parser.cpp

一个简单的图形解释语言编译程序,使用visual C++ 6.0开发

// Parser.cpp: implementation of the CParser class.
//
//////////////////////////////////////////////////////////////////////

#include "stdafx.h"
#include "Parser.h"
#include <stdio.h>
#include <stdarg.h>
#include <windows.h>
#include <wingdi.h>


#define enter(x) 
#define back(x)  
#define Tree_trace(x)  
#define call_match(x)  
#define color RGB(0,0,0) 
//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

CParser::CParser()
{

}

CParser::~CParser()
{

}
void CParser::Parser(char *FileName,HDC hDC)
{
	hdc = hDC;
	enter("Parser");
	if(!mylex.InitLex(FileName))
	{
		MessageBox(NULL,"Cannot Open Source File!\n","Wrong!",MB_OK);
		return;
	}
	FetchToken();
	Program();
	mylex.CloseLex();
	back("Parser");
}
void CParser::FetchToken()
{
	m_token = mylex.GetToken();
	if(m_token.type == ERRTOKEN)
		SyntaxError(1);
}
void CParser::SyntaxError(int caseof)
{
	switch(caseof)
	{
	case 1:ErrMsg(mylex.m_LineNo,"错误记号：",m_token.lexeme);break;
	case 2:ErrMsg(mylex.m_LineNo,"不是预期记号：",m_token.lexeme);break;
	}
}
void CParser::ErrMsg(int LineNo,char *descrip,char *str)
{

	char msg[256];
	memset(msg,0,256);
	sprintf(msg,"Line No %5d:%s %s!",LineNo,descrip,str);

	MessageBox(NULL,msg,"error",MB_OK);

	mylex.CloseLex();
	
}

void CParser::Program()
{
	enter("Program");
	while(m_token.type != NONTOKEN)
	{
		Statement();
		MatchToken(SEMICO);
	}
	back("Program");
}

void CParser::Statement()
{
	enter("Statement");
	switch(m_token.type)
	{
	case ORIGIN:OrignStatement();break;
	case SCALE:ScaleStatement();break;
	case ROT:RotStatement();break;
	case FOR:ForStatement();break;
	default:SyntaxError(2);break;
	}
	back("Statement");
}
void CParser::MatchToken(enum Token_Type tokentype)
{
	if(m_token.type != tokentype)
		SyntaxError(2);
	FetchToken();
}

void CParser::OrignStatement()
{
	struct  ExprNode * tmp;
	enter("OrignStatement");
	MatchToken(ORIGIN);
	MatchToken(IS);
	MatchToken(L_BRACKET);
	tmp = Expression();
	

	Origin_x = GetExprValue(tmp);
	DelExprTree(tmp);


	MatchToken(COMMA);
	tmp = Expression();


	Origin_y = GetExprValue(tmp);
	DelExprTree(tmp);

	MatchToken(R_BRACKET);
	back("OrignStatement");

}

ExprNode *CParser::Expression()
{
	struct ExprNode *left,*right;
	Token_Type token_tmp;
	enter("Expression");
	left = Term();
	while((m_token.type == PLUS) || (m_token.type == MINUS))
	{
		token_tmp = m_token.type;
		MatchToken(token_tmp);
		right = Term();
		left = MakeExprNode(token_tmp,left,right);
	}
	Tree_trace(left);
	back("Exprssion");
	return left;
}
ExprNode *CParser::Term()
{
	struct ExprNode *left,*right;
	Token_Type token_tmp;
	left = Factor();
	while((m_token.type == MUL) || (m_token.type == DIV))
	{
		token_tmp = m_token.type;
		MatchToken(token_tmp);
		right = Factor();
		left = MakeExprNode(token_tmp,left,right);
	}

	return left;

}
ExprNode * CParser::Factor()
{
	struct ExprNode *left,*right;
	if(m_token.type == PLUS)
	{
		MatchToken(PLUS);
		right = Factor();
	}
	else if(m_token.type == MINUS)
	{
		MatchToken(MINUS);
		right = Factor();
		left = new ExprNode;
		left->OpCode = CONST_ID;
		left->Content.CaseConst = 0.0;
		right = MakeExprNode(MINUS,left,right);
	}
	else right = Comp();
	return right;
}

