ITU-T Rec. Z.100 Annex F1 (11/2000) Specification and description language (SDL) Annex F1: Formal Definition of SDL: General

syntax rules Abstract syntax rules from the language definition are directly translated to the ASM notation, using certain conventions that will be explained by examples. Basically, an abstract syntax rule can be understood as declaring one or more (tuple) domains, and defining functions to construct and select values of the component domains. However, syntax nodes have an identity as opposed to ordinary tuples. There are syntax rules introducing named constructors as well as named and unnamed unions. Rules introducing constructors are composed of terminal and non-terminal symbols, they have the form: Symbol :: Symbol1 Symbol2 Symbol3-set [Symbol4] which is translated to: Symbol-aux =def Symbol1 × Symbol2 × Symbol3-set × Symbol4 controlled domain Symbol controlled contents-Symbol: Symbol → Symbol-aux s-Symbol1(x: Symbol): Symbol1 =def s-Symbol1(x.contents-Symbol) s-Symbol2-seq(x: Symbol): Symbol2 =def s-Symbol2-seq(x.contents-Symbol) s-Symbol3-set(x: Symbol): Symbol3-set =def s-Symbol3-set(x.contents-Symbol) s-Symbol4(x: Symbol): Symbol4 =def s-Symbol4(x.contents-Symbol) Moreover, there is an abbreviation mk-Symbol. This abbreviation amounts to creating a new object of domain Symbol using the extend primitive and to set the contents-Symbol value of the newly produced object to the result of mk-Symbol-aux. Note that this kind of abbreviation is not a function, but in fact a rule item. Therefore, it must be used only within rules. The fact that the optional Symbol4 is not present is expressed in the ASM model by leaving the corresponding value undefined. An empty sequence of symbols (constructor with no parts) is denoted by ( ).