named_expression.hpp

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//This file is part of Bertini 2.
//
//bertini2/function_tree/roots/named_expression.hpp is free software: you can redistribute it
//and/or modify it under the terms of the GNU General Public License as published by the Free
//Software Foundation, either version 3 of the License, or (at your option) any later version.
//
//bertini2/function_tree/roots/named_expression.hpp is distributed in the hope that it will be
//useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
//FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
//
//You should have received a copy of the GNU General Public License along with
//bertini2/function_tree/roots/named_expression.hpp.  If not, see <http://www.gnu.org/licenses/>.
//
// Copyright(C) Bertini2 Development Team
//
// See <http://www.gnu.org/licenses/> for a copy of the license,
// as well as COPYING.  Bertini2 is provided with permitted
// additional terms in the b2/licenses/ directory.

 
#ifndef BERTINI_NAMED_EXPRESSION_HPP
#define BERTINI_NAMED_EXPRESSION_HPP
 
#include "bertini2/function_tree/symbols/symbol.hpp"
 
namespace bertini {
namespace node{

    class NamedExpression : public NamedSymbol
    {
    public:
        BERTINI_DEFAULT_VISITABLE()
 
        
        template<typename... Ts>
        static
        std::shared_ptr<NamedExpression> Make(Ts&& ...ts){
            return std::static_pointer_cast<NamedExpression>(Intern(std::shared_ptr<Node>( new NamedExpression(ts...) )));
        }

        void print(std::ostream & target) const override
        {
            target << name();
        }
 
        // Hash-consed by (expression, name), so distinct names / expressions are distinct nodes.
        std::size_t HashImpl() const override
        {
            std::size_t h = typeid(NamedExpression).hash_code();
            HashCombine(h, EntryNode()->Hash());
            HashCombine(h, std::hash<std::string>{}(name()));
            return h;
        }
        bool IsSame(Node const& other) const override
        {
            auto o = dynamic_cast<NamedExpression const*>(&other);
            // entries are interned, so pointer identity is structural equality
            return o && name() == o->name() && EntryNode().get() == o->EntryNode().get();
        }

        void EnsureNotEmpty() const;


        const std::shared_ptr<Node>& EntryNode() const;

        std::shared_ptr<Node> Differentiate(std::shared_ptr<Variable> const& v = nullptr) const override;

        int Degree(std::shared_ptr<Variable> const& v = nullptr) const override;
        int Degree(VariableGroup const& vars) const override;
 
        std::vector<int> MultiDegreeImpl(VariableGroup const& vars) const override;
 
        std::shared_ptr<Node> Homogenized(VariableGroup const& vars, std::shared_ptr<Variable> const& homvar) const override;
 
        std::shared_ptr<Node> Subs(SubstitutionMap const& substitutions) const override;
 
        bool IsHomogeneous(std::shared_ptr<Variable> const& v = nullptr) const override;
        bool IsHomogeneous(VariableGroup const& vars) const override;

 
        virtual ~NamedExpression() = default;
 
    protected:
        NamedExpression() = default;
 
 
        std::shared_ptr<Node> entry_node_ = nullptr;  
 
    private:
        NamedExpression(std::shared_ptr<Node> const& entry, std::string const& name)
            : NamedSymbol(name), entry_node_(entry)
        {}
 
        friend class boost::serialization::access;
 
        template <typename Archive>
        void serialize(Archive& ar, const unsigned /*version*/) {
            ar & boost::serialization::base_object<NamedSymbol>(*this);
            ar & entry_node_;
        }
    };

    inline std::shared_ptr<NamedExpression> Named(std::shared_ptr<Node> const& expr, std::string const& name)
    {
        return NamedExpression::Make(expr, name);
    }
 
} // re: namespace node
} // re: namespace bertini
 
#endif