Explain associativity

chapters/operatorsandexpressions.tex

@@ -24,6 +24,15 @@ \section{Operator Precedence and Associativity}\label{operator-precedence-and-as
 
 Operator precedence determines the order of evaluation of operators in an expression.
 An operator with higher precedence is evaluated before an operator with lower precedence in the same expression.
+For example, `\lstinline!*!' having higher precedence than `\lstinline!+!' means that \lstinline!1 + 2 * 3! becomes evaluated as \lstinline!1 + (2 * 3)!.
+
+Operator associativity are used to determine the order of evaluation when operators have equal precedence.
+Left associativity means that evaluation proceeds from left to right.
+For example, left associativity of binary `\lstinline!-!' means that \lstinline!1 - 2 - 3! becomes evaluated as \lstinline!(1 - 2) - 3!.
+Right associativity means evaluation from right to left, but there are no operators with this associativity in Modelica.
+An operator may also be non-associative, meaning that evaluation order cannot be determined based on associativity.
+For example, non-associativity of `\lstinline!<!' means that \lstinline!1 < 2 < 3! is an invalid expression.
+Note that the operators don't need to be identical for associativity to matter; also \lstinline!1 == 2 < 3! is invalid, and \lstinline!1 - 2 + 3! becomes evaluated as \lstinline!(1 - 2) + 3!.
 
 The following table presents the precedence and associativity of all the expression operators, consistent with and complementing information that can be derived from the Modelica grammar in \cref{modelica-concrete-syntax}.
 \begin{table}[H]