<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
<meta name="description" content="How to add a new CPD language">
<meta name="keywords" content="devdocsextending,  ">
<title>How to add a new CPD language | PMD Source Code Analyzer</title>
<link rel="stylesheet" href="css/syntax.css">


<link rel="stylesheet" type="text/css" href="https://maxcdn.bootstrapcdn.com/font-awesome/4.5.0/css/font-awesome.min.css">
<!--<link rel="stylesheet" type="text/css" href="css/bootstrap.min.css">-->
<link rel="stylesheet" href="css/modern-business.css">
<link rel="stylesheet" href="css/lavish-bootstrap.css">
<link rel="stylesheet" href="css/customstyles.css">
<link rel="stylesheet" href="css/theme-blue.css">
<link rel="stylesheet" href="css/pmd-customstyles.css">

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/2.1.4/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery-cookie/1.4.1/jquery.cookie.min.js"></script>
<script src="js/jquery.navgoco.min.js"></script>


<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.4/js/bootstrap.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/anchor-js/2.0.0/anchor.min.js"></script>
<script src="js/toc.js"></script>
<script src="js/customscripts.js"></script>

<link rel="shortcut icon" href="images/favicon.ico" type="image/x-icon">
<link rel="icon" href="images/favicon.ico" type="image/x-icon">

<!-- HTML5 Shim and Respond.js IE8 support of HTML5 elements and media queries -->
<!-- WARNING: Respond.js doesn't work if you view the page via file:// -->
<!--[if lt IE 9]>
<script src="https://oss.maxcdn.com/libs/html5shiv/3.7.0/html5shiv.js"></script>
<script src="https://oss.maxcdn.com/libs/respond.js/1.4.2/respond.min.js"></script>
<![endif]-->

<link rel="alternate" type="application/rss+xml" title="" href="https://pmd.github.io/pmd/feed.xml">

    <script>
        $(document).ready(function() {
            // Initialize navgoco with default options
            $("#mysidebar").navgoco({
                caretHtml: '',
                accordion: true,
                openClass: 'active', // open
                save: false, // leave false or nav highlighting doesn't work right
                cookie: {
                    name: 'navgoco',
                    expires: false,
                    path: '/'
                },
                slide: {
                    duration: 400,
                    easing: 'swing'
                }
            });

            $("#collapseAll").click(function(e) {
                e.preventDefault();
                $("#mysidebar").navgoco('toggle', false);
            });

            $("#expandAll").click(function(e) {
                e.preventDefault();
                $("#mysidebar").navgoco('toggle', true);
            });

        });

    </script>
    <script>
        $(function () {
            $('[data-toggle="tooltip"]').tooltip()
        })
    </script>
    <script>
        $(document).ready(function() {
            $("#tg-sb-link").click(function() {
                $("#tg-sb-sidebar").toggle();
                $("#tg-sb-content").toggleClass('col-md-9');
                $("#tg-sb-content").toggleClass('col-md-12');
                $("#tg-sb-icon").toggleClass('fa-toggle-on');
                $("#tg-sb-icon").toggleClass('fa-toggle-off');
            });
        });
    </script>
    

</head>
<body>
<!-- Content is offset by the height of the topnav bar. -->
<!-- There's already a padding-top rule in modern-business.css, but it apparently doesn't work on Firefox 60 and Chrome 67 -->
<div id="topbar-content-offset">
<!-- Navigation -->
<nav class="navbar navbar-inverse navbar-fixed-top">
    <div class="container topnavlinks">
        <div class="navbar-header">
            <button type="button" class="navbar-toggle" data-toggle="collapse" data-target="#bs-example-navbar-collapse-1">
                <span class="sr-only">Toggle navigation</span>
                <span class="icon-bar"></span>
                <span class="icon-bar"></span>
                <span class="icon-bar"></span>
            </button>
            <a class="fa fa-home fa-lg navbar-brand" href="index.html">&nbsp;<span class="projectTitle"> PMD Source Code Analyzer Project</span></a>
        </div>
        <div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1">
            <ul class="nav navbar-nav navbar-right">
                <!-- toggle sidebar button -->
                <li><a id="tg-sb-link" href="#"><i id="tg-sb-icon" class="fa fa-toggle-on"></i> Nav</a></li>
                <!-- entries without drop-downs appear here -->
                
