recursive.java

这个是java版本的pl0语言的词法分析器,带有图形界面,很好的

package myCompiler;

import java.util.ArrayList;
import java.util.Stack;
import java.util.Vector;

public class Recursive {
	int CONST = 1;
	int VAR = 2;
	int PROCEDURE = 3;
	int IF = 4;
	int THEN = 5;
	int WHILE = 6;
	int DO = 7;
	int READ = 8;
	int WRITE = 9;
	int BEGIN = 10;
	int END = 11;
	int CALL = 12;
	int ODD = 13;
	int ADD = 14;
	int SUB = 15;
	int MUL = 16;
	int DIV = 17;
	int EQU = 18;
	int NEQ = 19;
	int LES = 20;
	int LEQ = 21;
	int LAG = 22;
	int GEQ = 23;
	int DOT = 24;
	int COM = 25;
	int SEM = 26;
	int ASS = 27;
	int LBR = 28;
	int RBR = 29;
	int INT = 30;
	int ID = 31;
	int EIN = 32;
	GetWords getwords;
	SYM sym;
	  String name;
	  String previous;

	Stack tbl=new Stack();
	Vector alltbls=new Vector();
	ArrayList alist;
	Header hdr;
	int LEV = -1;
	int DX;
    int line;
     
	Construct cstruct;
	Varstruct vstruct;
	Procstruct pstruct;
	public Recursive(String SourceFileName) {

		getwords = new GetWords(SourceFileName);
	}

	ArrayList makeTable(String previous,String name){
		Header header=new Header(previous,name);
		ArrayList arraylist=new ArrayList();
		arraylist.add(header);
		return arraylist;
	}
	Construct makeConstruct(String name,int value){
		Construct cstruct=new Construct(name,value);
		return cstruct;
	}
	Varstruct makeVarstruct(String name,int level,int adr){
		Varstruct vstruct=new Varstruct(name,level,adr);
		return vstruct;
	}
	Procstruct makeProcstruct(String name,int level){
		Procstruct pstruct=new Procstruct(name,level);
		return pstruct;
	}
	
	void adrclear(){
		DX=0;
	}
	void adrincrease(){
		DX++;
	}
	void levincrease(){
		LEV++;
	}
	void levdiscrease(){
		LEV--;
	}
	void setline(int line){
		this.line=line;
	}
	public void getword() {
		getwords.getsym();
	
		sym = getwords.sym;
		setline(getwords.line);
		System.out.print(sym.name);
		System.out.print(" " + sym.code);
		System.out.println(" "+line);
	}

	public void print(Object object) {

		if (object instanceof Construct) {

			System.out.println(((Construct) object).name + "      "
					+ ((Construct) object).kind + "      "
					+ ((Construct) object).value);

		} else if (object instanceof Varstruct) {

			System.out.println(((Varstruct) object).name + "      "
					+ ((Varstruct) object).kind + "      "
					+ ((Varstruct) object).level + "             "
					+ ((Varstruct) object).adr);

		} else if (object instanceof Procstruct) {

			System.out.println(((Procstruct) object).name + "      "
					+ ((Procstruct) object).kind + "     "
					+ ((Procstruct) object).level + "             "
					+ ((Procstruct) object).adr);

		}
	}

	public static void main(String args[]) {
		String s = "e:/pl0_1.txt";

		Recursive rr = new Recursive(s);

		rr.getword();

		rr.program();

		Object object;
ArrayList aa;
Header h;
		System.out.println("Name   Kind          Value/Level   Address");

		for(int i=0;i<rr.alltbls.size();i++){
			aa=(ArrayList) rr.alltbls.get(i);
			h=(Header) aa.get(0);
			System.out.println("==========================================");
			System.out.println(h.name+"  "+h.previous);
		  for (int j=1;j<aa.size();j++){
			  object=aa.get(j);
			  rr.print(object);
		  }
		}
	}

	public void program() {

		
		 alist=this.makeTable(null, "program");
          tbl.push(alist);
          alltbls.add(alist);
		block();

		if (sym.code == DOT) {

			getword();
		}else {
			Error2.error(line,"缺少 .");
		}

	}

	public void block() {

		levincrease();
		adrclear();
		
		conststatement();
		varstatement();
		procstatement();
		sentence();
	}

	public void conststatement() {

		if (sym.code == CONST) {

			getword();
			constdefine();
			constsuffix();
			if (sym.code == SEM) {

				getword();

