1. Transformational Software Evolution by Assertions
Programming Technology Lab
Tom Mens

2. Software Transformations
Can be used for
software evolution and upgrading
refactoring and restructuring
software merging
Are domain-independent
useful for implementation, design, analyis, software architecture
Can be formalised by
graph rewriting

3. Problem and Proposed Solution
Need for scalability
To deal with industrial large-size software systems
Approach
Express software transformations in terms of assertions only (i.e., pre-, postconditions and invariants)
Calculate dependencies in a transformation sequence based on these assertions
Treat transformation sequences as atomic transformations by calculating their assertions

4. Advantages
Uniform treatment of transformations and transformation sequences
e.g. to detect conflicts between parallel evolutions
Dependencies can be used
to remove redundancy in a transformation sequence
to factor out commonalities between parallel sequences
to detect independent subsequences that can be parallellised

5. Position Statement
Scalability and domain-independence are important in software evolution
Formal foundations should try to address both
Efficiency and usability of tools should not be sacrificed
Graphs + graph rewriting seems suitable as a uniform underlying formalism for software evolution