0,0 → 1,1620 |
/* |
** $Id: lparser.c,v 2.124 2011/12/02 13:23:56 roberto Exp $ |
** Lua Parser |
** See Copyright Notice in lua.h |
*/ |
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#include <string.h> |
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#define lparser_c |
#define LUA_CORE |
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#include "lua.h" |
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#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" |
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/* maximum number of local variables per function (must be smaller |
than 250, due to the bytecode format) */ |
#define MAXVARS 200 |
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#define hasmultret(k) ((k) == VCALL || (k) == VVARARG) |
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/* |
** nodes for block list (list of active blocks) |
*/ |
typedef struct BlockCnt { |
struct BlockCnt *previous; /* chain */ |
short firstlabel; /* index of first label in this block */ |
short 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 */ |
} BlockCnt; |
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/* |
** prototypes for recursive non-terminal functions |
*/ |
static void statement (LexState *ls); |
static void expr (LexState *ls, expdesc *v); |
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static void anchor_token (LexState *ls) { |
/* last token from outer function must be EOS */ |
lua_assert(ls->fs != NULL || ls->t.token == TK_EOS); |
if (ls->t.token == TK_NAME || ls->t.token == TK_STRING) { |
TString *ts = ls->t.seminfo.ts; |
luaX_newstring(ls, getstr(ts), ts->tsv.len); |
} |
} |
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/* semantic error */ |
static l_noret semerror (LexState *ls, const char *msg) { |
ls->t.token = 0; /* remove 'near to' from final message */ |
luaX_syntaxerror(ls, msg); |
} |
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static l_noret error_expected (LexState *ls, int token) { |
luaX_syntaxerror(ls, |
luaO_pushfstring(ls->L, "%s expected", luaX_token2str(ls, token))); |
} |
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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); |
} |
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static void checklimit (FuncState *fs, int v, int l, const char *what) { |
if (v > l) errorlimit(fs, l, what); |
} |
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static int testnext (LexState *ls, int c) { |
if (ls->t.token == c) { |
luaX_next(ls); |
return 1; |
} |
else return 0; |
} |
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static void check (LexState *ls, int c) { |
if (ls->t.token != c) |
error_expected(ls, c); |
} |
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static void checknext (LexState *ls, int c) { |
check(ls, c); |
luaX_next(ls); |
} |
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#define check_condition(ls,c,msg) { if (!(c)) luaX_syntaxerror(ls, msg); } |
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static void check_match (LexState *ls, int what, int who, int where) { |
if (!testnext(ls, what)) { |
if (where == ls->linenumber) |
error_expected(ls, what); |
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)); |
} |
} |
} |
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static TString *str_checkname (LexState *ls) { |
TString *ts; |
check(ls, TK_NAME); |
ts = ls->t.seminfo.ts; |
luaX_next(ls); |
return ts; |
} |
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static void init_exp (expdesc *e, expkind k, int i) { |
e->f = e->t = NO_JUMP; |
e->k = k; |
e->u.info = i; |
} |
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static void codestring (LexState *ls, expdesc *e, TString *s) { |
init_exp(e, VK, luaK_stringK(ls->fs, s)); |
} |
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static void checkname (LexState *ls, expdesc *e) { |
codestring(ls, e, str_checkname(ls)); |
} |
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static int registerlocalvar (LexState *ls, TString *varname) { |
