query_expression.h

/*
 Copyright (c) 2013 by ScaleOut Software, Inc.

 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at

 http://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
*/ 

#pragma once

#include <string>
#include <boost/shared_ptr.hpp>

namespace sosscli {

// Forward references...
class QueryExpression;
class ValueComparand;
class ReferenceComparand;

namespace internal {
 class ComparisonExpression;
 class StringContainsExpression;
 class AndExpression;
 class OrExpression;
 class EqualsExpression;
 class NotExpression;
}

class QueryExpression
{
public:

 class Visitor
 {
 public:
 virtual ~Visitor();

 virtual void visit(ValueComparand const & v);

 virtual void visit(ReferenceComparand const & r);

 virtual void visit(internal::ComparisonExpression const & c);

 virtual void visit(internal::StringContainsExpression const & s);

 virtual void visit(internal::AndExpression const & a);

 virtual void visit(internal::OrExpression const & o);

 virtual void visit(internal::EqualsExpression const & e);

 virtual void visit(internal::NotExpression const & n);
 };

 enum OpCode
 {
 Compare = 1,

 Not,

 And, 

 Or,

 Equals, 

 // TODO: not supported yet.
 HasAnyTag,

 // TODO: not supported yet.
 HasAllTags, 

 // TODO: not supported yet
 HasTags,

 StringContains,
 };

public:
 virtual ~QueryExpression();

 virtual void accept(Visitor &v) const = 0;
};

}