Re: [Yact-dev] Null object

[Daniel B. <ba...@we...>]

On Mon, Mar 13, 2000 at 08:54:22PM -0800, Marius Sundbakken wrote:
> I think we should add a YNullable interface (or similar):
> [..]
> Let's get rid of as many "if pointer is not null" statements as
> possible.

Well, there aren't that many of those there, actually.  Lots of them
disappeared when I pushed the gui logic to YInputHandler, and the ones
that are left are mostly in the subclasses to that class.

> I think this will make Yact a lot more stable (the risk of 
> coredumping is greatly reduced) and code-flow in general will be much 
> cleaner, prettier, and easier to read.  No more of those annoying null 
> pointer if's, and just go ahead and access the object directly.

I'm not so sure about that.  I kind of like core dumps, because they let
you know very quickly when something is wrong with the program.  If some
method gets a null pointer when it shouldn't, the fix is to get rid of
that null pointer, not add a "if (!p) return".

Sometimes null objects are ok though, and when that situation comes up,
I'll have no problem introducing YNull(able).  I don't see much use for
it right now, though.  Do you (apart from that bug below)?

> You can already get Yact to crash by playing around with adding new
> classes and adding inheritance and deleting them etc.  I don't know
> where the bug is exactly, but I bet it's a null pointer.

I don't remember where it was, but it was a bad pointer somewhere...
It's fixed now, anyway. :)

/Basic