ProvenanceNegation.h

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/*
 * Souffle - A Datalog Compiler
 * Copyright (c) 2018, The Souffle Developers. 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 ProvenanceNegation.h
 *
 * Defines the provenance negation class
 *
 ***********************************************************************/
 
#pragma once
 
#include "ast/Atom.h"
#include "ast/Negation.h"
#include "ast/Node.h"
#include "souffle/utility/MiscUtil.h"
#include <iostream>
#include <memory>
 
namespace souffle::ast {
 
/**
 * Subclass of Literal that represents a negated atom, * e.g., !parent(x,y).
 * A Negated atom occurs in a body of clause and cannot occur in a head of a clause.
 *
 * Specialised for provenance: used for existence check that tuple doesn't already exist
 */
class ProvenanceNegation : public Negation {
public:
    using Negation::Negation;
 
    ProvenanceNegation* clone() const override {
        return new ProvenanceNegation(souffle::clone(atom), getSrcLoc());
    }
 
protected:
    void print(std::ostream& os) const override {
        os << "prov!" << *atom;
    }
};
 
}  // namespace souffle::ast