Is there a GC-less array that we can use out of the box or do I have to create my own?

On Tuesday, 26 January 2016 at 03:03:40 UTC, Igor wrote:
> Is there a GC-less array that we can use out of the box or do I have to create my own?

https://dlang.org/phobos/std_container_array.html

On Tuesday, 26 January 2016 at 03:03:40 UTC, Igor wrote:
> Is there a GC-less array that we can use out of the box or do I have to create my own?

There's one in emsi containers.

On Tuesday, 26 January 2016 at 03:06:40 UTC, maik klein wrote:
> On Tuesday, 26 January 2016 at 03:03:40 UTC, Igor wrote:
>> Is there a GC-less array that we can use out of the box or do I have to create my own?
>
> https://dlang.org/phobos/std_container_array.html

How do we use std.algorithm with it? I could like to use find but I have no luck.

I have

std.container.array!MyClass classes;

then std.algorithm.find!("a.myInt == b")(classes, 3)

I was hoping this would find the first object in classes who has myInt == 3 but I just get many errors about not being able to find the right definition.

I guess std.container.array isn't a range? Or am I using it wrong?

On Tuesday, 26 January 2016 at 04:31:07 UTC, Igor wrote:
> then std.algorithm.find!("a.myInt == b")(classes, 3)

Try

std.algorithm.find!("a.myInt == b")(classes[], 3)

notice the [] after classes


> I guess std.container.array isn't a range? Or am I using it wrong?

Containers aren't really ranges, they instead *offer* ranges that iterate over them. Built in arrays are a bit special in that they do this implicitly so the line is more blurred there, but it is a general rule that you need to get a range out of a container.

Otherwise, consider that iterating over it with popFront would result in the container being automatically emptied and not reusable!

On Tuesday, 26 January 2016 at 04:31:07 UTC, Igor wrote:
> On Tuesday, 26 January 2016 at 03:06:40 UTC, maik klein wrote:
>> On Tuesday, 26 January 2016 at 03:03:40 UTC, Igor wrote:
>>> Is there a GC-less array that we can use out of the box or do I have to create my own?
>>
>> https://dlang.org/phobos/std_container_array.html
>
> How do we use std.algorithm with it? I could like to use find but I have no luck.
>
> I have
>
> std.container.array!MyClass classes;
>
> then std.algorithm.find!("a.myInt == b")(classes, 3)
>
> I was hoping this would find the first object in classes who has myInt == 3 but I just get many errors about not being able to find the right definition.
>
> I guess std.container.array isn't a range? Or am I using it wrong?

First, should be std.container.array.Array!MyClass. However I don't think(?) that the Array struct is a range itself, you might have to use classes[] instead to get a slice of the array.

On Tuesday, January 26, 2016 03:03:40 Igor via Digitalmars-d-learn wrote:
> Is there a GC-less array that we can use out of the box or do I have to create my own?

If what you want is a dynamic array (as opposed std.container.Array), then you can simply malloc the memory and then slice it to get a dynamic array. It's just that it's then up to you to manage the memory properly, and if you attempt to append or concatenate, it'll result in the GC allocating a new array.

- Jonathan M Davis

On Tuesday, 26 January 2016 at 04:38:13 UTC, Adam D. Ruppe wrote:
> On Tuesday, 26 January 2016 at 04:31:07 UTC, Igor wrote:
>> then std.algorithm.find!("a.myInt == b")(classes, 3)
>
> Try
>
> std.algorithm.find!("a.myInt == b")(classes[], 3)
>
> notice the [] after classes
>
>
>> I guess std.container.array isn't a range? Or am I using it wrong?
>
> Containers aren't really ranges, they instead *offer* ranges that iterate over them. Built in arrays are a bit special in that they do this implicitly so the line is more blurred there, but it is a general rule that you need to get a range out of a container.
>
> Otherwise, consider that iterating over it with popFront would result in the container being automatically emptied and not reusable!

Ok, does the [] do any conversion or any thing I don't want or does it just make the template know we are working over an array?

Are there any performance issues? I am already using a for loop to find the type, it's 6 lines of code. I was hoping to get that down to one or 2 and make it a bit easier to understand.

	App app = null;
	for(int i = 0; i < Apps.length(); i++)
		if ((Apps[i] !is null) && (Apps[i].hWnd == hWnd))
		{
			app = Apps[i];
			break;
		}

versus

find!("a.hWnd == b")(Apps[], hWnd);

Does [] take time to convert to a built in a array or range or whatever or will it be just as fast as the above code?

On Tuesday, 26 January 2016 at 05:53:29 UTC, Igor wrote:
> On Tuesday, 26 January 2016 at 04:38:13 UTC, Adam D. Ruppe wrote:
>> On Tuesday, 26 January 2016 at 04:31:07 UTC, Igor wrote:
>>> then std.algorithm.find!("a.myInt == b")(classes, 3)
>>
>> Try
>>
>> std.algorithm.find!("a.myInt == b")(classes[], 3)
>>
>> notice the [] after classes
>>
>>
>>> I guess std.container.array isn't a range? Or am I using it wrong?
>>
>> Containers aren't really ranges, they instead *offer* ranges that iterate over them. Built in arrays are a bit special in that they do this implicitly so the line is more blurred there, but it is a general rule that you need to get a range out of a container.
>>
>> Otherwise, consider that iterating over it with popFront would result in the container being automatically emptied and not reusable!
>
> Ok, does the [] do any conversion or any thing I don't want or does it just make the template know we are working over an array?
>
> Are there any performance issues? I am already using a for loop to find the type, it's 6 lines of code. I was hoping to get that down to one or 2 and make it a bit easier to understand.
>
> 	App app = null;
> 	for(int i = 0; i < Apps.length(); i++)
> 		if ((Apps[i] !is null) && (Apps[i].hWnd == hWnd))
> 		{
> 			app = Apps[i];
> 			break;
> 		}
>
> versus
>
> find!("a.hWnd == b")(Apps[], hWnd);
>
> Does [] take time to convert to a built in a array or range or whatever or will it be just as fast as the above code?

The [] operator returns a Range object iterating over the Array elements, similarly to what the begin()/end() cbegin()/cend() function pairs do in C++. The range object does not copy the array element, only contains a slice to them.
So your question ends up in comparing hand-written loops over std::find_if().

On Tuesday, 26 January 2016 at 03:03:40 UTC, Igor wrote:
> Is there a GC-less array that we can use out of the box or do I have to create my own?

If you want containers, use:
http://code.dlang.org/packages/emsi_containers

If you just need an array, use: http://dlang.org/phobos/std_experimental_allocator#.makeArray