FuncState *fs = ls->fs; |
Proto *f = fs->f; |
int oldsize = f->sizelocvars; |
luaM_growvector(ls->L, f->locvars, fs->nlocvars, f->sizelocvars, |
LocVar, SHRT_MAX, "local variables"); |
while (oldsize < f->sizelocvars) f->locvars[oldsize++].varname = NULL; |
f->locvars[fs->nlocvars].varname = varname; |
luaC_objbarrier(ls->L, f, varname); |
return fs->nlocvars++; |
} |
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static void new_localvar (LexState *ls, TString *name) { |
FuncState *fs = ls->fs; |
Dyndata *dyd = ls->dyd; |
int reg = registerlocalvar(ls, name); |
checklimit(fs, dyd->actvar.n + 1 - fs->firstlocal, |
MAXVARS, "local variables"); |
luaM_growvector(ls->L, dyd->actvar.arr, dyd->actvar.n + 1, |
dyd->actvar.size, Vardesc, MAX_INT, "local variables"); |
dyd->actvar.arr[dyd->actvar.n++].idx = cast(short, reg); |
} |
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static void new_localvarliteral_ (LexState *ls, const char *name, size_t sz) { |
new_localvar(ls, luaX_newstring(ls, name, sz)); |
} |
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#define new_localvarliteral(ls,v) \ |
new_localvarliteral_(ls, "" v, (sizeof(v)/sizeof(char))-1) |
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static LocVar *getlocvar (FuncState *fs, int i) { |
int idx = fs->ls->dyd->actvar.arr[fs->firstlocal + i].idx; |
lua_assert(idx < fs->nlocvars); |
return &fs->f->locvars[idx]; |
} |
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static void adjustlocalvars (LexState *ls, int nvars) { |
FuncState *fs = ls->fs; |
fs->nactvar = cast_byte(fs->nactvar + nvars); |
for (; nvars; nvars--) { |
getlocvar(fs, fs->nactvar - nvars)->startpc = fs->pc; |
} |
} |
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static void removevars (FuncState *fs, int tolevel) { |
fs->ls->dyd->actvar.n -= (fs->nactvar - tolevel); |
while (fs->nactvar > tolevel) |
getlocvar(fs, --fs->nactvar)->endpc = fs->pc; |
} |
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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 */ |
} |
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static int newupvalue (FuncState *fs, TString *name, expdesc *v) { |
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; |
f->upvalues[fs->nups].instack = (v->k == VLOCAL); |
f->upvalues[fs->nups].idx = cast_byte(v->u.info); |
f->upvalues[fs->nups].name = name; |
luaC_objbarrier(fs->ls->L, f, name); |
return fs->nups++; |
} |
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static int searchvar (FuncState *fs, TString *n) { |
int i; |
for (i=fs->nactvar-1; i >= 0; i--) { |
if (eqstr(n, getlocvar(fs, i)->varname)) |
return i; |
} |
return -1; /* not found */ |
} |
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/* |
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; |
} |
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/* |
Find variable with given name 'n'. If it is an upvalue, add this |
upvalue into all intermediate functions. |
*/ |
static int singlevaraux (FuncState *fs, TString *n, expdesc *var, int base) { |
if (fs == NULL) /* no more levels? */ |
return VVOID; /* default is global */ |
else { |
int v = searchvar(fs, n); /* look up locals at current level */ |
if (v >= 0) { /* found? */ |
init_exp(var, VLOCAL, v); /* variable is local */ |
if (!base) |
markupval(fs, v); /* local will be used as an upval */ |
return VLOCAL; |
} |
else { /* not found as local at current level; try upvalues */ |
int idx = searchupvalue(fs, n); /* try existing upvalues */ |
if (idx < 0) { /* not found? */ |
if (singlevaraux(fs->prev, n, var, 0) == VVOID) /* try upper levels */ |
return VVOID; /* not found; is a global */ |
/* else was LOCAL or UPVAL */ |
idx = newupvalue(fs, n, var); /* will be a new upvalue */ |
} |
init_exp(var, VUPVAL, idx); |
return VUPVAL; |
} |
} |
} |
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static void singlevar (LexState *ls, expdesc *var) { |
TString *varname = str_checkname(ls); |
FuncState *fs = ls->fs; |
if (singlevaraux(fs, varname, var, 1) == VVOID) { /* global name? */ |
