ResolveAnonymousRecordAliases.h

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/*
 * Souffle - A Datalog Compiler
 * Copyright (c) 2015, 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 ResolveAnonymousRecordAliases.h
 *
 ***********************************************************************/
 
#pragma once
 
#include "ast/Clause.h"
#include "ast/RecordInit.h"
#include "ast/TranslationUnit.h"
#include "ast/transform/Transformer.h"
#include <map>
#include <string>
 
namespace souffle::ast::transform {
 
/**
 * Transformer resolving aliases for anonymous records.
 *
 * The transformer works by searching the clause for equalities
 * of the form a = [...], where a is an anonymous record, and replacing
 * all occurrences of a with the RHS.
 *
 * The transformer is to be called in conjunction with FoldAnonymousRecords.
 **/
class ResolveAnonymousRecordAliasesTransformer : public Transformer {
public:
    std::string getName() const override {
        return "ResolveAnonymousRecordAliases";
    }
 
    ResolveAnonymousRecordAliasesTransformer* clone() const override {
        return new ResolveAnonymousRecordAliasesTransformer();
    }
 
private:
    bool transform(TranslationUnit& translationUnit) override;
 
    /**
     * Use mapping found by findVariablesRecordMapping to substitute
     * a records for each variable that operates on records.
     **/
    bool replaceNamedVariables(TranslationUnit&, Clause&);
 
    /**
     * For each variable equal to some anonymous record,
     * assign a value of that record.
     **/
    std::map<std::string, const RecordInit*> findVariablesRecordMapping(TranslationUnit&, const Clause&);
 
    /**
     * For unnamed variables, replace each equation _ op record with true.
     **/
    bool replaceUnnamedVariable(Clause&);
};
 
}  // namespace souffle::ast::transform