ANTLR grammar based C++ language module

cli/pom.xml

@@ -47,6 +47,11 @@
             <artifactId>cpp</artifactId>
             <version>${revision}</version>
         </dependency>
+        <dependency>
+            <groupId>de.jplag</groupId>
+            <artifactId>cpp2</artifactId>
+            <version>${revision}</version>
+        </dependency>
         <dependency>
             <groupId>de.jplag</groupId>
             <artifactId>golang</artifactId>

cli/src/test/java/de/jplag/cli/LanguageTest.java

@@ -6,7 +6,6 @@
 import java.util.Arrays;
 import java.util.List;
 
-import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
 
 import de.jplag.Language;
@@ -29,7 +28,7 @@ void testInvalidLanguage() throws Exception {
     @Test
     void testLoading() {
         var languages = LanguageLoader.getAllAvailableLanguages();
-        Assertions.assertEquals(13, languages.size(), "Loaded Languages: " + languages.keySet());
+        assertEquals(14, languages.size(), "Loaded Languages: " + languages.keySet());
     }
 
     @Test

languages/cpp2/README.md

@@ -0,0 +1,33 @@
+# JPlag C++ language module
+
+**Note**: This language module is meant to replace the existing C++ language module in the future.
+While the old language module is based on lexer tokens, this language module uses a parse tree for token extraction.
+The base package name of this language module and its identifier are `cpp2` currently, but this might change if the old
+language module gets replaced.
+
+The JPlag C++ frontend allows the use of JPlag with submissions in C/C++. <br>
+It is based on the [C++ ANTLR4 grammar](https://github.com/antlr/grammars-v4/tree/master/cpp), licensed under MIT.
+
+### C++ specification compatibility
+
+The grammar definition targets C++14.
+
+If the grammar is updated to a more recent<a href="#footnote-1"><sup>1</sup></a> syntax definition, this module should surely be updated as well.
+
+### Token Extraction
+
+The choice of tokens is intended to be similar to the Java language module.
+While the Java language module is based on an AST, this language module uses a parse tree only.
+There are differences, including:
+- `import` is extracted in Java, while `using` is not extracted due to the fact that it can be placed freely in the code.
+
+More syntactic elements of C/C++ may turn out to be helpful to include in the future, especially those that are newly introduced.
+
+### Usage
+
+To use the C++ frontend, add the `-l cpp2` flag in the CLI, or use a `JPlagOption` object with `new de.jplag.cpp2.CPPLanguage()` as `Language` in the Java API as described in the usage information in the [readme of the main project](https://github.com/jplag/JPlag#usage) and [in the wiki](https://github.com/jplag/JPlag/wiki/1.-How-to-Use-JPlag).
+
+<br>
+
+#### Footnotes
+<section id="footnote-1"><sup>1 </sup>The grammar files are taken from grammar-v4, with the most recent modifications in <a href="https://github.com/antlr/grammars-v4/tree/fa4aff92b58e40bd337ab9f27217dc3feafbc32e/cpp">commit 6e10f7e</a> from May 2021.</section>

languages/cpp2/pom.xml

@@ -0,0 +1,33 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <parent>
+        <groupId>de.jplag</groupId>
+        <artifactId>languages</artifactId>
+        <version>${revision}</version>
+    </parent>
+    <artifactId>cpp2</artifactId>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.antlr</groupId>
+            <artifactId>antlr4-runtime</artifactId>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.antlr</groupId>
+                <artifactId>antlr4-maven-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <goals>
+                            <goal>antlr4</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+</project>