java - ANTLR4 项目不会在 Eclipse 中显示任何内容

Question

根据“The Definitive ANTLR 4 Reference”一书，我尝试在 Eclipse 中运行 ArrayInit.g4 示例。我已经成功生成了必要的 java 文件和其他文件，但是当我运行示例并向控制台输入值并按 Enter 键时，什么也没有发生(第 29 和 30 页)。

ArrayInit.g4

/** Grammars always start with a grammar header. This grammar is called
* ArrayInit and must match the filename: ArrayInit.g4
*/
grammar ArrayInit;

@header
{
    package com.foo.bar;
}

/** A rule called init that matches comma-separated values between {...}. */
init : '{' value (',' value)* '}' ; // must match at least one value
/** A value can be either a nested array/struct or a simple integer (INT) */
value : init
| INT
;
// parser rules start with lowercase letters, lexer rules with uppercase
INT : [0-9]+ ; // Define token INT as one or more digits
WS : [ \t\r\n]+ -> skip ;

Main.java

package com.foo.bar;

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

public class Main 
{
    public static void main(String[] args) throws Exception
    {
        // create a CharStream that reads from standard input
        ANTLRInputStream input = new ANTLRInputStream(System.in);
        // create a lexer that feeds off of input CharStream
        ArrayInitLexer lexer = new ArrayInitLexer(input);
        // create a buffer of tokens pulled from the lexer
        CommonTokenStream tokens = new CommonTokenStream(lexer);
        // create a parser that feeds off the tokens buffer
        ArrayInitParser parser = new ArrayInitParser(tokens);
        ParseTree tree = parser.init(); // begin parsing at init rule

        // Create a generic parse tree walker that can trigger callbacks
        ParseTreeWalker walker = new ParseTreeWalker();
        // Walk the tree created during the parse, trigger callbacks
        walker.walk(new ShortToUnicodeString(), tree);
        System.out.println(); // print a \n after translation
    }
}

进入控制台: {99, 3, 451}

预期输出: “\u0063\u0003\u01c3”

Answer 1

输入 {99, 3, 451} 后，按 Enter 键换行，然后按 ctrl + Z(至少在 Windows 上)表示您已完成输入，然后就可以了。 最终，在本书中，您将看到“10.1 使用语法操作构建计算器”和副标题“构建交互式计算器”，在那里您将找到一些提供键盘输入的更好方法。