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lparser.c
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/*
** $Id: lparser.c,v 2.42 2006/06/05 15:57:59 roberto Exp $
** Lua Parser
** See Copyright Notice in lua.h
*/
#include <string.h>
#define lparser_c
#define LUA_CORE
#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"
#define hasmultret(k) ((k) == VCALL || (k) == VVARARG)
#define getlocvar(fs, i) ((fs)->f->locvars[(fs)->actvar[i]])
#define luaY_checklimit(fs,v,l,m) if ((v)>(l)) errorlimit(fs,l,m)
/*
** nodes for block list (list of active blocks)
*/
typedef struct BlockCnt {
struct BlockCnt *previous; /* chain */
int breaklist; /* list of jumps out of this loop */
lu_byte nactvar; /* # active locals outside the breakable structure */
lu_byte upval; /* true if some variable in the block is an upvalue */
lu_byte isbreakable; /* true if `block' is a loop */
} BlockCnt;
/*
** prototypes for recursive non-terminal functions
*/
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static void chunk (LexState *ls, int mainline);
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static void expr (LexState *ls, expdesc *v);
static void anchor_token (LexState *ls) {
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if (ls->t.token == TK_NAME || ls->t.token == TK_STRINGLIT) {
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TString *ts = ls->t.seminfo.ts;
luaX_newstring(ls, getstr(ts), ts->tsv.len);
}
}
static void error_expected (LexState *ls, int token) {
luaX_syntaxerror(ls,
luaO_pushfstring(ls->L, LUA_QS " expected", luaX_token2str(ls, token)));
}
static void errorlimit (FuncState *fs, int limit, const char *what) {
const char *msg = (fs->f->linedefined == 0) ?
luaO_pushfstring(fs->L, "main function has more than %d %s", limit, what) :
luaO_pushfstring(fs->L, "function at line %d has more than %d %s",
fs->f->linedefined, limit, what);
luaX_lexerror(fs->ls, msg, 0);
}
static int testnext (LexState *ls, int c) {
if (ls->t.token == c) {
luaX_next(ls);
return 1;
}
else return 0;
}
static void check (LexState *ls, int c) {
if (ls->t.token != c)
error_expected(ls, c);
}
static void checknext (LexState *ls, int c) {
check(ls, c);
luaX_next(ls);
}
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static void skip_blank_lines (LexState *ls) {
while (testnext(ls, TK_EOL)) {}
}
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#define check_condition(ls,c,msg) { if (!(c)) luaX_syntaxerror(ls, msg); }
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,
LUA_QS " expected (to close " LUA_QS " 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.s.info = i;
}
static void codestring (LexState *ls, expdesc *e, TString *s) {
init_exp(e, VK, luaK_stringK(ls->fs, s));
}
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, "too many 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++;
}
#define new_localvarliteral(ls,v,n) \
new_localvar(ls, luaX_newstring(ls, "" v, (sizeof(v)/sizeof(char))-1), n)
static void new_localvar (LexState *ls, TString *name, int n) {
FuncState *fs = ls->fs;
luaY_checklimit(fs, fs->nactvar+n+1, LUAI_MAXVARS, "local variables");
fs->actvar[fs->nactvar+n] = cast(unsigned short, registerlocalvar(ls, name));
}
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;
}
}
static void removevars (LexState *ls, int tolevel) {
FuncState *fs = ls->fs;
while (fs->nactvar > tolevel)
getlocvar(fs, --fs->nactvar).endpc = fs->pc;
}
static int indexupvalue (FuncState *fs, TString *name, expdesc *v) {
int i;
Proto *f = fs->f;
int oldsize = f->sizeupvalues;
for (i=0; i<f->nups; i++) {
if (fs->upvalues[i].k == v->k && fs->upvalues[i].info == v->u.s.info) {
lua_assert(f->upvalues[i] == name);
return i;
}
}
/* new one */
luaY_checklimit(fs, f->nups + 1, LUAI_MAXUPVALUES, "upvalues");
luaM_growvector(fs->L, f->upvalues, f->nups, f->sizeupvalues,
TString *, MAX_INT, "");
while (oldsize < f->sizeupvalues) f->upvalues[oldsize++] = NULL;
f->upvalues[f->nups] = name;
luaC_objbarrier(fs->L, f, name);
lua_assert(v->k == VLOCAL || v->k == VUPVAL);
