Clean up non-normative content in inheritance.tex

chapters/inheritance.tex

@@ -78,12 +78,11 @@ \section{Inheritance---Extends Clause}\doublelabel{inheritance-extends-clause}
 yields an instance with \lstinline!bcomp.b = 3!, which overrides \lstinline!b = 2!.
 \end{nonnormative}
 
-The declaration elements of the flattened base class shall either
-
+The declaration elements of the flattened base class shall either:
 \begin{itemize}
 \item
   Not already exist in the partially flattened enclosing class
-  {[}\emph{i.e., have different names}{]} .
+  (i.e., have different names).
 \item
   The new element is a long form of redeclare or uses the \lstinline!class extends A! syntax, see \autoref{redeclaration}.
 \item
@@ -117,9 +116,11 @@ \section{Inheritance---Extends Clause}\doublelabel{inheritance-extends-clause}
 to equations in the flattened enclosing class are discarded. This
 feature is deprecated, and it is recommend to give a warning when
 discarding them and for the future give a warning about all forms of
-equivalent equations due to inheritance. {[}\emph{Note: equations that
-are mathematically equivalent but not syntactically equivalent are not
-discarded, hence yield an overdetermined system of equations.}{]}
+equivalent equations due to inheritance.
+
+\begin{nonnormative}
+Equations that are mathematically equivalent but not syntactically equivalent are not discarded, hence yield an overdetermined system of equations.
+\end{nonnormative}
 
 \subsection{Multiple Inheritance}\doublelabel{multiple-inheritance}
 
@@ -192,21 +193,28 @@ \subsection{Restrictions on the Kind of Base Class}\doublelabel{restrictions-on-
 
 If a derived class is inherited from another type of specialized class,
 then the result is a specialized class of the derived class type.
-{[}\emph{For example, if a} \lstinline!block! \emph{inherits from a} \lstinline!record! \emph{, then the result
-is a} \lstinline!block!\emph{.}{]}
 
-All specialized classes can be derived from \lstinline!class! {[}\emph{provided the
-resulting class fulfills the restriction of the specialized class. It is
-recommended to use the most specific specialized class.}{]} A \lstinline!class! may
+\begin{nonnormative}
+For example, if a \lstinline!block! inherits from a \lstinline!record!, then the result is a \lstinline!block!.
+\end{nonnormative}
+
+All specialized classes can be derived from \lstinline!class!, provided that the
+resulting class fulfills the restriction of the specialized class.  A \lstinline!class! may
 only contain class-definitions, annotations, and extends-clauses (having
 any other contents is deprecated).
 
+\begin{nonnormative}
+It is recommended to use the most specific specialized class.
+\end{nonnormative}
+
 The specialized classes \lstinline!package!, \lstinline!operator!, \lstinline!function!,
 \lstinline!type,! \lstinline!record!,
-\lstinline!operator record,! and expandable connector can only be derived from their
-own kind {[}\emph{(e.g. a package can only be base class for packages.
-All other kinds of classes can use the import statement to use the
-contents of a package)}{]} and from \lstinline!class!\emph{.}
+\lstinline!operator record!, and \lstinline!expandable connector! can only be derived from their
+own kind and from \lstinline!class!.
+
+\begin{nonnormative}
+E.g. a package can only be base class for packages.  All other kinds of classes can use the import statement to use the contents of a package.
+\end{nonnormative}
 
 \begin{example}
 \begin{lstlisting}[language=modelica]
@@ -236,13 +244,20 @@ \subsection{Restrictions on Base Classes and Constraining Types to be Transitive
 
