T. Bull, An Introduction to the WSL Program Transformer, Conference on Software Maintenance 26th29th November 1990.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....reverse engineering has been successful in finding and expressing formally the generic function corresponding to the PRCHEN routine and the pre condition which must be satisfied in order for PRCHEN to be a correct implementation of this function. 6 Related and future work Maintainer s Assistant [2] is a reverse engineering tool which automates the application of transformations which have been proved to preserve the semantics of the program. Code containing GOTOs is first transformed into an action system. The user decides which transformations to apply (helped to a certain extent by the ....

T. Bull. An introduction to the WSL program transformer. In Proceedings of the Conference on Software Maintenance, San Diego, 1990, 1990. updated version available at http://www.dur.ac.uk/CSM/.

....parsing based is the most popular. Of note is the fact that the Software Refinery supports the use of transformations although the builtin tools do not use formal transformation as an analysis PA = PAT [29] CS = COBOL SRE [13, 30] DE = DECODE [12] LT = LANTRN [14] MA = Maintainer s Assistant [20, 31, 32, 33] RE = REDO Toolset [21] RI = Rigi [18, 34] AS = AutoSpec [22, 35] RM = RMTool [19, 36] Table 3. Index of Research Tools technique. Finally, of all the commercial tools, only the Xinotech tool uses a plan based approach. SR VR 4D XI LS EN DM C C COBOL ADA FORTRAN Other Languages PC Sun ....

Tim Bull. An Introduction to the WSL Program Transformer. In Proceedings for the Conference on Software Maintenance, pages 242--250. IEEE, 1990.

....In Section 5 we transform the WSL model into a simpler form, from which the timing constraints are derived in Section 6. Finally, we use this information to derive a speci cation of the program in Section 7. 2 The Language WSL In this section we give a brief introduction to the language WSL [13,42,44,45,48] the Wide Spectrum Language , used in Ward s program transformation work, which includes low level programming constructs and high level abstract speci cations within a single language. By working within a single formal language we are able to prove that a program correctly implements a ....

....indicate that these are used in a systematic way: moving assignments to time and calls to interrupt through the program to collect them together, unfolding and refolding where necessary. This suggests that much of the donkey work can be automated by a tool such as the Maintainer s Assistant [13,51] and this is currently being investigated under a SMART 2 2 project at the Centre for Software Maintenance Ltd. and as part of a three year SERC project at the University of Durham. 8.1 The Maintainer s Assistant Project In [50] we describe a practical program transformation system for ....

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T. Bull, An Introduction to the WSL Program Transformer, Conference on Software Maintenance 26th29th November 1990, San Diego (Nov., 1990).

....[13,24] and to reverse engineering in [23,25] The transformation system is intended as a practical tool for software maintenance, program comprehension, reverse engineering and program development. The rst prototype transformation system, called the Maintainer s Assistant , was written in LISP [5, 28]. It included a large number of transformations, but was vey much an academic prototype whose aim was to test the ideas rather than be a practical tool. In particular, little attention was paid to the time and space e ciency of the implementation. Despite these drawbacks, the tool proved to be ....

T. Bull, \An Introduction to the WSL Program Transformer, " Conference on Software Maintenance 26th{ 29th November 1990, San Diego (Nov., 1990).

....stepping on each others toes in [39,40] The transformation system is intended as a practical tool for software maintenance, program comprehension, reverse engineering and program development. The first prototype transformation system, called the Maintainer s Assistant , was written in LISP [4,41]. It included a large number of transformations, but was vey much an academic prototype whose aim was to test the ideas rather than be a practical tool. In particular, little attention was paid to the time and space efficiency of the implementation. Despite these drawbacks, the tool proved to ....

T. Bull, "An Introduction to the WSL Program Transformer," Conference on Software Maintenance 26th--29th November 1990, San Diego (Nov., 1990).

....semi automatically made concrete by a series of specification to implementation transformations. Modifications can be performed by reasoning about and changing the specification, then allowing the transformation system to automatically propagate changes down into the implementation automatically [Bull 90, Balzer et al. 76] In such a system, the programmer could reason about a restructuring as a change to the specification (for example, stating that the instantiation of two variables should occur in the same scopes) and then let the system rederive the implementation. Finally, Griswold s work ....

T. Bull. An introduction to the WSL program transformer. In Conference on Software Maintenance 1990, pages 242--250, 1990.

....of the construct and carrying out the actual manipulation in the previous level language. This technique has proved extremely powerful in the development of a practical transformation system which currently implements over four hundred transformations, accessible through a simple user interface [10]. 2.1 Syntax of Expressions Expressions include variable names, numbers, strings of the form text : the constants N, R, Q, Z, and the following operators and functions: in the following e 1 , e 2 etc. represent any valid expressions) Numeric operators: e 1 e 2 , e 1 Gamma e 2 , e 1 ....

....applicability, is that it can be applied to a given iterative algorithm which uses a stack or array in a particular way. This produces a recursive procedure which is often much easier to analyse and understand. This aspect of the work is being investigated in the Maintainer s Assistant project [10,28] at Durham University and the Centre for Software Maintenance Ltd. which aims to produce a prototype tool to assist a maintenance programmer to understand and modify an initially unfamiliar program, given only the source code. The project uses program transformations as a means of code analysis as ....

