digitalmars.D - Separate dynamic object arrays for multiple instances of overlying
- Jonathan (44/44) Mar 14 I'm having some trouble creating arrays that are themselves
- Richard (Rikki) Andrew Cattermole (4/4) Mar 14 That code example works fine as is.
- Mike Parker (14/41) Mar 14 Shouldn't be. Each non static class member is a distinct thing in
- Jonathan (8/57) Mar 14 You're right, my example code doesn't function as my nonworking
- Jonathan (64/64) Mar 14 The following seems the be the minimum required for this problem
- Basile B. (13/17) Mar 14 Classic. Instead of a static initializer rather uses a
- Jonathan (4/22) Mar 14 This seems to have solved the problem. This thought had crossed
- Matheus (9/27) Mar 14 I wonder how it would be if we had an error or warning for
- Timon Gehr (3/36) Mar 16 Well, I guess I can still point out that this is what OpenD does:
- matheus (3/7) Mar 16 Indeed and thanks for the info.
- Quirin Schroll (3/39) Mar 26 Too common.
- An Pham (8/29) Mar 14 You encounter a gotcha unfriendly construct of D. For every "new
I'm having some trouble creating arrays that are themselves
unique within multiple instances of an object. Example code:
```
class individual
{
int a = 1; // placeholder for data
}
class individualList
{
individual[] individuals; // Something likely has to change
here
}
void main()
{
individualList list1 = new individualList();
assert(list1.individuals.length == 0);
individual person1 = new individual();
list1.individuals ~= person1;
assert(list1.individuals.length == 1);
individualList list2 = new individualList();
assert(list2.individuals.length == 0); // breaks,
list2.individuals.length is 1
}
```
I'd like the array "individuals" to be unique for each instance
of individualList, but it seems to be using the same list among
the different instances. The following code doesn't work as I
don't know the required length of the arrays:
```
class individualList
{
individual[] individuals = new individual[]; // Doesn't
compile, requires length
}
```
I've looked a bit and don't see a solution to this within the
documentation for arrays or objects.
Further information:
This is being used to parse a xml-style file, the example code is
a base example, I'm having to do this list population a few
times, one within another. Some lists have their count displayed
before starting to add "individuals" so I could use a
constructor, but some do not (to my knowledge) have that
option, and I'd rather use one solution through the whole parser.
Mar 14
"Richard (Rikki) Andrew Cattermole" <richard cattermole.co.nz> That code example works fine as is. When you give a value to a field, it places whatever that is into the initialize state that is shared between all instances of that type. As long as its null or allocated in a constructor, it'll work.
Mar 14
On Thursday, 14 March 2024 at 09:43:09 UTC, Jonathan wrote:
I'm having some trouble creating arrays that are themselves
unique within multiple instances of an object. Example code:
```
class individual
{
int a = 1; // placeholder for data
}
class individualList
{
individual[] individuals; // Something likely has to
change here
}
void main()
{
individualList list1 = new individualList();
assert(list1.individuals.length == 0);
individual person1 = new individual();
list1.individuals ~= person1;
assert(list1.individuals.length == 1);
individualList list2 = new individualList();
assert(list2.individuals.length == 0); // breaks,
list2.individuals.length is 1
}
```
I'd like the array "individuals" to be unique for each instance
of individualList, but it seems to be using the same list among
the different instances.
Shouldn't be. Each non static class member is a distinct thing in
each instance of the class. They are not shared across instances.
When I paste your code into run.dlang.io and add this:
```D
writeln(list1.individuals.length);
writeln(list2.individuals.length);
```
No asserts trigger and I see this output as expected:
```
1
0
```
Is the code you pasted here exactly what you're running?
