public override Expression Visit(Expression node)
{
// Looking through allowed expression types.
if (AllowedExpressionTypes.Contains(node.NodeType))
{
return(base.Visit(node));
}
throw new Exception($"Unsupported expression type: '{node.NodeType}'");
}
protected override Expression VisitBinary(BinaryExpression node)
{
// Looking through allowed operation types.
if (!AllowedExpressionTypes.Contains(node.NodeType))
{
throw new Exception($"Unsupported operation: '{node.NodeType}'");
}
// Visiting both right and left part of a binary expression, then invoking arithmetic operation with constants.
var result = Expression.Lambda(node.Update(Visit(node.Left), node.Conversion, Visit(node.Right))).Compile().DynamicInvoke();
return(Expression.Constant(result, typeof(int)));
}