Re ections on Re
نویسنده
چکیده
In the functional programming literature, compiling is often expressed as a translation between source and target program calculi. In recent work, Sabry and Wadler proposed the notion of a reeection as a basis for relating the source and target calculi. A reeection elegantly describes the situation where there is a kernel of the source language that is isomorphic to the target language. However, we believe that the reeection criteria is so strong that it often excludes the usual situation in compiling where one is compiling from a higher-level to a lower-level language. We give a detailed analysis of several translations commonly used in compiling that fail to be reeections. We conclude that, in addition to the notion of reeection, there are several relations weaker a reeection that are useful for characterizing translations. We show that several familiar translations (that are not naturally reeections) form what we call a reduction correspondence. We introduce the more general notion of a (R1; R2; R3; R4)-correspondence as a framework for describing relations between source and target calculi.
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