我正在使用ANTLR 3.x创建一个解析器,该解析器以Java为目标。我编写了解析器语法(用于创建抽象语法树AST)和树语法(用于在AST上执行操作)。最后,为了测试这两个语法文件,我用Java编写了一个测试文件。ANTLR java测试文件无法创建树语法对象
看一看下面的代码,
协议语法
grammar protocol;
options {
language = Java;
output = AST;
}
tokens{ //imaginary tokens
PROT;
INITIALP;
PROC;
TRANSITIONS;
}
@header {
import twoprocess.Configuration;
package com.javadude.antlr3.x.tutorial;
}
@lexer::header {
package com.javadude.antlr3.x.tutorial;
}
/*
parser rules, in lowercase letters
*/
program
: declaration+
;
declaration
:protocol
|initialprocess
|process
|transitions
;
protocol
:'protocol' ID ';' -> ^(PROT ID)
;
initialprocess
:'pin' '=' INT ';' -> ^(INITIALP INT)
;
process
:'p' '=' INT ';' -> ^(PROC INT)
;
transitions
:'transitions' '=' INT ('(' INT ',' INT ')') + ';' -> ^(TRANSITIONS INT INT INT*)
;
/*
lexer rules (tokens), in upper case letters
*/
ID
: (('a'..'z' | 'A'..'Z'|'_')('a'..'z' | 'A'..'Z'|'0'..'9'|'_'))*;
INT
: ('0'..'9')+;
WHITESPACE
: ('\t' | ' ' | '\r' | '\n' | '\u000C')+ {$channel = HIDDEN;};
protocolWalker
grammar protocolWalker;
options {
language = Java;
//Error, eclipse can't access tokenVocab named protocol
tokenVocab = protocol; //import tokens from protocol.g i.e, from protocol.tokens file
ASTLabelType = CommonTree;
}
@header {
import twoprocess.Configuration;
package com.javadude.antlr3.x.tutorial;
}
program
: declaration+
;
declaration
:protocol
|initialprocess
|process
|transitions
;
protocol
:^(PROT ID)
{System.out.println("create protocol " +$ID.text);}
;
initialprocess
:^(INITIALP INT)
{System.out.println("");}
;
process
:^(PROC INT)
{System.out.println("");}
;
transitions
:^(TRANSITIONS INT INT INT*)
{System.out.println("");}
;
Protocoltest.java
个package com.javadude.antlr3.x.tutorial;
import org.antlr.runtime.*;
import org.antlr.runtime.tree.*;
import org.antlr.runtime.tree.CommonTree;
import org.antlr.runtime.tree.CommonTreeNodeStream;
public class Protocoltest {
/**
* @param args
*/
public static void main(String[] args) throws Exception {
//create input stream from standard input
ANTLRInputStream input = new ANTLRInputStream(System.in);
//create a lexer attached to that input stream
protocolLexer lexer = new protocolLexer(input);
//create a stream of tokens pulled from the lexer
CommonTokenStream tokens = new CommonTokenStream(lexer);
//create a pareser attached to teh token stream
protocolParser parser = new protocolParser(tokens);
//invoke the program rule in get return value
protocolParser.program_return r =parser.program();
CommonTree t = (CommonTree)r.getTree();
//output the extracted tree to the console
System.out.println(t.toStringTree());
//walk resulting tree; create treenode stream first
CommonTreeNodeStream nodes = new CommonTreeNodeStream(t);
//AST nodes have payloads that point into token stream
nodes.setTokenStream(tokens);
//create a tree walker attached to the nodes stream
//Error, can't create TreeGrammar object called walker
protocolWalker walker = new protocolWalker(nodes);
//invoke the start symbol, rule program
walker.program();
}
}
问题:
在protocolWalker,我无法访问令牌(protocol.tokens)
//Error, eclipse can't access tokenVocab named protocol tokenVocab = protocol; //import tokens from protocol.g i.e, from protocol.tokens file
在在protocolWalker,我可以创建Java的对象类,称为配置,在行动清单?
protocol :^(PROT ID) {System.out.println("create protocol " +$ID.text); Configuration conf = new Configuration(); } ;
在Protocoltest.java
//create a tree walker attached to the nodes stream //Error, can't create TreeGrammar object called walker protocolWalker walker = new protocolWalker(nodes);
protocolWalker的对象不能被创建。我在例子和教程中看到这样的对象被创建。
我已阅读该书The definitive antlr reference,构建领域特定语言,并且也遵循了一些在线教程。 –