COBOL Code Explanation

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Code Explanation is available in two types: chat experience and code selection. By using the chat experience feature, seamlessly engage in a conversation with AI, getting quick and accurate answers to questions about code.

Note: 2.2.0+ Code Explanation service for COBOL is available On Prem.
For code explanation examples, see COBOL examples topic.

Getting started with COBOL Explanation on VS Code

You can generate an explanation for an entire COBOL file or just a selection of code. A split editor panel opens on the right of the VS Code window to display the simple, detailed, or guided explanation.

2.4.10+ Obtain summary of large COBOL programs: This feature enables you to request a summary of large COBOL files. While this request is being processed in the background, you can continue to use Code Explanation to generate explanations for other code. The resulting explanation is a Summary, regardless of the level of explanation (Simple, Detailed, or Guided) you chose.

2.6.0+ The Obtain summary of large COBOL programs feature is available in the Chat Experience. For any known limitations, see Troubleshooting.

Note: Large COBOL files may take several minutes to generate an explanation.
Complete these steps to get started with COBOL explanation.
  1. On the VS Code window, in the explorer panel, left-click a COBOL file to open it in the editor panel.
  2. Select and right-click the portion of COBOL code that you want to generate an explanation for.
  3. Hover over watsonx Code Assistant™ for Z to open the menu.
  4. Select any one of the explanation types: Simple, Detailed, or Guided.

    Once the explanation generation is complete, a notification appears with an option to open the explanation.

Generate and insert comments

2.6.10+ You can generate and add code comments for a selected code block by using the Document Code Lens or for a complete file by using the /document command.

If the AI Chat option in VS Code extension settings is disabled, the output is displayed in the side panel. If the AI Chat option is enabled, the output is displayed in a chat window.

To generate and insert code comments in the side panel by using the Document Code Lens, complete these steps.
  1. On the VS Code window, in the explorer panel, left-click a file to open it in the editor panel.
  2. Click Document Code Lens above a relevant code block. If the AI Chat option in VS Code extension settings is disabled, the Code Explanation side panel opens to the right and displays the output for the selected code block.
  3. In the panel view, click the icon labeled Insert as comment to insert the generated comments above the corresponding code block in the source file.

Using the Chat Experience feature

Note: 2.7.10+ You can generate enhanced explanations by including the comments in the source code. To do so, enable the Z Code Assistant: Enable Include Comment option in the settings.

2.8.0+To generate explanation through watsonx Code Assistant for Z Chat, see Using watsonx Code Assistant for Z Agentic chat IDE.

(2.7.20+ or earlier) To generate explanation through Chat, do the following:

  1. Click the watsonx Code Assistant extension on the side panel to open the Chat Experience feature.
  2. Enter /explain and then enter @. A menu with a list of files opens in the VS Code workspace.
  3. Select the program and press Enter. Code explanation for the selected file is displayed in the chat window. You can type in follow-on questions in the chat area to seek further responses.

Alternatively with the code open in the VS Code workspace, right-click the code snippet, and select Generate Detailed Explanation to view code explanation in the chat window. Follow-on questions are not supported for this method.

Working with code comments by using Document Code Lens

2.6.10+ To generate and insert comments for a code block by using the Chat Experience feature, complete the steps mentioned for Document Code Lens procedure. However, make sure that the AI Chat option is enabled in VS Code extension settings.

The watsonx Code Assistant chat window opens to the left and displays output for the selected code block.
  1. In the chat response, click the title of a code block to navigate to its location in the source file.
  2. Next to each code block title in the chat response, click the Insert icon to insert the comments above that block in the source file.

Working with code comments by using /document command

To generate code comments for the selected code file by using the /document command, complete these steps.
  1. Click the watsonx Code Assistant extension on the side panel to open the Chat Experience feature.

    Make sure that the AI Chat option is enabled within the watsonx Code Assistant for Z extension

  2. Enter /document and then enter @. A menu with a list of files opens in the VS Code workspace.
  3. Choose the required file.

    After a few seconds, watsonx Code Assistant generates separate comments for all code blocks (outline items that have a code lens) within the selected file in the chat window. In the chat response, you can click the title of a code block to navigate to its location in the source file.

  4. Next to each code block title in the chat response, click the Insert icon to insert the comments above that block in the source file.

Getting started with COBOL Explanation on Eclipse

2.3.0+
You can generate an explanation of an entire COBOL file or just a selection of code. When used with IBM® Developer for z/OS®, these features are also available.
  • From the outline view for COBOL Editor, paragraphs are enabled for explanations. You can choose to use a context menu or a keyboard shortcut.
  • If you select a paragraph reference name for explanation, the source code of that paragraph is explained if it is contained within the same source file.

The procedure for code explanation is the same for both VS Code and Eclipse environments.