摘要：The importance of giving precise semantics to programming and specification languages was recognized since the sixties with the development of the first high-level programming languages (cf. e.g. [30, 206] for some early accounts). The use of operational semantics - i.e. of a semantics that explicitly describes how programs compute in stepwise fashion, and the possible state-transformations they perform - was already advocated by McCarthy in [147], and elaborated upon in references like [142, 143]. Examples of full-blown languages that have been endowed with an operational semantics are Algol 60 [140], PL/I [173], and CSP [178].
