A tool to generate documentation about Lisp projects through an HTML template.

About Staple

Staple is a documentation system. It provides you with a way to generate standalone documentation accumulated from various sources such as readmes, documentation files, and docstrings.

How To

The most trivial manner in which to use staple is to simply run it and let its inference mechanism figure out how to document your system. You can do that like so:

(staple:generate :my-system)

For best immediate results you should not load your system before you load Staple, so that Staple can record the packages the system defines as it is being loaded. If you later customise the documentation and set the packages explicitly, you don't have to watch out for that anymore, though. The documentation should land in a subdirectory called doc within the system's source directory. For ad-hoc usage you can change some of the behaviour through keyword arguments:

However, if you change any of these options, you will likely want to persist them somehow. The best way to do this is to use Staple's customisation mechanism. See the sections below for that.

You may also be interested in Staple's server system, which gives you a live documentation browser for all systems currently loaded in your Lisp image.


Staple organises itself around projects and pages. Every mechanism in it is an extension of those two concepts.


Projects represent a, well, project. This is distinct from an ASDF system, as a project might encompass multiple systems. Similarly, an ASDF system fed to generate might generate documentation for multiple ASDF systems at once. While a project might represent multiple systems, it is always identified by at least one "primary" system.

In order to get the project for a primary system, you can use find-project. This will return NIL if no specific project is defined for a system. In that case you may also use infer-project to let Staple try and figure out a project for the system automatically.

Each project is composed of a number of pages. When a project is generated, each of its pages are generated as well, producing the actual output of the project.


A page represents an output that should be generated as part of a project. Typically this will be some kind of file, like an HTML document. A page has a specific language and a title. Pages with the same title should represent the same page, but in different languages. This allows you to write multilingual documentation. More on that later.

All you can do with a page, aside from inspecting its language, title, and output, is to generate it. For anything more advanced, you should have a look at its subclasses:


This is a primitive subclass of the page that denotes some kind of input that is being transformed when the page is generated. It should be used for anything that bases its output on some kind of input file or stream.


This page simply copies the input to the output verbatim, providing a way to define static files such as images and so forth. Since images and such resources are not really "pages" per se, this might be a strange fit, but by simply leaving the title NIL, you can use the same mechanisms regardless.


Compiled pages use Staple's compile-source mechanism, which translates source in some other format like Markdown into HTML. By default only text and HTML itself is supported, but you can trivially add other formats, or use the staple-markdown system to add Markdown support automatically.


This kind of page uses the Clip system to perform a template expansion. If you want to use this kind of page, you should subclass it and add a method on template-data to supply the necessary data to the Clip template. See Clip for further information.


Often times you'll want to include a definitions index alongside the main documentation content. THis page adds additional support for this by including a list of packages to define, and several methods to aid in formatting the definitions, such as format-documentation, resolve-source-link, definition-wanted-p, and definitions. Note that this is a subclass of templated-page, meaning that if you want a definitions index, but don't want to use Clip, you'll need to do some work of your own.


This page adds some additional convenience when dealing with pages that document a specific ASDF system.


Finally, the simple page is used for inferred projects and offers a base page for easy customisation. It provides sensible defaults for definition inclusion, template data, and so forth.


Customising Staple should happen through a file called staple.ext.lisp within your primary system's root source directory. This file is automatically loaded by Staple when the system is generated, making it convenient to add extra functionality.

There's two ways in which to customise how Staple generates the documentation for your system. You can either define your own project manually for maximum control, or influence the inference mechanism for some quick and easy changes.

Custom Projects

Customising projects is easy to explain, as it simply involves adding a method to find-project specialising on your system's name that returns the readily made project instance.

(defmethod staple:find-project ((system (eql (asdf:find-system :my-system))) &key)
  #|.. create project ..|#)

See the documentation for the different kinds of pages to see what you can do with them. One thing you should always respect is the :output-directory keyword argument, which should provide the root directory in which the documentation is stored. You can find a good default using the output-directory function on your system.

You should still read the following sections, as they will show examples on how to customise pages and what kinds of functions there are to influence behaviour so that you don't necessarily need to write everything from scratch unless you want to.

Custom Inference

As mentioned in the How To section above, you can persist the different options you can pass to generate by changing the project inference. The following functions are called to determine the default values for the respective keyword arguments:

In order to override these, just write a method specialising on your system:

(defmethod staple:template ((system (eql (asdf:find-system :my-system))))
  (asdf:system-relative-pathname system #p"my-template.ctml"))

Some properties like the way documentation and docstrings are formatted require changing the way pages behave. For that, you can override the page-type similar to the above code snippet, and implement a custom page subclass as illustrated in the next section.

