Editorial

Managing source code real estate is a wide concept that can cover very different things, ranging from making the source code compliant to defined coding standards, to plain migrations. In all cases, quality is of course a major concern.

A simple word, and quite a popular topic, quality is often a subjective matter. Organisations tend to find it difficult to define precisely what is really meant by quality, but they will surely agree on one thing though: a good quality source code should be easily readable and maintainable. And that is what this newsletter is all about: achieving a sufficient level of readability and facilitating maintenance using RainCode.

The following case study is about an extreme case of quality improvement in automatically generated COBOL code.

Case Study

VisualAge Pacbase is a fourth generation language, marketed and supported by Big Blue (IBM). One interesting characteristic of this environment language lies in its intermediate COBOL code generation for compilation purposes.

This property opens a possible migration path for organizations that wish to move away from PACBASE, such as DVV.

DVV Insurance is one of the leading insurance companies in Belgium and part of Dexia, Belgium's second largest financial group. The consolidated premium income of DVV in 2001 amounted to EUR 927 million. DVV offers a full range of insurance, savings and investment products and more than ever emphasizes on satisfying customers by means of an effective distribution strategy that meets their needs. DVV's well developed multi-channel distribution system is based on an exclusive agents' network, bankinsurance with banks of the Dexia group, brokerage via Belstar and Luxstar, direct writing through CoronaDirect and sectoral pensions with Sepia.

DVV has several applications, represented by thousands of programs, all written in Pacbase. DVV would like to leave the Pacbase world.

They have in fact two alternative ways out:

• Either re-write the whole application park in another programming language; a solution that will be very expensive and error-prone.
• Start with the generated COBOL code. As it was never generated with maintenance or migration in mind, the generated code is unreadable, unstructured and excessively verbose. It would be totally unreasonable to consider maintaining this generated code directly.

The Renovation process

Our approach is to opt for the second alternative; but to renovate the generated code systematically through the application of automatic improvements. The re-structuring of the code is done by applying a sequence of passes on the source, among which:

• Cosmetic enhancements such as: systematic indentation, adding the optional reserved words (THEN, END-IF, etc.).
• Removal of dead components.
• Replacing complicated loops by natural constructs.
• Replacing GO TO's by equivalent, but structured constructs.
• Replacing sequences of IF's by EVALUATE statements.

Each step can take advantage of the result of the other steps, incrementally rising the abstraction level of the code.

This method proves to be advantageous in many ways.

• Executability is guaranteed. The risk of error is quite low. If an error were made, it would be infinitely repeated through the automatic process, which means that the probability of not catching it is close to null.
• Semantic equivalence between the initial code and the renovated code is guaranteed.
• The process can be applied at will, even after potential manual changes were made; improvements can be made incrementally.
• As variable names, labels and even comments are retained from the original PACBASE programs, the programmers who were familiar with the old system can maintain the migrated system proficiently.
• There is no eclipse effect: the program continues to run during the renovation process, and can be tested at any time.

Some Results

To give you an idea of what RainCode was able to accomplish on the first application we renovated (about 600 programs), we recorded the following statistics:

• For 49% of the programs, all the GOTOs were removed.
• For more than 92% of the programs, less than 15% of GOTOs are remaining.
• We typically reduce the size of a program to 60-90% of its original size, in terms of number of statements.

The resulting reshaped sources are equivalent to the Pacbase sources in terms of functionality and semantics; they are shorter, better structured and way more readable.

That's all folks !!!

In our next newsletter, we will expose the new developments of Ride, a RainCode based development environment that allows you to write and execute your RainCode scripts in a user-friendly interface.