On Thu, 18 Aug 2011 06:47:32 -0400, nrgyzer <nrgy...@gmail.com> wrote:
== Auszug aus Robert Clipsham (rob...@octarineparrot.com)'s Artikel
On 16/08/2011 20:17, nrgyzer wrote:
> Hi everyone,
>
> I've the following:
>
> private static ubyte[][2][hash_t] classInstances;
>
> this() {
>
> classInstances[toHash()] = new ubyte[2]; // does not work
>
> }
>
> I want insert every class instance into the hashmap. Every class
> instance should be contained in the map after the constructor was
> called. When I compile my code, I get "Error: cannot implicitly
> convert expression (new ubyte[](2u)) of type ubyte[] to ubyte[][]"
> which is logical. But is there any way to insert every instance into
> the array and define the array/map for this entry?
>
> Thanks in advance!
Is there any particular reason you're using ubyte[][2][hash_t] there? To
keep a reference to each instance simply use:
----
class MyClass {
static MyClass[] classInstances;
this() {
classInstances ~= this;
}
}
----
If you in fact want to have a hashmap indexed by the instances with
values of type ubyte[][2], you can do this:
----
class MyClass {
static ubyte[][2][MyClass] classInstances;
this() {
classInstances[this] = new ubyte[][2];
}
}
----
The problem in your original code is that you were using = new ubyte[2]
rather than = new ubyte[][2]. Hope this helps.
Ok, that works - thx.
@Steve: I'll delete the entries from the map, but what's about
overriding the toHash()-function and return a simply int value?
If two instances return the same hash value (as is easily possible, but
maybe not for your context), then a collision occurs. Then opCmp is used
to determine if they are actually identical.
If you use hash_t as your key, then only one object is stored in the map,
the other is simply overwritten.
I also need this map-structure for further steps in my application. I's
possible to change it to
ubyte[][hash_t] classInstancesOne; // or ubyte[][MyClass]
ubyte[][hash_t] classInstancesTwo; // or ubyte[][MyClass]
but I thought one map for the same sense is better.
ubyte[][Object] should work for all class types.
Btw: I've two classes where one inherits:
class MyClassOne {
protected {
static __gshared {
uint counter;
uint[MyClassOne] fixedData;
}
uint otherData;
this(uint d) {
otherData = d;
}
}
this() {
fixedData[this] = ++counter;
}
@property ref {
uint myPropOne() { return fixedData[this]; }
uint myPropTwo() { return otherData; }
}
}
class MyClassTwo : MyClassOne {
shared(MyClassOne) supInstance;
this(uint d, MyClassOne mco) {
super(d);
supInstance = mco;
}
override ref alias supInstance.myPropOne myPropOne;
}
When I create an instance of MyClassOne and call myPropOne on it, I get
"1". When I'm using this instance to create an instance of
MyClassTwo and call myPropOne, I get "0". Is there anything I'm doing
wrong?
That crazy override ref alias line, I have no idea what you're doing
there. For sure, override ref is not needed.
I'm surprised all of this compiles.
What I'm trying to do is: One super-class which contains some fixed data
(not inheritable) and some data which are different for each
class.
Note that protected does not prevent MyClassTwo from changing it.
Also note that even though you've only created one instance of MyClassOne,
every MyClassTwo instance is a MyClassOne (and calls MyClassOne's
constructor). I think you have applied the wrong techniques to solving
your design. Without knowing further your design/context, I can't really
help.
-Steve
