[ruby-dev:14959] Re: alias $gvar

なかだです。

At Thu, 18 Oct 2001 10:23:26 +0900,
K.Kosako <[e-mail]> wrote:
> 最新版で、二点不具合があるようです。

　そうか、global_entryが消えることはないと思って油断してました。
aliasで変わっちゃうんだな。

> ## aliased original variable
> $c
> $a = 10
> alias $b $a
> p $b         # => 10
> alias $a $c
> p $b         # => in `p': method `inspect' called on
>                       terminated object (0x8109918) (NotImplementedError)

　やっぱりalias_fixup()は無理があったようです。

> ## cyclic alias
> $a = 10
> alias $a $a
> p $a         # => Abort core dumped

　こっちはaliasの時点で例外でどうでしょうか。


Index: variable.c
===================================================================
RCS file: /cvs/ruby/src/ruby/variable.c,v
retrieving revision 1.48
diff -u -2 -p -r1.48 variable.c
--- variable.c	2001/10/17 05:28:02	1.48
+++ variable.c	2001/10/18 02:27:59
@@ -426,18 +426,4 @@ readonly_setter(val, id, var)
 }
 
-static int
-alias_fixup(entry1, entry2)
-    struct global_entry *entry1, *entry2;
-{
-    if (entry2->getter != val_getter) return 0;
-    entry1->data   = &entry2->data;
-    entry1->getter = var_getter;
-    if (entry2->setter == val_setter)
-	entry1->setter = var_setter;
-    else
-	entry1->setter = entry2->setter;
-    return 1;
-}
-
 static VALUE
 alias_getter(id, data, entry)
@@ -447,7 +433,5 @@ alias_getter(id, data, entry)
 {
     struct global_entry *entry2 = data;
-    VALUE val = (*entry2->getter)(id, entry2->data, entry2);
-    alias_fixup(entry, entry2);
-    return val;
+    return (*entry2->getter)(id, entry2->data, entry2);
 }
 
@@ -461,5 +445,4 @@ alias_setter(val, id, data, entry)
     struct global_entry *entry2 = data;
     (*entry2->setter)(val, id, entry2->data, entry2);
-    alias_fixup(entry, entry2);
 }
 
@@ -772,10 +755,17 @@ rb_alias_variable(name1, name2)
     entry2 = rb_global_entry(name2);
 
-    if (entry2->getter == undef_getter) {
+    if (entry2->getter == alias_getter) {
+	entry2 = entry2->data;
+    }
+    if (entry1 == entry2) {
+	rb_raise(rb_eArgError, "recursive alias");
+    }
+
+    if (entry2->getter == undef_getter || entry2->getter == val_getter) {
 	entry1->data   = entry2;
 	entry1->getter = alias_getter;
 	entry1->setter = alias_setter;
     }
-    else if (!alias_fixup(entry1, entry2)) {
+    else {
 	entry1->data   = entry2->data;
 	entry1->getter = entry2->getter;


-- 
--- 僕の前にBugはない。
--- 僕の後ろにBugはできる。
    中田 伸悦