include/basix/evaluator.hpp

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/******************************************************************************
* MODULE     : evaluator.hpp
* DESCRIPTION: Abstract evaluators for symbolic expressions
* COPYRIGHT  : (C) 2006  Joris van der Hoeven
*******************************************************************************
* This software falls under the GNU general public license and comes WITHOUT
* ANY WARRANTY WHATSOEVER. See the file $TEXMACS_PATH/LICENSE for more details.
* If you don't have this file, write to the Free Software Foundation, Inc.,
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
******************************************************************************/

#ifndef __EVALUATOR_HPP
#define __EVALUATOR_HPP
#include <basix/exception.hpp>
#include <basix/lisp_syntax.hpp>


namespace mmx {
class evaluator_rep;
class evaluator;

#define PENALTY_NONE             ((nat) 0)
#define PENALTY_AUTOMATIC        ((nat) 1)
#define PENALTY_INCLUSION        ((nat) 2)
#define PENALTY_HOMOMORPHISM     ((nat) 3)
#define PENALTY_VARIANT          ((nat) 4)
#define PENALTY_CAST             ((nat) 5)
#define PENALTY_FALL_BACK        ((nat) 6)
#define PENALTY_PROMOTE_GENERIC  ((nat) 7)
#define PENALTY_INVALID          ((nat) 8)

class evaluator_rep: public rep_struct {
public:
  virtual void* get_internal_data () const;
  virtual void set (const generic& var, const generic& val) const;
  virtual void reset (const generic& var) const;
  virtual void overload (const generic& var, const generic& val,
                         nat penalty= PENALTY_INCLUSION) const;
  virtual bool contains (const generic& var) const;
  virtual generic get (const generic& var) const;
  virtual bool get (const generic& var, generic& val) const;

  virtual generic eval (const generic& x) const;
  virtual generic construct (const generic& x) const;
  virtual generic apply (const generic& fun) const;
  virtual generic apply (const generic& fun, const generic& x1) const;
  virtual generic apply (const generic& fun,
                         const generic& x1, const generic& x2) const;
  virtual generic apply (const generic& fun, const vector<generic>& a) const;

public:
  inline evaluator_rep () {}
  inline virtual ~evaluator_rep () {}
  friend class evaluator;
};

class evaluator {
INDIRECT_PROTO (evaluator, evaluator_rep)
public:
  inline evaluator (): rep (new evaluator_rep ()) {}
  friend class evaluator_rep;
};
INDIRECT_IMPL (evaluator, evaluator_rep)

extern evaluator current_ev;

void select_evaluator (const evaluator& ev);
void restore_evaluator ();

} // namespace mmx
#endif // __EVALUATOR_HPP

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