18. Commenter

Edit pageLast modified: 19 March 2025

Reference: Comment Code

Code: SimpleCommenter

Testing: 9. Commenter Test

tip

This page is part of multi-step Custom Language Support Tutorial. All previous steps must be executed in sequence for the code to work.

A commenter enables the user to comment-out a line of code at the cursor or selected code automatically. The Commenter defines support for Code | Comment with Line Comment and Code | Comment with Block Comment actions.

Define a Commenter

The SimpleCommenter for Simple Language defines the line comment prefix as #.

final class SimpleCommenter implements Commenter {

  @Override
  public String getLineCommentPrefix() {
    return "#";
  }

  @Override
  public String getBlockCommentPrefix() {
    return "";
  }

  @Nullable
  @Override
  public String getBlockCommentSuffix() {
    return null;
  }

  @Nullable
  @Override
  public String getCommentedBlockCommentPrefix() {
    return null;
  }

  @Nullable
  @Override
  public String getCommentedBlockCommentSuffix() {
    return null;
  }

}

Register the Commenter

The SimpleCommenter implementation is registered in the plugin configuration file using the com.intellij.lang.commenter extension point.

<extensions defaultExtensionNs="com.intellij">
  <lang.commenter
      language="Simple"
      implementationClass="org.intellij.sdk.language.SimpleCommenter"/>
</extensions>

Run the Project

Run the plugin by using the Gradle runIde task.

Open the example Simple Language properties file in the IDE Development Instance. Place the cursor at the website line. Select Code | Comment with Line Comment. The line is converted to a comment. Select Code | Comment with Line Comment again, and the comment is converted back to active code.

Commenter