Learn Handlebar Templates with Code2Prompt

Tutorial Overview

This tutorial demonstrates how to use and create custom Handlebars templates for prompt generation in code2prompt CLI.

Prerequisites

Ensure you have code2prompt installed. If you haven’t installed it yet, refer to the Installation Guide.

What are Handlebars Templates ?

Handlebars is a popular templating engine that allows you to create dynamic templates using placeholders. In code2prompt, Handlebars templates are used to format the generated prompts based on the codebase structure and user-defined variables.

How to use Handlebars Templates ?

You can use these templates by passing the -t or --template flag followed by the path to the template file. For example:

code2prompt path/to/codebase -t templates/document-the-code.hbs

Template Syntax

Handlebars templates use a simple syntax for placeholders and expressions. You will place variables in double curly braces {{variable_name}} to include them in the generated prompt. Code2prompt provides a set of default variables that you can use in your templates:

absolute_code_path: The absolute path to the codebase.
source_tree: The source tree of the codebase, which includes all files and directories.
files: A list of files in the codebase, including their paths and contents.
git_diff: The git diff of the codebase, if applicable.
code: The code content of the file being processed.
path: The path of the file being processed.

You can also use Handlebars helpers to perform conditional logic, loops, and other operations within your templates. For example:

{{#if files}}
  {{#each files}}
    File:
    {{this.path}}
    Content:
    {{this.content}}
  {{/each}}
{{else}}
  No files found.
{{/if}}

Existing Templates

code2prompt comes with a set of built-in templates for common use cases. You can find them in the templates directory.

`document-the-code.hbs`

Use this template to generate prompts for documenting the code. It will add documentation comments to all public functions, methods, classes and modules in the codebase.

`find-security-vulnerabilities.hbs`

Use this template to generate prompts for finding potential security vulnerabilities in the codebase. It will look for common security issues and provide recommendations on how to fix or mitigate them.

`clean-up-code.hbs`

Use this template to generate prompts for cleaning up and improving the code quality. It will look for opportunities to improve readability, adherence to best practices, efficiency, error handling, and more.

`fix-bugs.hbs`

Use this template to generate prompts for fixing bugs in the codebase. It will help diagnose issues, provide fix suggestions, and update the code with proposed fixes.

`write-github-pull-request.hbs`

Use this template to create GitHub pull request description in markdown by comparing the git diff and git log of two branches.

`write-github-readme.hbs`

Use this template to generate a high-quality README file for the project, suitable for hosting on GitHub. It will analyze the codebase to understand its purpose and functionality, and generate the README content in Markdown format.

`write-git-commit.hbs`

Use this template to generate git commits from the staged files in your git directory. It will analyze the codebase to understand its purpose and functionality, and generate the git commit message content in Markdown format.

`improve-performance.hbs`

Use this template to generate prompts for improving the performance of the codebase. It will look for optimization opportunities, provide specific suggestions, and update the code with the changes.

User Defined Variables

code2prompt supports the use of user defined variables in the Handlebars templates. Any variables in the template that are not part of the default context (absolute_code_path, source_tree, files) will be treated as user defined variables.

During prompt generation, code2prompt will prompt the user to enter values for these user defined variables. This allows for further customization of the generated prompts based on user input.

For example, if your template includes {{challenge_name}} and {{challenge_description}}, you will be prompted to enter values for these variables when running code2prompt.

This feature enables creating reusable templates that can be adapted to different scenarios based on user provided information.