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"if" expressions.

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This commit is contained in:
Roberto Ierusalimschy
1999-02-01 16:52:05 -02:00
parent 68267ed878
commit 0f0079f394
1 changed files with 34 additions and 27 deletions
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61
lparser.c
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@@ -1,5 +1,5 @@
/* /*
** $Id: lparser.c,v 1.9 1999/01/21 18:38:39 roberto Exp roberto $ ** $Id: lparser.c,v 1.10 1999/01/29 13:48:58 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
*/ */
@@ -118,7 +118,7 @@ static void exp1 (LexState *ls);
static void exp2 (LexState *ls, vardesc *v); static void exp2 (LexState *ls, vardesc *v);
static void explist (LexState *ls, listdesc *e); static void explist (LexState *ls, listdesc *e);
static void explist1 (LexState *ls, listdesc *e); static void explist1 (LexState *ls, listdesc *e);
static void ifpart (LexState *ls); static void ifpart (LexState *ls, int isexp, int line);
static void parlist (LexState *ls); static void parlist (LexState *ls);
static void part (LexState *ls, constdesc *cd); static void part (LexState *ls, constdesc *cd);
static void recfield (LexState *ls); static void recfield (LexState *ls);
@@ -689,12 +689,9 @@ static int stat (LexState *ls) {
int line = ls->linenumber; /* may be needed for error messages */ int line = ls->linenumber; /* may be needed for error messages */
FuncState *fs = ls->fs; FuncState *fs = ls->fs;
switch (ls->token) { switch (ls->token) {
case IF: { /* stat -> IF ifpart END */ case IF: /* stat -> IF ifpart END */
next(ls); ifpart(ls, 0, line);
ifpart(ls);
check_match(ls, END, IF, line);
return 1; return 1;
}
case WHILE: { /* stat -> WHILE cond DO block END */ case WHILE: { /* stat -> WHILE cond DO block END */
TProtoFunc *f = fs->f; TProtoFunc *f = fs->f;
@@ -841,27 +838,35 @@ static void body (LexState *ls, int needself, int line) {
func_onstack(ls, &newfs); func_onstack(ls, &newfs);
} }
static void ifpart (LexState *ls) {
/* ifpart -> cond THEN block [ELSE block | ELSEIF ifpart] */
int c = cond(ls);
int e;
check(ls, THEN);
block(ls);
e = SaveWord(ls);
switch (ls->token) {
case ELSE:
next(ls);
block(ls);
break;
case ELSEIF: static void ifpart (LexState *ls, int isexp, int line) {
next(ls); /* ifpart -> cond THEN block [ELSE block | ELSEIF ifpart] */
ifpart(ls); /* ifpart -> cond THEN exp [ELSE exp | ELSEIF ifpart] */
break; int c;
int e;
next(ls); /* skip IF or ELSEIF */
c = cond(ls);
check(ls, THEN);
if (isexp) exp1(ls);
else block(ls);
e = SaveWord(ls);
if (ls->token == ELSEIF)
ifpart(ls, isexp, line);
else {
int elsepart = optional(ls, ELSE);
if (!isexp) {
if (elsepart) block(ls);
}
else { /* is exp */
if (elsepart) exp1(ls);
else code_oparg(ls, PUSHNIL, 1, 0, 1); /* empty else exp */
}
check_match(ls, END, IF, line);
} }
codeIf(ls, c, e); codeIf(ls, c, e);
} }
static void ret (LexState *ls) { static void ret (LexState *ls) {
/* ret -> [RETURN explist sc] */ /* ret -> [RETURN explist sc] */
if (ls->token == RETURN) { if (ls->token == RETURN) {
@@ -986,12 +991,14 @@ static void simpleexp (LexState *ls, vardesc *v, stack_op *s) {
constructor(ls); constructor(ls);
break; break;
case FUNCTION: { /* simpleexp -> FUNCTION body */ case FUNCTION: /* simpleexp -> FUNCTION body */
int line = ls->linenumber;
next(ls); next(ls);
body(ls, 0, line); body(ls, 0, ls->linenumber);
break;
case IF: /* simpleexp -> IF ifpart END */
ifpart(ls, 1, ls->linenumber);
break; break;
}
case '(': /* simpleexp -> '(' exp0 ')' */ case '(': /* simpleexp -> '(' exp0 ')' */
next(ls); next(ls);