Program transformation with metasystem transitions

Abstract

A new program transformation method is presented. It is a further refinement of supercompilation where the supercompiler is not applied directly to the function to be transformed, but to a metafunction, namely an interpreter which computes this function using its definition and an abstract (i.e. including variables) input. It is shown that with this method such tranformations become possible which the direct application of the supercompiler cannot perform. Examples include the merging of iterative loops, function inversion, and transformation of deterministic into non-deterministic algorithms, and vice-versa.

Distillation with labelled transition systems

“…There have been several attempts to do this, the first one by Turchin himself using walk grammars [23]. In this approach, traces through residual graphs are represented by regular grammars that are subsequently analysed and simplified.…”

A Program Inverter for a Functional Language with Equality and Constructors

“…This is the usual trade-off. Inversion based on Refal graphs [18,11,20,17] is related to the present method in that both use atomic operations for inversion; a more detailed comparison will be a topic of future work. An algorithm for inverse computation can be found in [1,2].…”

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