Full list of in-depth articles - Feedback and questions - Request demo -

1 - The sample "form" application

The reference development environment for this article is the Series 60 2nd Edition SDK for Symbian OS, Supporting Feature Pack 2, For C++, Supporting Metrowerks CodeWarrior. This SDK is available after registration on www.forum.nokia.com. It contains several example applications, one of which is the Form Example used for the sample custom-made generator described in this article.

The Form example application, also referred to as AknExForm, demonstrates how to use the forms and editor controls available on the Series 60 Developer Platform. The class diagram of this application is shown in the figure below, taken from the SDK documentation.

In a way, the above class diagram defines a class, or macroclass, of form applications. The custom-made generator here described (hereinafter referred to as SoProMach/S60FormGen) produces complete applications belonging to this macroclass.

2 - Generating a simplified AknExForm

The original AknExForm contains all the know-how necessary to build different types of forms, such as single-page vs. multi-page, or view-or-edit vs. always-edit. The sample custom-made SoProMach/S60FormGen produces one-form or multi-form, single-page, view-or-edit form applications. The first sample application generated with SoProMach/S60FormGen is the one-form application shown in the following screenshots of the Series 60 emulator running the application. This generated application is a subset of AknExForm.

3 - Gen-build-run

How can a developer produce the application above with SoProMach/S60FormGen? How can the application form, or forms, be designed and described?

SoProMach is a purely textual software production machine, and so are the custom generators built on top of it. Therefore to "configure" the generation job, the developer writes one or more textual files. Several formats are accepted by SoProMach: Somusar/EF (see below), XML, CSV, or ad-hoc domain-specific languages (DSL).

For this specific SoProMach/S60FormGen generator, the sole input required is an EF (entity file) description as the one shown below. (Note by the way that SoProMach-based generators can be integrated with any IDE providing support for external tool invocation: see examples of integration with Eclipse and with Visual Basic Express 2005 Beta).

The careful reader might have noticed that generating and building the application required about twelve seconds, including compiling, linking and deploying the application, which is then ready to be run in the emulator.

4 - More form applications

Now that the software production mechanism is in place, it is easy to create new applications by simply creating new EF files, as the ones shown below.

5 - Adding application logic

When the forms of the applications are ready, the developer can extend the generated application as desired. Several options would be available that go beyond the scope of this article. Here we will mention only that both IDE-oriented and text-editor developers will be able to extend the application in their preferred way. In particular, users of Metrowerks CodeWarrior can import the project directly into the IDE, as the following picture shows.

6 - Machine-made source code

The links to the code files generated by SoProMach/S60FormGen for the three applications are listed below. The code looks very similar to the code of the original AknExForm example application.

6.1 - Simplified AknExForm

6.2 - Two-form

6.3 - Three-form

Appendix A - Statistics

A measure of the efficiency of SoProMach/S60FormGen can be given by the output-to-input ratio: the higher the number, the more efficient is the generator. Under this respect, the measure in terms of files is given by the number of generated files divided by the number of input files, which is

    20 / 1 = 20

    6653 / 133 = 50.02

Appendix B - Sample SoProMach/S60FormGen software molds

SoProMach-based generators utilizing EF files produce software by means of so-called Software Molds. Molds can range in complexity from very simple to very complex. SoProMach/S60FormGen provides some good examples of software molds.

The mold for generating the <<AppName>>Document.cpp files of the applications is very simple. In fact, it is just a one-file template (code/moldkit/UI/mold18-Document.cpp/file.hdr)

The structure of the <<AppName>>SaveForm.cpp files is more complex, and the corresponding mold reflects this complexity. Note that the mold's complexity is roughly equivalent to the internal complexity of a compiler, the major difference being that SoProMach allows to build "open" compilers, in that they are made up of text files that might be adapted and extended as required.

A first block of <<AppName>>SaveForm.cpp code is produced with a file.hdr introduction. Then, two molding steps are required, described below. Finally, a trailing block is produced with file.trl.

The intermediate steps produce leading and trailing blocks of code for each step and for each form defined in the input EF file, generating additional code for each member of the form.

The details for step #1 are as follows:

• step.hdr is processed first;

• collection.hdr is processed for each form;

• depending on the type of the form field, one of string, number, or time is processed;

• collection.trl is processed for each form;

• finally, step.trl is processed.