fs->upvalues[f->nups].k = cast_byte(v->k);
fs->upvalues[f->nups].info = cast_byte(v->u.s.info);
return f->nups++;
}
static int searchvar (FuncState *fs, TString *n) {
int i;
for (i=fs->nactvar-1; i >= 0; i--) {
if (n == getlocvar(fs, i).varname)
return i;
}
return -1; /* not found */
}
static void markupval (FuncState *fs, int level) {
BlockCnt *bl = fs->bl;
while (bl && bl->nactvar > level) bl = bl->previous;
if (bl) bl->upval = 1;
}
static int singlevaraux (FuncState *fs, TString *n, expdesc *var, int base) {
if (fs == NULL) { /* no more levels? */
init_exp(var, VGLOBAL, NO_REG); /* default is global variable */
return VGLOBAL;
}
else {
int v = searchvar(fs, n); /* look up at current level */
if (v >= 0) {
init_exp(var, VLOCAL, v);
if (!base)
markupval(fs, v); /* local will be used as an upval */
return VLOCAL;
}
else { /* not found at current level; try upper one */
if (singlevaraux(fs->prev, n, var, 0) == VGLOBAL)
return VGLOBAL;
var->u.s.info = indexupvalue(fs, n, var); /* else was LOCAL or UPVAL */
var->k = VUPVAL; /* upvalue in this level */
return VUPVAL;
}
}
}
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static void lookupvar(LexState *ls, TString *varname, expdesc *var,
int create)
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{
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FuncState *fs = ls->fs;
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int add_to_table = ls->resolved_table;
int already_added = 0;
lua_State *L = ls->L;
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if (singlevaraux(fs, varname, var, 1) == VGLOBAL) {
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int missing;
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/* see if it's an existing global provided in native code... */
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lua_getglobal(ls->L, getstr(varname));
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missing = lua_isnil(ls->L, -1);
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lua_pop(ls->L, 1);
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if (create) {
int on_line = 0;
if (missing) {
/* see if it's an existing symbol in the user's program. */
lua_getfield(L, ls->resolved_table, getstr(varname));
missing = lua_isnil(L, -1);
if (!missing)
on_line = lua_tointeger(L, -1);
lua_pop(L, 1);
}
if (!missing) {
luaX_syntaxerror(ls,
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luaO_pushfstring(ls->L, LUA_QS " already defined on line %d", getstr(varname), on_line));
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}
} else { /* add it to a table to resolve after parsing... */
if (missing)
add_to_table = ls->to_resolve_table;
else
already_added = 1;
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}
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if (!already_added) {
lua_getfield(L, add_to_table, getstr(varname));
already_added = !lua_isnil(L, -1);
lua_pop(L, 1);
if (!already_added) {
lua_pushinteger(L, ls->linenumber);
lua_setfield(L, add_to_table, getstr(varname));
}
}
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var->u.s.info = luaK_stringK(fs, varname); /* info points to global name */
}
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}
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static void singlevar (LexState *ls, expdesc *var) {
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lookupvar(ls, str_checkname(ls), var, 0);
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}
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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);
}
}
}
static void enterlevel (LexState *ls) {
if (++ls->L->nCcalls > LUAI_MAXCCALLS)
luaX_lexerror(ls, "chunk has too many syntax levels", 0);
}
#define leavelevel(ls) ((ls)->L->nCcalls--)
static void enterblock (FuncState *fs, BlockCnt *bl, lu_byte isbreakable) {
bl->breaklist = NO_JUMP;
bl->isbreakable = isbreakable;
bl->nactvar = fs->nactvar;
bl->upval = 0;
bl->previous = fs->bl;
fs->bl = bl;
lua_assert(fs->freereg == fs->nactvar);
}