			}

		}
	}

	public void constdefine() {
     
     
		if (sym.code == ID) {
            name=sym.name;
			
			getword();
			if (sym.code == EQU) {

				getword();
				if (sym.code == INT) {
					cstruct=makeConstruct(name,sym.code);
					alist=(ArrayList) tbl.pop();
					alist.add(cstruct);
					tbl.push(alist);
					//constvalue();
					getword();
				} else
					Error2.error(line,"缺少整数!");
			} else
				Error2.error(line,"缺少标识符!");
		} else
			Error2.error(line,"多余的CONST!");
	}

	public void constsuffix() {

		if (sym.code == COM) {

			getword();
			constdefine();
			constsuffix();
			if (sym.code == SEM) {
				getword();

			} else
				Error2.error(line,"缺少分号!");
		}
	}

	public void varstatement() {

		if (sym.code == VAR) {

			getword();
			if (sym.code == ID) {
				adrincrease();
				vstruct=makeVarstruct(sym.name,LEV,DX);
				alist=(ArrayList) tbl.pop();
				alist.add(vstruct);
				tbl.push(alist);
				//varadd();
				getword();
				identsuffix();
				if (sym.code == SEM)
					getword();
				else
					Error2.error(line,"缺少分号!");
			} else
				Error2.error(line,"多余的VAR");

		}
	}

	public void identsuffix() {

		if (sym.code == COM) {

			getword();

			if (sym.code == ID) {
				//varadd();
				adrincrease();
				vstruct=makeVarstruct(sym.name,LEV,DX);
				alist=(ArrayList) tbl.pop();
				alist.add(vstruct);
				tbl.push(alist);
				
				getword();

				identsuffix();
			} else
				Error2.error(line,"多余的逗号!");
		}

	}

	public void procstatement() {

		if (sym.code == PROCEDURE) {

			prochead();

			block();
			if (sym.code == SEM) {
               tbl.pop();
               levdiscrease();
				getword();
				procsuffix();
			} else
				Error2.error(line,"缺少分号!");
		}
	}

	public void prochead() {
		if (sym.code == PROCEDURE) {

			getword();
			if (sym.code == ID) {
                pstruct=this.makeProcstruct(sym.name, LEV);
                alist=(ArrayList) tbl.pop();
                alist.add(pstruct);
                tbl.push(alist);
                hdr=(Header) alist.get(0);
                previous=hdr.name;
                name=sym.name;
                alist=this.makeTable(previous, name);
                tbl.push(alist);
                alltbls.add(alist);
				//procadd();
				getword();
				if (sym.code == SEM) {

					getword();
				} else
					Error2.error(line,"缺少分号!");
			} else
				Error2.error(line,"缺少过程名称!");
		}
		else Error2.error(line,"缺少过程声明!");
	}

	public void procsuffix() {
		if (sym.code == PROCEDURE) {
			prochead();
			block();
			if (sym.code == SEM) {
				 tbl.pop();
	               levdiscrease();
				getword();
				procsuffix();
			} else
				Error2.error(line,"缺少分号!");
		}
	}

	public void sentence() {

		if (sym.code == ID) 
			assinsent();
		else if (sym.code == IF)
			ifsent();
		else if (sym.code == WHILE)
			whilesent();
		else if (sym.code == CALL)
			callsent();
		else if (sym.code == READ)
			readsent();
		else if (sym.code == WRITE)
			writesent();
		else if (sym.code == BEGIN)
			complsent();
	}

