private QueryClause VisitSelectMany(MethodCallExpression node, LambdaExpression selector, LambdaExpression projector)
{
if (projector != selector)
{
Type transparentType = projector.ReturnType;
if (transparentType.IsCompilerGenerated())
{
// from {item1} in {collection1}
// from {item2} in {collection2}
ParameterExpression firstVar = GetVariable(projector.Parameters[0]);
ParameterExpression secondVar = GetVariable(projector.Parameters[1]);
_clauses.Add(Expressive.From(firstVar, node.Arguments[0]));
return(Expressive.From(secondVar, selector.Body));
}
else
{
// from {item} in {collection}
// select {item}
ParameterExpression newItem = GetVariable(projector.Parameters[1]);
_clauses.Add(Expressive.From(newItem, selector.Body));
return(Expressive.Select(projector.Body));
}
}
return(null);
}
/// <inheritdoc cref="UnaryExpression.Update(Expression)" select="summary"/>
public FromClause Update(ParameterExpression variable, Expression enumerable)
{
if (Variable == variable && Enumerable == enumerable)
{
return(this);
}
return(Expressive.From(variable, enumerable));
}
private QueryClause VisitOrderBy(MethodCallExpression node, LambdaExpression lambda, bool descending)
{
if (_clauses.Count == 0)
{
_clauses.Add(Expressive.From(GetVariable(lambda.Parameters[1]), node.Arguments[0]));
}
return(Expressive.OrderBy(lambda.Body, !descending));
}
private QueryClause VisitWhere(MethodCallExpression node, LambdaExpression predicate)
{
if (_clauses.Count == 0)
{
_clauses.Add(Expressive.From(GetVariable(predicate.Parameters[0]), node.Arguments[0]));
}
return(Expressive.Where(predicate.Body));
}
private QueryClause VisitContinuationClause(QueryClauseSyntax clause)
{
switch (clause)
{
case FromClauseSyntax from:
return(Expressive.From(null, from.Expression.Accept(this)));
case LetClauseSyntax let:
return(Expressive.Let(null, let.Expression.Accept(this)));
case JoinClauseSyntax join:
return(Expressive.Join(null, join.InExpression.Accept(this), join.LeftExpression.Accept(this), join.RightExpression.Accept(this)));
case WhereClauseSyntax where:
return(Expressive.Where(where.Condition.Accept(this)));
case OrderByClauseSyntax orderby:
return(Expressive.OrderBy(Utils.Select(@orderby.Orderings, x => Expressive.Ordering(x.Expression.Accept(this), x.AscendingOrDescendingKeyword.Text == "ascending"))));
default:
throw new ArgumentException("Invalid clause.");
}
}
