Re: Alternatives to pointers?
On Saturday, 30 September 2017 at 08:27:26 UTC, Timon Gehr wrote:
On 29.09.2017 03:51, Jerry wrote:
I miss ref variables, for the simple fact that using the
square brackets with a ref variable doesn't access the
pointer. Don't know how many times I've accidentially used a
pointer as an array. Not very easy to catch especially if the
object has pointers to other objects of the same type.
Possibly adding something like this, if ref variables are off
the table?
@noarray int* value;
value[x] = 10; // compile error, pointer is not an array.
void main()@safe{
int x;
int* value;
value[x]=10;
}
Error: safe function 'D main' cannot index pointer 'value'
Need it in unsafe/trusted code though.
Re: Alternatives to pointers?
On Saturday, 30 September 2017 at 04:15:52 UTC, bitwise wrote:
On Friday, 29 September 2017 at 01:51:36 UTC, Jerry wrote:
[...]
Maybe this?
ref auto at(T : U[], U)(T arr, size_t index) {
return arr[index];
}
int main(string[] argv)
{
int* a = new int(1);
int[] b = [1];
int[1] c = [1];
a.at(0); // won't compile
b.at(0);
c.at(0);
reutnr 0;
}
That is interesting, it would mean not using "[]" or "[..]",
which would kind of suck.
Re: Alternatives to pointers?
On 29.09.2017 03:51, Jerry wrote:
I miss ref variables, for the simple fact that using the square brackets
with a ref variable doesn't access the pointer. Don't know how many
times I've accidentially used a pointer as an array. Not very easy to
catch especially if the object has pointers to other objects of the same
type. Possibly adding something like this, if ref variables are off the
table?
@noarray int* value;
value[x] = 10; // compile error, pointer is not an array.
void main()@safe{
int x;
int* value;
value[x]=10;
}
Error: safe function 'D main' cannot index pointer 'value'
Re: Alternatives to pointers?
On Friday, 29 September 2017 at 01:51:36 UTC, Jerry wrote:
[...]
Maybe this?
ref auto at(T : U[], U)(T arr, size_t index) {
return arr[index];
}
int main(string[] argv)
{
int* a = new int(1);
int[] b = [1];
int[1] c = [1];
a.at(0); // won't compile
b.at(0);
c.at(0);
reutnr 0;
}
Re: Alternatives to pointers?
On Friday, 29 September 2017 at 03:37:53 UTC, Jonathan M Davis wrote: On Friday, September 29, 2017 01:51:36 Jerry via Digitalmars-d wrote: I miss ref variables, for the simple fact that using the square brackets with a ref variable doesn't access the pointer. Don't know how many times I've accidentially used a pointer as an array. Not very easy to catch especially if the object has pointers to other objects of the same type. Possibly adding something like this, if ref variables are off the table? @noarray int* value; value[x] = 10; // compile error, pointer is not an array. You could always create a wrapper struct for the pointer and then not overload opIndex. - Jonathan M Davis Not the most ideal solution, doesn't work with several other features like auto.
Re: Alternatives to pointers?
On Friday, 29 September 2017 at 01:51:36 UTC, Jerry wrote: Don't know how many times I've accidentially used a pointer as an array. Using @safe let's the compiler to catch that. Well, in it you can't use pointer arithmetic even explicitly, but if you have many elements to point at you're usually better off using a real array anyway.
Re: Alternatives to pointers?
On Friday, 29 September 2017 at 03:37:53 UTC, Jonathan M Davis
wrote:
You could always create a wrapper struct for the pointer and
then not overload opIndex.
...alternatively, you could create a wrapper struct for the
pointer, do 'alias this' on said pointer, and then overload
opIndex to call static assert(0);. Like this:
struct Ptr(T) {
private T *_ptr;
alias _ptr this;
this(T *val) {
_ptr = val;
}
void opIndex(size_t index)() {
static assert(0);
}
}
Re: Alternatives to pointers?
On Friday, September 29, 2017 01:51:36 Jerry via Digitalmars-d wrote: > I miss ref variables, for the simple fact that using the square > brackets with a ref variable doesn't access the pointer. Don't > know how many times I've accidentially used a pointer as an > array. Not very easy to catch especially if the object has > pointers to other objects of the same type. Possibly adding > something like this, if ref variables are off the table? > > @noarray int* value; > value[x] = 10; // compile error, pointer is not an array. You could always create a wrapper struct for the pointer and then not overload opIndex. - Jonathan M Davis
