[fpc-pascal] IntList

[Michael Van Canneyt]

Sorry,

This was meant to be a private message.

For those interested: the idea is to have a standard set of generics 
definitions that implement some commonly-used templates. 
A kind of STL in pascal.

Michael.



On Thu, 4 Nov 2010, Michael Van Canneyt wrote:

>
> Hi,
>
> I asked around.
>
> We'd like to propose the following:
> - We import the code in the FPC subversion repository, in a package.
> - You get read/write access to the package, so you can maintain it.
> Subject to 2 conditions:
>
> - You use the FPC license.
> - Please remove all _ characters at the start of identifiers.
>  This goes against our coding rules.
>  (we try to avoid _ as much as possible)
>
> If you can agree with this, I'll import the code in the FPC repository.
>
> Michael.
>
>
> On Wed, 3 Nov 2010, Vlado Boza wrote:
>
>> On 10/19/2010 08:28 PM, Michael Van Canneyt wrote:
>>> 
>>> 
>>> On Tue, 19 Oct 2010, Sven Barth wrote:
>>> 
>>>> Am 19.10.2010 19:54, schrieb Juha Manninen (gmail):
>>>>> On Tuesday 19 October 2010 19:10:39 Luiz Americo Pereira Camara wrote:
>>>>>> Yes it's ready in fpc 240:
>>>>>> 
>>>>>> uses
>>>>>>    Fgl;
>>>>>> 
>>>>>> type
>>>>>>    TIntegerList = specialize TFPGList<Integer>;
>>>>> 
>>>>> Well, yes. It is almost as good as a dedicated class. It has a Sort 
>>>>> method but
>>>>> you must feed the compare function for it.
>>>>> It does not have a Find method for a binary search in a sorted list.
>>>>> Indexof does a linear search.
>>>>> 
>>>>> Anyway, it could be used as a base class in Lazarus. I don't know what 
>>>>> is the
>>>>> Lazarus team's policy for using generics in Lazarus code-base.
>>>>> 
>>>>> In FPC 2.4.0 I had problems with memory consumption of generics 
>>>>> containers.
>>>>> A<Integer, Integer>  map hogged gigabytes of memory while my data took 
>>>>> only
>>>>> kilobytes (less than 1 MB for sure), on a 64 bit Linux.
>>>>> Now I have the latest FPC trunk 2.5.1 and the problems are gone. I added
>>>>> 100000 integers to both a List and to a Map and didn't even notice the 
>>>>> memory
>>>>> increase in resource monitor.
>>>>>
>>>>>    TIntegerList = specialize TFPGList<Integer>;
>>>>>    TIntegerMap = specialize TFPGMap<Integer, Integer>;
>>>>> 
>>>>> TFPGMap's problem still is that it is not a hash map and is butt-slow 
>>>>> with
>>>>> lots of data. A hash map is a superior container type, it really should 
>>>>> be
>>>>> changed.
>>>>> Besides, people expect to get a hash map when they see "map" in the 
>>>>> class
>>>>> name. Now they get a list which is deceivingly named as "map".
>>>> 
>>>> As you seem to have experience with efficient data structures, what about 
>>>> creating such a generic hash map? :)
>>>> 
>>>> (but don't use 2.4.2rc1 and current/unpatched 2.4.3 as a test base as 
>>>> those don't have the fixes from trunk to make "specialize" working again)
>>> 
>>> Currently, the FPC team is looking at an implementation of Vlado Boza 
>>> <usama at ksp.sk> for a standard template library for inclusion in FPC.
>>> 
>>> The code is on
>>> 
>>> http://code.google.com/p/stlpascal
>>> 
>>> Please have a look and comment on it.
>>> 
>>> I'm not a generics expert and am not in the position to judge whether this 
>>> library is good or not.
>>> 
>>> Michael.
>>> 
>> 
>> Hash_map implementation shouldn't be a big problem. But I also think, that 
>> other structures can be usefull as well (for example in map done by 
>> red-black tree you can find greatest key which less than X in a good time, 
>> ...).
>> 
>> A is there any decision if it is worth to put it in FPC and where to put 
>> it?
>> 
>> Vlad.
>> _______________________________________________
>> fpc-pascal maillist  -  fpc-pascal at lists.freepascal.org
>> http://lists.freepascal.org/mailman/listinfo/fpc-pascal
>> 
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