public override VfpExpression Visit(VfpFilterExpression expression)
{
var isEmptyExpression = expression.Predicate as VfpIsEmptyExpression;
if (isEmptyExpression == null)
{
return(base.Visit(expression));
}
var projectExpression = isEmptyExpression.Argument as VfpProjectExpression;
if (projectExpression == null)
{
return(base.Visit(expression));
}
var filterExpression = projectExpression.Input.Expression as VfpFilterExpression;
var variables = VariableReferenceGatherer.Gather(filterExpression);
if (variables.All(x => expression.Input.VariableName != x.VariableName))
{
return(base.Visit(expression));
}
// TODO: verify inner join
//var joinExpression = VfpExpression.Join(VfpExpressionKind.InnerJoin, expression.ResultType, expression.Input, filterExpression.Input, filterExpression.Predicate);
//var binding = VfpExpression.Binding(joinExpression, VfpExpression.VariableRef(PrimitiveTypeKind.String.ToTypeUsage(), "X" + (++_count)));
//return base.Visit(binding);
return(base.Visit(expression));
}
private static VfpExpression GetProjection(VfpFilterExpression filterExpression, string filterVariableName, VfpExpression projectionExpression)
{
var newInstanceExpression = projectionExpression as VfpNewInstanceExpression;
if (newInstanceExpression == null)
{
return(projectionExpression);
}
var newInstanceVariableNames = VariableReferenceGatherer.Gather(newInstanceExpression)
.Select(x => x.VariableName)
.Distinct()
.ToArray();
if (newInstanceVariableNames.Length != 1)
{
return(projectionExpression);
}
if (filterVariableName != newInstanceVariableNames.First())
{
return(projectionExpression);
}
return(VariableReferenceReplacer.Replace(filterExpression.Input.Variable, newInstanceExpression));
}
public override VfpExpression Visit(VfpFilterExpression expression)
{
VisitVfpExpressionBinding(expression.Input);
WriteLine(Indentation.Same);
Write("WHERE ");
expression.Predicate.Accept(this);
return(expression);
}
public override VfpExpression Visit(VfpFilterExpression expression)
{
var result = base.Visit(expression);
expression = result as VfpFilterExpression;
if (expression == null)
{
return(result);
}
if (IsValidXmlToCursorExpression(expression.Predicate as VfpXmlToCursorExpression))
{
var predicate = VfpExpressionBuilder.Constant(0).ExpressionEquals(VfpExpressionBuilder.Constant(0));
return(new VfpFilterExpression(expression.ResultType, expression.Input, predicate));
}
return(result);
}
public override VfpExpression Visit(VfpFilterExpression expression)
{
expression = (VfpFilterExpression)base.Visit(expression);
var innerFilter = expression.Input.Expression as VfpFilterExpression;
if (innerFilter == null)
{
return(expression);
}
var variables = VariableReferenceGatherer.Gather(innerFilter.Predicate);
if (!variables.Any() || variables.Select(x => x.VariableName).Distinct().Count() > 1)
{
return(expression);
}
var predicate = VariableReferenceReplacer.Replace(variables.First(), expression.Predicate);
return(innerFilter.Input.Filter(predicate.And(innerFilter.Predicate)));
}
private static bool IsZeroEqualsZero(VfpFilterExpression expression)
{
return(expression != null && IsZeroEqualsZero(expression.Predicate as VfpComparisonExpression));
}
private static IEnumerable <EdmMember> GetKeyMembers(VfpFilterExpression expression)
{
return(expression == null ? new EdmMember[] { } : GetKeyMembers(expression.Input, expression));
}
private static VfpLimitExpression GetVfpLimitExpression(VfpLimitExpression limitExpression, VfpFilterExpression filterExpression)
{
var keyMembers = GetKeyMembers(filterExpression);
if (!keyMembers.Any())
{
return(null);
}
var sortBinding = GetSortBinding(keyMembers, filterExpression.Input, filterExpression);
var newFilter = sortBinding.Filter(filterExpression.Predicate);
return(new VfpLimitExpression(limitExpression.ResultType,
newFilter,
limitExpression.Limit,
limitExpression.WithTies));
}
public virtual VfpExpression Visit(VfpFilterExpression expression)
{
return(new VfpFilterExpression(expression.ResultType, VisitVfpExpressionBinding(expression.Input), expression.Predicate.Accept(this)));
}