static void leaveblock (FuncState *fs) {
BlockCnt *bl = fs->bl;
fs->bl = bl->previous;
removevars(fs->ls, bl->nactvar);
if (bl->upval)
luaK_codeABC(fs, OP_CLOSE, bl->nactvar, 0, 0);
/* a block either controls scope or breaks (never both) */
lua_assert(!bl->isbreakable || !bl->upval);
lua_assert(bl->nactvar == fs->nactvar);
fs->freereg = fs->nactvar; /* free registers */
luaK_patchtohere(fs, bl->breaklist);
}
static void pushclosure (LexState *ls, FuncState *func, expdesc *v) {
FuncState *fs = ls->fs;
Proto *f = fs->f;
int oldsize = f->sizep;
int i;
luaM_growvector(ls->L, f->p, fs->np, f->sizep, Proto *,
MAXARG_Bx, "constant table overflow");
while (oldsize < f->sizep) f->p[oldsize++] = NULL;
f->p[fs->np++] = func->f;
luaC_objbarrier(ls->L, f, func->f);
init_exp(v, VRELOCABLE, luaK_codeABx(fs, OP_CLOSURE, 0, fs->np-1));
for (i=0; i<func->f->nups; i++) {
OpCode o = (func->upvalues[i].k == VLOCAL) ? OP_MOVE : OP_GETUPVAL;
luaK_codeABC(fs, o, 0, func->upvalues[i].info, 0);
}
}
static void open_func (LexState *ls, FuncState *fs) {
lua_State *L = ls->L;
Proto *f = luaF_newproto(L);
fs->f = f;
fs->prev = ls->fs; /* linked list of funcstates */
fs->ls = ls;
fs->L = L;
ls->fs = fs;
fs->pc = 0;
fs->lasttarget = -1;
fs->jpc = NO_JUMP;
fs->freereg = 0;
fs->nk = 0;
fs->np = 0;
fs->nlocvars = 0;
fs->nactvar = 0;
fs->bl = NULL;
f->source = ls->source;
f->maxstacksize = 2; /* registers 0/1 are always valid */
fs->h = luaH_new(L, 0, 0);
/* anchor table of constants and prototype (to avoid being collected) */
sethvalue2s(L, L->top, fs->h);
incr_top(L);
setptvalue2s(L, L->top, f);
incr_top(L);
}
static void close_func (LexState *ls) {
lua_State *L = ls->L;
FuncState *fs = ls->fs;
Proto *f = fs->f;
removevars(ls, 0);
luaK_ret(fs, 0, 0); /* final return */
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, f->nups, TString *);
f->sizeupvalues = f->nups;
lua_assert(luaG_checkcode(f));
lua_assert(fs->bl == NULL);
ls->fs = fs->prev;
L->top -= 2; /* remove table and prototype from the stack */
/* last token read was anchored in defunct function; must reanchor it */
if (fs) anchor_token(ls);
}
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static void resolve_toby_functions(LexState *ls) {
lua_State *L = ls->L;
const int to_resolve_table = ls->to_resolve_table;
const int resolved_table = ls->resolved_table;
int missing = 0;
lua_pushnil(L); /* first key for iteration... */
while (lua_next(L, to_resolve_table)) { /* replaces key, pushes value. */
const char *sym = lua_tostring(L, -2);
const int on_line = lua_tointeger(L, -1);
lua_getfield(L, resolved_table, sym);
missing = lua_isnil(L, -1);
lua_pop(L, 1);
if (missing) {
lua_pop(L, 2); /* remove iterator value and key. */
luaX_syntaxerror(ls,
luaO_pushfstring(ls->L, "undefined symbol " LUA_QS " on line %d", sym, on_line));
}
lua_pop(L, 1); /* remove value, keep key for next iteration. */
}
}
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Proto *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff, const char *name) {
struct LexState lexstate;
struct FuncState funcstate;
lexstate.buff = buff;
luaX_setinput(L, &lexstate, z, luaS_new(L, name));
open_func(&lexstate, &funcstate);
funcstate.f->is_vararg = VARARG_ISVARARG; /* main func. is always vararg */
luaX_next(&lexstate); /* read first token */
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chunk(&lexstate, 1);
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check(&lexstate, TK_EOS);
close_func(&lexstate);
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resolve_toby_functions(&lexstate); /* we're less dynamic than Lua. :) */
lua_assert(lexstate.to_resolve_table == lua_gettop(L)-1);
lua_assert(lexstate.resolved_table == lua_gettop(L));
lua_pop(L, 2);
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lua_assert(funcstate.prev == NULL);
lua_assert(funcstate.f->nups == 0);
lua_assert(lexstate.fs == NULL);
return funcstate.f;
}
/*============================================================*/
/* GRAMMAR RULES */
/*============================================================*/
