/** @file ncmul.h
 *
 *  Interface to GiNaC's non-commutative products of expressions. */

/*
 *  GiNaC Copyright (C) 1999-2001 Johannes Gutenberg University Mainz, Germany
 *
 *  This program 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 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program 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 this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#ifndef __GINAC_NCMUL_H__
#define __GINAC_NCMUL_H__

#include "exprseq.h"

namespace GiNaC {

/** Non-commutative product of expressions. */
class ncmul : public exprseq
{
	GINAC_DECLARE_REGISTERED_CLASS(ncmul, exprseq)

	friend class power;
	friend ex nonsimplified_ncmul(const exvector & v);
	friend ex simplified_ncmul(const exvector & v);

// member functions

	// other constructors
public:
	ncmul(const ex & lh, const ex & rh);
	ncmul(const ex & f1, const ex & f2, const ex & f3);
	ncmul(const ex & f1, const ex & f2, const ex & f3,
	      const ex & f4);
	ncmul(const ex & f1, const ex & f2, const ex & f3,
	      const ex & f4, const ex & f5);
	ncmul(const ex & f1, const ex & f2, const ex & f3,
	      const ex & f4, const ex & f5, const ex & f6);
	ncmul(const exvector & v, bool discardable=false);
	ncmul(exvector * vp); // vp will be deleted

	// functions overriding virtual functions from base classes
public:
	void print(const print_context & c, unsigned level = 0) const;
	unsigned precedence(void) const {return 50;}
	bool info(unsigned inf) const;
	int degree(const ex & s) const;
	int ldegree(const ex & s) const;
	ex expand(unsigned options=0) const;
	ex coeff(const ex & s, int n=1) const;
	ex eval(int level=0) const;
	ex evalm(void) const;
	exvector get_free_indices(void) const;
	ex thisexprseq(const exvector & v) const;
	ex thisexprseq(exvector * vp) const;
protected:
	ex derivative(const symbol & s) const;
	unsigned return_type(void) const;
	unsigned return_type_tinfo(void) const;
	
	// new virtual functions which can be overridden by derived classes
	// none

	// non-virtual functions in this class
protected:
	unsigned count_factors(const ex & e) const;
	void append_factors(exvector & v, const ex & e) const;
	exvector expandchildren(unsigned options) const;
public:
	const exvector & get_factors(void) const;
};

// friend funtions 

ex nonsimplified_ncmul(const exvector & v);
ex simplified_ncmul(const exvector & v);

// utility functions

/** Return the ncmul object handled by an ex.  Deprecated: use ex_to<ncmul>().
 *  This is unsafe: you need to check the type first. */
inline const ncmul &ex_to_ncmul(const ex &e)
{
	return static_cast <const ncmul &>(*e.bp);
}

/** Specialization of is_exactly_a<ncmul>(obj) for ncmul objects. */
template<> inline bool is_exactly_a<ncmul>(const basic & obj)
{
	return obj.tinfo()==TINFO_ncmul;
}

} // namespace GiNaC

#endif // ndef __GINAC_NCMUL_H__