expdesc key; |
singlevaraux(fs, ls->envn, var, 1); /* get environment variable */ |
lua_assert(var->k == VLOCAL || var->k == VUPVAL); |
codestring(ls, &key, varname); /* key is variable name */ |
luaK_indexed(fs, var, &key); /* env[varname] */ |
} |
} |
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static void adjust_assign (LexState *ls, int nvars, int nexps, expdesc *e) { |
FuncState *fs = ls->fs; |
int extra = nvars - nexps; |
if (hasmultret(e->k)) { |
extra++; /* includes call itself */ |
if (extra < 0) extra = 0; |
luaK_setreturns(fs, e, extra); /* last exp. provides the difference */ |
if (extra > 1) luaK_reserveregs(fs, extra-1); |
} |
else { |
if (e->k != VVOID) luaK_exp2nextreg(fs, e); /* close last expression */ |
if (extra > 0) { |
int reg = fs->freereg; |
luaK_reserveregs(fs, extra); |
luaK_nil(fs, reg, extra); |
} |
} |
} |
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static void enterlevel (LexState *ls) { |
lua_State *L = ls->L; |
++L->nCcalls; |
checklimit(ls->fs, L->nCcalls, LUAI_MAXCCALLS, "C levels"); |
} |
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#define leavelevel(ls) ((ls)->L->nCcalls--) |
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static void closegoto (LexState *ls, int g, Labeldesc *label) { |
int i; |
FuncState *fs = ls->fs; |
Labellist *gl = &ls->dyd->gt; |
Labeldesc *gt = &gl->arr[g]; |
lua_assert(eqstr(gt->name, label->name)); |
if (gt->nactvar < label->nactvar) { |
TString *vname = getlocvar(fs, gt->nactvar)->varname; |
const char *msg = luaO_pushfstring(ls->L, |
"<goto %s> at line %d jumps into the scope of local " LUA_QS, |
getstr(gt->name), gt->line, getstr(vname)); |
semerror(ls, msg); |
} |
luaK_patchlist(fs, gt->pc, label->pc); |
/* remove goto from pending list */ |
for (i = g; i < gl->n - 1; i++) |
gl->arr[i] = gl->arr[i + 1]; |
gl->n--; |
} |
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/* |
** try to close a goto with existing labels; this solves backward jumps |
*/ |
static int findlabel (LexState *ls, int g) { |
int i; |
BlockCnt *bl = ls->fs->bl; |
Dyndata *dyd = ls->dyd; |
Labeldesc *gt = &dyd->gt.arr[g]; |
/* check labels in current block for a match */ |
for (i = bl->firstlabel; i < dyd->label.n; i++) { |
Labeldesc *lb = &dyd->label.arr[i]; |
if (eqstr(lb->name, gt->name)) { /* correct label? */ |
if (gt->nactvar > lb->nactvar && |
(bl->upval || dyd->label.n > bl->firstlabel)) |
luaK_patchclose(ls->fs, gt->pc, lb->nactvar); |
closegoto(ls, g, lb); /* close it */ |
return 1; |
} |
} |
return 0; /* label not found; cannot close goto */ |
} |
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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].pc = pc; |
l->n++; |
return n; |
} |
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/* |
** check whether new label 'lb' matches any pending gotos in current |
** block; solves forward jumps |
*/ |
static void findgotos (LexState *ls, Labeldesc *lb) { |
Labellist *gl = &ls->dyd->gt; |
int i = ls->fs->bl->firstgoto; |
while (i < gl->n) { |
if (eqstr(gl->arr[i].name, lb->name)) |
closegoto(ls, i, lb); |
else |
i++; |
} |
} |
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/* |
** "export" pending gotos to outer level, to check them against |
** outer labels; if the block being exited has upvalues, and |
** the goto exits the scope of any variable (which can be the |
** upvalue), close those variables being exited. |
*/ |
static void movegotosout (FuncState *fs, BlockCnt *bl) { |
int i = bl->firstgoto; |
Labellist *gl = &fs->ls->dyd->gt; |
/* correct pending gotos to current block and try to close it |
with visible labels */ |
while (i < gl->n) { |
Labeldesc *gt = &gl->arr[i]; |
if (gt->nactvar > bl->nactvar) { |
if (bl->upval) |
luaK_patchclose(fs, gt->pc, bl->nactvar); |
gt->nactvar = bl->nactvar; |
} |
if (!findlabel(fs->ls, i)) |
i++; /* move to next one */ |
} |
} |
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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->previous = fs->bl; |
fs->bl = bl; |
lua_assert(fs->freereg == fs->nactvar); |