                
                
                <li><a href="https://github.com/pmd/pmd/releases/latest" target="_blank">Download</a></li>
                
                
                
                <li><a href="https://github.com/pmd/pmd" target="_blank">Fork us on github</a></li>
                
                
                
                <!-- entries with drop-downs appear here -->
                <!-- conditional logic to control which topnav appears for the audience defined in the configuration file.-->
                
                
                <!--comment out this block if you want to hide search-->
                <li>
                    <!--start search-->
                    <div id="search-demo-container">
                        <input type="text" id="search-input" placeholder="search...">
                        <ul id="results-container"></ul>
                    </div>
                    <script src="js/jekyll-search.js" type="text/javascript"></script>
                    <script type="text/javascript">
                            SimpleJekyllSearch.init({
                                searchInput: document.getElementById('search-input'),
                                resultsContainer: document.getElementById('results-container'),
                                dataSource: 'search.json',
                                searchResultTemplate: '<li><a href="{url}" title="How to add a new CPD language">{title}</a></li>',
                    noResultsText: 'No results found.',
                            limit: 10,
                            fuzzy: true,
                    })
                    </script>
                    <!--end search-->
                </li>
            </ul>
        </div>
        </div>
        <!-- /.container -->
</nav>

<!-- Page Content -->
<div class="container">
    <div class="col-lg-12">&nbsp;</div>
    <!-- Content Row -->
    <div class="row">
        
        
        <!-- Sidebar Column -->
        <div class="col-md-3" id="tg-sb-sidebar">
            








<ul id="mysidebar" class="nav">
    <li class="sidebarTitle">PMD 6.42.0</li>
    
    
    
        
    
    <li>
        
        <a href="#">About</a>
        
        <ul>
            
            

            

                
                <li><a href="index.html">Home</a></li>
                

            

            
            
            

            

                
                <li><a href="pmd_release_notes.html">Release notes</a></li>
                

            

            
            
            

            

                
                <li><a href="pmd_next_major_development.html">PMD 7.0.0 development</a></li>
                

            

            
            
            

            

                
                <li><a href="pmd_about_help.html">Getting help</a></li>
                

            

            
            
        </ul>
     </li>
       
        
    
    <li>
        
        <a href="#">User Documentation</a>
        
        <ul>
            
            

            

                
                <li><a href="pmd_userdocs_installation.html">Installation and basic CLI usage</a></li>
                

            

            
            
            

            

                
                <li><a href="pmd_userdocs_making_rulesets.html">Making rulesets</a></li>
                

            

            
            
            

            

                
                <li><a href="pmd_userdocs_configuring_rules.html">Configuring rules</a></li>
                

            

            
            
            

            

                
                <li><a href="pmd_userdocs_best_practices.html">Best practices</a></li>
                

            

            
            
            

            

                
                <li><a href="pmd_userdocs_suppressing_warnings.html">Suppressing warnings</a></li>
                

            

            
            
            

            

                
                <li><a href="pmd_userdocs_incremental_analysis.html">Incremental analysis</a></li>
                

            

            
            
            

            

                
                <li><a href="pmd_userdocs_cli_reference.html">PMD CLI reference</a></li>
                

            

            
            
            

            

                
                <li><a href="pmd_userdocs_report_formats.html">PMD Report formats</a></li>
                

            

            
            
            

            

                
                
                <li class="subfolders">
                    <a href="#">CPD reference</a>
                    <ul>
                        
                        
                        
                        <li><a href="pmd_userdocs_cpd.html">Copy-paste detection</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_userdocs_cpd_report_formats.html">CPD Report formats</a></li>
                        
