Make use of component variability when defining expression variability

chapters/operatorsandexpressions.tex

@@ -1409,7 +1409,7 @@ \subsection{Constant Expressions}\label{constant-expressions}
 \item
   \lstinline!Real!, \lstinline!Integer!, \lstinline!Boolean!, \lstinline!String!, and \lstinline!enumeration! literals.
 \item
-  Variables declared as \lstinline!constant!.
+  Constant variables, see \cref{component-variability-prefixes-discrete-parameter-constant}.
 \item
   Except for the special built-in operators \lstinline!initial!, \lstinline!terminal!, \lstinline!der!,
   \lstinline!edge!, \lstinline!change!, \lstinline!sample!, and \lstinline!pre!, a function or operator with constant
@@ -1430,7 +1430,7 @@ \subsection{Parameter Expressions}\label{parameter-expressions}
 \item
   Constant expressions.
 \item
-  Variables declared as \lstinline!parameter!.
+  Parameter variables, see \cref{component-variability-prefixes-discrete-parameter-constant}.
 \item
   Input variables in functions behave as though they were parameter expressions.
 \item
@@ -1460,7 +1460,7 @@ \subsection{Discrete-Time Expressions}\label{discrete-time-expressions}
 \item
   Parameter expressions.
 \item
-  Discrete-time variables, i.e., \lstinline!Integer!, \lstinline!Boolean!, \lstinline!String! variables and \lstinline!enumeration! variables, as well as \lstinline!Real! variables assigned in \lstinline!when!-clauses.
+  Discrete-time variables, see \cref{component-variability-prefixes-discrete-parameter-constant}.
 \item
   Function calls where all input arguments of the function are discrete-time expressions.
 \item
@@ -1536,4 +1536,4 @@ \subsection{Discrete-Time Expressions}\label{discrete-time-expressions}
 \subsection{Continuous-Time Expressions}\label{continuous-time-expressions}
 
 All expressions are continuous-time expressions\index{continuous-time!expression}\index{expression variability!continuous-time} including constant, parameter and discrete expressions.
-The term \firstuse{non-discrete-time expression}\index{non-discrete-time expression}\index{expression variability!non-discrete-time} refers to expressions that are neither constant, parameter nor discrete-time expressions.
+The term \firstuse{non-discrete-time expression}\index{non-discrete-time expression}\index{expression variability!non-discrete-time} refers to expressions that are neither constant, parameter nor discrete-time expressions.  For example, a continuous-time variable (see \cref{component-variability-prefixes-discrete-parameter-constant}) is a non-discrete-time expression.