Tutorial: A Guide to the Hakyll Module Zoo

Core modules
Pre-packaged solutions
Useful utilities
Advanced customization

The hakyll package contains a bewildering array of modules, and it’s hard to know where to look when you are just getting started – especially since many of them are mostly just used by Hakyll internally and not that useful to website authors. This guide provides a quick reference to the contents of the most important and useful modules.

Core modules

These are the modules containing the fundamental tools and concepts you need to get started building a site with hakyll.

Hakyll.Core.Compiler

This is one of the modules you should look at first. It defines the fundamental Compiler type and primitive Compilers as well as several variants on load, which allow you to bring together multiple resources to create a single output.
Hakyll.Core.Routes

Specify where compiled items should go in the output site.
Hakyll.Core.Rules

Specify which compilers and routes should be used on which resources. Also has combinators for versions (necessary if you want to use the same resources for multiple purposes).
Hakyll.Core.Identifier.Pattern

Combinators for creating patterns, i.e. predicates that pick out a set of resources: filesystem globs, explicit lists, regular expressions, and so on.
Hakyll.Web.Page

Provides functions for rendering your pages using pandoc, with a varying degree of high-levelness.
Hakyll.Web.Template

Templates specify how to take the content of an item and turn it into HTML output.
Hakyll.Web.Template.Context

You can’t do much with a Template if you don’t have a Context: this module provides some predefined Contexts and the tools to build your own.
Hakyll.Main

The main hakyll function that runs the whole show. There is also a hakyllWith function which allows for a custom configuration.

Pre-packaged solutions

These modules contain some “pre-packaged” solutions for common situations. They can be used as-is, or their source can be used as inspiration for your own tools.

Hakyll.Web.Template.List

Combine several pages into a list, such as a list of posts, images in a gallery, etc.
Hakyll.Web.Feed

Create RSS feeds.
Hakyll.Web.Tags

Work with tags and categories.

Useful utilities

Hakyll.Core.UnixFilter

Use any unix utility as a compiler.
Hakyll.Core.Util.String

A few utility functions for working with Strings (trim spaces, find and replace, split on regexp).

Advanced customization

Hakyll.Core.Writable

The Writable class is for resources which can be written to disk as part of the output site. You can specify how to write your own custom types to disk by giving them a Writable instance.

Documentation inaccurate or out-of-date? Found a typo?

Hakyll is an open source project, and one of the hardest parts is writing correct, up-to-date, and understandable documentation. Therefore, the authors would really appreciate it if you would give feedback about the tutorials, and especially report errors or difficulties you encountered. If you have a github account, you can use the issue system. Thanks! If you run into any problems, all questions are welcome in the above google group, or you could try the IRC channel, #hakyll on irc.libera.chat (we do not have a channel on Freenode anymore).