I'm not sure, but I suspect this is because of 80-bit intermediary float
point operation result. Its precision too excessive and gives us this
inexpectible result. But when you use an intermediary variable this
exessive intermediary result is rounded properly and you get what you
expect. See he
Hi,
Why in D this expression does not call the class constructor?
class A {
int myVal;
this(int val) {
myVal = val;
}
}
int main() {
A myA = 8;
}
I would like to have a feature like this, because i want to
create my own data type. I think it's possible, but i don't
Classes are instanciated with new, structs are not. The following
program compiles:
class A {
int myVal;
this(int val) {
myVal = val;
}
}
struct B {
int myVal;
this(int val) {
myVal = val;
}
}
void main() {
On Saturday, 13 April 2013 at 07:57:30 UTC, Nicolas Guillemot
wrote:
Classes are instanciated with new, structs are not. The
following program compiles:
class A {
int myVal;
this(int val) {
myVal = val;
}
}
struct B {
int myVal;
this(in
Hi,
I have an associative array: string values[string], and i want to
remove all the values from this array. I looked at the
documentation here: http://dlang.org/hash-map.html and i can't
see any method for this action.
There is a nice way to remove the values, or I should use foreach?
Than
Hey gedaiu,
I'm still a novice to D, but here are some solutions I found.
They can probably be improved.
1) Assigning to it an empty map
https://ideone.com/h7ffmD
2) Removing all entries
https://ideone.com/E7k2WL
My guess is that the first method is more efficient. I wish I
knew how to do i
On Saturday, 13 April 2013 at 09:09:36 UTC, Nicolas Guillemot
wrote:
Hey gedaiu,
I'm still a novice to D, but here are some solutions I found.
They can probably be improved.
1) Assigning to it an empty map
https://ideone.com/h7ffmD
2) Removing all entries
https://ideone.com/E7k2WL
My guess
values = null;
and it seems it works great. But, i don't know how correct is
this... I was expecting to have a clear() method on array.
Makes sense to me! Looks like the technique you described is
explained here: http://ddili.org/ders/d.en/null_is.html
Good find, thanks for sharing!
On 4/13/13, gedaiu wrote:
> looks great, but i cleared the array like this:
>
> values = null;
That's not clearing the array, that's clearing the reference to the
array. For example:
void main()
{
int[int] hash;
hash[1] = 1;
auto hash2 = hash; // new reference
hash = null; //
Hi again!
I don't understand why we have opIndex() and opIndexAssign()...
can anyone explain this for me?
Because in c++ there is only one operator overload for "[]" and
it looks like this:
Value& Value::operator[] (constValue offset) {
return container[offset];
}
and with this ope
On Saturday, 13 April 2013 at 09:52:45 UTC, Andrej Mitrovic wrote:
On 4/13/13, gedaiu wrote:
looks great, but i cleared the array like this:
values = null;
That's not clearing the array, that's clearing the reference to
the
array. For example:
void main()
{
int[int] hash;
hash[1]
On 4/13/13, gedaiu wrote:
> I know, that's why I am asking how i should do this...
I think we should introduce a removeAll function for hashes. Either
through Druntime or through a UFCS function that we could put in
std.array or somewhere.
Putting it in Druntime is probably the most efficient wa
Nicolas Guillemot:
Classes are instanciated with new, structs are not.
structs are created with new if you want them on the heap.
Bye,
bearophile
Alexandr Druzhinin:
I'm not sure, but I suspect this is because of 80-bit
intermediary float point operation result.
Maybe D uses higher precision FP values in some of those
intermediate computations.
In general float is useful if you have to store many of them, for
storage reasons (reduce m
On Saturday, 13 April 2013 at 09:53:01 UTC, gedaiu wrote:
Hi again!
I don't understand why we have opIndex() and opIndexAssign()...
can anyone explain this for me?
opIndex returns the value contained in the "array", while
opIndexAssign does the opposite, it puts in your "array" the
given va
Hi,
thanks for the answer, but it's not the solution what i was
expectig. What i want to create, is an array structure like the
one from PHP where array levels are not fixed and the sintax to
access rhe values is val[][] so returning a reference to a struct
that have the same type as the curr
gedaiu:
What i want to create, is an array structure like the one from
PHP where array levels are not fixed and the sintax to access
rhe values is val[][] so returning a reference to a struct that
have the same type as the current type is useful.
there is a way to do this in D?
Instead of
On Sat, 13 Apr 2013 08:07:39 +0200, Jeremy DeHaan
wrote:
In debug mode this works as expected. Let's say the radius is 50.
getPoint(0) returns a vector that prints X: 50 Y: 0. For some reason,
the same function will return a vector that prints X: 50 Y: 4.77673e-14.
Now, 4.77673e-14 is a
void f() nothrow { // Error: _arrayExpSliceAddass_i is not
nothrow
int[3] d;
d[] += 3;
}
Hello,
I noticed there are two different packed bit array
implementations in Phobos: the specialised version of
std.container.Array and std.bitmanip.BitArray. Which one should
be used?