} |
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/* |
** create a label named "break" to resolve break statements |
*/ |
static void breaklabel (LexState *ls) { |
TString *n = luaS_new(ls->L, "break"); |
int l = newlabelentry(ls, &ls->dyd->label, n, 0, ls->fs->pc); |
findgotos(ls, &ls->dyd->label.arr[l]); |
} |
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/* |
** generates an error for an undefined 'goto'; choose appropriate |
** message when label name is a reserved word (which can only be 'break') |
*/ |
static l_noret undefgoto (LexState *ls, Labeldesc *gt) { |
const char *msg = (gt->name->tsv.reserved > 0) |
? "<%s> at line %d not inside a loop" |
: "no visible label " LUA_QS " for <goto> at line %d"; |
msg = luaO_pushfstring(ls->L, msg, getstr(gt->name), gt->line); |
semerror(ls, msg); |
} |
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static void leaveblock (FuncState *fs) { |
BlockCnt *bl = fs->bl; |
LexState *ls = fs->ls; |
if (bl->previous && bl->upval) { |
/* create a 'jump to here' to close upvalues */ |
int j = luaK_jump(fs); |
luaK_patchclose(fs, j, bl->nactvar); |
luaK_patchtohere(fs, j); |
} |
if (bl->isloop) |
breaklabel(ls); /* close pending breaks */ |
fs->bl = bl->previous; |
removevars(fs, bl->nactvar); |
lua_assert(bl->nactvar == fs->nactvar); |
fs->freereg = fs->nactvar; /* free registers */ |
ls->dyd->label.n = bl->firstlabel; /* remove local labels */ |
if (bl->previous) /* inner block? */ |
movegotosout(fs, bl); /* update pending gotos to outer block */ |
else if (bl->firstgoto < ls->dyd->gt.n) /* pending gotos in outer block? */ |
undefgoto(ls, &ls->dyd->gt.arr[bl->firstgoto]); /* error */ |
} |
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/* |
** adds prototype being created into its parent list of prototypes |
** and codes instruction to create new closure |
*/ |
static void codeclosure (LexState *ls, Proto *clp, expdesc *v) { |
FuncState *fs = ls->fs->prev; |
Proto *f = fs->f; /* prototype of function creating new closure */ |
if (fs->np >= f->sizep) { |
int oldsize = f->sizep; |
luaM_growvector(ls->L, f->p, fs->np, f->sizep, Proto *, |
MAXARG_Bx, "functions"); |
while (oldsize < f->sizep) f->p[oldsize++] = NULL; |
} |
f->p[fs->np++] = clp; |
luaC_objbarrier(ls->L, f, clp); |
init_exp(v, VRELOCABLE, luaK_codeABx(fs, OP_CLOSURE, 0, fs->np-1)); |
luaK_exp2nextreg(fs, v); /* fix it at stack top (for GC) */ |
} |
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static void open_func (LexState *ls, FuncState *fs, BlockCnt *bl) { |
lua_State *L = ls->L; |
Proto *f; |
fs->prev = ls->fs; /* linked list of funcstates */ |
fs->ls = ls; |
ls->fs = fs; |
fs->pc = 0; |
fs->lasttarget = 0; |
fs->jpc = NO_JUMP; |
fs->freereg = 0; |
fs->nk = 0; |
fs->np = 0; |
fs->nups = 0; |
fs->nlocvars = 0; |
fs->nactvar = 0; |
fs->firstlocal = ls->dyd->actvar.n; |
fs->bl = NULL; |
f = luaF_newproto(L); |
fs->f = f; |
f->source = ls->source; |
f->maxstacksize = 2; /* registers 0/1 are always valid */ |
/* anchor prototype (to avoid being collected) */ |
setptvalue2s(L, L->top, f); |
incr_top(L); |
fs->h = luaH_new(L); |
/* anchor table of constants (to avoid being collected) */ |
sethvalue2s(L, L->top, fs->h); |
incr_top(L); |
enterblock(fs, bl, 0); |
} |
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static void close_func (LexState *ls) { |
lua_State *L = ls->L; |
FuncState *fs = ls->fs; |
Proto *f = fs->f; |
luaK_ret(fs, 0, 0); /* final return */ |
leaveblock(fs); |
luaM_reallocvector(L, f->code, f->sizecode, fs->pc, Instruction); |
f->sizecode = fs->pc; |
luaM_reallocvector(L, f->lineinfo, f->sizelineinfo, fs->pc, int); |
f->sizelineinfo = fs->pc; |
luaM_reallocvector(L, f->k, f->sizek, fs->nk, TValue); |
f->sizek = fs->nk; |
luaM_reallocvector(L, f->p, f->sizep, fs->np, Proto *); |
f->sizep = fs->np; |
luaM_reallocvector(L, f->locvars, f->sizelocvars, fs->nlocvars, LocVar); |
f->sizelocvars = fs->nlocvars; |
luaM_reallocvector(L, f->upvalues, f->sizeupvalues, fs->nups, Upvaldesc); |
f->sizeupvalues = fs->nups; |