Mar 14
On Thursday, 14 March 2024 at 09:53:27 UTC, Mike Parker wrote:On Thursday, 14 March 2024 at 09:43:09 UTC, Jonathan wrote:You're right, my example code doesn't function as my nonworking code does, sorry about that. No, this is not the same, the code that doesn't work is part of a 1000+ line parser, I thought this example would work the same. I'm trying multiple loops to get the same problem, but I'm having trouble getting it to do so. Will get back when I have a proper example.I'm having some trouble creating arrays that are themselves unique within multiple instances of an object. Example code: ``` class individual { int a = 1; // placeholder for data } class individualList { individual[] individuals; // Something likely has to change here } void main() { individualList list1 = new individualList(); assert(list1.individuals.length == 0); individual person1 = new individual(); list1.individuals ~= person1; assert(list1.individuals.length == 1); individualList list2 = new individualList(); assert(list2.individuals.length == 0); // breaks, list2.individuals.length is 1 } ``` I'd like the array "individuals" to be unique for each instance of individualList, but it seems to be using the same list among the different instances.Shouldn't be. Each non static class member is a distinct thing in each instance of the class. They are not shared across instances. When I paste your code into run.dlang.io and add this: ```D writeln(list1.individuals.length); writeln(list2.individuals.length); ``` No asserts trigger and I see this output as expected: ``` 1 0 ``` Is the code you pasted here exactly what you're running?
Mar 14
The following seems the be the minimum required for this problem
to pop up. I've changed the names to what I'm using in my code
to make it more clear for me.
```
import std;
class SpectrumList
{
int count = 2;
Spectrum[] spectra;
}
class Spectrum
{
PrecursorList precursorList = new PrecursorList();
}
class PrecursorList
{
int count = 3;
Precursor[] precursors;
}
class Precursor
{
string a = "placeholder";
string b = "loren ipsum";
}
void main()
{
SpectrumList mySpectrumList = new SpectrumList;
for(int j=0; j<mySpectrumList.count; ++j)
{
Spectrum mySpectrum = new Spectrum;
writeln(mySpectrum.precursorList.precursors.length); //
should always be 0
assert(mySpectrum.precursorList.precursors.length == 0);
for(int k=0; k<mySpectrum.precursorList.count; ++k)
{
Precursor myPrecursor = new Precursor;
mySpectrum.precursorList.precursors ~= myPrecursor;
}
mySpectrumList.spectra ~= mySpectrum;
}
}
```
Output from run.dlang.io:
```
0
3
core.exception.AssertError onlineapp.d(32): Assertion failure
----------------
??:? [0x55676698b006]
??:? [0x55676698ac82]
??:? [0x5567669b11d6]
??:? [0x5567669927ef]
??:? [0x556766989d92]
onlineapp.d:32 [0x556766959f4c]
??:? [0x5567669924bc]
??:? [0x5567669923b6]
??:? [0x55676699220d]
/dlang/ldc-1.35.0/bin/../import/core/internal/entrypoint.d:42
[0x55676695a1d1]
??:? [0x7efc3bed5d8f]
??:? __libc_start_main [0x7efc3bed5e3f]
??:? [0x556766959c54]
Error: /tmp/onlineapp-ae55ed failed with status: 1
```
Mar 14
On Thursday, 14 March 2024 at 10:21:41 UTC, Jonathan wrote:The following seems the be the minimum required for this problem to pop up. I've changed the names to what I'm using in my code to make it more clear for me. [...]Classic. Instead of a static initializer rather uses a constructor for instances. ```d class Spectrum { PrecursorList precursorList; this() { precursorList = new PrecursorList(); } } ```
Mar 14
On Thursday, 14 March 2024 at 12:00:37 UTC, Basile B. wrote:On Thursday, 14 March 2024 at 10:21:41 UTC, Jonathan wrote:This seems to have solved the problem. This thought had crossed my mind at one point, then left before I could implement it. Really appreciate the help!The following seems the be the minimum required for this problem to pop up. I've changed the names to what I'm using in my code to make it more clear for me. [...]Classic. Instead of a static initializer rather uses a constructor for instances. ```d class Spectrum { PrecursorList precursorList; this() { precursorList = new PrecursorList(); } } ```
Mar 14