Thanks,
Matej
Currently is there a way to get all of the subclasses of a class
at compile time?
It seems like something that should be possible using traits but
I can't seems to see how.
Something like
class A{...}
class B:A{...}
class C:A{...}
...
foreach(auto t ; getsubclass(A))
{
...
}
Any help wou
On Saturday, 13 April 2013 at 11:59:12 UTC, Simen Kjaeraas wrote:
On Sat, 13 Apr 2013 08:07:39 +0200, Jeremy DeHaan
wrote:
In debug mode this works as expected. Let's say the radius is
50. getPoint(0) returns a vector that prints X: 50 Y: 0. For
some reason, the same function will return a v
On 4/13/13, Tofu Ninja wrote:
> Currently is there a way to get all of the subclasses of a class
> at compile time?
There might be things like using .moduleinfo and traversing imports to
find all classes, but I think separate compilation makes this
unreliable.
There is however BaseClassTuple in
On Saturday, 13 April 2013 at 16:16:03 UTC, Tofu Ninja wrote:
Currently is there a way to get all of the subclasses of a
class at compile time?
It seems like something that should be possible using traits
but I can't seems to see how.
Something like
class A{...}
class B:A{...}
class C:A{...}
Maybe this is helpfully:
http://forum.dlang.org/thread/scgjnudclnwlbdqqd...@forum.dlang.org
Oddly enough, I found that at about the same time you posted it.
On Saturday, 13 April 2013 at 17:45:12 UTC, Tofu Ninja wrote:
Maybe this is helpfully:
http://forum.dlang.org/thread/scgjnudclnwlbdqqd...@forum.dlang.org
Oddly enough, I found that at about the same time you posted it.
Sadly this does not provide a compile time solution, only runtime.
simendsjo:
void f() nothrow { // Error: _arrayExpSliceAddass_i is not
nothrow
int[3] d;
d[] += 3;
}
Currently those ops are not nothrow. I think they will eventually
become nothrow...
Bye,
bearophile
I think we should introduce a removeAll function for hashes.
Either
through Druntime or through a UFCS function that we could put in
std.array or somewhere.
How about .clear() for consistency with C++ containers?
I have a problem and maybe one you can explain, why this failure
happen.
Initial situation:
I have a opengl texture and I want to copy the pixel. I store the
original pixel in an ubyte pointer and allocate new pixel memory
with:
ubyte[] newPixel = new ubyte[this.width * this.height *
this.dept
Forget to say: Of course I use the .ptr property to load the
newPixel into the texture, if I use the ubyte storage.
On 04/13/2013 02:22 PM, Namespace wrote:
> I have a opengl texture and I want to copy the pixel. I store the
> original pixel in an ubyte pointer and allocate new pixel memory with:
> ubyte[] newPixel = new ubyte[this.width * this.height * this.depth];
Make sure that you really do not need to mu
Namespace:
I have a problem and maybe one you can explain, why this
failure happen.
Consider using something like:
auto newPixel = orgPixel[0 .. this.width * this.height *
this.depth].dup;
Bye,
bearophile
On Saturday, 13 April 2013 at 22:18:21 UTC, bearophile wrote:
Namespace:
I have a problem and maybe one you can explain, why this
failure happen.
Consider using something like:
auto newPixel = orgPixel[0 .. this.width * this.height *
this.depth].dup;
Bye,
bearophile
Nice idea. That works
Two things that I can't seem to nail down a strict definition for
are value types and reference types. I know very well their basic
definitions: a variable of a value type holds its own data and
assignment copies the data, and a variable of a reference type
holds a pointer to its data and assig
Re-wording my last paragraph because of incorrect wording:
In essence, don't all variables act as structs, with different
operator overloads to give different semantics? If so, how do we
classify 'value type' versus 'reference type'? What if I have a
struct whose members are a fixed-length arr
Nicholas Smith:
it is said that slices are reference types. Sure, slices hold
references to an array, but they also carry their own data,
which gives them value semantics.
Slices are a small value, that contains in place a length and a
pointer. The pointer refers to memory allocated elsewher
On Sunday, 14 April 2013 at 02:51:35 UTC, bearophile wrote:
slices are kind of hybrids between values and references. You
can also think of them as fat references. When you program in D
you must remember this nature of sliced, otherwise your code
will not work...
Bye,
bearophile
Ali Çehreli
On 04/13/2013 08:46 PM, Nicholas Smith wrote:
> On Sunday, 14 April 2013 at 02:51:35 UTC, bearophile wrote:
>> slices are kind of hybrids between values and references. You can also
>> think of them as fat references. When you program in D you must
>> remember this nature of sliced, otherwise you
On Saturday, 13 April 2013 at 21:10:16 UTC, Nicolas Guillemot
wrote:
I think we should introduce a removeAll function for hashes.
Either
through Druntime or through a UFCS function that we could put
in
std.array or somewhere.
How about .clear() for consistency with C++ containers?
It looks
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