expr.h

由matlab开发的hybrid系统的描述语言

/*
	HYSDEL
	Copyright (C) 1999-2002  Fabio D. Torrisi

	This file is part of HYSDEL.
    
	HYSDEL 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.

	HYSDEL 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 library; if not, write to the Free Software
	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

	CONTACT INFORMATION
	===================
	Fabio D. Torrisi
	ETH Zentrum
	Physikstrasse. 3 ETL,
	CH-8032 Zurich
	Switzerland
	mailto:[e-mail] (preferred)
*/

#ifndef D_EXPR
#define D_EXPR
#ifndef STD_NS
#define STD_NS
using namespace std;
#endif
#include <string>
#include <list>
class CNF_clause;
class Affine_func;
class Symbol;
class Number;
class Item;
class Globals;

/** describes an Expression. The structure corresponds to the parse tree
 * of the expression. Note that also simple constants are expressions. */
class Expr {
public:
	Expr(const Globals * glob) { globals = glob; }

	Expr(const Expr * e) { globals = e->globals; }

	virtual ~Expr() { }

	/** returns a copy of the Item. copying is done deep, i.e. children
	 * are cloned recursively */
	virtual Expr * clone() const = 0;

	/** produce and collect all the Items this Expression wants to unroll */
	virtual list < Item * > unroll() = 0;


	/** translate the expression into CNF-representation.
	 * Raises an error if not is_logic(). */
	virtual CNF_clause * compute_CNF() const = 0;

	/** checks whether the expression is a logic expression (i.e.
	 * whether the expression is either true or false). */
	virtual bool is_logic() const = 0;

	/** translate the expression into the affine-representation. The
	 * variables are real state, input or auxiliary variables.<BR>
	 * Raises an error if not is_affine(). */
	virtual Affine_func * compute_affine() const {
		assert(0);
		return 0;
	};

	/** check if expression can be transformed into an Affine_func. */
	virtual bool is_affine() const {
		assert(0);
		return 0;
	}

	/** returns true iff value does not contain any symbolic parameters */
	virtual bool is_symbolic() const = 0;

	/** instanceof Variable_expr */
	virtual bool is_variable_expr() const { return false; }

	virtual bool is_parameter_expr() const { return false; }

	virtual bool is_unary_expr() const { return false; }

	virtual bool is_binary_expr() const { return false; }

	/** returns true if the expression does not contain any variables. */
	virtual bool is_const() const = 0;

	/** write the expression in Matlab-readable form. */
	virtual string to_matlab() const {
		assert(0);
		return 0;
	}

	/** returns true if the expression is a real value (i.e. contains
	 * no logic variables\operations). */
	virtual bool is_real() const = 0;

	/** check whether the Expression is semantically correct, i.e.
	 * whether all logic/real operators have logic/real arguments,
	 * no OUTPUT var used */
	virtual void semantic_checks() = 0;

	/** perform argument range checks: For numeric arguments do it
	 * immediately, for symbolic arguments produce matlab code */
	virtual string arg_range_check_matlab() const = 0;

	/** return true, iff the expression can by represented as a
	 * Number, i.e. it contains no variables and no symbolic parameters. */
	virtual bool is_number() const = 0;

	virtual bool is_neg_expr() const {return false;}

	/** if is_number, evaluate the expression by executing the
	 * operations (evalf in Maple)  */
	virtual Number * compute_number() const = 0;

	/** does the job of "instanceof Not_expr", needed by DA_item */
	virtual bool is_not_expr() const { return false; }

	void set_source(string s) { source = s; }

	void set_source_line(int i) { source_line = i; }

	string get_source() const { return source; }

	int get_source_line() const { return source_line; }

	const Globals * get_globals() const { return globals; }

	virtual void simplify()=0;
	
	/** return simplified input, delete in */
	static Expr* simpl(Expr *in);

	bool is_one() const;
	bool is_zero() const;

protected:
	virtual Expr * shallow_copy() const = 0;

	const Globals * globals;

	string source;

	int source_line;

};
#endif //D_EXPR