                        
                        
                    </ul>
                </li>
                
                

            

            
            
            

            

                
                
                <li class="subfolders">
                    <a href="#">Extending PMD</a>
                    <ul>
                        
                        
                        
                        <li><a href="pmd_userdocs_extending_writing_rules_intro.html">Introduction to writing rules</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_userdocs_extending_your_first_rule.html">Your first rule</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_userdocs_extending_writing_xpath_rules.html">XPath rules</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_userdocs_extending_writing_java_rules.html">Java rules</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_userdocs_extending_designer_reference.html">Rule designer reference</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_userdocs_extending_defining_properties.html">Defining rule properties</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_userdocs_extending_metrics_howto.html">Using and defining code metrics</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_userdocs_extending_rule_guidelines.html">Rule guidelines</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_userdocs_extending_testing.html">Testing your rules</a></li>
                        
                        
                        
                    </ul>
                </li>
                
                

            

            
            
            

            

                
                
                <li class="subfolders">
                    <a href="#">Tools / Integrations</a>
                    <ul>
                        
                        
                        
                        <li><a href="pmd_userdocs_tools_maven.html">Maven PMD Plugin</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_userdocs_tools_gradle.html">Gradle</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_userdocs_tools_ant.html">Ant</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_userdocs_tools_java_api.html">PMD Java API</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_userdocs_tools_ci.html">CI integrations</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_userdocs_tools.html">Other Tools / Integrations</a></li>
                        
                        
                        
                    </ul>
                </li>
                
                

            

            
            
        </ul>
     </li>
       
        
    
    <li>
        
        <a href="#">Rule Reference</a>
        
        <ul>
            
            

            

                
                
                <li class="subfolders">
                    <a href="#">Apex Rules</a>
                    <ul>
                        
                        
                        
                        <li><a href="pmd_rules_apex.html">Index</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_rules_apex_bestpractices.html">Best Practices</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_rules_apex_codestyle.html">Code Style</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_rules_apex_design.html">Design</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_rules_apex_documentation.html">Documentation</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_rules_apex_errorprone.html">Error Prone</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_rules_apex_performance.html">Performance</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_rules_apex_security.html">Security</a></li>
                        
                        
                        
                    </ul>
                </li>
                
                

            

            
            
            

            

                
                
                <li class="subfolders">
                    <a href="#">Ecmascript Rules</a>
                    <ul>
                        
                        
                        
                        <li><a href="pmd_rules_ecmascript.html">Index</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_rules_ecmascript_bestpractices.html">Best Practices</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_rules_ecmascript_codestyle.html">Code Style</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_rules_ecmascript_errorprone.html">Error Prone</a></li>
                        
                        
                        
                    </ul>
                </li>
                
                

            

            
            
            

            

                
                
                <li class="subfolders">
                    <a href="#">Java Rules</a>
                    <ul>
                        
                        
                        
                        <li><a href="pmd_rules_java.html">Index</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_rules_java_bestpractices.html">Best Practices</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_rules_java_codestyle.html">Code Style</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_rules_java_design.html">Design</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_rules_java_documentation.html">Documentation</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_rules_java_errorprone.html">Error Prone</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_rules_java_multithreading.html">Multithreading</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_rules_java_performance.html">Performance</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_rules_java_security.html">Security</a></li>
                        
                        
                        
                    </ul>
                </li>
                
                

            

            
            
            

            

                
                
                <li class="subfolders">
                    <a href="#">Java Server Pages Rules</a>
                    <ul>
                        
                        
                        
                        <li><a href="pmd_rules_jsp.html">Index</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_rules_jsp_bestpractices.html">Best Practices</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_rules_jsp_codestyle.html">Code Style</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_rules_jsp_design.html">Design</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_rules_jsp_errorprone.html">Error Prone</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_rules_jsp_security.html">Security</a></li>
                        
                        
                        
                    </ul>
                </li>
                
                