T. Bull, "An Introduction to the WSL Program Transformer," Conference on Software Maintenance 26th--29th November 1990, San Diego (Nov., 1990).

....transformation. The program transformation process is a user driven activity where a programmer browses through code with a graphical interface and chooses when to apply transformations. The final by product of the Maintainer s Assistant is a formal specification written in the wsl language [85]. As such, the specification can consist of several statements expressed at different levels of abstraction. As such, the specification may retain the sequential style of the original program. The Maintainer s Assistant toolset was initially developed to support the IBM370 Assembler language and a ....

T. Bull, "An Introduction to the WSL Program Transformer," in Proceedings for the Conference on Software Maintenance, pp. 242--250, IEEE, 1990.

....of the construct and carrying out the actual manipulation in the previous level language. This technique has proved extremely powerful in the development of a practical transformation system which currently implements over three hundred transformations, accessible through a simple user interface [10]. Within expressions we use the following notation: Sequences: s = ha 1 ; a 2 ; a n i is a sequence, the ith element a i is denoted s[i] s[i : j] is the subsequence hs[i] s[i 1] s[j]i, where s[i : j] hi (the empty sequence) if i j. The length of sequence s is denoted ....

....n 1 elsif n = 0 then A(m 1; 1) else A(m 1; A(m;n 1) where we have replaced calls to F by equivalent calls to A. This is the famous Ackermann function [1] 10 Conclusion The program transformation theory used in this paper forms the foundation of the Maintainer s Assistant project [10,22] at Durham University and the Centre for Software Maintenance Ltd. which aims to produce a prototype tool to assist a maintenance programmer to understand and modify an initially unfamiliar program, given only the source code. The tool consists of a structure editor, a library of proven ....

T. Bull, An Introduction to the WSL Program Transformer, Conference on Software Maintenance 26th29th November 1990, San Diego (Nov., 1990).

....on a loop and comparing the results with a number of standard superpatterns. 8.1.2 A Knowledge Based Transformational System Transformational systems have been widely used for forward engineering. The application of transformational systems to reverse engineering has been proposed by Ward et al. [38, 39, 40]. The approach relies on proving that two versions of a program are equivalent. A kernel language that includes both imperative programming constructs and general specifications as part of a single language is defined. By using a kernel or Wide Spectrum Language (WSL) that is mathematically based, ....

....into specifications. The rest of this section outlines the major aspects of the Maintainer s Assistant. Wide Spectrum Languages Software development classically proceeds through multiple stages ranging from requirements specification to program development. Figure 8. 1 illustrates this concept [39]. Typically each stage uses a different language to express the problem. For instance, natural language may be used for requirements stage S 0 while a formal specification language may be used for specification stage S n as can be seen in Figure 8.2 [39] A WSL provides a unified language for use ....

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T. Bull, "An Introduction to the WSL Program Transformer," in Proceedings for the Conference on Software Maintenance, pp. 242--250, IEEE, 1990. 78

....software engineering is now widely recognised. According to Fikas [11] for instance, the process of developing a program can be formalised as a set of transformations. This approach has been put forward in reverse engineering by an increasing number of authors and researchers over several years [4, 7, 20, 29, 30, 41, 42, 44]. We adopted incremental transformational approach in the ITOC project to transform the static schema of the source application to the target schema of the target application. The required transformation process is specified by the Concept Mapping specification. function = Defun function name ....

Bull, L. (1990). An Introduction to the WSL Program Transformer. Proceedings of IEEE Conference on Software Maintenance. IEEE, New York, pp. 242-250.

....5 a 02 = 10 (Y swapa2 = 5 X swapa1 = 10 Y swapa1 = 15) b 01 = 10 a 01 = 5) U ) Figure 10: Output created by applying AutoSpec to example (cont. et al. use a knowledge based transformational approach to the reverse engineering of program code into formal specifications [27, 28, 29]. A knowledge base manages the correctness preserving transformations of concrete, implementation constructs in a Wide Spectrum Language (WSL) to abstract specification constructs in the same WSL. Finally, Linger et al. describe a high level approach to reverse engineering using function ....

T. Bull, "An Introduction to the WSL Program Transformer," in Proceedings for the Conference on Software Maintenance, pp. 242--250, IEEE, 1990.

....stage is to load the source code into the tool, and this is achieved by the source language to WSL translator as a batch job. The equivalent WSL code is stored internally as an abstract syntax tree (together with ancillary information to aid applicability checking) Further details are given in [7,43] and in Section 5.1.1. The system is interactive and incorporates a graphical front end, pretty printer and browser. This allows the programmer to move through the program, apply transformations, undo changes he or she has made, and in special circumstances, edit the program manually: but always ....

T. Bull, "An Introduction to the WSL Program Transformer," Conference on Software Maintenance 26th--29th November 1990, San Diego (Nov., 1990).

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T. Bull, An Introduction to the WSL Program Transformer, Conference on Software Maintenance 26th29th November 1990.

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