Proposal : allocations made easier with non nullable types.

Alex Burton alexibu at mac.com
Mon Feb 9 02:48:39 PST 2009


I think it makes no sense to have nullable pointers in a high level language like D.

In D :

X x = new X;
This is a bit redundant, if we take away the ability to write X x; to mean X x = 0; then we can have X x; mean X x = new X;
If the class has a ctor then we can write X x(32); instead of X x = new X(32);
Only when the types of the pointer and class are different do we need to write X x = new Y;
We can do this syntactically in D because classes cannot be instantiated on the stack (unless scope is used, which I have found a bit pointless, as members are not scope so no deterministic dtor)

This makes the code much less verbose and allows code to change from X being a struct to X being a class without having to go around and change all the X x; to X = new X;

As I said in the nullable types thread:
Passing 0 or 0x012345A or anything else that is not a pointer to an instance of X to a variable declared as X x is the same as mixing in a bicycle when a recipe asks for a cup of olive oil.

There are much better, and less error prone ways to write code in a high level language than allowing null pointers.

Alex



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