            

            
            
            

            

                
                
                <li class="subfolders">
                    <a href="#">Maven POM Rules</a>
                    <ul>
                        
                        
                        
                        <li><a href="pmd_rules_pom.html">Index</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_rules_pom_errorprone.html">Error Prone</a></li>
                        
                        
                        
                    </ul>
                </li>
                
                

            

            
            
            

            

                
                
                <li class="subfolders">
                    <a href="#">Modelica Rules</a>
                    <ul>
                        
                        
                        
                        <li><a href="pmd_rules_modelica.html">Index</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_rules_modelica_bestpractices.html">Best Practices</a></li>
                        
                        
                        
                    </ul>
                </li>
                
                

            

            
            
            

            

                
                
                <li class="subfolders">
                    <a href="#">PLSQL Rules</a>
                    <ul>
                        
                        
                        
                        <li><a href="pmd_rules_plsql.html">Index</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_rules_plsql_bestpractices.html">Best Practices</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_rules_plsql_codestyle.html">Code Style</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_rules_plsql_design.html">Design</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_rules_plsql_errorprone.html">Error Prone</a></li>
                        
                        
                        
                    </ul>
                </li>
                
                

            

            
            
            

            

                
                
                <li class="subfolders">
                    <a href="#">Salesforce VisualForce Rules</a>
                    <ul>
                        
                        
                        
                        <li><a href="pmd_rules_vf.html">Index</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_rules_vf_security.html">Security</a></li>
                        
                        
                        
                    </ul>
                </li>
                
                

            

            
            
            

            

                
                
                <li class="subfolders">
                    <a href="#">VM Rules</a>
                    <ul>
                        
                        
                        
                        <li><a href="pmd_rules_vm.html">Index</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_rules_vm_bestpractices.html">Best Practices</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_rules_vm_design.html">Design</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_rules_vm_errorprone.html">Error Prone</a></li>
                        
                        
                        
                    </ul>
                </li>
                
                

            

            
            
            

            

                
                
                <li class="subfolders">
                    <a href="#">XML Rules</a>
                    <ul>
                        
                        
                        
                        <li><a href="pmd_rules_xml.html">Index</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_rules_xml_errorprone.html">Error Prone</a></li>
                        
                        
                        
                    </ul>
                </li>
                
                

            

            
            
            

            

                
                
                <li class="subfolders">
                    <a href="#">XSL Rules</a>
                    <ul>
                        
                        
                        
                        <li><a href="pmd_rules_xsl.html">Index</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_rules_xsl_codestyle.html">Code Style</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_rules_xsl_performance.html">Performance</a></li>
                        
                        
                        
                    </ul>
                </li>
                
                

            

            
            
        </ul>
     </li>
       
        
    
    <li>
        
        <a href="#">Language Specific Documentation</a>
        
        <ul>
            
            

            

                
                <li><a href="pmd_languages_jsp.html">JSP Support</a></li>
                

            

            
            
            

            

                
                <li><a href="pmd_java_metrics_index.html">Java code metrics</a></li>
                

            

            
            
            

            

                
                <li><a href="pmd_apex_metrics_index.html">Apex code metrics</a></li>
                

            

            
            
            

            

                
                <li><a href="pmd_languages_plsql.html">PLSQL</a></li>
                

            

            
            
            

            

                
                <li><a href="pmd_languages_visualforce.html">Visualforce</a></li>
                

            

            
            
        </ul>
     </li>
       
        
    
    <li>
        
        <a href="#">Developer Documentation</a>
        
        <ul>
            
            

            

                
                <li><a href="pmd_devdocs_development.html">Developer resources</a></li>
                

            

            
            
            

            

                
                <li><a href="pmd_devdocs_building.html">Building PMD from source</a></li>
                

            

            
            
            

            

                
                <li><a href="https://github.com/pmd/pmd/blob/master/CONTRIBUTING.md" target="_blank">Contributing</a></li>
                

            

            
            
            

