RELAX NG implementation of High-level Petri Nets Terms grammar. This schema implements the core signature shared by High-level Petri Nets. File name: terms.rng Version: 2009 (c) 2007-2009 Lom Hillah (AFNOR) Revision: July 2008 - L.H A core signature starts by zero or more declarations A declaration may be a Sort, Variable or Operator declaration. It has a name and an id. It is extended by each definition of Sort, Variable and Operator. A declaration is part of a group of declarations. It defines known concrete declarations A variable declaration is a user-declared variable. It refers to a Sort. A Sort declaration content is derived from Declaration.content A Sort declaration is a user-declared sort, using built-in sorts. It defines known concrete sort declarations. The content of OperatorDeclaration is the one of Declaration constructs. An Operator declaration is a user-declared operator using built-in. constructs. A simple variable refers to a VariableDeclaration. As a Term, a variable also refers to a Sort, which is derived. See Term definition in the corresponding section of this grammar. A named sort is the concrete definition of a SortDeclaration. It contains a Sort definition. A named operator is the concrete definition of and OperatorDeclaration. User-defined operators typically use this construct. VariableDeclaration is used as the construct for its parameters (ordered), and Term for its body definition. A Term involves operators and variables. It refers to a Sort, which is usually derived A sort is not specified. Its is extended by common or high-level specific sorts. A sort may be a basis for a MultisetSort. Actually we don't need to export the "multi" attribute, since it is most important to have the relation from the opposite direction, i.e., from MultiSet. This attribute can thus be made transient (not exported) in the PNML tool. Sorts don't seem to need an ID since their definition is always included as sub-element of Declaration. Base definition of a built-in Sort. Further definitions should refine this one using choice as the value of combine attribute. A multiset sort is built upon a basis sort. There is an issue regarding infinite recursion induced by the fact that a MultisetSort is a Sort. We then have the possibility to define a multiset sort of multiset sorts. In part 1, set of multiset is allowed, which seems akin to this definition. So beware of infinite recursion when using this construct. A product sort is a sort. It refers to an ordered list of members which are sorts. A user sort is used as an abbreviation of existing users-declared sort. It thus refers to a SortDeclaration. Recursion is forbidden. The sub-terms of an operator. An operator has an ordered list of inputs and an output, which are derived. They are thus not exported in the XML (transient for the tools). All refer to sorts of the arguments over which the operator is applied. It is applied on an ordered set of subterms which are either variables or application of operator on other subterms. The operator is either built-in, or user-declared from built-in. The content of BuiltInOperator.content is the one of Operator.content Base definition of a built-in operator. Further definitions should refine this one using choice as the value of combine attribute. The content of BuiltInConstant.content is the one of Operator.content Base definitin of a built-in constant. Further definitions should refine this one using choice as the value of combine attribute. The content of MultisetOperator.content is the one of Operator.content The Multiset Operator base definition. Further definitions should refine this one using choice as the value of combine attribute. The 'Tuple' construct. A user operator is used as an abbreviation of existing user-declared operators. It thus refers to an OperatorDeclaration. Recursion is forbidden.