In article <3iihp2$h6c@seattle.polstra.com>, jdp@polstra.com (John Polstra) wrote:
>>In article <3idrse$k8f@giga.bga.com>, Jamshid Afshar <jamshid@ses.com> wrote:
>> Is it legal to use a typedef to initialize a base class in a
>> constructor as in the following.  I seem to remember the ARM grammar
>> does not strictly allow it, but ANSI/ISO probably would.
>> [example elided]
>
>The way I read it, even the ARM allows this.  The key phrase is toward
>the end of section 9.1:
>
>    A typedef-name (7.1.3) that names a class is a class-name;
>
>So, except for explicitly restricted cases, such a typedef-name should
>be legal anywhere the grammar calls for a class-name.

Thanks, I looked it up and the ARM restrictions on using a
typedef-name in place of a class-name are (from 7.1.3) "The synonym
may not be used after a class, struct, or union prefix and not in the
names for constructors or destructors within the class declaration
itself.  For example:
 struct S;
 typedef struct S T;
 struct S {
    S();
    ~T(); // error
 };
 S::T() {} // okay

So, it does appear that IBM's xlC compiler is just plain wrong
according to even the 1990 ARM when it gives an error for:

 class Base {
 public:
     Base(int);
 };

 class Derived : public Base {
     typedef Base inherited;
 public:
     Derived(int)
        : inherited(i)  // ARM legal, but xlC complains
     {}
 };

Btw, Cfront also gives an error for this code but only in the case
when the Derived ctor is inline.  Also, I believe Visual C++ has the
same bug.

Jamshid Afshar
jamshid@ses.com

In article <3idrse$k8f@giga.bga.com>, Jamshid Afshar <jamshid@ses.com> wrote:
> Is it legal to use a typedef to initialize a base class in a
> constructor as in the following.  I seem to remember the ARM grammar
> does not strictly allow it, but ANSI/ISO probably would.
>
> [example elided]

The way I read it, even the ARM allows this.  The key phrase is toward
the end of section 9.1:

    A typedef-name (7.1.3) that names a class is a class-name;

So, except for explicitly restricted cases, such a typedef-name should
be legal anywhere the grammar calls for a class-name.
--
   John Polstra                                       jdp@polstra.com
   John D. Polstra & Co., Inc.                Seattle, Washington USA
   "Self-knowledge is always bad news."                 -- John Barth

Is it legal to use a typedef to initialize a base class in a
constructor as in the following.  I seem to remember the ARM grammar
does not strictly allow it, but ANSI/ISO probably would.

class Base {
public:
    Base(int);
};

class Derived : public Base {
    typedef Base inherited;
public:
    Derived(int);
};

Derived::Derived(int i)
  : inherited(i)  // legal?
{}


Thanks,
Jamshid Afshar
jamshid@ses.com