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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static void vardeclstat (LexState *ls, int global, int initialize);
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static int toby_intrinsic_type(int token, int allownothing);
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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 {
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vardeclstat(ls, 0, 0);
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nparams++;
} while (testnext(ls, ','));
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}
f->numparams = cast_byte(fs->nactvar - (f->is_vararg & VARARG_HASARG));
luaK_reserveregs(fs, fs->nactvar); /* reserve register for parameters */
}
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static void check_intrinsic_type(LexState *ls, int allownothing) {
const int c = toby_intrinsic_type(ls->t.token, allownothing);
check_condition(ls, c, "data type expected");
}
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static void body (LexState *ls, expdesc *e, int line) {
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/* body -> `(' parlist `)' chunk END */
FuncState new_fs;
open_func(ls, &new_fs);
new_fs.f->linedefined = line;
checknext(ls, '(');
parlist(ls);
checknext(ls, ')');
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checknext(ls, TK_RETURNS);
check_intrinsic_type(ls, 1);
luaX_next(ls); /* !!! FIXME: store return type info somewhere... */
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checknext(ls, TK_EOL);
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/* Toby requires variable predeclaration at the start of a function. */
/* ...maybe we should change that... */
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skip_blank_lines(ls);
while (toby_intrinsic_type(ls->t.token, 0)) {
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vardeclstat(ls, 0, 1);
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checknext(ls, TK_EOL);
skip_blank_lines(ls);
}
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chunk(ls, 0);
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new_fs.f->lastlinedefined = ls->linenumber;
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check_match(ls, TK_ENDFUNCTION, TK_FUNCTION, line);
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checknext(ls, TK_EOL);
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close_func(ls);
pushclosure(ls, &new_fs, e);
}
static int explist1 (LexState *ls, expdesc *v) {
/* explist1 -> expr { `,' expr } */
int n = 1; /* at least one expression */
expr(ls, v);
while (testnext(ls, ',')) {
luaK_exp2nextreg(ls->fs, v);
expr(ls, v);
n++;
}
return n;
}
static void funcargs (LexState *ls, expdesc *f) {
FuncState *fs = ls->fs;
expdesc args;
int base, nparams;
int line = ls->linenumber;
switch (ls->t.token) {
case '(': { /* funcargs -> `(' [ explist1 ] `)' */
if (line != ls->lastline)
luaX_syntaxerror(ls,"ambiguous syntax (function call x new statement)");
luaX_next(ls);
if (ls->t.token == ')') /* arg list is empty? */
args.k = VVOID;
else {
explist1(ls, &args);
luaK_setmultret(fs, &args);
}
check_match(ls, ')', '(', line);
break;
}
default: {
luaX_syntaxerror(ls, "function arguments expected");
return;
}
}
lua_assert(f->k == VNONRELOC);
base = f->u.s.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");
return;
}
}
}
static void primaryexp (LexState *ls, expdesc *v) {
/* primaryexp ->
prefixexp { `.' NAME | `[' exp `]' | `:' NAME funcargs | funcargs } */
FuncState *fs = ls->fs;
prefixexp(ls, v);
for (;;) {
switch (ls->t.token) {
case '[': { /* `[' exp1 `]' */
expdesc key;
luaK_exp2anyreg(fs, v);
yindex(ls, &key);
luaK_indexed(fs, v, &key);
break;
}
643
case '(': { /* funcargs */
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645
646
647
648
649
650
651
652
653
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655
656
657
luaK_exp2nextreg(fs, v);
funcargs(ls, v);
break;
}
default: return;
}
}
}
static void simpleexp (LexState *ls, expdesc *v) {