ExprNode* CParser::Comp()
{
	struct ExprNode *left,*right;
	left = AtomComp();
	if(m_token.type == POWER)
	{
		MatchToken(POWER);
		right = Comp();
		left = MakeExprNode(POWER,left,right);

	}
	return left;
}

struct ExprNode * CParser::AtomComp()
{
	struct Token t = m_token;
	struct ExprNode *address,*tmp;
	switch(t.type)
	{
	case CONST_ID:
		MatchToken(CONST_ID);
		address = MakeExprNode(CONST_ID,t.value);
		break;
	case L_BRACKET:
		MatchToken(L_BRACKET);
		address = Expression();
		MatchToken(R_BRACKET);
		break;
	case T:
		MatchToken(T);
		address = MakeExprNode(T);
		break;
	case FUNC:
		MatchToken(FUNC);
		MatchToken(L_BRACKET);
		tmp = Expression();
		address = MakeExprNode(FUNC,t.FuncPtr,tmp);
		MatchToken(R_BRACKET);
		break;
	default:
		SyntaxError(2);
		break;

	}
	return address;
}

struct ExprNode * CParser::MakeExprNode(enum Token_Type opcode,...)
{
	struct ExprNode*ExprPtr = new ExprNode;
	ExprPtr->OpCode = opcode;
	va_list ArgPtr;
	va_start(ArgPtr,opcode);
	switch(opcode)
	{
	case CONST_ID:
		ExprPtr->Content.CaseConst = (double)va_arg(ArgPtr,double);
		break;
	case T:
		ExprPtr->Content.CaseParmPtr = &Parameter;
		break;
	case FUNC:
		ExprPtr->Content.CaseFunc.MathFuncPtr = (FuncPtr)va_arg(ArgPtr,FuncPtr);
		ExprPtr->Content.CaseFunc.Child = (ExprNode*)va_arg(ArgPtr,ExprNode *) ;
		break;
	default:
		ExprPtr->Content.CaseOperator.Left = (ExprNode*)va_arg(ArgPtr,ExprNode*);
		ExprPtr->Content.CaseOperator.Right = (ExprNode*)va_arg(ArgPtr,ExprNode*);
		
		break;
	}
	va_end(ArgPtr);
	return ExprPtr;
}

void CParser::PrintSyntaxTree(ExprNode*root,int indent)
{
	int tmp;
	for(tmp = 1;tmp <= indent;tmp++)
	{
		printf("\t");
	}
	switch(root->OpCode)
	{
	case PLUS:printf("%s\n","+");break;
	case MINUS:printf("%s\n","-");break;
	case MUL:printf("%s\n","*");break;
	case DIV:printf("%s\n","/");break;
	case POWER:printf("%s\n","**");break;
	case FUNC:printf("%x\n",root->Content.CaseFunc.MathFuncPtr);
		break;
	case CONST_ID:printf("%f\n",root->Content.CaseConst);break;
	case T:printf("%s\n","T");break;
	default:printf("Error Tree Node!\n");break;
	}
	if(root->OpCode == CONST_ID || root->OpCode == T)
		return;
	if(root->OpCode == FUNC)
		PrintSyntaxTree(root->Content.CaseFunc.Child,indent+1);
	else
	{
		PrintSyntaxTree(root->Content.CaseOperator.Left,indent+1);
		PrintSyntaxTree(root->Content.CaseOperator.Right,indent+1);
	}
}

void CParser::DelExprTree(ExprNode*root)
{
	if(root)
	{
		switch(root->OpCode)
		{
		case PLUS:
		case MUL:
		case MINUS:
		case DIV:
		case POWER:
			DelExprTree(root->Content.CaseOperator.Left);
			DelExprTree(root->Content.CaseOperator.Right);
			break;
		case FUNC:
			DelExprTree(root->Content.CaseFunc.Child);
			break;
		default:break;
		}
		delete(root);
	}
}