lua_assert(fs->bl == NULL); |
ls->fs = fs->prev; |
/* last token read was anchored in defunct function; must re-anchor it */ |
anchor_token(ls); |
L->top--; /* pop table of constants */ |
luaC_checkGC(L); |
L->top--; /* pop prototype (after possible collection) */ |
} |
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/* |
** opens the main function, which is a regular vararg function with an |
** upvalue named LUA_ENV |
*/ |
static void open_mainfunc (LexState *ls, FuncState *fs, BlockCnt *bl) { |
expdesc v; |
open_func(ls, fs, bl); |
fs->f->is_vararg = 1; /* main function is always vararg */ |
init_exp(&v, VLOCAL, 0); |
newupvalue(fs, ls->envn, &v); /* create environment upvalue */ |
} |
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/*============================================================*/ |
/* GRAMMAR RULES */ |
/*============================================================*/ |
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/* |
** check whether current token is in the follow set of a block. |
** 'until' closes syntactical blocks, but do not close scope, |
** so it 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; |
} |
} |
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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); |
} |
} |
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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 */ |
checkname(ls, &key); |
luaK_indexed(fs, v, &key); |
} |
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static void yindex (LexState *ls, expdesc *v) { |
/* index -> '[' expr ']' */ |
luaX_next(ls); /* skip the '[' */ |
expr(ls, v); |
luaK_exp2val(ls->fs, v); |
checknext(ls, ']'); |
} |
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/* |
** {====================================================================== |
** Rules for Constructors |
** ======================================================================= |
*/ |
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struct ConsControl { |
expdesc v; /* last list item read */ |
expdesc *t; /* table descriptor */ |
int nh; /* total number of `record' elements */ |
int na; /* total number of array elements */ |
int tostore; /* number of array elements pending to be stored */ |
}; |
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static void recfield (LexState *ls, struct ConsControl *cc) { |
/* recfield -> (NAME | `['exp1`]') = exp1 */ |
FuncState *fs = ls->fs; |
int reg = ls->fs->freereg; |
expdesc key, val; |
int rkkey; |
if (ls->t.token == TK_NAME) { |
checklimit(fs, cc->nh, MAX_INT, "items in a constructor"); |
checkname(ls, &key); |
} |
else /* ls->t.token == '[' */ |
yindex(ls, &key); |
cc->nh++; |
checknext(ls, '='); |
rkkey = luaK_exp2RK(fs, &key); |
expr(ls, &val); |
luaK_codeABC(fs, OP_SETTABLE, cc->t->u.info, rkkey, luaK_exp2RK(fs, &val)); |
fs->freereg = reg; /* free registers */ |
} |
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static void closelistfield (FuncState *fs, struct 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->tostore = 0; /* no more items pending */ |
} |
} |
|
|
static void lastlistfield (FuncState *fs, struct 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); |
} |
} |
|
|
static void listfield (LexState *ls, struct ConsControl *cc) { |
/* listfield -> exp */ |
expr(ls, &cc->v); |
checklimit(ls->fs, cc->na, MAX_INT, "items in a constructor"); |
cc->na++; |
cc->tostore++; |
} |
|
|
static void field (LexState *ls, struct 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); |
struct ConsControl cc; |
cc.na = cc.nh = cc.tostore = 0; |
cc.t = t; |
init_exp(t, VRELOCABLE, pc); |
init_exp(&cc.v, VVOID, 0); /* no value (yet) */ |
luaK_exp2nextreg(ls->fs, t); /* fix it at stack top */ |
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); |
SETARG_B(fs->f->code[pc], luaO_int2fb(cc.na)); /* set initial array size */ |
SETARG_C(fs->f->code[pc], luaO_int2fb(cc.nh)); /* set initial table size */ |
} |
|
/* }====================================================================== */ |
|
|
|
