operational semantics

In computer science, operational semantics is a way to give meaning to computer programs in a mathematically rigorous way (See formal semantics of programming languages).The operational semantics for a programming language describes how a valid program is interpreted as sequences of computational steps. These sequences then are the meaning of the program. In the context of functional programs, the final step in a terminating sequence returns the value of the program. (In general there can be many computation sequences and many return values for a single program, because the program could be nondeterministic.)
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<theory> A set of rules specifying how the state of an actual or hypothetical computer changes while executing a program. The overall state is typically divided into a number of components, e.g. stack, heap, registers etc. Each rule specifies certain preconditions on the contents of some components and their new contents after the application of the rule.
It is similar in spirit to the notion of a Turing machine, in which actions are precisely described in a mathematical way.
Compuare axiomatic semantics, denotational semantics.
(1996-08-21)