syntaxtree.cpp

2006-04-17 作者：ideawu Document for: 用C++语言手工编写的词法分析器,语法分析器。

/************************************************************
* file: SyntaxTree.cpp
* date: 2006-04-12
* author: wuzuyang
* describe: none; SyntaxTree
*************************************************************/

#include <stdio.h>
#include <string.h>
#include "SyntaxTree.h"


char* tokenToString(TokenType type);

/*======================================================================*/

SyntaxTree::SyntaxTree(TokenType t, int val){
	root = new SyntaxTreeNode(t, val);
}
SyntaxTree::SyntaxTree(SyntaxTreeNode *n){
	setRootNode(n);
}
SyntaxTree::SyntaxTree(SyntaxTree *tree){
	setRootNode(tree->getRootNode());
}
SyntaxTree::SyntaxTree(){
	setRootNode();
}

SyntaxTree::~SyntaxTree(){
	if(root != NULL){
		delete root;
	}
}

/*====================================================================*/

void SyntaxTree::display(SyntaxTreeNode *n, int tabcount, FILE *fo){
	static int tab[200];	// is it enough?
	
	SyntaxTreeNode * node = n;
	if(node == NULL) return;
	
	if(node->type == NUM){
		fprintf(fo, "%-3d", node->value);
	}else{
		fprintf(fo, "%-3s", tokenToString(node->type));
	}
		
	if(node->left != NULL){
		tab[tabcount] = 1;
	}
	
	if(node->right != NULL){
		fprintf(fo, "---");
		this->display(node->right, tabcount + 1, fo);
	}
	
	if(node->left != NULL){
		fprintf(fo, "\n");
		for(int i=0;i<tabcount;i++){
			if(tab[i] == 1){
				fprintf(fo, "|%5s", "");
			}else{
				fprintf(fo, "%6s", "");
			}
		}
		fprintf(fo, "+-----");
		tab[tabcount] = 0;
		this->display(node->left, tabcount + 1, fo);
	}
	
}

void SyntaxTree::display(FILE *fo){
	if(fo == NULL){
		fo = stdout;
		printf("\nFILE* NULL, will write to STDOUT.\n\n");
	}
		
	fprintf(fo, "\n");
	this->display(root, 0, fo);
	fprintf(fo, "\n");
}


void SyntaxTree::setRootNode(TokenType t, int val){
	root = new SyntaxTreeNode(t, val);
}
void SyntaxTree::setRootNode(SyntaxTreeNode *n){
	if(n == NULL){
		root = new SyntaxTreeNode();
	}else{
		root = n;
	}
}
void SyntaxTree::setRootNode(){
	root = new SyntaxTreeNode();
}


void SyntaxTree::addLeft(TokenType t, int val){
	root->left = new SyntaxTreeNode(t, val);
}
void SyntaxTree::addLeft(SyntaxTree *n){
	if(n == NULL) return;
	root->left = n->getRootNode();
}


void SyntaxTree::addRight(TokenType t, int val){
	root->right = new SyntaxTreeNode(t, val);
}
void SyntaxTree::addRight(SyntaxTree *n){
	if(n == NULL) return;
	root->right = n->getRootNode();
}


void SyntaxTree::addChild3(TokenType t, int val){
	root->child3 = new SyntaxTreeNode(t, val);
}
void SyntaxTree::addChild3(SyntaxTree *n){
	if(n == NULL) return;
	root->child3 = n->getRootNode();
}


SyntaxTreeNode* SyntaxTree::getRootNode(){
	return root;
}


SyntaxTree* SyntaxTree::getLeft(){
	if(root->left == NULL)
		return NULL;
	else
		return new SyntaxTree(root->left);
}

SyntaxTree* SyntaxTree::getRight(){
	if(root->right == NULL)
		return NULL;
	else
		return new SyntaxTree(root->right);
}


SyntaxTree* SyntaxTree::getChild3(){
	if(root->child3 == NULL)
		return NULL;
	else
		return new SyntaxTree(root->child3);
}

/*==================================================================*/

char* tokenToString(TokenType type){
	char *s = NULL;
	switch(type){
		case ID:
			s = "ID";
			break;
		case NUM:
			s = "NUM";
			break;
		case IF:
			s = "if";
			break;
		case THEN:
			s = "thn";
			break;
		case ELSE:
			s = "els";
			break;
		case WHILE:
			s = "whl";
			break;
		case DO:
			s = "do";
			break;
		case BEGIN:
			s = "blk";
			break;
		case END:
			s = "end";	// "end"
			break;
		case ASSIGN:
			s = "'='";
			break;
		case EQ:
			s = "==";
			break;
		case LT:
			s = "'<'";
			break;
		case GT:
			s = "'>'";
			break;
		case PLUS:
			s = "'+'";
			break;
		case MUL:
			s = "'*'";
			break;
		case MINUS:
			s = "'-'";
			break;
		case DIV:
			s = "'/'";
			break;
		case OR:
			s = "'|'";
			break;
		case AND:
			s = "'&'";
			break;
		default:
			s = "undef";
	}
	return s;
}