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more liberal syntax for expressions

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This commit is contained in:
Roberto Ierusalimschy 2001-02-14 15:19:28 -02:00
parent 29371ecfe8
commit 40f4e931f3
1 changed files with 70 additions and 81 deletions
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151
lparser.c
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@ -1,5 +1,5 @@
/* /*
** $Id: lparser.c,v 1.131 2001/02/09 18:37:33 roberto Exp roberto $ ** $Id: lparser.c,v 1.132 2001/02/09 20:22:29 roberto Exp roberto $
** LL(1) Parser and code generator for Lua ** LL(1) Parser and code generator for Lua
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@ -352,7 +352,7 @@ static void close_func (LexState *ls) {
luaM_reallocvector(L, f->lineinfo, f->sizelineinfo, fs->nlineinfo+1, int); luaM_reallocvector(L, f->lineinfo, f->sizelineinfo, fs->nlineinfo+1, int);
f->lineinfo[fs->nlineinfo++] = MAX_INT; /* end flag */ f->lineinfo[fs->nlineinfo++] = MAX_INT; /* end flag */
f->sizelineinfo = fs->nlineinfo; f->sizelineinfo = fs->nlineinfo;
lua_assert(luaG_checkcode(f)); lua_assert(luaG_checkcode(L, f));
ls->fs = fs->prev; ls->fs = fs->prev;
lua_assert(fs->bl == NULL); lua_assert(fs->bl == NULL);
} }
@ -433,60 +433,6 @@ static void funcargs (LexState *ls, int slf) {
} }
static void var_or_func_tail (LexState *ls, expdesc *v) {
for (;;) {
switch (ls->t.token) {
case '.': { /* var_or_func_tail -> '.' NAME */
next(ls);
luaK_tostack(ls, v, 1); /* `v' must be on stack */
luaK_kstr(ls, checkname(ls));
v->k = VINDEXED;
break;
}
case '[': { /* var_or_func_tail -> '[' exp1 ']' */
next(ls);
luaK_tostack(ls, v, 1); /* `v' must be on stack */
v->k = VINDEXED;
exp1(ls);
check(ls, ']');
break;
}
case ':': { /* var_or_func_tail -> ':' NAME funcargs */
next(ls);
luaK_tostack(ls, v, 1); /* `v' must be on stack */
luaK_code1(ls->fs, OP_PUSHSELF, checkname(ls));
funcargs(ls, 1);
v->k = VEXP;
v->u.l.t = v->u.l.f = NO_JUMP;
break;
}
case '(': case TK_STRING: case '{': { /* var_or_func_tail -> funcargs */
luaK_tostack(ls, v, 1); /* `v' must be on stack */
funcargs(ls, 0);
v->k = VEXP;
v->u.l.t = v->u.l.f = NO_JUMP;
break;
}
default: return; /* should be follow... */
}
}
}
static void var_or_func (LexState *ls, expdesc *v) {
/* var_or_func -> ['%'] NAME var_or_func_tail */
if (optional(ls, '%')) { /* upvalue? */
pushupvalue(ls, str_checkname(ls));
v->k = VEXP;
v->u.l.t = v->u.l.f = NO_JUMP;
}
else /* variable name */
singlevar(ls, str_checkname(ls), v);
var_or_func_tail(ls, v);
}
/* /*
** {====================================================================== ** {======================================================================
** Rules for Constructors ** Rules for Constructors
@ -615,47 +561,51 @@ static void constructor (LexState *ls) {
** ======================================================================= ** =======================================================================
*/ */
static void primaryexp (LexState *ls, expdesc *v) {
static void simpleexp (LexState *ls, expdesc *v) {
FuncState *fs = ls->fs; FuncState *fs = ls->fs;
switch (ls->t.token) { switch (ls->t.token) {
case TK_NUMBER: { /* simpleexp -> NUMBER */ case TK_NUMBER: {
lua_Number r = ls->t.seminfo.r; lua_Number r = ls->t.seminfo.r;
next(ls); next(ls);
luaK_number(fs, r); luaK_number(fs, r);
break; break;
} }
case TK_STRING: { /* simpleexp -> STRING */ case TK_STRING: {
code_string(ls, ls->t.seminfo.ts); /* must use `seminfo' before `next' */ code_string(ls, ls->t.seminfo.ts); /* must use `seminfo' before `next' */
next(ls); next(ls);
break; break;
} }
case TK_NIL: { /* simpleexp -> NIL */ case TK_NIL: {
luaK_adjuststack(fs, -1); luaK_adjuststack(fs, -1);
next(ls); next(ls);
break; break;
} }
case '{': { /* simpleexp -> constructor */ case '{': { /* constructor */
constructor(ls); constructor(ls);
break; break;
} }
case TK_FUNCTION: { /* simpleexp -> FUNCTION body */ case TK_FUNCTION: {
next(ls); next(ls);
body(ls, 0, ls->linenumber); body(ls, 0, ls->linenumber);
break; break;
} }
case '(': { /* simpleexp -> '(' expr ')' */ case '(': {
next(ls); next(ls);
expr(ls, v); expr(ls, v);
check(ls, ')'); check(ls, ')');
return; return;
} }
case TK_NAME: case '%': { case TK_NAME: {
