/// <summary>
/// Tries to evaluate the current expression and add it as a projection
/// </summary>
private Expression AddProjection(Expression node, string columnName = null)
{
var value = Expression.Lambda(node).Compile().DynamicInvoke();
if (columnName == null)
{
columnName = _pocoData.GetColumnNameByMemberName(_currentBindingName.Get());
if (columnName == null)
{
throw new CqlLinqNotSupportedException(node, _parsePhase.Get());
}
}
_projections.Add(Tuple.Create(columnName, value, ExpressionType.Assign));
return(node);
}
protected override Expression VisitConstant(ConstantExpression node)
{
if (node.Value is ITable)
{
return(node);
}
switch (_parsePhase.Get())
{
case ParsePhase.Condition:
_currentCondition.Get().Item1.Append("?");
_currentCondition.Get().Item2.Add(node.Value);
return(node);
case ParsePhase.SelectBinding:
{
var column = _pocoData.GetColumnByMemberName(_currentBindingName.Get());
if (column == null)
{
//selecting a field that is not part of PocoType
break;
}
var expressionType = ExpressionType.Assign;
if (column.IsCounter)
{
if (!(node.Value is long || node.Value is int))
{
throw new ArgumentException("Only Int64 and Int32 values are supported as counter increment of decrement values");
}
expressionType = ExpressionType.Increment;
}
_projections.Add(Tuple.Create(column, node.Value, expressionType));
_selectFields.Add(column.ColumnName);
return(node);
}
case ParsePhase.Take:
_limit = (int)node.Value;
return(node);
case ParsePhase.OrderBy:
case ParsePhase.OrderByDescending:
{
var columnName = _pocoData.GetColumnNameByMemberName((string)node.Value);
if (columnName == null)
{
//order by a field that is not part of PocoType
break;
}
_orderBy.Add(Tuple.Create(columnName, _parsePhase.Get() == ParsePhase.OrderBy));
return(node);
}
}
throw new CqlLinqNotSupportedException(node, _parsePhase.Get());
}