static void parlist (LexState *ls) { |
/* parlist -> [ param { `,' param } ] */ |
FuncState *fs = ls->fs; |
Proto *f = fs->f; |
int nparams = 0; |
f->is_vararg = 0; |
if (ls->t.token != ')') { /* is `parlist' not empty? */ |
do { |
switch (ls->t.token) { |
case TK_NAME: { /* param -> NAME */ |
new_localvar(ls, str_checkname(ls)); |
nparams++; |
break; |
} |
case TK_DOTS: { /* param -> `...' */ |
luaX_next(ls); |
f->is_vararg = 1; |
break; |
} |
default: luaX_syntaxerror(ls, "<name> or " LUA_QL("...") " expected"); |
} |
} while (!f->is_vararg && testnext(ls, ',')); |
} |
adjustlocalvars(ls, nparams); |
f->numparams = cast_byte(fs->nactvar); |
luaK_reserveregs(fs, fs->nactvar); /* reserve register for parameters */ |
} |
|
|
static void body (LexState *ls, expdesc *e, int ismethod, int line) { |
/* body -> `(' parlist `)' block END */ |
FuncState new_fs; |
BlockCnt bl; |
open_func(ls, &new_fs, &bl); |
new_fs.f->linedefined = line; |
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, new_fs.f, 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); |
luaK_setmultret(fs, &args); |
} |
check_match(ls, ')', '(', line); |
break; |
} |
case '{': { /* funcargs -> constructor */ |
constructor(ls, &args); |
break; |
} |
case TK_STRING: { /* funcargs -> STRING */ |
codestring(ls, &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 prefixexp (LexState *ls, expdesc *v) { |
/* prefixexp -> 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 primaryexp (LexState *ls, expdesc *v) { |
/* primaryexp -> |
prefixexp { `.' NAME | `[' exp `]' | `:' NAME funcargs | funcargs } */ |
FuncState *fs = ls->fs; |
int line = ls->linenumber; |
prefixexp(ls, v); |
for (;;) { |
switch (ls->t.token) { |
case '.': { /* fieldsel */ |
fieldsel(ls, v); |
break; |
} |
case '[': { /* `[' exp1 `]' */ |
expdesc key; |
luaK_exp2anyregup(fs, v); |
yindex(ls, &key); |
luaK_indexed(fs, v, &key); |
break; |
} |
case ':': { /* `:' NAME funcargs */ |
expdesc key; |
luaX_next(ls); |
checkname(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 -> NUMBER | STRING | NIL | TRUE | FALSE | ... | |
constructor | FUNCTION body | primaryexp */ |
switch (ls->t.token) { |
case TK_NUMBER: { |
init_exp(v, VKNUM, 0); |
v->u.nval = ls->t.seminfo.r; |
break; |
} |
case TK_STRING: { |
codestring(ls, 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 " LUA_QL("...") " outside a vararg function"); |
init_exp(v, VVARARG, luaK_codeABC(fs, OP_VARARG, 0, 1, 0)); |
break; |
} |
case '{': { /* constructor */ |
constructor(ls, v); |
return; |
} |
case TK_FUNCTION: { |
luaX_next(ls); |
body(ls, v, 0, ls->linenumber); |
return; |
} |
default: { |
primaryexp(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_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_DIV; |
case '%': return OPR_MOD; |
case '^': return OPR_POW; |
case TK_CONCAT: return OPR_CONCAT; |
case TK_NE: return OPR_NE; |
case TK_EQ: return OPR_EQ; |
case '<': return OPR_LT; |
case TK_LE: return OPR_LE; |
case '>': return OPR_GT; |
case TK_GE: return OPR_GE; |
case TK_AND: return OPR_AND; |
case TK_OR: return OPR_OR; |
default: return OPR_NOBINOPR; |
} |
} |
|
|
static const struct { |
lu_byte left; /* left priority for each binary operator */ |
lu_byte right; /* right priority */ |
} priority[] = { /* ORDER OPR */ |
{6, 6}, {6, 6}, {7, 7}, {7, 7}, {7, 7}, /* `+' `-' `*' `/' `%' */ |
{10, 9}, {5, 4}, /* ^, .. (right associative) */ |
{3, 3}, {3, 3}, {3, 3}, /* ==, <, <= */ |
{3, 3}, {3, 3}, {3, 3}, /* ~=, >, >= */ |
{2, 2}, {1, 1} /* and, or */ |
}; |
|
#define UNARY_PRIORITY 8 /* 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) { |
int line = ls->linenumber; |
luaX_next(ls); |
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); |
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 (lh->v.k == VINDEXED) { /* assigning to a table? */ |
/* table is the upvalue/local being assigned now? */ |
if (lh->v.u.ind.vt == v->k && lh->v.u.ind.t == v->u.info) { |
conflict = 1; |
lh->v.u.ind.vt = VLOCAL; |
lh->v.u.ind.t = extra; /* previous assignment will use safe copy */ |
} |