            

                
                <li><a href="pmd_devdocs_writing_documentation.html">Writing documentation</a></li>
                

            

            
            
            

            

                
                <li><a href="pmd_devdocs_roadmap.html">Roadmap</a></li>
                

            

            
            
            

            

                
                <li><a href="pmd_devdocs_how_pmd_works.html">How PMD works</a></li>
                

            

            
            
            

            

                
                <li><a href="pmd_devdocs_pmdtester.html">Pmdtester</a></li>
                

            

            
            
            

            

                
                <li><a href="pmd_devdocs_rule_deprecation_policy.html">Rule Deprecation Policy</a></li>
                

            

            
            
            

            

                
                
                <li class="subfolders">
                    <a href="#">Major contributions</a>
                    <ul>
                        
                        
                        
                        <li><a href="pmd_devdocs_major_rule_guidelines.html">Rule Guidelines</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_devdocs_major_adding_new_language.html">Adding a new language</a></li>
                        
                        
                        
                        
                        
                        <li class="active"><a href="pmd_devdocs_major_adding_new_cpd_language.html">Adding a new CPD language</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_devdocs_major_adding_new_metrics_framework.html">Adding metrics support to a language</a></li>
                        
                        
                        
                    </ul>
                </li>
                
                
                
                <li class="subfolders">
                    <a href="#">Experimental features</a>
                    <ul>
                        
                        
                        
                        <li><a href="pmd_devdocs_experimental_ast_dump.html">Creating (XML) dump of the AST</a></li>
                        
                        
                        
                    </ul>
                </li>
                
                

            

            
            
        </ul>
     </li>
       
        
    
    <li>
        
        <a href="#">Project documentation</a>
        
        <ul>
            
            

            

                
                
                <li class="subfolders">
                    <a href="#">Trivia about PMD</a>
                    <ul>
                        
                        
                        
                        <li><a href="pmd_projectdocs_trivia_news.html">PMD in the press</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_projectdocs_trivia_products.html">Products & books related to PMD</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_projectdocs_trivia_similarprojects.html">Similar projects</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_projectdocs_trivia_meaning.html">What does 'PMD' mean?</a></li>
                        
                        
                        
                    </ul>
                </li>
                
                

            

            
            
            

            

                
                <li><a href="pmd_projectdocs_faq.html">FAQ</a></li>
                

            

            
            
            

            

                
                <li><a href="license.html">License</a></li>
                

            

            
            
            

            

                
                <li><a href="pmd_projectdocs_credits.html">Credits</a></li>
                

            

            
            
            

            

                
                <li><a href="pmd_release_notes_old.html">Old release notes</a></li>
                

            

            
            
            

            

                
                
                <li class="subfolders">
                    <a href="#">Project management</a>
                    <ul>
                        
                        
                        
                        <li><a href="pmd_projectdocs_committers_infrastructure.html">Infrastructure</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_projectdocs_committers_releasing.html">Release process</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_projectdocs_committers_merging_pull_requests.html">Merging pull requests</a></li>
                        
                        
                        
                        
                        
                        <li><a href="pmd_projectdocs_committers_main_landing_page.html">Main Landing page</a></li>
                        
                        
                        
                    </ul>
                </li>
                
                

            

            
            
        </ul>
     </li>
       
        
        
        <!-- if you aren't using the accordion, uncomment this block:
           <p class="external">
               <a href="#" id="collapseAll">Collapse All</a> | <a href="#" id="expandAll">Expand All</a>
           </p>
           -->
</ul>

<!-- this highlights the active parent class in the navgoco sidebar. this is critical so that the parent expands when you're viewing a page. This must appear below the sidebar code above. Otherwise, if placed inside customscripts.js, the script runs before the sidebar code runs and the class never gets inserted.-->
<script>$("li.active").parents('li').toggleClass("active");</script>

        </div>
        
        

        <!-- Content Column -->
        <div class="col-md-9" id="tg-sb-content">
            <div class="post-header">
   <h1 class="post-title-main">How to add a new CPD language</h1>
</div>



<div class="post-content">

   
    <div class="summary">How to add a new CPD language</div>
   

    
    
<!-- this handles the automatic toc. use ## for subheads to auto-generate the on-page minitoc. if you use html tags, you must supply an ID for the heading element in order for it to appear in the minitoc. -->
<script>
$( document ).ready(function() {
  // Handler for .ready() called.