/* simpleexp -> NUMBER | STRING | NIL | true | false | ... |
constructor | FUNCTION body | primaryexp */
switch (ls->t.token) {
658
case TK_NUMBERLIT: {
659
660
661
662
init_exp(v, VKNUM, 0);
v->u.nval = ls->t.seminfo.r;
break;
}
663
case TK_STRINGLIT: {
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671
672
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681
682
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700
701
702
703
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708
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712
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715
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717
718
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720
721
722
723
724
725
726
727
728
729
730
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732
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734
735
736
737
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739
740
741
742
743
744
745
746
747
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749
750
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752
753
754
755
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757
758
759
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761
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771
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codestring(ls, v, ls->t.seminfo.ts);
break;
}
case TK_TRUE: {
init_exp(v, VTRUE, 0);
break;
}
case TK_FALSE: {
init_exp(v, VFALSE, 0);
break;
}
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}, /* power and concat (right associative) */
{3, 3}, {3, 3}, /* equality and inequality */
{3, 3}, {3, 3}, {3, 3}, {3, 3}, /* order */
{2, 2}, {1, 1} /* logical (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, unsigned int limit) {
BinOpr op;
UnOpr uop;
enterlevel(ls);
uop = getunopr(ls->t.token);
if (uop != OPR_NOUNOPR) {
luaX_next(ls);
subexpr(ls, v, UNARY_PRIORITY);
luaK_prefix(ls->fs, uop, v);
}
else simpleexp(ls, v);
/* expand while operators have priorities higher than `limit' */
op = getbinopr(ls->t.token);
while (op != OPR_NOBINOPR && priority[op].left > limit) {
expdesc v2;
BinOpr nextop;
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);
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 int block_follow (int token) {
switch (token) {
779
780
781
782
783
784
785
case TK_ELSE:
case TK_ELSEIF:
case TK_ENDFUNCTION:
case TK_ENDIF:
case TK_ENDFOR:
case TK_ENDWHILE:
case TK_EOS:
786
787
788
789
790
791
return 1;
default: return 0;
}
}
792
static int toby_intrinsic_type(int token, int allownothing)
793
794
795
796
797
{
switch (token) {
case TK_NUMBER:
case TK_STRING:
case TK_BOOLEAN:
798
case TK_ARRAY:
799
return 1;
800
801
case TK_NOTHING:
return allownothing ? 1 : 0;
802
803
804
805
806
default: return 0;
}
}
807
808
809
810
811
static void block (LexState *ls) {
/* block -> chunk */
FuncState *fs = ls->fs;
BlockCnt bl;
enterblock(fs, &bl, 0);
812
chunk(ls, 0);
813
814
815
816
lua_assert(bl.breaklist == NO_JUMP);
leaveblock(fs);
}
817
static void assignment (LexState *ls, expdesc *v) {
818
/* Toby form: var = expr */
819
expdesc e;
820
check_condition(ls, VLOCAL <= v->k && v->k <= VINDEXED, "syntax error");
821
822
823
checknext(ls, '=');
expr(ls, &e);
luaK_setoneret(ls->fs, &e); /* close last expression */
824
luaK_storevar(ls->fs, v, &e);
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
}
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 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);
846
checknext(ls, TK_EOL);
847
848
849
enterblock(fs, &bl, 1);
block(ls);
luaK_patchlist(fs, luaK_jump(fs), whileinit);
850
check_match(ls, TK_ENDWHILE, TK_WHILE, line);
851
checknext(ls, TK_EOL);
852
853
854
855
856
857
858
859
860
861
862
863
864
leaveblock(fs);
luaK_patchtohere(fs, condexit); /* false conditions finish the loop */
}
static int exp1 (LexState *ls) {
expdesc e;
int k;
expr(ls, &e);
k = e.k;
luaK_exp2nextreg(ls->fs, &e);
return k;
}
865
866
static void forstat (LexState *ls, int line) {
