Well, after a couple of hours of reading the apis for libcurl, json_spirit and testing, I have successfully added google portfolios to my application. You provide your email and password and it will authenticate with google and retrieve your portfolios, complete with transactions and positions.

Basket Pane showing Google Portfolio

                <Abbreviation>ACCBANDS</Abbreviation>
                <CamelCaseName>Accbands</CamelCaseName>
                <ShortDescription>Acceleration Bands</ShortDescription>
                <GroupId>Overlap Studies</GroupId>
                <Flags>
                        <Flag>Overlap</Flag>
                </Flags>
                <RequiredInputArguments>
                        <RequiredInputArgument>
                                <Type>High</Type>
                                <Name>High</Name>
                        </RequiredInputArgument>
                        <RequiredInputArgument>
                                <Type>Low</Type>
                                <Name>Low</Name>
                        </RequiredInputArgument>
                        <RequiredInputArgument>
                                <Type>Close</Type>
                                <Name>Close</Name>
                        </RequiredInputArgument>
                </RequiredInputArguments>
                <OptionalInputArguments>
                        <OptionalInputArgument>
                                <Name>Time Period</Name>
                                <ShortDescription>Number of period</ShortDescription>
                                <Type>Integer</Type>
                                <Range>
                                        <Minimum>2</Minimum>
                                        <Maximum>100000</Maximum>
                                        <SuggestedStart>100000</SuggestedStart>
                                        <SuggestedEnd>100000</SuggestedEnd>
                                        <SuggestedIncrement>100000</SuggestedIncrement>
                                </Range>
                                <DefaultValue>20</DefaultValue>
                        </OptionalInputArgument>
                </OptionalInputArguments>

I have highlighted the relevant parts. The file contains several hundreds of these listings and some have multiple optional input parameters (OptionalInputArgument) of different types (Integer, Double, etc) and precisions.

This is what I was trying to achieve:

ACCBANDS control generated from xml file

I was using tinyxpath to parse this file and create spinboxes for each range using the gtk adjustments. These were then placed in a scrollwindow and added to a notebook for later retrieval. It was fairly straighforward code with the help of the stringstreams classes. The only problem was that it was terribly slow. I therefore deviced a plan to give it its own thread and dull/desensitive the toolbar item that was used to get to the charts. This gave me the following whenever the application started:

Dulled Chart Toolbar Item

After a couple of runs with it it quickly became annoying and I decided to get rid of it. In comes code generation. Since I was already parsing it with the tinyxpath I had the framework to generate the C++ code for this. I wrote a basic class extending Gtk::ScrolledWindow and adding all the features that I wanted. I then modified my code for dynamically parsing the file to output C++ code for it. The relevant line is below:

            ofs << "\t fc_" << j << "->add_item(\"" << name << "\","
            << val << ", " << min << ", " << max << ", " << inc
            << ", " << digits << ");" << std::endl;

After a few more modifications I have this now compiled and there is no need to utilize the “dulling” anymore. I have also totally eliminated the need for tinyxpath and I think that’s a positive improvement.

I have the source code for sqlite since I’m using the amalgamated version because I need to write some of my own functions to load either as dynamic shared libraries or statically linked into the code (I prefer the latter). I spent a while reading through the code and btrees for a while thinking of a clever way to do it and then I had an “Aha!” moment. I can simply do this in C++! A few enums, a couple of classes and some simple ternary lines and presto I’ve got it working. Was much quicker and more efficient than adding my own code, which would’ve had to be thoroughly tested in a multithreaded environment to make make sure it really worked.

I like how it turned out and I have one more screenshot to show

New Screenshot

Now I need to do some more code generation.

Screenshots
Enough words. Here are some screenshots of what I have so far

Open Source Libraries
These are some of the important libraries being used:

• gtkmm/glibmm – GUI, dates and threads
• libsigc++ – signals and slots
• cairomm – plotting charts
• sqlite3 – embedded database
• soci – abstraction layer for sqlite
• tinyXpath – parsing xml files
• ta-lib – technical analysis library
• libcurl – url transfer
• boost – multipurpose libraries

Development Environment
Most of my development is done on Ubuntu and would have been difficult without the following development tools:

• vi
• screen
• glade
• autotools