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Fold and Unfold for Program Semantics

Hutton, Graham



In this paper we explain how recursion operators can be used to structure and reason about program semantics within a functional language. In particular, we show how the recursion operator fold can be used to structure denotational semantics, how the dual recursion operator unfold can be used to structure operational semantics, and how algebraic properties of these operators can be used to reason about program semantics. The techniques are explained with the aid of two main examples, the first concerning arithmetic expressions, and the second concerning Milner's concurrent language CCS. The aim of the paper is to give functional programmers new insights into recursion operators, program semantics, and the relationships between them.


Hutton, G. (1998). Fold and Unfold for Program Semantics.

Conference Name Proceedings of the 3rd ACM SIGPLAN International Conference on Functional Programming
Publication Date Jan 1, 1998
Deposit Date Oct 26, 2005
Publicly Available Date Oct 9, 2007
Peer Reviewed Peer Reviewed
Public URL


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