 The class name used after extends for base-classes and for constraining
 classes must use a class reference considered transitively
-non-replaceable, see definition in \autoref{transitively-non-replaceable}. {[}\emph{This
-formulation excludes the long form of redeclare, i.e.} \lstinline!redeclare model extends M...! \emph{where} \lstinline!M! \emph{must be an inherited replaceable
-class.}{]} For a replaceable component declaration without constraining
+non-replaceable, see definition in \autoref{transitively-non-replaceable}.
+For a replaceable component declaration without constraining
 clause the class must use a class reference considered transitively
-non-replaceable. {[}\emph{This implies that constraining classes are
-always transitively non-replaceable -- both if explicitly given or
-implicitly by the declaration.}{]}
+non-replaceable.
+
+\begin{nonnormative}
+The requirement to use a transitively non-replaceable name excludes the long form of redeclare, i.e. \lstinline!redeclare model extends M...! where
+\lstinline!M! must be an inherited replaceable class.
+\end{nonnormative}
+
+\begin{nonnormative}
+The rule for a replaceable component declaration without constraining clause implies that constraining classes are always transitively non-replaceable --- both
+if explicitly given or implicitly by the declaration.
+\end{nonnormative}
 
 \section{Modifications}\doublelabel{modifications}
 
@@ -270,14 +285,14 @@ \section{Modifications}\doublelabel{modifications}
 \end{lstlisting}
 \end{example}
 
-A modification (i.e. C1 c1(x = 5) is considered a modification equation,
-if the modified variable is a non-parameter (here: c1.x) variable.
-{[}\emph{This equation is created, if the modified component (here: c1)
-is also created (see \autoref{class-declarations}). In most cases a
-modification equation for a non-parameter variable requires that the
-variable was declared with a declaration equation, see \autoref{balanced-models};
-in those cases the declaration equation is replaced by the
-modification equation.}{]}
+A modification (e.g. \lstinline!C1 c1(x = 5)!) is considered a modification equation,
+if the modified variable (here: \lstinline!c1.x!) is a non-parameter variable.
+
+\begin{nonnormative}
+The modification equation is created, if the modified component (here: \lstinline!c1!) is also created (see \autoref{class-declarations}). In most cases
+a modification equation for a non-parameter variable requires that the variable was declared with a declaration equation, see \autoref{balanced-models};
+in those cases the declaration equation is replaced by the modification equation.
+\end{nonnormative}
 
 A more dramatic change is to modify the \emph{type} and/or the
 \emph{prefixes} and possibly the \emph{dimension sizes} of a declared
@@ -326,8 +341,11 @@ \subsection{Modification Environment}\doublelabel{modification-environment}
 The modification environment contains arguments which modify elements of
 the class (e.g., parameter changes). The modification environment is
 built by merging class modifications, where outer modifications override
-inner modifications. {[}\emph{Note: this should not be confused with}
-\lstinline!inner outer! \emph{prefixes described in \autoref{instance-hierarchy-name-lookup-of-inner-declarations}}{]}
+inner modifications.
+
+\begin{nonnormative}
+This should not be confused with \lstinline!inner outer! prefixes described in \autoref{instance-hierarchy-name-lookup-of-inner-declarations}.
+\end{nonnormative}
 
 \subsection{Merging of Modifications}\doublelabel{merging-of-modifications}
 
@@ -544,10 +562,11 @@ \subsection{Final Element Modification Prevention}\doublelabel{final-element-mod
 An element defined as final by the \lstinline!final! prefix in an element
 modification or declaration cannot be modified by a modification or by a
 redeclaration. All elements of a final element are also final.
-{[}\emph{Setting the value of a parameter in an experiment environment
-is conceptually treated as a modification. This implies that a final
-modification equation of a parameter cannot be changed in a simulation
-environment}{]}.
+
+\begin{nonnormative}
+Setting the value of a parameter in an experiment environment is conceptually treated as a modification.  This implies that a final modification equation
+of a parameter cannot be changed in a simulation environment.
+\end{nonnormative}
 
 \begin{example}
 \begin{lstlisting}[language=modelica]
@@ -670,19 +689,22 @@ \subsection{The class extends Redeclaration Mechanism}\doublelabel{the-class-ext
 where \lstinline!class! as usual can be replaced by any other specialized class,
 replaces the inherited class \lstinline!B! with another declaration that extends the
 inherited class where the optional class-modification is applied to the
-inherited class. {[}\emph{Since this implies that all declarations are
-inherited with modifications applied there is no need to apply modifiers
-to the new declaration.}{]} Inherited B here means that the class
-containing \lstinline!redeclare class extends! B(\ldots{}) should also inherit
-another declaration of B from one of its extends-clauses. The new
+inherited class.  Inherited \lstinline!B! here means that the class
+containing \lstinline!redeclare class extends B(...)! should also inherit
+another declaration of \lstinline!B! from one of its extends-clauses. The new
 declaration should explicitly include redeclare.
 
