internal override Expression CreateExpression(Expression parameter)
{
var leftExpression = _left.CreateExpression(parameter);
var innerType = leftExpression.Type.GetGenericArguments()[0];
var enumerableCall = Expression.Call(typeof(Enumerable), AggregateMethodName, new[] { innerType }, leftExpression);
return(enumerableCall);
}
internal override Expression CreateExpression(Expression parameter)
{
if (_left.IsMultiValue)
{
if (_right.IsMultiValue)
{
// left.SelectMany(x=>right)
var left = _left.CreateExpression(parameter);
var innerType = left.Type.GetGenericArguments()[0];
var innerParameter = Expression.Parameter(innerType);
var right = _right.CreateExpression(innerParameter);
var rightType = right.Type.GetGenericArguments()[0];
var lambda = Expression.Lambda(right, innerParameter);
return(Expression.Call(typeof(Enumerable), "SelectMany", new[] { innerType, rightType }, left, lambda));
}
else
{
// left.Select(x=>right)
var left = _left.CreateExpression(parameter);
var innerType = left.Type.GetGenericArguments()[0];
var innerParameter = Expression.Parameter(innerType);
var right = _right.CreateExpression(innerParameter);
var lambda = Expression.Lambda(right, innerParameter);
return(Expression.Call(typeof(Enumerable), "Select", new[] { innerType, lambda.ReturnType }, left, lambda));
}
}
else
{
// left.right
var left = _left.CreateExpression(parameter);
//TODO: what happens if left is null?
return(_right.CreateExpression(left));
}
}