Automated Code Transformation

CodeTurn is a powerful tool to automatically transforms legacy source code into modern source code that is both very well maintainable and guaranteed to be 100% functionally equivalent to the original.

CodeTurn is typically used in conjunction with other Astadia tools such as the legacy data migration tool DataTurn and the automated testing tools TestMatch and DataMatch.

Product Highlights

CodeTurn takes an application’s source code and automatically converts it to functionally identical sources, now ready to run within an alternative environment on the same platform, or on a different platform altogether.

Since both the conversion and the testing is fully automated, the outcome of the project is highly predictable, in terms of risks, costs, and duration.

The migrated application relies on native industry standard technologies.

Three Strong Promises

All Astadia conversions ensure three types of equivalence:

Functional equivalence: the converted application’s behavior is identical to that of the original one

Performance equivalence: the converted application will perform as well as the original one  

Maintenance equivalence: maintenance of the converted application will be comparable in effort to the original application


CodeTurn is currently available for the following technologies:

CodeTurn also converts any embedded statements in the COBOL programs, such as those accessing an IDMS, DB2, or Adabas database, or CICS.

If other languages such as PL/I or EGL are in scope of the application migration, Astadia works with established migration partners to offer a complete solution.

CodeTurn integrates all aspects of the conversion to automatically produce high quality, functionally equivalent code.


CodeTurn consists of several language parsers, analyzers, rule-based convertors and generators that together can perform complex transformations on existing source code. The convertors and generators can be easily configured to produce optimal code (e.g. to adhere to company specific coding standards).


CodeTurn keeps the converted code concise, readable and maintainable, without code blow, by centralizing pieces of code in libraries and software services, which are an integral part – delivered in source code format – of the produced converted code.

Automated Testing

CodeTurn converted applications integrate with Astadia's automated testing products TestMatch and DataMatch to prove 100% functional equivalence with the original application. See the TestMatch and DataMatch fact sheets for more details.


CodeTurn is designed in such a way that it can flexibly be extended to cover additional source and target programming languages. At the same time, third-party conversion tools have already been integrated to cover the conversion of legacy languages such as PL/I and EGL.

Native Code

The generated code will run as a native, first-citizen application on the target infrastructure. No sandboxing or emulation is involved.


CodeTurn will also handle the automatic conversion and functional equivalence of code that ran under CICS or IDMS (z/OS or z/VSE) as well as OpenUTM (BS2000/OSD) environments.

Screen Definitions

Code Turn converts the screen definitions to XML and offers a standalone WYSIWYG tool to edit them.

Batch and Utilities

Astadia provides drop-in replacements for the commonly used mainframe system utilities, to complement the conversion of batch applications and JCL. Additional or custom utility replacements are typically added based on project specific requirements.

Additional Resources

CodeTurn: Automated Mainframe Code Conversion

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