[Kde-finance-apps] Brainstorming requirements for an Alkimia Quotes Backend: Feedback/Reality-Check Needed Please :)

Alvaro Soliverez asoliverez at gmail.com
Tue May 25 14:08:00 CEST 2010


On Tue, May 25, 2010 at 7:30 AM, Brian Cappello <briancappello at gmail.com> wrote:
>
>
> On Sun, May 23, 2010 at 2:48 PM, Alvaro Soliverez <asoliverez at gmail.com>
> wrote:
>>
>> On Sat, May 22, 2010 at 8:18 PM, Brian Cappello <briancappello at gmail.com>
>> wrote:
>> >>
>> >> It is normally better to have more work than schedule. It often makes
>> >> for
>> >> amazing results, and if the work does not get finished, it makes
>> >> planning
>> >> for
>> >> release n+1 easy :-).
>> >
>> > I like this philosophy very much :D
>> >
>> > I just "finished" putting together a Wiki page that's a lot more
>> > readable/sensible than the above email, excess dreams included :)
>> > For now, it lives at:
>> > http://techbase.kde.org/User:Bpeller#
>> >
>>
>> I'd only add to this "release early - release often" which does not
>> equal to "release crap", but "get something working fast, and then
>> build on it" :)
>
> Sounds good to me :)  I'm still digging through the DBus docs, but in the
> mean time I got something *really* basic working... it's just a download
> results previewer. For now it lives at:
> git://gitorious.org/quotebackend/quotebackend.git
>
> To start with, I'm getting hung up on what's the best way to download stuff.
> That code uses KIO Jobs, but, it just doesn't "feel right." I could very
> well be doing something dumb. Maybe not initially, but eventually, I'd like
> to be able to support parallel downloads as well as not lock-up/block
> anything else. But I don't know how to do that..? Also, has there been a
> firm decision either way on alkimia being strictly Qt? One alternative to
> KIO I'm considering is QNetworkAccessManager and friends, as mentioned in
> the Qt docs under Network Examples, but I haven't gotten the time yet to
> play around with that stuff...
>>
>> In this particular case, I'd concentrate on getting the prices right,
>> and any other data you can get "for free", and then you can build on
>> it.
>
>
> I'm a little confused by what you mean by "right." I'm taking it to mean the
> price-algorithms are logically verified? Pretty much all the code I have
> related to that stuff was literally the first C++ code I ever wrote, so
> needless to say, it all needs to be rewritten. But this time I've been
> through it once, so hopefully I learned at least a few lessons... :)  For
> instance, storing the most recent close at index 0 makes life hella
> easier... I still need to write the code to make sure, but, I think I at
> least got the math all worked out and verified for the time conversion and
> adjusted prices algorithms.
>

That's kind of what I mean. As you grow your application, you need to
know which areas are a "Work in Progress" and which areas "Just Work".
So, downloading daily prices should "Just Work".


> I think what I'm most uncomfortable with would be creating code not
> controlled by a UI, so at least personally, I'm thinking my next step is to
> split up that previewer UI from the 'core' into two programs, and get the
> same functionality working over DBus. Any thoughts on that?
>

Yes, that's exactly what I had in mind. You'd have Alikimia and its
DBus services storing the stock data, and your program (KChartViewer?)
would control Alkimia, retrieve the data from Alkimia via DBus and
display the data.



> Also, is there any way I could maybe get a consensus on whether or not "the
> powers that be" would ever allow TA-Lib to eventually be integrated into
> this? The reason I ask is because it seems to me to determine whether I use
> std arrays or QLists for storing prices. QLists are obviously more
> convenient/less bookkeeping, but, they also don't work with TA-Lib. At least
> not without copying all the data first, which I suppose isn't the end of the
> world. Any strong opinions either way?
>

It has a BSD-license, which is open, but not quite easy to mix with
GPL code without a special exception. We went through such a problem
with OpenGPG and it was such a big deal Thomas had to use a whole
different library.
Does TA-lib provide such an advantage?
KOffice has a good library for math, we could try to use that one if it fits.

Regards,
Alvaro


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