#ifndef EXPRESSION_H_INCLUDED
#define EXPRESSION_H_INCLUDED

#include <iostream>
#include <sstream>
#include <string>
#include <math.h>
#include <map>
#include <set>

using namespace std;

extern string string_from_double(double val);

class Expression {
    protected:
        string _nom;
    private:
        static set<Expression*> _pool;
    public:
        /* applique itérativement l'operateur delete au premier element
        du pool tant que le pool n’est pas vide */
        static void toutLiberer();
    public:
        Expression(const string& nom);
        virtual ~Expression();
        virtual double eval() const = 0;
        virtual string str() const;
        friend ostream& operator<<(ostream& os, const Expression& exp) {
            return os << exp.str();
        }
};

class Constante : public Expression {
    double _value;
    public:
        Constante(double val);
        virtual double eval() const;
};

class Unaire : public Expression {
    protected:
        Expression *_op;
    public:
        Unaire(const string& nom, Expression* op);
        virtual double eval() const = 0;
        virtual string str() const;
};

class Cos : public Unaire {
    public:
        Cos(Expression* op);
        double eval() const;
};

class Sin : public Unaire {
    public:
        Sin(Expression* op);
        double eval() const;
};

#endif // EXPRESSION_H_INCLUDED