var_or_func(ls, v); singlevar(ls, str_checkname(ls), v);
return; return;
} }
case '%': {
next(ls); /* skip `%' */
pushupvalue(ls, str_checkname(ls));
break;
}
default: { default: {
luaK_error(ls, "<expression> expected"); luaK_error(ls, "unexpected symbol");
return; return;
} }
} }
@ -664,10 +614,46 @@ static void simpleexp (LexState *ls, expdesc *v) {
} }
static void exp1 (LexState *ls) { static void simpleexp (LexState *ls, expdesc *v) {
expdesc v; /* simpleexp ->
expr(ls, &v); primaryexp { '.' NAME | '[' exp ']' | ':' NAME funcargs | funcargs } */
luaK_tostack(ls, &v, 1); primaryexp(ls, v);
for (;;) {
switch (ls->t.token) {
case '.': { /* '.' NAME */
next(ls);
luaK_tostack(ls, v, 1); /* `v' must be on stack */
luaK_kstr(ls, checkname(ls));
v->k = VINDEXED;
break;
}
case '[': { /* '[' exp1 ']' */
next(ls);
luaK_tostack(ls, v, 1); /* `v' must be on stack */
v->k = VINDEXED;
exp1(ls);
check(ls, ']');
break;
}
case ':': { /* ':' NAME funcargs */
next(ls);
luaK_tostack(ls, v, 1); /* `v' must be on stack */
luaK_code1(ls->fs, OP_PUSHSELF, checkname(ls));
funcargs(ls, 1);
v->k = VEXP;
v->u.l.t = v->u.l.f = NO_JUMP;
break;
}
case '(': case TK_STRING: case '{': { /* funcargs */
luaK_tostack(ls, v, 1); /* `v' must be on stack */
funcargs(ls, 0);
v->k = VEXP;
v->u.l.t = v->u.l.f = NO_JUMP;
break;
}
default: return; /* should be follow... */
}
}
} }
@ -748,6 +734,13 @@ static void expr (LexState *ls, expdesc *v) {
subexpr(ls, v, -1); subexpr(ls, v, -1);
} }
static void exp1 (LexState *ls) {
expdesc v;
expr(ls, &v);
luaK_tostack(ls, &v, 1);
}
/* }==================================================================== */ /* }==================================================================== */
@ -781,10 +774,10 @@ static void block (LexState *ls) {
static int assignment (LexState *ls, expdesc *v, int nvars) { static int assignment (LexState *ls, expdesc *v, int nvars) {
int left = 0; /* number of values left in the stack after assignment */ int left = 0; /* number of values left in the stack after assignment */
luaX_checklimit(ls, nvars, MAXVARSLH, "variables in a multiple assignment"); luaX_checklimit(ls, nvars, MAXVARSLH, "variables in a multiple assignment");
if (ls->t.token == ',') { /* assignment -> ',' NAME assignment */ if (ls->t.token == ',') { /* assignment -> ',' simpleexp assignment */
expdesc nv; expdesc nv;
next(ls); next(ls);
var_or_func(ls, &nv); simpleexp(ls, &nv);
check_condition(ls, (nv.k != VEXP), "syntax error"); check_condition(ls, (nv.k != VEXP), "syntax error");
left = assignment(ls, &nv, nvars+1); left = assignment(ls, &nv, nvars+1);
} }
@ -998,15 +991,15 @@ static void funcstat (LexState *ls, int line) {
static void namestat (LexState *ls) { static void namestat (LexState *ls) {
/* stat -> func | ['%'] NAME assignment */ /* stat -> func | assignment */
FuncState *fs = ls->fs; FuncState *fs = ls->fs;
expdesc v; expdesc v;
var_or_func(ls, &v); simpleexp(ls, &v);
if (v.k == VEXP) { /* stat -> func */ if (v.k == VEXP) { /* stat -> func */
check_condition(ls, luaK_lastisopen(fs), "syntax error"); /* an upvalue? */ check_condition(ls, luaK_lastisopen(fs), "syntax error"); /* an upvalue? */
luaK_setcallreturns(fs, 0); /* call statement uses no results */ luaK_setcallreturns(fs, 0); /* call statement uses no results */
} }
else { /* stat -> ['%'] NAME assignment */ else { /* stat -> assignment */
int left = assignment(ls, &v, 1); int left = assignment(ls, &v, 1);
luaK_adjuststack(fs, left); /* remove eventual garbage left on stack */ luaK_adjuststack(fs, left); /* remove eventual garbage left on stack */
} }
@ -1072,10 +1065,6 @@ static int stat (LexState *ls) {
localstat(ls); localstat(ls);
return 0; return 0;
} }
case TK_NAME: case '%': { /* stat -> namestat */
namestat(ls);
return 0;
}
case TK_RETURN: { /* stat -> retstat */ case TK_RETURN: { /* stat -> retstat */
retstat(ls); retstat(ls);
return 1; /* must be last statement */ return 1; /* must be last statement */
@ -1085,7 +1074,7 @@ static int stat (LexState *ls) {
return 1; /* must be last statement */ return 1; /* must be last statement */
} }
default: { default: {
luaK_error(ls, "<statement> expected"); namestat(ls);
return 0; /* to avoid warnings */ return 0; /* to avoid warnings */
} }
} }