منابع مشابه
Observational Purity and Encapsulation
Practical specification languages for imperative and object-oriented programs, such as JML, Eiffel, and Spec#, allow the use of program expressions including method calls in specification formulas. For coherent semantics of specifications, and to avoid anomalies with runtime assertion checking, expressions in specifications and assertions are typically required to be weakly pure in the sense th...
متن کاملExtensions of the theory of observational purity and a practical design for JML
To prevent erratic behavior during runtime checking, JML only allows assertions to call pure, i.e., side-effect free, methods. However, JML’s notion of purity checking is too conservative. For example, Object’s equals method needs to be used in assertions, but some classes use side effects in their equals method to maintain hidden caches or to trigger lazy evaluation, and so these methods canno...
متن کاملCovers, Preenvelopes, and Purity
We show that if a class of modules is closed under pure quotients, then it is precovering if and only if it is covering, and this happens if and only if it is closed under direct sums. This is inspired by a dual result by Rada and Saorín. We also show that if a class of modules contains the ground ring and is closed under extensions, direct sums, pure submodules, and pure quotients, then it for...
متن کاملK-purity and Orthogonality
Adámek and Sousa recently solved the problem of characterizing the subcategories K of a locally λ-presentable category C which are λ-orthogonal in C, using their concept of Kλ-pure morphism. We strenghten the latter definition, in order to obtain a characterization of the classes defined by orthogonality with respect to λ-presentable morphisms (where f :A B is called λ-presentable if it is a λ-...
متن کاملLogical and Semantic Purity
Many mathematicians have sought ‘pure’ proofs of theorems. There are different takes on what a ‘pure’ proof is, though, and it’s important to be clear on their differences, because they can easily be conflated. In this paper I want to distinguish between two of them. I want to begin with a classical formulation of purity, due to Hilbert: In modern mathematics one strives to preserve the purity ...
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ژورنال
عنوان ژورنال: Theoretical Computer Science
سال: 2007
ISSN: 0304-3975
DOI: 10.1016/j.tcs.2007.02.004