+\begin{nonnormative}
+Since the rule about applying the optional class-modification implies that all declarations are inherited with modifications applied, there is no need
+to apply modifiers to the new declaration.
+\end{nonnormative}
+
 For \lstinline!redeclare class extends B(...)! the inherited class is subject
 to the same restrictions as a redeclare of the inherited element, and
-the original class B should be replaceable, and the new element is only
+the original class \lstinline!B! should be replaceable, and the new element is only
 replaceable if the new definition is replaceable. In contrast to normal
-extends it is not subject to the restriction that B should be
-transitively non-replaceable (since B should be replaceable).
+extends it is not subject to the restriction that \lstinline!B! should be
+transitively non-replaceable (since \lstinline!B! should be replaceable).
 
 The syntax rule for \lstinline!class extends! construct is in the definition of the
 \lstinline!class-specifier! nonterminal (see also class declarations in \autoref{class-declarations}):
@@ -977,9 +999,11 @@ \subsubsection{Constraining-clause annotations}\doublelabel{constraining-clause-
 
 Description and annotations on the constraining-clause are applied to
 the entire declaration, and it is an error if they also appear on the
-definition. \emph{{[}The intent is that the description and/or
-annotation are at the end of the declaration, but it is not
-straightforward to specify this in the grammar.{]}}
+definition.
+
+\begin{nonnormative}
+The intent is that the description and/or annotation are at the end of the declaration, but it is not straightforward to specify this in the grammar.
+\end{nonnormative}
 
 \begin{example}
 \begin{lstlisting}[language=modelica]
@@ -999,27 +1023,27 @@ \subsection{Restrictions on Redeclarations}\doublelabel{restrictions-on-redeclar
 
 The following additional constraints apply to redeclarations (after
 prefixes are inherited, \autoref{redeclaration}):
-
-Only classes and components declared as replaceable can be redeclared
-with a new type {[}\emph{redeclaration with the same type can be used to
-restrict variability and/or change array dimensions}{]}, which must have
-an interface compatible with the constraining interface of the original
-declaration, and to allow further redeclarations one must use
-\lstinline!redeclare replaceable!.
-
 \begin{itemize}
 \item
-  an element declared as constant cannot be redeclared
+  Only classes and components declared as replaceable can be redeclared with a new type, which must have an interface compatible with the constraining
+  interface of the original declaration, and to allow further redeclarations one must use \lstinline!redeclare replaceable!.
+  \begin{nonnormative}
+  Redeclaration with the same type can be used to restrict variability and/or change array dimensions.
+  \end{nonnormative}
+\item
+  An element declared as constant cannot be redeclared
 \item
-  an element declared as final may not be modified, and thus not
+  An element declared as final may not be modified, and thus not
   redeclared
 \item
   Modelica does not allow a protected element to be redeclared as
   public, or a public element to be redeclared as protected.
 \item
   Array dimensions may be redeclared; provided the sub-typing rules in
-  \autoref{interface-compatibility-or-subtyping} are satisfied. {[}\emph{This is one example of redeclare of
-  non-replaceable elements.}{]}
+  \autoref{interface-compatibility-or-subtyping} are satisfied.
+  \begin{nonnormative}
+  This is one example of redeclare of non-replaceable elements.
+  \end{nonnormative}
 \end{itemize}
 
 \subsection{Annotation Choices for Suggested Redeclarations and Modifications}\doublelabel{annotation-choices-for-suggested-redeclarations-and-modifications}