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

  1 package LabeledExpr.Imp;
  2 
  3 /**
  4  * Created by IntelliJ IDEA.
  5  * User: han
  6  * Date: 14-1-22
  7  * Time: 下午2:12
  8  * To change this template use File | Settings | File Templates.
  9  */
 10 import LabeledExpr.LabeledExprBaseVisitor;
 11 import LabeledExpr.LabeledExprParser;
 12 
 13 import java.util.HashMap;
 14 import java.util.LinkedHashMap;
 15 import java.util.Map;
 16 
 17 public class EvalVisitor extends LabeledExprBaseVisitor<Integer> {
 18     /** "memory" for our calculator; variable/value pairs go here */
 19     Map<String, Integer> memory = new LinkedHashMap<String, Integer>();
 20 
 21 
 22 
 23     /** ID '=' expr NEWLINE */
 24     @Override
 25     public Integer visitAssign(LabeledExprParser.AssignContext ctx) {
 26         String id = ctx.ID().getText();  // id is left-hand side of '='
 27         int value = visit(ctx.expr());   // compute value of expression on right
 28         memory.put(id, value);           // store it in our memory
 29         int i = new Mem(id).invoke();
 30         System.out.println("mov bx ," + Integer.toHexString(i));
 31        //  System.out.println("mov bx ," + (id));
 32         System.out.println("pop ax ");
 33         System.out.println("mov [bx]+100," + "ax");
 34         return value;
 35     }
 36 
 37     /** expr NEWLINE */
 38     @Override
 39     public Integer visitPrintExpr(LabeledExprParser.PrintExprContext ctx) {
 40         Integer value = visit(ctx.expr()); // evaluate the expr child
 41         System.out.println(value);         // print the result
 42         return 0;                          // return dummy value
 43     }
 44 
 45     /** INT */
 46     @Override
 47     public Integer visitInt(LabeledExprParser.IntContext ctx) {
 48         int i=  Integer.valueOf(ctx.INT().getText());
 49         System.out.println("mov  ax," + i);
 50         System.out.println("push  ax");
 51         return i;
 52     }
 53 
 54     /** ID */
 55     @Override
 56     public Integer visitId(LabeledExprParser.IdContext ctx) {
 57         String id = ctx.ID().getText();
 58         if ( memory.containsKey(id) ) {
 59             int i = new Mem(id).invoke();
 60             System.out.println("mov bx ," + Integer.toHexString(i));
 61             System.out.println("mov ax ,[bx+100]");
 62             System.out.println("push ax"); 
 63             return memory.get(id);
 64         }
 65         return 0;
 66     }
 67 
 68     /** expr op=('*'|'/') expr */
 69     @Override
 70     public Integer visitMulDiv(LabeledExprParser.MulDivContext ctx) {
 71         int left = visit(ctx.expr(0));  // get value of left subexpression
 72 
 73         int right = visit(ctx.expr(1)); // get value of right subexpression
 74         System.out.println("pop cx");   System.out.println("pop ax");
 75         if ( ctx.op.getType() == LabeledExprParser.MUL ){
 76             System.out.println("mul ax,cx");
 77             System.out.println("push ax ");
 78           //  System.out.println("push dx ");
 79             return left * right;
 80         }
 81         System.out.println("div ax,cx");
 82         System.out.println("push ax ");
 83        // System.out.println("push dx ");
 84         return left / right; // must be DIV
 85     }
 86 
 87     /** expr op=('+'|'-') expr */
 88     @Override
 89     public Integer visitAddSub(LabeledExprParser.AddSubContext ctx) {
 90         int left = visit(ctx.expr(0));  // get value of left subexpression
 91 
 92         int right = visit(ctx.expr(1)); // get value of right subexpression
 93         System.out.println("pop cx");  System.out.println("pop ax");
 94         if ( ctx.op.getType() == LabeledExprParser.ADD )
 95         {   System.out.println("add ax,cx");
 96             System.out.println("push ax ");
 97             return left + right;
 98 
 99         }
100         System.out.println("sub ax,cx");
101         System.out.println("push ax ");
102         return left - right; // must be SUB
103     }
104 
105     /** '(' expr ')' */
106     @Override
107     public Integer visitParens(LabeledExprParser.ParensContext ctx) {
108         return visit(ctx.expr()); // return child expr's value
109     }
110 
111     private class Mem {
112         private String id;
113 
114         public Mem(String id) {
115             this.id = id;
116         }
117 
118         public int invoke() {
119             int i=0;
120             for (String s : memory.keySet()){
121                
122                 if (s.equals(id))  {
123                    break; 
124                 }
125                     
126                     i++ ;
127             }
128             return i;
129         }
130     }
131 }

View Code

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)

 1 mov  ax,4
 2 push  ax
 3 mov bx ,0
 4 pop ax 
 5 mov [bx]+100,ax
 6 mov  ax,2
 7 push  ax
 8 mov bx ,1
 9 pop ax 
10 mov [bx]+100,ax
11 mov  ax,10
12 push  ax
13 mov bx ,0
14 mov ax ,[bx+100]
15 push ax
16 mov bx ,1
17 mov ax ,[bx+100]
18 push ax
19 pop cx
20 pop ax
21 div ax,cx
22 push ax 
23 pop cx
24 pop ax
25 mul ax,cx
26 push ax 
27 mov bx ,2
28 pop ax 
29 mov [bx]+100,ax

View Code

没有优化

相关阅读:
Oracle使用序列创建自增字段（主键自动增长）
Oracle 增加修改删除字段
 JavaScript trim函数大赏
 js跨域问题
 document.getElementsByClassName的理想实现
 IIS启用Gzip的方法与优缺点分析
 浅释跳转漏洞
 js跨域及解决方法
 C#编写COM组件
 50种方法巧妙优化你的SQL Server数据库
原文地址：https://www.cnblogs.com/cndavy/p/3532192.html