mathlex.h

这是在wince下面可以跑的一个画函数的软件

//
//	Graphite For WinCE(Pocket PC)
//  Initially Written By Hyouck "Hawk" Kim, [e-mail]
//	2002, All Rights Reserved
//
//	This is GPLed, open source based, software development project.
//	For more question about GPL,
//	visit http://www.gnu.org/licenses/gpl.txt
//
//	
//	Revision History
//	Nov/30/2002,		Initial Release		hkim	
//
//

#pragma once

typedef enum mathTokenType
{
	MATH_TOKEN_TYPE_OP,
	MATH_TOKEN_TYPE_VAR,
	MATH_TOKEN_TYPE_NUM,
	MATH_TOKEN_TYPE_FUNC,
	MATH_TOKEN_TYPE_OPENING_PAREN,
	MATH_TOKEN_TYPE_CLOSING_PAREN,
	MATH_TOKEN_TYPE_UNRECOGNIZED,
} MathTokenType;

class CMathToken
{
public:
	CMathToken(CString& str, MathTokenType type);
	CMathToken(const CMathToken& rhs);
public:
	CString			m_str;
	MathTokenType	m_type;
};

class CMathLex
{
public:
	CMathLex(CString& str);
	~CMathLex(void);
	CMathToken*	 getNextToken(void);
private:
	CString		m_input;
	int			m_ndx;
public:
	bool isReservedFunc(CString& str);
};

/*	This is our parser syntax
    On WINCE, we don't have lex and yacc yet.
	So, till we port it to WinCE,
	we gotta hand code it.

arith: expr
;

expr:	term moreterms
;

term:	factor morefactors
;

moreterms:	'+'	term { push(+) } moreterms
	|		'-' term { push(-) } moreterms
	|		empty
;

factor:	( expr )
	|	var			{ push(id)	}
	|	num			{ push(var)	}
	|	func_term { push(func) } "(" expr ")"
;

morefactors: '*' factor { push(*) } morefactors
	|		 '/' factor { push(/) } morefactors
	|		 empty
;

func_term:	"sin" | "cos" | "tan"
;

*/
class CTokenList;

class CMathParser
{
public:
	CMathParser(CString& str, CTokenList* list);
	bool parse(void);
protected:
	void arith(void);
	void expr(void);
public:
	void factor(void);
	void term(void);
	bool match(CString& str);
	CString			m_errString;
	CTokenList*		m_list;
private:
	CMathLex	m_scanner;
	bool		m_success;
	CMathToken*	m_lookahead;
	CTokenList*	m_tokenParsed;
};