Scan.h

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/*
 * Souffle - A Datalog Compiler
 * Copyright (c) 2013, 2014, Oracle and/or its affiliates. All rights reserved
 * Licensed under the Universal Permissive License v 1.0 as shown at:
 * - https://opensource.org/licenses/UPL
 * - <souffle root>/licenses/SOUFFLE-UPL.txt
 */
 
/************************************************************************
 *
 * @file Scan.h
 *
 ***********************************************************************/
 
#pragma once
 
#include "ram/Operation.h"
#include "ram/Relation.h"
#include "ram/RelationOperation.h"
#include "souffle/utility/MiscUtil.h"
#include "souffle/utility/StreamUtil.h"
#include <iosfwd>
#include <memory>
#include <ostream>
#include <string>
#include <utility>
 
namespace souffle::ram {
 
/**
 * @class Scan
 * @brief Iterate all tuples of a relation
 *
 * The following example iterates over all tuples
 * in the set A:
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *  QUERY
 *   ...
 *   FOR t0 IN A
 *     ...
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */
class Scan : public RelationOperation {
public:
    Scan(std::string rel, int ident, Own<Operation> nested, std::string profileText = "")
            : RelationOperation(rel, ident, std::move(nested), std::move(profileText)) {}
 
    Scan* clone() const override {
        return new Scan(relation, getTupleId(), souffle::clone(&getOperation()), getProfileText());
    }
 
protected:
    void print(std::ostream& os, int tabpos) const override {
        os << times(" ", tabpos);
        os << "FOR t" << getTupleId();
        os << " IN " << relation << std::endl;
        RelationOperation::print(os, tabpos + 1);
    }
};
 
}  // namespace souffle::ram