TY - JOUR
T1 - Circular expressions
T2 - elimination of static environments
AU - Sethi, Ravi
PY - 1982/5
Y1 - 1982/5
N2 - Consider the connection between denotational semantics for a language with goto statements and flow diagrams for programs in such a language. The main point of interest is that the denotational semantics uses a recursively defined environment to give the meaning of labels, while a flow diagram merely has a jump to the appropriate program point. A simple reduction called "indirection elimination" strips away the environment from the denotational semantics and extracts an expression with cycles that is very close to the flow diagram of a program. The same idea applies to associating bodies with recursive procedures, or to any construct whose semantics is not wedded to the syntax. In addition to being a useful data structure and conceptual device, expressions with cycles are well defined mathematical objects-their semantics can be given by unfolding them into infinite structures that have been well studied. The practicality of the elimination of environments has been tested by constructing a trial implementation, which serves as the front end of a semantics directed compiler generator. The implementation takes a denotational semantics of a language and constructs a "black box" that maps programs in the language into an intermediate representation. The intermediate representation is a circular expression.
AB - Consider the connection between denotational semantics for a language with goto statements and flow diagrams for programs in such a language. The main point of interest is that the denotational semantics uses a recursively defined environment to give the meaning of labels, while a flow diagram merely has a jump to the appropriate program point. A simple reduction called "indirection elimination" strips away the environment from the denotational semantics and extracts an expression with cycles that is very close to the flow diagram of a program. The same idea applies to associating bodies with recursive procedures, or to any construct whose semantics is not wedded to the syntax. In addition to being a useful data structure and conceptual device, expressions with cycles are well defined mathematical objects-their semantics can be given by unfolding them into infinite structures that have been well studied. The practicality of the elimination of environments has been tested by constructing a trial implementation, which serves as the front end of a semantics directed compiler generator. The implementation takes a denotational semantics of a language and constructs a "black box" that maps programs in the language into an intermediate representation. The intermediate representation is a circular expression.
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U2 - 10.1016/0167-6423(82)90015-6
DO - 10.1016/0167-6423(82)90015-6
M3 - Article
AN - SCOPUS:0020127598
SN - 0167-6423
VL - 1
SP - 203
EP - 222
JO - Science of Computer Programming
JF - Science of Computer Programming
IS - 3
ER -