Antlr 练习

下载 antlrWorks 2.1 和  antlr4.1

从网上找了个例子

grammar LabeledExpr; //  

prog:   stat+ ;

stat:   expr NEWLINE                # printExpr
    |   ID '=' expr NEWLINE         # assign
    |   NEWLINE                     # blank
    ;

expr:   expr op=('*'|'/') expr      # MulDiv
    |   expr op=('+'|'-') expr      # AddSub
    |   INT                         # int
    |   ID                          # id
    |   '(' expr ')'                # parens
    ;

MUL :   '*' ; // assigns token name to '*' used above in grammar
DIV :   '/' ;
ADD :   '+' ;
SUB :   '-' ;
ID  :   [a-zA-Z]+ ;      // match identifiers
INT :   [0-9]+ ;         // match integers
NEWLINE:'
'? '
' ;     // return newlines to parser (is end-statement signal)
WS  :   [ 	]+ -> skip ; // toss out whitespace

使用antlrworks的 run - 生成识别器 选择生成vistor

派生自己的vistor

package LabeledExpr.Imp;

/**
 * Created by IntelliJ IDEA.
 * User: han
 * Date: 14-1-22
 * Time: 下午2:12
 * To change this template use File | Settings | File Templates.
 */
import LabeledExpr.LabeledExprBaseVisitor;
import LabeledExpr.LabeledExprParser;

import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.Map;

public class EvalVisitor extends LabeledExprBaseVisitor<Integer> {
    /** "memory" for our calculator; variable/value pairs go here */
    Map<String, Integer> memory = new LinkedHashMap<String, Integer>();



    /** ID '=' expr NEWLINE */
    @Override
    public Integer visitAssign(LabeledExprParser.AssignContext ctx) {
        String id = ctx.ID().getText();  // id is left-hand side of '='
        int value = visit(ctx.expr());   // compute value of expression on right
        memory.put(id, value);           // store it in our memory
        int i = new Mem(id).invoke();
        System.out.println("mov bx ," + Integer.toHexString(i));
       //  System.out.println("mov bx ," + (id));
        System.out.println("pop ax ");
        System.out.println("mov [bx]+100," + "ax");
        return value;
    }

    /** expr NEWLINE */
    @Override
    public Integer visitPrintExpr(LabeledExprParser.PrintExprContext ctx) {
        Integer value = visit(ctx.expr()); // evaluate the expr child
        System.out.println(value);         // print the result
        return 0;                          // return dummy value
    }

    /** INT */
    @Override
    public Integer visitInt(LabeledExprParser.IntContext ctx) {
        int i=  Integer.valueOf(ctx.INT().getText());
        System.out.println("mov  ax," + i);
        System.out.println("push  ax");
        return i;
    }

    /** ID */
    @Override
    public Integer visitId(LabeledExprParser.IdContext ctx) {
        String id = ctx.ID().getText();
        if ( memory.containsKey(id) ) {
            int i = new Mem(id).invoke();
            System.out.println("mov bx ," + Integer.toHexString(i));
            System.out.println("mov ax ,[bx+100]");
            System.out.println("push ax"); 
            return memory.get(id);
        }
        return 0;
    }

    /** expr op=('*'|'/') expr */
    @Override
    public Integer visitMulDiv(LabeledExprParser.MulDivContext ctx) {
        int left = visit(ctx.expr(0));  // get value of left subexpression

        int right = visit(ctx.expr(1)); // get value of right subexpression
        System.out.println("pop cx");   System.out.println("pop ax");
        if ( ctx.op.getType() == LabeledExprParser.MUL ){
            System.out.println("mul ax,cx");
            System.out.println("push ax ");
          //  System.out.println("push dx ");
            return left * right;
        }
        System.out.println("div ax,cx");
        System.out.println("push ax ");
       // System.out.println("push dx ");
        return left / right; // must be DIV
    }

    /** expr op=('+'|'-') expr */
    @Override
    public Integer visitAddSub(LabeledExprParser.AddSubContext ctx) {
        int left = visit(ctx.expr(0));  // get value of left subexpression

        int right = visit(ctx.expr(1)); // get value of right subexpression
        System.out.println("pop cx");  System.out.println("pop ax");
        if ( ctx.op.getType() == LabeledExprParser.ADD )
        {   System.out.println("add ax,cx");
            System.out.println("push ax ");
            return left + right;

        }
        System.out.println("sub ax,cx");
        System.out.println("push ax ");
        return left - right; // must be SUB
    }

    /** '(' expr ')' */
    @Override
    public Integer visitParens(LabeledExprParser.ParensContext ctx) {
        return visit(ctx.expr()); // return child expr's value
    }

    private class Mem {
        private String id;

        public Mem(String id) {
            this.id = id;
        }

        public int invoke() {
            int i=0;
            for (String s : memory.keySet()){
               
                if (s.equals(id))  {
                   break; 
                }
                    
                    i++ ;
            }
            return i;
        }
    }
}

 测试

　　

package LabeledExpr.Imp;

/**
 * Created by IntelliJ IDEA.
 * User: han
 * Date: 14-1-22
 * Time: 下午2:15
 * To change this template use File | Settings | File Templates.
 */
import LabeledExpr.LabeledExprLexer;
import LabeledExpr.LabeledExprParser;

import org.antlr.runtime.tree.CommonTreeNodeStream;
import org.antlr.v4.runtime.*;
import org.antlr.v4.runtime.tree.ParseTree;

import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.InputStream;
import java.io.InputStreamReader;

public class Calc {
    public static void main(String[] args) throws Exception {
        String inputFile = null;
        if ( args.length>0 ) inputFile = args[0];
        InputStream is = System.in;
        if ( inputFile!=null ) is = new FileInputStream(inputFile);
       // InputStreamReader in = new InputStreamReader(is);
      //  BufferedReader read = new BufferedReader(in );
      //  String s= read.readLine();

        ANTLRInputStream input = new ANTLRInputStream( is);
        LabeledExprLexer lexer = new LabeledExprLexer(input);
        CommonTokenStream tokens = new CommonTokenStream(lexer);
        LabeledExprParser parser = new LabeledExprParser(tokens);
        LabeledExprParser.ProgContext tree = parser.prog(); // parse

        tree.inspect(parser)  ;

        EvalVisitor eval = new EvalVisitor();
        eval.visit(tree);
    }
}

　　

原来的例子是解释执行

增加了汇编语言，好久没有使用汇编了语句有些不熟练

参数文件内容

a=4
b=2
c=10*(a/b)
 

mov  ax,4
push  ax
mov bx ,0
pop ax 
mov [bx]+100,ax
mov  ax,2
push  ax
mov bx ,1
pop ax 
mov [bx]+100,ax
mov  ax,10
push  ax
mov bx ,0
mov ax ,[bx+100]
push ax
mov bx ,1
mov ax ,[bx+100]
push ax
pop cx
pop ax
div ax,cx
push ax 
pop cx
pop ax
mul ax,cx
push ax 
mov bx ,2
pop ax 
mov [bx]+100,ax

没有优化