$('#toc').toc({ minimumHeaders: 0, listType: 'ul', showSpeed: 0, headers: 'h2,h3,h4' });

});
</script>

<div id="toc"></div>

    


    

        
        
        
        <a target="_blank" href="https://github.com/pmd/pmd/blob/master/docs/pages/pmd/devdocs/major_contributions/adding_new_cpd_language.md" class="btn btn-default githubEditButton" role="button"><i class="fa fa-github fa-lg"></i> Edit me</a>
        

    

  <p>First of all, thanks for the contribution!</p>

<p>Happily for you, to add CPD support for a new language is now easier than ever!</p>

<div class="bs-callout bs-callout-primary"><strong>Pro Tip</strong>: If you wish to add a new language, there are more than 50 languages you could easily add with just an <a href="https://github.com/antlr/grammars-v4">Antlr grammar</a>.</div>

<p>All you need to do is follow this few steps:</p>

<ol>
  <li>Create a new module for your language, you can take <a href="https://github.com/pmd/pmd/tree/master/pmd-go">GO as an example</a></li>
  <li>
    <p>Create a Tokenizer</p>

    <ul>
      <li>For Antlr grammars you can take the grammar from <a href="https://github.com/antlr/grammars-v4">here</a>  and extend <a href="https://github.com/pmd/pmd/blob/master/pmd-core/src/main/java/net/sourceforge/pmd/cpd/AntlrTokenizer.java">AntlrTokenizer</a>  taking Go as an example</li>
    </ul>

    <div class="language-java highlighter-rouge"><div class="highlight"><pre class="highlight"><code>   <span class="kd">public</span> <span class="kd">class</span> <span class="nc">GoTokenizer</span> <span class="kd">extends</span> <span class="nc">AntlrTokenizer</span> <span class="o">{</span>    
        
       <span class="nd">@Override</span> <span class="kd">protected</span> <span class="nc">AntlrTokenManager</span> <span class="nf">getLexerForSource</span><span class="o">(</span><span class="nc">SourceCode</span> <span class="n">sourceCode</span><span class="o">)</span> <span class="o">{</span>   
           <span class="nc">CharStream</span> <span class="n">charStream</span> <span class="o">=</span> <span class="nc">AntlrTokenizer</span><span class="o">.</span><span class="na">getCharStreamFromSourceCode</span><span class="o">(</span><span class="n">sourceCode</span><span class="o">);</span>   
           <span class="k">return</span> <span class="k">new</span> <span class="nf">AntlrTokenManager</span><span class="o">(</span><span class="k">new</span> <span class="nc">GolangLexer</span><span class="o">(</span><span class="n">charStream</span><span class="o">),</span> <span class="n">sourceCode</span><span class="o">.</span><span class="na">getFileName</span><span class="o">());</span>   
       <span class="o">}</span>
   <span class="o">}</span>
</code></pre></div>    </div>

    <ul>
      <li>For JavaCC grammars you should subclass <a href="https://github.com/pmd/pmd/blob/master/pmd-core/src/main/java/net/sourceforge/pmd/cpd/internal/JavaCCTokenizer.java">JavaCCTokenizer</a> wich has many examples you could follow, you should also take the <a href="https://github.com/pmd/pmd/blob/master/pmd-python/src/main/java/net/sourceforge/pmd/cpd/PythonTokenizer.java">Python implementation</a> as reference</li>
      <li>For any other scenario you can use <a href="https://github.com/pmd/pmd/blob/master/pmd-core/src/main/java/net/sourceforge/pmd/cpd/AnyTokenizer.java">AnyTokenizer</a></li>
    </ul>
  </li>
  <li>
    <p>Create your <a href="https://github.com/pmd/pmd/blob/master/pmd-core/src/main/java/net/sourceforge/pmd/cpd/AbstractLanguage.java">Language</a> class</p>

