Question

我已经使用Terence Parr的 The Definitive ANTLR 4 Reference 了解了ANTLR 4，到目前为止，我一直在使用Gradle 2.10及其构建在ANTLR插件中。但是，我在使用第4章第38-41页改编的代码时遇到了一些麻烦，无法正常使用我的Gradle构建脚本。（我之所以使用Gradle，而不是直接使用ANTLR，是因为我想最终将ANTLR集成到我正在为我的论文制作的Java Web应用程序中，我非常喜欢使用这是一个构建工具，因此我可以自动化ANTLR到Java代码生成过程并轻松管理我的依赖项。）

我创建了两个ANTLR 4语法（我在这个问题的最后粘贴了它）： src / main / antlr / org / jbduncan / Expr.g4 （标准语法）和 src / main / antlr / org / jbduncan / CommonLexerRules.g4 （词法分析器语法），其中 Expr.g4 取决于 CommonLexerRules.g4 通过import CommonLexerRules声明。但是当我尝试使用我的 build.gradle 在命令行运行gradlew generateGrammarSource时（也粘贴到此问题的末尾以及我的 gradle.properties ）），我收到以下错误：

12:45:21: Executing external task 'generateGrammarSource'...
:generateGrammarSource
error(110): org\jbduncan\Expr.g4:3:7: can't find or load grammar CommonLexerRules
warning(125): org\jbduncan\Expr.g4:12:11: implicit definition of token NEWLINE in parser
warning(125): org\jbduncan\Expr.g4:13:6: implicit definition of token ID in parser
warning(125): org\jbduncan\Expr.g4:19:6: implicit definition of token INT in parser
:generateGrammarSource FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':generateGrammarSource'.
> There was 1 error during grammar generation

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.

BUILD FAILED

Total time: 3.166 secs
There was 1 error during grammar generation
12:45:24: External task execution finished 'generateGrammarSource'.

查看此错误消息，在我看来，Gradle的ANTLR插件能够找到 Expr.g4 ，但无论如何都找不到 CommonLexerRules.g4 。

我尝试使用一些外部Gradle插件（https://github.com/melix/antlr4-gradle-plugin和https://github.com/Abnaxos/gradle-antlr4-plugin）而不是内置插件来解决此错误，但是当我尝试了每个插件时，他们介绍了我自己无法解决的问题。

使用直接从ANTLR网站下载的ANTLR 4.5.2 jar 让让我可以毫无问题地编译我的两个语法，但正如我之前所讨论的，这对我来说是一个非常不合适的选择，因为我和＃39; d必须手动编译我的语法，而我相信Gradle可以自动为我做。

我的问题是：如何解决上面的错误并让Gradle将我的词法分析器语法导入我的其他语法？

的build.gradle

apply plugin: 'java'
apply plugin: 'application'
apply plugin: 'antlr'

sourceCompatibility = 1.8
targetCompatibility = 1.8

[compileJava, compileTestJava]*.options*.encoding = 'UTF-8'

group = 'org.jbduncan'
version = '1.0-SNAPSHOT'
mainClassName = 'org.jbduncan.Application'

repositories {
    jcenter()
}

dependencies {
    antlr "org.antlr:antlr4:$antlrVersion"
    compile "com.google.guava:guava:$guavaVersion"
    testCompile "com.google.guava:guava-testlib:$guavaVersion"
    testCompile "com.google.truth:truth:$truthVersion"
    testCompile "junit:junit:$junitVersion"
}

// Send all generated source code to a directory other than build/, to workaround an issue in
// IntelliJ IDEA where it fails to recognise source files in build/.
def generatedJavaSourcesDir = 'src/generated/java'

generateGrammarSource {
    arguments += ['-visitor']
    outputDirectory = file(generatedJavaSourcesDir)
}

sourceSets {
    main {
        java {
            srcDir generatedJavaSourcesDir
        }
    }
}

clean {
    delete generatedJavaSourcesDir
}

task wrapper(type: Wrapper) {
    distributionUrl = "http://services.gradle.org/distributions/gradle-$gradleVersion-bin.zip"
}

gradle.properties

gradleVersion=2.10

# Dependency versions
antlrVersion=4.5
guavaVersion=19.0
junitVersion=4.12
truthVersion=0.28

的src /主/ ANTLR /组织/ jbduncan / Expr.g4

grammar Expr;

import CommonLexerRules; // includes all rules from CommonLexerRules.g4

@header {
    package org.jbduncan;
}

/** The start rule; begin parsing here. */
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: '-';

的src /主/ ANTLR /组织/ jbduncan / CommonLexerRules.g4

lexer grammar CommonLexerRules; // note "lexer grammar"

ID: [a-zA-Z]+ ; // match identifiers
INT: [0-9]+ ; // match integers
NEWLINE: '\r'? '\n' ; // return newlines to parser (is end-statement signal)
WS: [ \t] -> skip ; // toss out whitespace

的src /主/ JAVA /组织/ jbduncan / Application.java

package org.jbduncan;

import org.antlr.v4.runtime.ANTLRInputStream;
import org.antlr.v4.runtime.CommonTokenStream;
import org.antlr.v4.runtime.tree.ParseTree;

import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;

public final class Application {
  public static void main(String[] args) throws IOException {
    String inputFile = (args.length > 0) ? args[0] : null;

    InputStream inputStream = (inputFile == null) ? System.in : new FileInputStream(inputFile);
    ANTLRInputStream input = new ANTLRInputStream(inputStream);
    ExprLexer lexer = new ExprLexer(input);
    CommonTokenStream tokens = new CommonTokenStream(lexer);
    ExprParser parser = new ExprParser(tokens);
    ParseTree tree = parser.prog(); // parse; start at prog

    System.out.println(tree.toStringTree(parser)); // print tree as text
  }
}

Answer 1

我在https://discuss.gradle.org/t/using-gradle-2-10s-antlr-plugin-to-import-an-antlr-4-lexer-grammar-into-another-grammar/14970的Gradle论坛上发布后，设法找到了我的问题的答案。

如何使用Gradle 2.10将ANTLR词法分析器语法导入另一种语法？

1 个答案: