ll1parse.java

词法和语法分析器

package cminusCompiler;

import java.util.HashMap;
import java.util.LinkedList;
import java.util.Stack;

/**
 * @author tanfei E-mail:[e-mail]
 * @version Create Time：2007-12-9 上午09:51:11 description:
 */
public class LL1Parse {
	
	private HashMap<String, Integer> ter;
	
	private HashMap<String, Integer> nont;
	
	private Stack<InputLine> input = new Stack<InputLine>();
	
	private Stack<String> parse = new Stack<String>();
	
	private LinkedList[][] table;

	public LL1Parse(HashMap<String, Integer> ter, HashMap<String, Integer> nont,
			Stack<InputLine> input, Stack<String> parse, LinkedList[][] table) {
		this.ter = ter;
		this.nont = nont;
		this.input = input;
		this.parse = parse;
		this.table = table;
	}
	
	public void parseTheInput(boolean trace){
		boolean conti = true;
		while(loopCondition()){
			if(choiceCondition1()){
				System.out.println("Match: " + parse.peek() + " " + input.peek().getInputToken());
				parse.pop();
				input.pop();
			}else if(choiceCondition2()){
				generate(trace);
			}
			else{
				printError();
				conti = false;
				break;
			}
		}
		
		if(input.peek().getInputToken().equals("EOF")){
			System.out.println("No syntax error in the file!");
		}else if(conti){
			printError();
		}
	}
	
	private boolean loopCondition(){
		if(parse.isEmpty()){
			return false;
		}
		
		if(input.peek().getInputToken().equals("EOF")){
			return false;
		}
		
		return true;
	}
	
	private void generate(boolean trace){
		int i, j, count;
		String nonter;
		InputLine line;
		LinkedList tempList;
		nonter = parse.pop();
		line = input.peek();
		i = nont.get(nonter);
		j = ter.get(line.getInputToken());
		tempList = table[i][j];
		count = tempList.size() - 1;
		if(trace){
		System.out.println(nonter + ":");
		}
		for(; count >= 0; count--){
			parse.push((String) tempList.get(count));
			if(trace){
			System.out.print((String) tempList.get(count) + " ");
			}
		}
		check();
		if(trace){
		System.out.println();
		System.out.println("input stack top element: " + input.peek().getInputToken());
		}
		System.gc();
	}
	
	private void check(){
		if(parse.peek().equals("empty")){
			parse.pop();
		}
	}
	
	private boolean choiceCondition1(){
		String topParse;
		topParse = parse.peek();
		if(!ter.containsKey(topParse)){
			return false;
		}else if(input.peek().getInputToken().equals(topParse)){
			return true;
		}
		return false;			
	}
	
	private boolean choiceCondition2(){
		String topParse;
		LinkedList tempList;
		int i, j;
		topParse = parse.peek();
		if(!nont.containsKey(topParse)){
			return false;
		}else if(!ter.containsKey(input.peek().getInputToken())){
			return false;
		}else{
			i = nont.get(topParse);
			j = ter.get(input.peek().getInputToken());
			tempList = table[i][j];
			if(table[i][j].size() != 0){
				return true;
			}
		}
		return false;
	}
	
	private void printError(){
		InputLine line;
		int errorLine;
		line = input.peek();
		errorLine = line.getLineNo();
		System.out.println("Error in line: " + errorLine);
		//System.exit(1);
	}
	

}