/* index is the local being assigned? (index cannot be upvalue) */ |
if (v->k == VLOCAL && lh->v.u.ind.idx == v->u.info) { |
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') */ |
OpCode op = (v->k == VLOCAL) ? OP_MOVE : OP_GETUPVAL; |
luaK_codeABC(fs, op, extra, v->u.info, 0); |
luaK_reserveregs(fs, 1); |
} |
} |
|
|
static void assignment (LexState *ls, struct LHS_assign *lh, int nvars) { |
expdesc e; |
check_condition(ls, vkisvar(lh->v.k), "syntax error"); |
if (testnext(ls, ',')) { /* assignment -> `,' primaryexp assignment */ |
struct LHS_assign nv; |
nv.prev = lh; |
primaryexp(ls, &nv.v); |
if (nv.v.k != VINDEXED) |
check_conflict(ls, lh, &nv.v); |
checklimit(ls->fs, nvars + ls->L->nCcalls, LUAI_MAXCCALLS, |
"C levels"); |
assignment(ls, &nv, nvars+1); |
} |
else { /* assignment -> `=' explist */ |
int nexps; |
checknext(ls, '='); |
nexps = explist(ls, &e); |
if (nexps != nvars) { |
adjust_assign(ls, nvars, nexps, &e); |
if (nexps > nvars) |
ls->fs->freereg -= nexps - nvars; /* remove extra values */ |
} |
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, int pc) { |
int line = ls->linenumber; |
TString *label; |
int g; |
if (testnext(ls, TK_GOTO)) |
label = str_checkname(ls); |
else { |
luaX_next(ls); /* skip break */ |
label = luaS_new(ls->L, "break"); |
} |
g = newlabelentry(ls, &ls->dyd->gt, label, line, pc); |
findlabel(ls, g); /* close it if label already defined */ |
} |
|
|
/* check for repeated labels on the same block */ |
static void checkrepeated (FuncState *fs, Labellist *ll, TString *label) { |
int i; |
for (i = fs->bl->firstlabel; i < ll->n; i++) { |
if (eqstr(label, ll->arr[i].name)) { |
const char *msg = luaO_pushfstring(fs->ls->L, |
"label " LUA_QS " already defined on line %d", |
getstr(label), ll->arr[i].line); |
semerror(fs->ls, msg); |
} |
} |
} |
|
|
static void labelstat (LexState *ls, TString *label, int line) { |
/* label -> '::' NAME '::' */ |
FuncState *fs = ls->fs; |
Labellist *ll = &ls->dyd->label; |
int l; /* index of new label being created */ |
checkrepeated(fs, ll, label); /* check for repeated labels */ |
checknext(ls, TK_DBCOLON); /* skip double colon */ |
/* create new entry for this label */ |
l = newlabelentry(ls, ll, label, line, fs->pc); |
/* skip other no-op statements */ |
while (ls->t.token == ';' || ls->t.token == TK_DBCOLON) |
statement(ls); |
if (block_follow(ls, 0)) { /* label is last no-op statement in the block? */ |
/* assume that locals are already out of scope */ |
ll->arr[l].nactvar = fs->bl->nactvar; |
} |
findgotos(ls, &ll->arr[l]); |
} |
|
|
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) */ |
if (bl2.upval) /* upvalues? */ |
luaK_patchclose(fs, condexit, bl2.nactvar); |
leaveblock(fs); /* finish scope */ |
luaK_patchlist(fs, condexit, repeat_init); /* close the loop */ |
leaveblock(fs); /* finish loop */ |
} |
|
|
static int exp1 (LexState *ls) { |
expdesc e; |
int reg; |
expr(ls, &e); |
luaK_exp2nextreg(ls->fs, &e); |
lua_assert(e.k == VNONRELOC); |
reg = e.u.info; |
return reg; |
} |
|
|
static void forbody (LexState *ls, int base, int line, int nvars, int isnum) { |
/* forbody -> DO block */ |
BlockCnt bl; |
FuncState *fs = ls->fs; |
int prep, endfor; |
adjustlocalvars(ls, 3); /* control variables */ |
checknext(ls, TK_DO); |
prep = isnum ? luaK_codeAsBx(fs, OP_FORPREP, base, NO_JUMP) : luaK_jump(fs); |
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 */ |
luaK_patchtohere(fs, prep); |
if (isnum) /* numeric for? */ |
endfor = luaK_codeAsBx(fs, OP_FORLOOP, base, NO_JUMP); |
else { /* generic for */ |
luaK_codeABC(fs, OP_TFORCALL, base, 0, nvars); |
luaK_fixline(fs, line); |
endfor = luaK_codeAsBx(fs, OP_TFORLOOP, base + 2, NO_JUMP); |
} |
luaK_patchlist(fs, endfor, prep + 1); |
luaK_fixline(fs, line); |
} |
|
|
static void fornum (LexState *ls, TString *varname, int line) { |
/* fornum -> NAME = exp1,exp1[,exp1] forbody */ |
FuncState *fs = ls->fs; |
int base = fs->freereg; |
new_localvarliteral(ls, "(for index)"); |
new_localvarliteral(ls, "(for limit)"); |
new_localvarliteral(ls, "(for step)"); |