    <div class="language-java highlighter-rouge"><div class="highlight"><pre class="highlight"><code> <span class="kd">public</span> <span class="kd">class</span> <span class="nc">GoLanguage</span> <span class="kd">extends</span> <span class="nc">AbstractLanguage</span> <span class="o">{</span>    
        
     <span class="kd">public</span> <span class="nf">GoLanguage</span><span class="o">()</span> <span class="o">{</span>   
         <span class="kd">super</span><span class="o">(</span><span class="s">"Go"</span><span class="o">,</span> <span class="s">"go"</span><span class="o">,</span> <span class="k">new</span> <span class="nc">GoTokenizer</span><span class="o">(),</span> <span class="s">".go"</span><span class="o">);</span>   
     <span class="o">}</span>  
 <span class="o">}</span> 
</code></pre></div>    </div>

    <div class="bs-callout bs-callout-primary"><strong>Pro Tip</strong>: Yes, keep looking at Go!</div>

    <p><strong>You are almost there!</strong></p>
  </li>
  <li>
    <p>Update the list of supported languages</p>

    <ul>
      <li>
        <p>Write the fully-qualified name of your Language class to the file <code class="language-plaintext highlighter-rouge">src/main/resources/META-INF/services/net.sourceforge.pmd.cpd.Language</code></p>
      </li>
      <li>
        <p>Update the test that asserts the list of supported languages by updating the <code class="language-plaintext highlighter-rouge">SUPPORTED_LANGUAGES</code> constant in <a href="https://github.com/pmd/pmd/blob/master/pmd-dist/src/test/java/net/sourceforge/pmd/it/BinaryDistributionIT.java">BinaryDistributionIT</a></p>
      </li>
    </ul>
  </li>
  <li>
    <p>Please don’t forget to add some test, you can again.. look at Go implementation ;)</p>

    <p>If you read this far, I’m keen to think you would also love to support some extra CPD configuration (ignore imports or crazy things like that)  <br />
 If that’s your case , you came to the right place!</p>
  </li>
  <li>
    <p>You can add your custom properties using a Token filter</p>

    <ul>
      <li>
        <p>For Antlr grammars all you need to do is implement your own <a href="https://github.com/pmd/pmd/blob/master/pmd-core/src/main/java/net/sourceforge/pmd/cpd/token/AntlrTokenFilter.java">AntlrTokenFilter</a></p>

        <p>And by now, I know where you are going to look…</p>

        <p><strong>WRONG</strong></p>

        <p>Why do you want GO to solve all your problems?</p>

        <p>You should take a look to <a href="https://github.com/pmd/pmd/blob/master/pmd-kotlin/src/main/java/net/sourceforge/pmd/cpd/KotlinTokenizer.java">Kotlin token filter implementation</a></p>
      </li>
      <li>
        <p>For non-Antlr grammars you can use <a href="https://github.com/pmd/pmd/blob/master/pmd-core/src/main/java/net/sourceforge/pmd/cpd/token/internal/BaseTokenFilter.java">BaseTokenFilter</a> directly or take a peek to <a href="https://github.com/pmd/pmd/blob/master/pmd-java/src/main/java/net/sourceforge/pmd/cpd/JavaTokenizer.java">Java’s token filter</a></p>
      </li>
    </ul>
  </li>
</ol>

<h3 id="testing-your-implementation">Testing your implementation</h3>

<p>Add a Maven dependency on <code class="language-plaintext highlighter-rouge">pmd-lang-test</code> (scope <code class="language-plaintext highlighter-rouge">test</code>) in your <code class="language-plaintext highlighter-rouge">pom.xml</code>.
This contains utilities to test your Tokenizer.</p>

