/// <summary>
        /// Visit a parse tree produced by <see cref="Z80TestParser.breakpoint"/>.
        /// <para>
        /// The default implementation returns the result of calling <see cref="AbstractParseTreeVisitor{Result}.VisitChildren(IRuleNode)"/>
        /// on <paramref name="context"/>.
        /// </para>
        /// </summary>
        /// <param name="context">The parse tree.</param>
        /// <return>The visitor result.</return>
        public override object VisitBreakpoint(Z80TestParser.BreakpointContext context)
        {
            if (IsInvalidContext(context))
            {
                return(null);
            }
            var node = new BreakpointsNode(context);

            foreach (var expr in context.expr())
            {
                node.Expressions.Add((ExpressionNode)VisitExpr(expr));
            }
            return(node);
        }