protected virtual Expression VisitFrom(FromExpression from)
{
this.Write(".From(");
this.WriteLine(Indentation.Inner);
this.Visit(from.From);
this.WriteLine(Indentation.Outer);
this.Write(")");
return from;
}
internal SelectExpression(LambdaExpression projection, FromExpression from, WhereExpression where, string alias, bool isProjection, Expression take, OrderByClause orderBy)
: base(CompleteExpressionType.Select, typeof(IEnumerable<>).MakeGenericType(projection.ReturnType))
{
this.Projection = projection;
this.Alias = alias;
this.From = from;
this.Where = where;
this.Take = take;
this.OrderBy = orderBy;
this.IsProjection = isProjection;
var ce = ColumnExtractor.ExtractColumns(this, projection);
this._Columns = ce.Columns.ToList();
this._Assignments = ce.Assignments.ToList();
}
protected virtual Expression VisitFrom(FromExpression from)
{
var source = (SourceExpression)this.Visit(from.From);
if (source == from.From)
return from;
return CompleteExpression.From(source);
}
protected override Expression VisitFrom(FromExpression from)
{
switch ((CompleteExpressionType)from.From.NodeType)
{
case CompleteExpressionType.Table:
case CompleteExpressionType.Select:
this.VisitSource(from.From);
break;
case CompleteExpressionType.Join:
this.VisitJoin(from.From as JoinExpression);
break;
}
this.AppendNewLine(Indentation.Same);
return from;
}
protected LambdaExpression VisitSelectProjection(FromExpression from, Expression expr)
{
var projection = VisitSourceReferencedProjection(from, expr);
if (!projection.ReturnType.IsComplexType())
{
var body = FixUpBooleanValue(projection.Body);
var column = body as ColumnExpression;
var name = column != null ? column.Name : string.Format("x{0:hhMMssffffff}", DateTime.UtcNow);
projection = Expression.Lambda(
CompleteExpression.Column(
body,
name),
projection.Parameters.ToArray());
}
return projection;
}
protected LambdaExpression VisitSourceReferencedProjection(FromExpression from, Expression expression)
{
fromExpressions.Push(from);
var projection = this.Visit(PartialEvaluator.Eval(expression.StripQuotes())) as LambdaExpression;
fromExpressions.Pop();
return projection;
}
public static SelectExpression Select(string alias, LambdaExpression projection, FromExpression from, OrderByClause orderBy, WhereExpression where = null, bool isProjection = true, Expression take = null)
{
return new SelectExpression(projection, from, where, alias, isProjection, take, orderBy);
}
