The D Language: A sweet-spot between Python and C

Rikki Cattermole via Digitalmars-d digitalmars-d at puremagic.com
Sun Mar 29 22:58:36 PDT 2015


On 30/03/2015 6:43 p.m., Laeeth Isharc wrote:
> On Monday, 30 March 2015 at 05:04:57 UTC, Rikki Cattermole wrote:
>> On 30/03/2015 5:48 p.m., weaselcat wrote:
>>> On Monday, 30 March 2015 at 04:35:44 UTC, Rikki Cattermole wrote:
>>>> On 30/03/2015 5:25 p.m., Laeeth Isharc wrote:
>>>>> On Monday, 30 March 2015 at 04:16:38 UTC, weaselcat wrote:
>>>>>> On Monday, 30 March 2015 at 00:57:06 UTC, Walter Bright wrote:
>>>>>>> http://blog.experimentalworks.net/2015/01/the-d-language-a-sweet-spot-between-python-and-c/
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> Reddit:
>>>>>>> https://www.reddit.com/r/programming/comments/30qqck/the_d_language_a_sweetspot_between_python_and_c/
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>
>>>>>> a lot of the people in the thread are unaware that D even has RAII
>>>>>> like C++, and think it's just a GC language like java/etc. Maybe this
>>>>>> is something worth mentioning more on the introduction?
>>>>>
>>>>> Also, there is a perception that you can't  use the standard
>>>>> library and
>>>>> nicer language features if you do your own allocation and don't depend
>>>>> on the GC.  A guy worrying about hygiene problems mixing GC and Raii
>>>>> libraries.  Whereas most garbage is small and fine to use GC for in
>>>>> some
>>>>> applications - only a subset of real time applications suffer from
>>>>> generating gazillions of tiny objects.  It would be good to set out
>>>>> somewhere what you lose as regards std library by insisting on using
>>>>> nogc.  The point about std.algorithm should be made more prominent.
>>>>
>>>> I'm currently working on the forcing GC cleanup mechanism for my web
>>>> server. I would like to add, that post GC disabled it can be forced to
>>>> do a cleanup.
>>>>
>>>> But I would go a step further, do a force minimize of memory back to
>>>> the OS and reserve e.g. 32mb. Really what would be nice is a,
>>>> reserveMax function that and anything else is free'd back to the OS.
>>>>
>>>> The reserve, means that even if you are sloppy and end up using the GC
>>>> in critical code, it won't matter. The memory is already allocated.
>>>> Cleaning up can happen during non critical times. After all, if you
>>>> are using more then e.g. 32mb in critical code, you are doing
>>>> something wrong.
>>>
>>>
>>> I actually use D for a pet project of mine(a game! ;) ) and this is what
>>> I do. I leave the GC disabled and essentially just use it as a free
>>> store(while not haphazardly abusing it,) and just manually clean it
>>> during opportune times.
>>>
>>> It's also better to have a single pause for a large cleanup than many
>>> small pauses, the overhead of actually scanning the memory will kill
>>> you.
>>
>> Atleast with web servers, a whole bunch of pauses can't be dealt with.
>> But one large one, can easily be via load balances.
>
> How about we (ie you, the language expert!) jot down a few more points
> to later turn into a short but useful article on how to deal with the GC
> in practical  situations?

I'm by far not a language expert, especially with manual memory 
management. I can only discuss what I've dealt with my own projects.

I have yet to get to the part where I have to actually try to be @nogc 
or pre allocate + buffers.

But there will be an article at some point. But only when it is ready to 
go public. I am sure there will be a lot of interest in an Apache 
equivalent web server in D. With shared library support.


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