */ + expdesc key; + singlevaraux(fs, ls->envn, var, 1); /* get environment variable */ + lua_assert(var->k != VVOID); /* this one must exist */ + luaK_exp2anyregup(fs, var); /* but could be a constant */ + codestring(&key, varname); /* key is variable name */ + luaK_indexed(fs, var, &key); /* env[varname] */ + } +} + + +/* +** Adjust the number of results from an expression list 'e' with 'nexps' +** expressions to 'nvars' values. +*/ +static void adjust_assign (LexState *ls, int nvars, int nexps, expdesc *e) { + FuncState *fs = ls->fs; + int needed = nvars - nexps; /* extra values needed */ + if (hasmultret(e->k)) { /* last expression has multiple returns? */ + int extra = needed + 1; /* discount last expression itself */ + if (extra < 0) + extra = 0; + luaK_setreturns(fs, e, extra); /* last exp. provides the difference */ + } + else { + if (e->k != VVOID) /* at least one expression? */ + luaK_exp2nextreg(fs, e); /* close last expression */ + if (needed > 0) /* missing values? */ + luaK_nil(fs, fs->freereg, needed); /* complete with nils */ + } + if (needed > 0) + luaK_reserveregs(fs, needed); /* registers for extra values */ + else /* adding 'needed' is actually a subtraction */ + 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) { + const char *varname = getstr(getlocalvardesc(ls->fs, gt->nactvar)->vd.name); + 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 goto's. +** 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 goto's */ + 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 goto's 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 goto's 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; + int 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 */ +} ConsControl; + + +static void recfield (LexState *ls, ConsControl *cc) { + /* recfield -> (NAME | '['exp']') = exp */ + FuncState *fs = ls->fs; + int reg = ls->fs->freereg; + expdesc tab, key, val; + if (ls->t.token == TK_NAME) { + checklimit(fs, cc->nh, MAX_INT, "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 == LFIELDS_PER_FLUSH) { + 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; + } + } +} + + +static void constructor (LexState *ls, expdesc *t) { + /* constructor -> '{' [ field { sep field } [sep] ] '}' + sep -> ',' | ';' */ + FuncState *fs = ls->fs; + int line = ls->linenumber; + int pc = luaK_codeABC(fs, OP_NEWTABLE, 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, '{'); + 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->is_vararg = 1; + 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, int line) { + FuncState *fs = ls->fs; + expdesc args; + int base, nparams; + 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); + fs->freereg = base+1; /* call remove function and arguments and leaves + (unless changed) one result */ +} + + + + +/* +** {====================================================================== +** 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; + int line = ls->linenumber; + 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, line); + break; + } + case '(': case TK_STRING: case '{': { /* funcargs */ + luaK_exp2nextreg(fs, v); + funcargs(ls, v, line); + 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->is_vararg, + "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; + int 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); + 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_localvarliteral(ls, "(for state)"); + new_localvar(ls, varname); + 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, 3); /* control 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 = 5; /* gen, state, control, toclose, 'indexname' */ + int line; + int base = fs->freereg; + /* create control variables */ + new_localvarliteral(ls, "(for state)"); + new_localvarliteral(ls, "(for state)"); + new_localvarliteral(ls, "(for state)"); + new_localvarliteral(ls, "(for state)"); + /* create declared variables */ + new_localvar(ls, indexname); + 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, 4); /* control variables */ + marktobeclosed(fs); /* last control var. must be closed */ + luaK_checkstack(fs, 3); /* extra space to call generator */ + forbody(ls, base, line, nvars - 4, 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 int getlocalattribute (LexState *ls) { + /* ATTRIB -> ['<' Name '>'] */ + if (testnext(ls, '<')) { + const char *attr = getstr(str_checkname(ls)); + 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, kind; /* index and kind of last variable */ + int nvars = 0; + int nexps; + expdesc e; + do { + vidx = new_localvar(ls, str_checkname(ls)); + kind = getlocalattribute(ls); + getlocalvardesc(fs, vidx)->vd.kind = 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, cl); /* anchor it (to avoid being collected) */ + luaD_inctop(L); + lexstate.h = luaH_new(L); /* create table for scanner */ + sethvalue2s(L, L->top, 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--; /* remove scanner's table */ + return cl; /* closure is on the stack, too */ +} + |