On Thursday, 14 March 2024 at 12:00:37 UTC, Basile B. wrote:On Thursday, 14 March 2024 at 10:21:41 UTC, Jonathan wrote:I wonder how it would be if we had an error or warning for something like this. For example displaying a message forcing the use of the word "static" and initialize with "static this" when expecting static initialization or construct for new instances. Before someone points out: https://dlang.org/spec/class.html Yes I know, but unfortunately this mistake as Basile noted as "classic", is very common. Matheus.The following seems the be the minimum required for this problem to pop up. I've changed the names to what I'm using in my code to make it more clear for me. [...]Classic. Instead of a static initializer rather uses a constructor for instances. ```d class Spectrum { PrecursorList precursorList; this() { precursorList = new PrecursorList(); } } ```
Mar 14
On 3/14/24 15:44, Matheus wrote:On Thursday, 14 March 2024 at 12:00:37 UTC, Basile B. wrote:Well, I guess I can still point out that this is what OpenD does: https://github.com/opendlang/opend/pull/8On Thursday, 14 March 2024 at 10:21:41 UTC, Jonathan wrote:I wonder how it would be if we had an error or warning for something like this. For example displaying a message forcing the use of the word "static" and initialize with "static this" when expecting static initialization or construct for new instances. Before someone points out: https://dlang.org/spec/class.html Yes I know, but unfortunately this mistake as Basile noted as "classic", is very common. Matheus.The following seems the be the minimum required for this problem to pop up. I've changed the names to what I'm using in my code to make it more clear for me. [...]Classic. Instead of a static initializer rather uses a constructor for instances. ```d class Spectrum { PrecursorList precursorList; this() { precursorList = new PrecursorList(); } } ```
Mar 16
On Saturday, 16 March 2024 at 13:47:42 UTC, Timon Gehr wrote:... Well, I guess I can still point out that this is what OpenD does: https://github.com/opendlang/opend/pull/8Indeed and thanks for the info. Matheus.
Mar 16
On Saturday, 16 March 2024 at 13:47:42 UTC, Timon Gehr wrote:On 3/14/24 15:44, Matheus wrote:Too common. https://issues.dlang.org/show_bug.cgi?id=24454On Thursday, 14 March 2024 at 12:00:37 UTC, Basile B. wrote:Well, I guess I can still point out that this is what OpenD does: https://github.com/opendlang/opend/pull/8On Thursday, 14 March 2024 at 10:21:41 UTC, Jonathan wrote:I wonder how it would be if we had an error or warning for something like this. For example displaying a message forcing the use of the word "static" and initialize with "static this" when expecting static initialization or construct for new instances. Before someone points out: https://dlang.org/spec/class.html Yes I know, but unfortunately this mistake as Basile noted as "classic", is very common.The following seems the be the minimum required for this problem to pop up. I've changed the names to what I'm using in my code to make it more clear for me. [...]Classic. Instead of a static initializer rather uses a constructor for instances. ```d class Spectrum { PrecursorList precursorList; this() { precursorList = new PrecursorList(); } } ```
Mar 26
On Thursday, 14 March 2024 at 10:21:41 UTC, Jonathan wrote:class Spectrum { PrecursorList precursorList = new PrecursorList(); }void main() { SpectrumList mySpectrumList = new SpectrumList; for(int j=0; j<mySpectrumList.count; ++j) { Spectrum mySpectrum = new Spectrum; writeln(mySpectrum.precursorList.precursors.length); // should always be 0 assert(mySpectrum.precursorList.precursors.length == 0); for(int k=0; k<mySpectrum.precursorList.count; ++k) { Precursor myPrecursor = new Precursor; mySpectrum.precursorList.precursors ~= myPrecursor; } mySpectrumList.spectra ~= mySpectrum; }```You encounter a gotcha unfriendly construct of D. For every "new Spectrum", there is only one instant of mySpectrum.precursorList hence for subsequence iteration, the list is already filled with myPrecursor hence the assert problem. So either move that static new to constructor or in the loop Cheers Happy coding
Mar 14