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_codek(fs, fs->freereg, luaK_numberK(fs, 1)); |
luaK_reserveregs(fs, 1); |
} |
forbody(ls, base, line, 1, 1); |
} |
|
|
static void forlist (LexState *ls, TString *indexname) { |
/* forlist -> NAME {,NAME} IN explist forbody */ |
FuncState *fs = ls->fs; |
expdesc e; |
int nvars = 4; /* gen, state, control, plus at least one declared var */ |
int line; |
int base = fs->freereg; |
/* create control variables */ |
new_localvarliteral(ls, "(for generator)"); |
new_localvarliteral(ls, "(for state)"); |
new_localvarliteral(ls, "(for control)"); |
/* 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, 3, explist(ls, &e), &e); |
luaK_checkstack(fs, 3); /* extra space to call generator */ |
forbody(ls, base, line, nvars - 3, 0); |
} |
|
|
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, LUA_QL("=") " or " LUA_QL("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_GOTO || ls->t.token == TK_BREAK) { |
luaK_goiffalse(ls->fs, &v); /* will jump to label if condition is true */ |
enterblock(fs, &bl, 0); /* must enter block before 'goto' */ |
gotostat(ls, v.t); /* handle goto/break */ |
if (block_follow(ls, 0)) { /* 'goto' 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 goto/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; |
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! */ |
getlocvar(fs, b.u.info)->startpc = fs->pc; |
} |
|
|
static void localstat (LexState *ls) { |
/* stat -> LOCAL NAME {`,' NAME} [`=' explist] */ |
int nvars = 0; |
int nexps; |
expdesc e; |
do { |
new_localvar(ls, str_checkname(ls)); |
nvars++; |
} while (testnext(ls, ',')); |
if (testnext(ls, '=')) |
nexps = explist(ls, &e); |
else { |
e.k = VVOID; |
nexps = 0; |
} |
adjust_assign(ls, nvars, nexps, &e); |
adjustlocalvars(ls, nvars); |
} |
|
|
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); |
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; |
primaryexp(ls, &v.v); |
if (v.v.k == VCALL) /* stat -> func */ |
SETARG_C(getcode(fs, &v.v), 1); /* call statement uses no results */ |
else { /* stat -> assignment */ |
v.prev = NULL; |
assignment(ls, &v, 1); |
} |
} |
|
|
static void retstat (LexState *ls) { |
/* stat -> RETURN [explist] [';'] */ |
FuncState *fs = ls->fs; |
expdesc e; |
int first, nret; /* registers with returned values */ |
if (block_follow(ls, 1) || ls->t.token == ';') |
first = 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) { /* tail call? */ |
SET_OPCODE(getcode(fs,&e), OP_TAILCALL); |
lua_assert(GETARG_A(getcode(fs,&e)) == fs->nactvar); |
} |
first = fs->nactvar; |
nret = LUA_MULTRET; /* return all values */ |
} |
else { |
if (nret == 1) /* only one single value? */ |
first = luaK_exp2anyreg(fs, &e); |
else { |
luaK_exp2nextreg(fs, &e); /* values must go to the `stack' */ |
first = fs->nactvar; /* return all `active' values */ |
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 */ |
case TK_GOTO: { /* stat -> 'goto' NAME */ |
gotostat(ls, luaK_jump(ls->fs)); |
break; |
} |
default: { /* stat -> func | assignment */ |
exprstat(ls); |
break; |
} |
} |
lua_assert(ls->fs->f->maxstacksize >= ls->fs->freereg && |
ls->fs->freereg >= ls->fs->nactvar); |
ls->fs->freereg = ls->fs->nactvar; /* free registers */ |
leavelevel(ls); |
} |
|
/* }====================================================================== */ |
|
|
Proto *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff, |
Dyndata *dyd, const char *name, int firstchar) { |
LexState lexstate; |
FuncState funcstate; |
BlockCnt bl; |
TString *tname = luaS_new(L, name); |
setsvalue2s(L, L->top, tname); /* push name to protect it */ |
incr_top(L); |
lexstate.buff = buff; |
lexstate.dyd = dyd; |
dyd->actvar.n = dyd->gt.n = dyd->label.n = 0; |
luaX_setinput(L, &lexstate, z, tname, firstchar); |
open_mainfunc(&lexstate, &funcstate, &bl); |
luaX_next(&lexstate); /* read first token */ |
statlist(&lexstate); /* main body */ |
check(&lexstate, TK_EOS); |
close_func(&lexstate); |
L->top--; /* pop name */ |
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); |
return funcstate.f; |
} |
|