Download Logical Expressions: Analyzing, Generalizing, Rewriting

1.2 The Project
TriLoc, however, has taken the challenge to investigate whether state of the art
scientific technology can be adapted to be useful within the Logic Mining process. In close cooperation with the University of Amsterdam and the National
Research Institute for Mathematics and Computer Science (CWI) a project was
initiated to accomplish this.
The project contains four subprojects:
1. Describing a rewriter in the algebraic specification formalism ASF+SDF that can
be used to normalize COBOL logical expressions.
2. Defining other rewriters and grammars including a language independent logical
format on which various normalization techniques can be applied.
3. Porting the rewriting component (that supports execution of ASF+SDF rewriting systems) of the ASF+SDF Meta-Environment to Windows NT.
4. Embedding its functionality in the Logic Mining system.
We will describe the process in two parts which can be read independently:
1. The analysis, normalization, generalization and rewriting of (COBOL) logical
expressions.
2. Porting parts of the ASF+SDF Meta-Environment to a non-Unix environment
and embedding these parts in an external commercial software renovation system.
A key feature of this project is the communication between science and practice:
• the cooperation between TriLoc on one side and the University and the CWI on the other, the port of a Unix-system to Windows NT,
• the embedding of a scientific system within a commercial
system and
• the extending of a system made with conventional languages
with a system designed with an algebraic formalism.
1.3 Related Work
There have been projects that focussed on rewriting COBOL. We will name a few
here. Control flow normalization, in order to improve maintainability of COBOL/CICS
systems, which also makes use of normalized logical expressions is described in [BSV98].
Normalization of COBOL conditions is also a subject in [SV98]. In [BKV98] a global
description regarding the rewriting of COBOL systems is given. Issues regarding COBOL grammar in SDF, disambiguation, preprocessing and restricting can be found in
[BSV97].
In this thesis we will try to be more thorough. We will introduce a language independent format for logical expressions and normalizations on this language independent
format.
In [BKV96] possible software re-engineering applications of the Meta-Environment
technologies are described. A software renovation factory is described in [BSV98]. It
contains a number of assembly lines that perform a number of tasks in a fixed order. Our
project is not quite the same since it integrates a component in a system on a more object-oriented way, it can be called at any given time from another process.
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