/// <summary>
/// Evaluates the Algebra in the given context
/// </summary>
/// <param name="context">Evaluation Context</param>
/// <returns></returns>
public BaseMultiset Evaluate(SparqlEvaluationContext context)
{
// First evaluate the inner algebra
BaseMultiset results = context.Evaluate(_inner);
context.OutputMultiset = new Multiset();
if (results is NullMultiset)
{
context.OutputMultiset = results;
}
else if (results is IdentityMultiset)
{
context.OutputMultiset.AddVariable(_var);
Set s = new Set();
try
{
INode temp = _expr.Evaluate(context, 0);
s.Add(_var, temp);
}
catch
{
// No assignment if there's an error
s.Add(_var, null);
}
context.OutputMultiset.Add(s.Copy());
}
else
{
if (results.ContainsVariable(_var))
{
throw new RdfQueryException("Cannot assign to the variable ?" + _var + "since it has previously been used in the Query");
}
context.InputMultiset = results;
context.OutputMultiset.AddVariable(_var);
#if NET40
if (Options.UsePLinqEvaluation && this._expr.CanParallelise)
{
results.SetIDs.AsParallel().ForAll(id => EvalExtend(context, results, id));
}
else
{
foreach (int id in results.SetIDs)
{
EvalExtend(context, results, id);
}
}
#else
foreach (var id in results.SetIDs)
{
EvalExtend(context, results, id);
}
#endif
}
return(context.OutputMultiset);
}
/// <summary>
/// Determines whether this Multiset is disjoint with another Multiset.
/// </summary>
/// <param name="other">Other Multiset.</param>
/// <returns></returns>
public override bool IsDisjointWith(BaseMultiset other)
{
if (other is IdentityMultiset || other is NullMultiset)
{
return(false);
}
return(this.Variables.All(v => !other.ContainsVariable(v)));
}
/// <summary>
/// Evaluates the Algebra in the given context
/// </summary>
/// <param name="context">Evaluation Context</param>
/// <returns></returns>
public BaseMultiset Evaluate(SparqlEvaluationContext context)
{
//First evaluate the inner algebra
BaseMultiset results = context.Evaluate(this._inner);
context.OutputMultiset = new Multiset();
if (results is NullMultiset)
{
context.OutputMultiset = results;
}
else if (results is IdentityMultiset)
{
context.OutputMultiset.AddVariable(this._var);
Set s = new Set();
try
{
INode temp = this._expr.Evaluate(context, 0);
s.Add(this._var, temp);
}
catch
{
//No assignment if there's an error
s.Add(this._var, null);
}
context.OutputMultiset.Add(s.Copy());
}
else
{
if (results.ContainsVariable(this._var))
{
throw new RdfQueryException("Cannot use a BIND assigment to BIND to a variable that has previously been used in the Query");
}
context.OutputMultiset.AddVariable(this._var);
foreach (int id in results.SetIDs.ToList())
{
ISet s = results[id].Copy();
try
{
//Make a new assignment
INode temp = this._expr.Evaluate(context, id);
s.Add(this._var, temp);
}
catch
{
//No assignment if there's an error but the solution is preserved
}
context.OutputMultiset.Add(s);
}
}
return(context.OutputMultiset);
}
/// <summary>
/// Determines whether this Multiset is disjoint with another Multiset
/// </summary>
/// <param name="other">Other Multiset</param>
/// <returns></returns>
public override bool IsDisjointWith(BaseMultiset other)
{
if (other is IdentityMultiset || other is NullMultiset) return false;
return this._variables.All(v => !other.ContainsVariable(v));
}