	public void assinsent() {

		if (sym.code == ID) {

			getword();

			if (sym.code == ASS) {

				getword();
				express();
			} else
				Error2.error(line,"缺少赋值号!");
		} else
			Error2.error(line,"多余的赋值号!");
	}

	public void ifsent() {

		if (sym.code == IF) {

			getword();
			condition();
			if (sym.code == THEN) {

				getword();
				sentence();
			} else
				Error2.error(line,"缺少then");
		} else
			Error2.error(line,"多余的IF!");
	}

	public void whilesent() {

		if (sym.code == WHILE) {

			getword();
			condition();
			if (sym.code == DO) {

				getword();
				sentence();
			} else
				Error2.error(line,"缺少while!");

		} else
			Error2.error(line,"多余的while!");
	}

	public void callsent() {
		if (sym.code == CALL) {
			getword();
			if (sym.code == ID)
				getword();
			else
				Error2.error(line,"call语句缺少参数!");
		} else
			Error2.error(line,"多余的call!");
	}

	public void readsent() {

		if (sym.code == READ) {

			getword();
			if (sym.code == LBR) {

				getword();
				if (sym.code == ID) {

					getword();
					identsuffix();
					if (sym.code == RBR) {

						getword();

					} else
						Error2.error(line,"缺少右括号");
				} else
					Error2.error(line,"缺少参数!");
			} else
				Error2.error(line,"缺少左括号!");
		} else
			Error2.error(line,"多余的Read!");
	}

	public void writesent() {

		if (sym.code == WRITE) {

			getword();
			if (sym.code == LBR) {

				getword();

				express();
				exprsuffix();

				if (sym.code == RBR) {

					getword();

				} else
					Error2.error(line,"缺少右括号");

			} else
				Error2.error(line,"缺少参数!");
		} else
			Error2.error(line,"多余的write");
	}

	public void complsent() {

		if (sym.code == BEGIN) {

			getword();
			sentence();
			sentsuffix();
			if (sym.code == END) {

				getword();
			} else
				Error2.error(line,"缺少end");
		} else
			Error2.error(line,"多余的begin");
	}

	public void sentsuffix() {

		if (sym.code == SEM) {

			getword();
			sentence();
			sentsuffix();
		}

	}

	public void condition() {

		if (sym.code == ODD) {

			getword();
			express();
		} 
		else {
			express();
			respoperater();
			express();
		}

	}

	public void exprsuffix(){
	
		if(sym.code==COM){
			
			getword();
			express();
			exprsuffix();
		}
	}
	public void express() {

		if (sym.code == ADD | sym.code == SUB)
         		getword();
		term();
		termsuffix();

	}

	public void termsuffix() {

		if (sym.code == ADD | sym.code == SUB) {

			addoperater();
			term();
			termsuffix();
		}
	}

	public void term() {

		factor();
		factorsuffix();
	}

	public void factorsuffix() {

		if (sym.code == MUL | sym.code == DIV) {

			muloperater();
			factor();
			factorsuffix();
		}
	}

	public void factor() {

		if (sym.code == ID) {

			getword();

		} else if (sym.code == INT) {

			getword();

		} else if (sym.code == LBR) {

			getword();
			express();
			if (sym.code == RBR) {

				getword();
			} else
				Error2.error(line,"缺少右括号!");
		} else
			Error2.error(line,"缺少左括号!");
	}

	public void addoperater() {

		if (sym.code == ADD | sym.code == SUB) {
			getword();

		} else
			Error2.error(line,"缺少加减运算符!");
	}

	public void muloperater() {

		if (sym.code == MUL | sym.code == DIV) {

			getword();
		} else
			Error2.error(line,"缺少乘除运算符!");
	}

	public void respoperater() {
		if (sym.code >= EQU && sym.code <= GEQ) {

			getword();
		} else
			Error2.error(line,"缺少关系运算符!");
	}
}