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Programming Languages and Compilers
College of Engineering and Computer Science - Former Departments, Centers, Institutes and Projects
Articles 1 - 4 of 4
Full-Text Articles in Physical Sciences and Mathematics
Objects, Interference, And The Yoneda Embedding, Peter W. O'Hearn, Uday S. Reddy
Objects, Interference, And The Yoneda Embedding, Peter W. O'Hearn, Uday S. Reddy
College of Engineering and Computer Science - Former Departments, Centers, Institutes and Projects
We present a new semantics for Algol-like languages that combines methods from two prior lines of development: [1] the object-based approach of [28,29], where the meaning of an imperative program is described in terms of sequences of observable actions, and [2] the functor-category approach initiated by Reynolds [31], where the varying nature of the run-time stack is explained using functors from a category of store shapes to a category of cpos. The semantics gives an account of both the phenomena of local state and irreversibility of state change. As an indication of the accuracy obtained, we present a full abstraction …
Syntactic Control Of Interference Revisited, Peter W. O'Hearn, A. J. Power, M. Takeyama, R. D. Tennent
Syntactic Control Of Interference Revisited, Peter W. O'Hearn, A. J. Power, M. Takeyama, R. D. Tennent
College of Engineering and Computer Science - Former Departments, Centers, Institutes and Projects
In "Syntactic Control of Interference" (POPL, 1978), J. C. Reynolds proposes three design principles intended to constrain the scope of imperative state effects in Algol-like languages. The resulting linguistic framework seems to be a very satisfactory way of combining functional and imperative concepts, having the desirable attributes of both purely functional languages (such as pcf) and simple imperative languages (such as the language of while programs). However, Reynolds points out that the "obvious" syntax for interference control has the unfortunate property that fi-reductions do not always preserve typings. Reynolds has subsequently presented a solution to this problem (ICALP, 1989), but …
Parametricity And Local Variables, Peter W. O'Hearn, R. D. Tennent
Parametricity And Local Variables, Peter W. O'Hearn, R. D. Tennent
College of Engineering and Computer Science - Former Departments, Centers, Institutes and Projects
We propose that the phenomenon of local state may be understood in terms of Strachey 's concept of parametric (i.e., uniform) polymorphism. The intuitive basis for our proposal is the following analogy: a non-local procedure is independent of locally-declared variables in the same way that a parametrically polymorphic function is independent of types to which it is instantiated. A connection between parametricity and representational abstraction was first suggested by J. C. Reynolds. Reynolds used logical relations to formalize this connection in languages with type variables and user-defined types. We use relational parametricity to construct a model for an Algol-like language …
Note On Algol And Conservatively Extending Functional Programming, Peter W. O'Hearn
Note On Algol And Conservatively Extending Functional Programming, Peter W. O'Hearn
College of Engineering and Computer Science - Former Departments, Centers, Institutes and Projects
A simple Idealized Algol is considered, based on Reynolds's "essence of Algol." It is shown that observational equivalence in this language conservatively extends observational equivalence in its assignment-free functional sublanguage.