/* forstat -> FOR var = exp1 [TO|DOWNTO] exp1 [STEP exp1] block ENDFOR */
867
FuncState *fs = ls->fs;
868
BinOpr op;
869
expdesc v;
870
871
872
873
874
875
876
877
878
expdesc v1;
expdesc v1copy;
expdesc v1copy2;
expdesc v2;
int base = 0;
int defaultstep = 1;
int whileinit = 0;
int condexit = 0;
BlockCnt bl;
879
880
luaX_next(ls); /* skip `for' */
881
882
883
singlevar(ls, &v);
memcpy(&v1, &v, sizeof (expdesc)); /* save for later... */
884
885
memcpy(&v1copy, &v1, sizeof (expdesc)); /* for when v1 gets mangled... */
memcpy(&v1copy2, &v1, sizeof (expdesc)); /* and so on... */
886
assignment(ls, &v);
887
888
if (testnext(ls, TK_TO)) {
889
defaultstep = 1;
890
891
892
893
894
895
} else if (testnext(ls, TK_DOWNTO)) {
defaultstep = -1;
} else {
luaX_syntaxerror(ls, LUA_QL("TO") " or " LUA_QL("DOWNTO") " expected");
}
896
897
898
899
900
901
base = fs->freereg;
new_localvarliteral(ls, "(for limit)", 0);
new_localvarliteral(ls, "(for step)", 1);
exp1(ls); /* limit */
902
if (testnext(ls, TK_STEP))
903
exp1(ls); /* optional step */
904
905
else { /* default step = 1 (or -1 for downto) */
luaK_codeABx(fs, OP_LOADK, fs->freereg, luaK_numberK(fs, defaultstep));
906
907
luaK_reserveregs(fs, 1);
}
908
checknext(ls, TK_EOL);
909
910
adjustlocalvars(ls, 2); /* control variables */
911
912
whileinit = luaK_getlabel(fs);
913
914
915
916
917
918
op = ((defaultstep > 0) ? OPR_LE : OPR_GE);
luaK_infix(fs, op, &v1);
init_exp(&v2, VLOCAL, base);
luaK_posfix(fs, op, &v1, &v2);
luaK_goiftrue(fs, &v1);
919
920
921
922
923
condexit = v1.f;
enterblock(fs, &bl, 1);
block(ls);
924
check_match(ls, TK_ENDFOR, TK_FOR, line);
925
checknext(ls, TK_EOL);
926
927
928
929
930
931
932
933
934
935
op = OPR_ADD;
luaK_infix(fs, OPR_ADD, &v1copy);
init_exp(&v2, VLOCAL, base+1); /* add step value to iterator variable. */
luaK_posfix(fs, op, &v1copy, &v2);
luaK_storevar(ls->fs, &v1copy2, &v1copy);
luaK_patchlist(fs, luaK_jump(fs), whileinit);
leaveblock(fs);
luaK_patchtohere(fs, condexit); /* false conditions finish the loop */
936
937
938
939
940
941
942
943
}
static int test_then_block (LexState *ls) {
/* test_then_block -> [IF | ELSEIF] cond THEN block */
int condexit;
luaX_next(ls); /* skip IF or ELSEIF */
condexit = cond(ls);
944
checknext(ls, TK_EOL);
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
block(ls); /* `then' part */
return condexit;
}
static void ifstat (LexState *ls, int line) {
/* ifstat -> IF cond THEN block {ELSEIF cond THEN block} [ELSE block] END */
FuncState *fs = ls->fs;
int flist;
int escapelist = NO_JUMP;
flist = test_then_block(ls); /* IF cond THEN block */
while (ls->t.token == TK_ELSEIF) {
luaK_concat(fs, &escapelist, luaK_jump(fs));
luaK_patchtohere(fs, flist);
flist = test_then_block(ls); /* ELSEIF cond THEN block */
}
if (ls->t.token == TK_ELSE) {
luaK_concat(fs, &escapelist, luaK_jump(fs));
luaK_patchtohere(fs, flist);
luaX_next(ls); /* skip ELSE (after patch, for correct line info) */
965
checknext(ls, TK_EOL);
966
967
968
969
970
block(ls); /* `else' part */
}
else
luaK_concat(fs, &escapelist, flist);
luaK_patchtohere(fs, escapelist);
971
check_match(ls, TK_ENDIF, TK_IF, line);
972
checknext(ls, TK_EOL);
973
974
975
}
976
977
static void funcstat (LexState *ls, int line) {
/* funcstat -> FUNCTION funcname body */
978
expdesc v, b;
979
980
981
982
983
/* No nested functions in Toby. */
check_condition(ls, !ls->infunc, "function inside function");
ls->infunc = 1;
984
985
986
987
988
989
luaX_next(ls); /* skip FUNCTION */
lookupvar(ls, str_checkname(ls), &v, 1);
lua_assert(v.k == VGLOBAL); /* All functions are globals in Toby. */
body(ls, &b, line);
luaK_storevar(ls->fs, &v, &b);
luaK_fixline(ls->fs, line); /* definition `happens' in the first line */
990
ls->infunc = 0;
991
992
}
993
static void default_var_value (LexState *ls, int token, expdesc *e) {
994
/* Initialize variables with a sane default. */
995
996
997
998
999
1000
if (token == TK_NUMBER) {
init_exp(e, VKNUM, 0);
e->u.nval = 0;
} else if (token == TK_BOOLEAN) {
init_exp(e, VFALSE, 0);
} else if (token == TK_STRING) {