On Fri, 2010-06-11 at 08:44 +0800, yuanbin wrote:
> typedef struct CBase { int i; } CBase;
> typedef struct CT1 { EXTENDS(CBase) ... } CT1;
> typedef struct CT2 { EXTENDS(CT1) ... } CT2;
> ...
> typedef struct CTN { EXTENDS(CTN_1) ... } CTN;
> CTN t;
> t.i=1; //need not t.CTN_1....CT2.CT1.CBase.i ---complex
> CBase* p=&t.CBase; //need not t.CTN_1....CT2.CT1.CBase, need not
> (CBase*)&t ---not safe
struct CBase { int i; };
struct CT1 : CBase { ... };
struct CT2 : CT1 { ... };
struct CTN : CTN_1 { ... };
CTN t;
t.i = 1; // assumes this is in function scope
CBase* p = &t; // Even simpler than your proposal and still safe.
Yep, this is valid C++. I think Dave is right, you really want C++.
/MF
>
> 2010/6/11 Dave Korn <dave.korn.cyg...@gmail.com>:
> > On 10/06/2010 18:07, yuanbin wrote:
> >> This compiler's extension is valuable
> >
> > No, it isn't very valuable, sorry to be blunt. I think you are following a
> > really wrong path here. You are trying to implement a C++-alike
> > object-oriented system in C. That makes sense as far as it goes, but if you
> > find yourself having to propose modifying the C compiler in a direction that
> > basically makes it speak C++, you might as well just use C++ in the first
> > place. You want the compiler to automatically choose one of several
> > different
> > ways to initialise a union according to the data type of the argument you
> > use
> > to initialise it with; basically, that means you want overloaded
> > constructors.
> > So you should just use C++, which already is C with overloaded
> > constructors.
> > And it also already has all the other features that you'll discover you
> > need
> > in the compiler as you carry along this path.
> >
> > By the time you get to the end of your journey, "coo.h" will be an empty
> > file and all the functionality will have been added to the C compiler until
> > it
> > turns into a C++ compiler. I think you need to choose a different plan.
> >
> > cheers,
> > DaveK
> >
> >
