Abstract
Constraint Handling Rules (CHR) is a high-level programming language based on multi-headed guarded rules. The original high-level operational semantics of CHR is very nondeterministic. Recently, instantiations of the high-level operational semantics have been proposed and implemented, removing sources of nondeterminism and hence allowing better execution control. Rule guards may be redundant under a more instantiated semantics while being necessary in the general high-level semantics. Expert CHR programmers tend to remove such redundant guards. Although this tends to improve the performance, it also destroys the local logical reading of CHR rules: in order to understand the meaning of a rule, the entire program and the details of the instantiated operational semantics have to be taken into account. As a solution, we propose compiler optimizations that automatically detect and remove redundant guards.
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Sneyers, J., Schrijvers, T., Demoen, B. (2008). Guard Reasoning in the Refined Operational Semantics of CHR. In: Schrijvers, T., Frühwirth, T. (eds) Constraint Handling Rules. Lecture Notes in Computer Science(), vol 5388. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-540-92243-8_8
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DOI: https://doi.org/10.1007/978-3-540-92243-8_8
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