double CParser::GetExprValue(ExprNode *root)
{
	if(NULL == root)
		return 0.0;
	switch(root->OpCode)
	{
	case PLUS:
		return GetExprValue(root->Content.CaseOperator.Left) + 
			GetExprValue(root->Content.CaseOperator.Right);
		break;
	case MINUS:
		return GetExprValue(root->Content.CaseOperator.Left) - 
			GetExprValue(root->Content.CaseOperator.Right);
		break;
	case MUL:
		return GetExprValue(root->Content.CaseOperator.Left) * 
			GetExprValue(root->Content.CaseOperator.Right);
		break;
	case DIV:
		return GetExprValue(root->Content.CaseOperator.Left) / 
			GetExprValue(root->Content.CaseOperator.Right);
		break;
	case POWER:
		return pow(GetExprValue(root->Content.CaseOperator.Left),
			GetExprValue(root->Content.CaseOperator.Right));
		break;
	case FUNC:
		return (*(root->Content.CaseFunc.MathFuncPtr))(GetExprValue(root->Content.CaseFunc.Child));
		break;
	case CONST_ID:
		return root->Content.CaseConst;
		break;
	case T:
		return *(root->Content.CaseParmPtr);
		break;
	default :return 0.0;
	
	}
}

void CParser::ScaleStatement(void)
{
	struct ExprNode*tmp;
	enter("ScaleStatement");
	MatchToken(SCALE);
	MatchToken(IS);
	MatchToken(L_BRACKET);
	tmp = Expression();
	Scale_x = GetExprValue(tmp);
	DelExprTree(tmp);
	MatchToken(COMMA);
	tmp = Expression();
	Scale_y = GetExprValue(tmp);
	DelExprTree(tmp);
	MatchToken(R_BRACKET);
	back("ScaleStatement");

}

void CParser::RotStatement(void)
{
	struct ExprNode*tmp;
	enter("RotStatement");
	MatchToken(ROT);
	MatchToken(IS);
	tmp = Expression();
	Rot_angle = GetExprValue(tmp);
	DelExprTree(tmp);
	back("RotStatement");
}

void CParser::ForStatement(void)
{
	double Start,End,Step;
	struct ExprNode *start_ptr,*end_ptr,*step_ptr,*x_ptr,*y_ptr;
	enter("ForStatement");
	MatchToken(FOR);call_match("FOR");
	MatchToken(T);call_match("T");
	MatchToken(FROM);call_match("FROM");
	start_ptr = Expression();
	Start = GetExprValue(start_ptr);
	DelExprTree(start_ptr);
	MatchToken(TO);call_match("TO");
	end_ptr = Expression();
	End = GetExprValue(end_ptr);
	DelExprTree(end_ptr);
	MatchToken(STEP);call_match("STEP");
	step_ptr = Expression();
	Step = GetExprValue(step_ptr);
	DelExprTree(step_ptr);
	MatchToken(DRAW);call_match("DRAW");
	MatchToken(L_BRACKET);call_match("(");
	x_ptr = Expression();
	MatchToken(COMMA);call_match(",");
	y_ptr = Expression();
	MatchToken(R_BRACKET);call_match(")");
	DrawLoop(Start,End,Step,x_ptr,y_ptr);
	DelExprTree(x_ptr);
	DelExprTree(y_ptr);
	back("ForStatement");
}

void CParser::DrawLoop(double Start,double End,double Step,
					   ExprNode*HorPtr,ExprNode*VerPtr)
{
	
	for(Parameter = Start;Parameter <= End;Parameter += Step)
	{
		
		CalcCoord(HorPtr,VerPtr);
		DrawPixel();
	}
}

void CParser::CalcCoord(ExprNode*Hor_Exp,ExprNode*Ver_Exp)
{
	double HorCord,VerCord,tmp;
	double cx,cy;
	HorCord = GetExprValue(Hor_Exp);
	VerCord =GetExprValue(Ver_Exp);
	HorCord *= Scale_x;
	VerCord *= Scale_y;
	tmp = HorCord*cos(Rot_angle) + VerCord * sin(Rot_angle);
	VerCord = VerCord*cos(Rot_angle) - HorCord*sin(Rot_angle);
	HorCord = tmp;
	cx = 2*HorCord + Origin_x;
	cy = 2*VerCord + Origin_y;
	x = cx;
	y = cy;
	

}

void CParser::DrawPixel()
{
	SetPixel(hdc,(int)x,(int)y,color);
}