Approaches to Software

On this page, I have abstracted various software elements to show my general design approach, focusing strictly on features that could be used in a wide variety of applications. All of these were in fact used in a project that was undertaken to assist in the research work of a Department at Cambridge University. The project was written in C#.

As shown on this page, all these examples are of course showing “spoof” data, akin to the Lorem Ipsum examples so often used to show features of the design of web pages. For reasons of confidentiality, no references to the actual application appear here.

Such features as these are frequently needed in a huge range of desktop applications, and can be extended to web applications too. But although they are very “standard” things, they do illustrate my approach to incorporating such standard features into a large system.

11th March 2018/by r_lumsden@btinternet.com

Design

An Expression Builder

Often in any kind of data collection, and indeed in the manipulation of any data on any software platform, it’s useful to have the means for creating complex expressions referring to the underlying data without having to understand the actual object structure used to implement the system. Here the data is formatted in a question-and-answer form, so you build your expression by selecting questions and specific answers. The Expression Builder opens as shown immediately below, defaulting to the selection of an operand, and you might first select a question:

The Expression Builder now switches to operator mode, with the options to select an operand all greyed off, and so next you select an operator, most commonly “=”:

With an operator selected, it reverts to operand mode, and you might select a possible answer to the original question:

Carrying on in this way, you quickly build up the full expression, “(” opening brackets being available in operand mode, and closing brackets “)” in operator mode, because that reflects their natural place in the flow of the logic:

If the question text obscures the actual logical structure of the expression you have an option (“Simplify“) to hide it:

You can view much of the code supporting this expression builder HERE. There are further examples of C# programming on my Programmatic Design page.

Flag Conditions

Even though you may not want to get into the details of programming in using the system, it’s often useful to have the effect of programming. The system provided this by means of flags also sometimes called semaphores, which allow a participant’s response to be “flagged” so that subsequent questions and answers may be made conditional on that answer. A sketch of flag setting and use is shown below. First you define a flag, which may be Boolean or integer, and in the latter case may have mnemonic labels attached to indicate which value means what (these appear in the list lower right):

Then you set whatever item you want to be conditional on that flag to be so:

Image Support

Any data collection system frequently has reason to use images, if only to ask people, say in an opinion poll, whether they like the image or not, as I illustrate below using the Windows Koala:

In practice, a more common requirement is to have a number of images and to ask a set of questions about each. I call this a repeat list, and its implementation can be seen in the images below:

Layout

I put in an elaborate system for specifying the layout for data collection screens online, which constituted an advanced GUI feature.

Unfortunately my initial contract terminated before this system had been fully tested and finalised, so in the form in which I then left it it had a somewhat “ragged” look. Fortunately I was able to go back later and put this right!

The Layout Manager opened with two windows simultaneously active, a background layout panel, and a foreground list of the immediate survey element’s questions. In this way you could simply “drop” items – questions or answers – from the survey element into the layout behind.

You first set up a basic framework of rows and columns on the layout panel, and then dropped questions and answers into it until you got a page which might look a bit like this:

There were lots of options to control details of alignment, fonts, etc.:

Some questions could be made conditional on others, so, for example, the whole block of “countries you may have visited” shown in grey below is only asked if the participant gives a “yes” to the preceding question. This, called a subsidiary question, was introduced as a simpler alternative to the use of flags :

The images here show the state of the project before my contract resumed. The options are no longer greyed off, which was the bit that mattered, but the question text itself remained greyed off: this has now been corrected!

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