On Sun, 03 May 2009 01:02:41 +0400, Tyro[a.c.edwards] <[email protected]> wrote:
On 5/3/2009 3:44 AM, flourish wrote:
Hi,
why does the following code not compile -- or how to declare a (usable)
property of an associative array field?
//////////////////////
class Test
{
private int[int] _testMap;
public int[int] testMap() {return _testMap;}
}
testMap() is a getter and can only return the value it is designed to.
You must implement a setter to accomplish what you are trying to di.
Unfortunately I'm not sure how you do that with AAs so I'll leave that
to someone that's a little smarter than I.
I think that maybe implementing opIndexAssign might work for you though:
public void opIndexAssign(int val, int ndx){ _testMap[ndx] = val; }
Then you can simply "test[0] = 1;" to get the desired effect.
void main()
{
Test test = new Test();
test.testMap[0] = 1;
}
/////////////////
*** Error: test.testMap() is not an lvalue
Regards,
flourish
No, you are wrong, testMap works like a property here. I believe, original code
_should_ work. For example, it works if you replace int[int] with int[].
All the trouble is because of an awful properties implementation in D, and
temporaries not being able to be passed by reference:
struct Foo
{
private int[] _arr;
int[] arr() { return _arr; }
}
void doSomething(int[] a)
{
}
void doSomethingElse(ref int[] a)
{
}
void doSomethingElseConst(ref const(int)[] a)
{
}
void main()
{
Foo foo;
foo.arr[0] = 1; // works
//foo.arr.length = 1; // doesn't
foo.arr().doSomething(); // works
//foo.arr.doSomething(); // doesn't
//foo.arr().doSomethingElse(); // doesn't
//foo.arr().doSomethingElseConst(); // doesn't
}