<p>For simple tests, create a test class extending from <code class="language-plaintext highlighter-rouge">CpdTextComparisonTest</code>.
That class is written in Kotlin, but you can extend it in Java as well.</p>

<p>To add tests, you need to write regular JUnit <code class="language-plaintext highlighter-rouge">@Test</code>-annotated methods, and
call the method <code class="language-plaintext highlighter-rouge">doTest</code> with the name of the test file.</p>

<p>For example, for the Dart language:</p>

<div class="language-java highlighter-rouge"><div class="highlight"><pre class="highlight"><code>
<span class="kd">public</span> <span class="kd">class</span> <span class="nc">DartTokenizerTest</span> <span class="kd">extends</span> <span class="nc">CpdTextComparisonTest</span> <span class="o">{</span>

    <span class="cm">/**********************************
      Implementation of the superclass
    ***********************************/</span>


    <span class="kd">public</span> <span class="nf">DartTokenizerTest</span><span class="o">()</span> <span class="o">{</span>
        <span class="kd">super</span><span class="o">(</span><span class="s">".dart"</span><span class="o">);</span> <span class="c1">// the file extension for the dart language</span>
    <span class="o">}</span>

    <span class="nd">@Override</span>
    <span class="kd">protected</span> <span class="nc">String</span> <span class="nf">getResourcePrefix</span><span class="o">()</span> <span class="o">{</span>
        <span class="c1">// If your class is in                  src/test/java     /some/package</span>
        <span class="c1">// you need to place the test files in  src/test/resources/some/package/cpdData</span>
        <span class="k">return</span> <span class="s">"cpdData"</span><span class="o">;</span>
    <span class="o">}</span>

    <span class="nd">@Override</span>
    <span class="kd">public</span> <span class="nc">Tokenizer</span> <span class="nf">newTokenizer</span><span class="o">()</span> <span class="o">{</span>
        <span class="c1">// Override this abstract method to return the correct tokenizer</span>
        <span class="k">return</span> <span class="k">new</span> <span class="nf">DartTokenizer</span><span class="o">();</span>
    <span class="o">}</span>

    <span class="cm">/**************
      Test methods
    ***************/</span>


    <span class="nd">@Test</span>  <span class="c1">// don't forget the JUnit annotation</span>
    <span class="kd">public</span> <span class="kt">void</span> <span class="nf">testLiterals</span><span class="o">()</span> <span class="o">{</span>
        <span class="c1">// This will look for a file named literals.dart</span>
        <span class="c1">// in the directory identified by getResourcePrefix,</span>
        <span class="c1">// tokenize it, then compare the result against a baseline</span>
        <span class="c1">// literals.txt file in the same directory</span>

        <span class="c1">// If the baseline file does not exist, it is created automatically</span>
        <span class="n">doTest</span><span class="o">(</span><span class="s">"literals"</span><span class="o">);</span>
    <span class="o">}</span>

<span class="o">}</span>
</code></pre></div></div>


    <div class="tags">
        
        <b>Tags: </b>
        
        
        
        <a href="tag_devdocs.html" class="btn btn-default navbar-btn cursorNorm" role="button">devdocs</a>
        
        
        
        <a href="tag_extending.html" class="btn btn-default navbar-btn cursorNorm" role="button">extending</a>
        
        
        
    </div>



</div>

<hr class="shaded"/>

<footer>
            <div class="row">
                <div class="col-lg-12 footer">
               &copy;2022 PMD Open Source Project. All rights reserved. <br />
<span>Page last updated:</span> March 18, 2019 (6.13.0)<br/> Site last generated: Jan 29, 2022 <br />
<p><img src="images/pmd-logo-small.png" alt="Company logo"/></p>
                </div>
            </div>
</footer>


        </div>
        <!-- /.row -->
    </div>
    <!-- /.container -->
</div>
</div>
</body>

</html>