Action Semantic Descriptions
Peter D. Mosses · Cambridge University Press eBooks · 1992
Action semantic descriptions are divided into modules . Grammars are used to specify abstract syntax . Semantic equations are used to specify semantic functions . Action semantics provides a standard notation for specifying semantic entities (actions, data, yielders) . The standard notation can be extended and specialized by means of algebraic specifications . A semantic description consists of three main parts, concerned with specifying abstract syntax, semantic functions, and semantic entities. We specify these parts as separate modules , which, in larger specifications, may themselves be divided into submodules , just as we normally divide technical reports and textbooks into sections and subsections. Let us adopt the following discipline in our modular specifications: each module has to have a title , and it has to be self-contained , in the sense that all the notation used in a module must be specified there too. Of course, when some module M uses notation that is already specified in another module M ′, there is no point in repeating all of M ′ literally in M : it is sufficient to refer to M i from M , using its title. Similarly, when the submodules M i of a module M use some common notation, we may as well specify that notation just once, at the level of M , letting it be inherited by each M i . A reference to a module M thus provides not only the notation specified directly in M and its submodules, but also that which is specified in modules referenced by M and in supermodules enclosing M .