Custom Pages

By subclassing simple-page, you can customise all sorts of behaviours.

(defclass my-page (staple:simple-page) ())

Following are a few examples for things one might frequently want to change about the default behaviour of a page. If you are customising project inference, you can use page-type to use this page:

(defmethod staple:page-type ((system (eql (asdf:find-system :my-system))))

Changing Which Definitions are Shown

(defmethod staple:definition-wanted-p ((_ definitions:method) (__ my-page)) T)
(defmethod staple:definition-wanted-p ((_ definitions:compiler-macro) (__ my-page)) T)
(defmethod staple:definition-wanted-p ((_ definitions:macro) (__ my-page)) NIL)

This will show methods and compiler-macros, but hide macros. By default all definitions for external symbols are shown except for methods, packages, compiler-macros, and declarations.

Including Additional Definitions

(defmethod staple:definitions ((page my-page) package)
  (append (definitions:find-definitions 'cl:if)

This forces the definitions for cl:if to be included with the rest of the definitions for the packages of the page.

(defmethod staple:resolve-source-link (source (page my-page))
  (format NIL "http://someplace/view-file/~a#line-~a" 
    (make-path-relative-somehow (getf source :file))
    (getf source :row)))

Note that by default, if you set the :homepage property in your ASDF system definition to a GitHub or GitLab project URL, it will try to automatically compute the URL to GitHub's or GitLab's file viewer.

Changing Docstring Formatting

(defmethod staple:format-documentation ((docstring string) (page my-page))
  (let ((*package* (first (staple:packages page))))
     (staple:compile-source docstring :markdown))))

This will parse the docstring as Markdown and cross-reference all code snippets. Make sure to also load the staple-markdown system in your extension file.

Changing Document Formatting

(defmethod staple:compile-source ((document pathname) (page my-page))
  (staple:compile-source document :text))

This will force the document to be parsed as raw text.

Changing the Filename

(defmethod staple:filename ((page my-page))
  (make-pathname :name "foo" :type "html"))

This will force the file name of all pages to be foo.html.

Changing or Adding Template Data

(defmethod staple:template-data append ((page my-page))
  (list :title "My Title"
        :generation-time (get-universal-time)))

Due to the append method-combination and the way getf works, this will override the :title value, and add the new :generation-time value which can now be referenced from the template.

Changing Generation Behaviour

(defmethod staple:generate :after ((page my-page) &key)
  (format *debug-io* "~& Generated ~a.~%" page))

This adds a method that is called once the generation has completed, and simply prints a status message saying as much. You can use all the usual tricks of the standard method combination to customise things to your heart's content.

Custom Templates

Writing a custom template is mostly a question of writing an HTML document that you want, and then filling in the necessary Clip attributes to add the data in the right spots. Figuring this out should be pretty trivial if you have a look at the existing default template and the Clip documentation

Fixing GitHub

By default Staple outputs the documentation into the source tree of your project. This will cause GitHub to index the HTML file and, depending on circumstances, think that your project is now primarily an HTML project. To fix this issue, you should mark the documentation as ignored for GitHub's indexer. You can do this by putting the following into a .gitattributes file at the repository root:

doc/ linguist-vendored

An Example Customisation File

This is a simple example customisation file that changes the inferred project to use a custom markup syntax and package list.

(asdf:load-system :staple-markdown)

(defclass my-page (staple:simple-page) ())

(defmethod staple:page-type ((system (eql (asdf:find-system :my-system))))

(defmethod staple:packages ((system (eql (asdf:find-system :my-system))))
  (mapcar #'find-package '(:my-system :my-system-other)))

(defmethod staple:format-documentation ((docstring string) (page my-page))
  (let ((*package* (first (staple:packages page))))
     (staple:compile-source docstring :markdown))))

Custom Global Definitions

Staple has support for documenting arbitrary definition types aside from the standard top level definition types that Common Lisp exposes. This is done through the Definitions library. Please see its documentation on how to add custom definitions. You can write this extra glue code into your staple.ext.lisp file along with all the other Staple customisations. When a new definition type is defined, Staple will automatically try to find it and include it in your simple-pages. If you would like to be more selective, see definition-wanted-p above.

Also of interest are definition-id, definition-order, and definition-importance, which control the page anchors and order of appearance of definitions in an index.

System Information

Nicolas Hafner

Definition Index