public virtual void Visit(ComparisonExpression expression)
{
this.LoadQuery();
this.Descend(this.FieldNames(expression.Left()));
expression.Right().Accept(this.ComparisonEmitter());
this.Constrain(expression.Op());
}
public virtual void Visit(ComparisonExpression expression)
{
IQuery subQuery = Descend(expression.Left());
ComparisonQueryGeneratingVisitor visitor = new ComparisonQueryGeneratingVisitor(_predicate
, _classSource, _referenceResolver);
expression.Right().Accept(visitor);
_constraint = subQuery.Constrain(visitor.Value());
ComparisonOperator op = expression.Op();
if (op.Equals(ComparisonOperator.ValueEquality))
{
return;
}
if (op.Equals(ComparisonOperator.ReferenceEquality))
{
_constraint.Identity();
return;
}
if (op.Equals(ComparisonOperator.Greater))
{
_constraint.Greater();
return;
}
if (op.Equals(ComparisonOperator.Smaller))
{
_constraint.Smaller();
return;
}
if (op.Equals(ComparisonOperator.Contains))
{
_constraint.Contains();
return;
}
if (op.Equals(ComparisonOperator.StartsWith))
{
_constraint.StartsWith(true);
return;
}
if (op.Equals(ComparisonOperator.EndsWith))
{
_constraint.EndsWith(true);
return;
}
throw new Exception("Can't handle constraint: " + op);
}
/// <summary>Optimizations: !(Bool)->(!Bool), !!X->X, !(X==Bool)->(X==!Bool)
/// </summary>
public virtual IExpression Not(IExpression expr)
{
if (expr.Equals(BoolConstExpression.True))
{
return(BoolConstExpression.False);
}
if (expr.Equals(BoolConstExpression.False))
{
return(BoolConstExpression.True);
}
if (expr is NotExpression)
{
return(((NotExpression)expr).Expr());
}
if (expr is ComparisonExpression)
{
ComparisonExpression cmpExpr = (ComparisonExpression)expr;
if (cmpExpr.Right() is ConstValue)
{
ConstValue rightConst = (ConstValue)cmpExpr.Right();
if (rightConst.Value() is bool)
{
bool boolVal = (bool)rightConst.Value();
// new Boolean() instead of Boolean.valueOf() for .NET conversion
return(new ComparisonExpression(cmpExpr.Left(), new ConstValue(!boolVal), cmpExpr
.Op()));
}
}
}
return(new NotExpression(expr));
}