# 40Ants Doc Manual¶

This system is a fork of MGL-PAX.

There are a few reasons, why I've created the fork.

The main goal is to extract a core features into the 40ants-doc system with as little dependencies as possible. This is important, because with MGL-PAX's style, you define documentation sections in your library's code, which makes it dependent on the documentation system. However, heavy weight dependencies like IRONCLAD, 3BMD or SWANK should not be required.

The seconds goal was to refactor a 3.5k lines of pax.lisp file into a smaller modules to make navigation easier. This will help any person who will decide to learn how the documentation builder works. Also, granular design will make it possible loading subsystems like SLIME or SLY integration.

The third goal was to make documentation processing more sequential and hackable. To introduce hooks for adding new markup languages, and HTML themes.

### Why this fork is different ¶

Here are features already implemented in this fork:

• Core system 40ants-doc now has only two dependencies on NAMED-READTABLES and PYTHONIC-STRING-READER. If you want to compile a documentation, load 40ants-doc-full system which will download such dependencies as markdown parser and more.

• Now you don't have to import any locative symbols into your package. Import only a defsection macro and it will be enough to define documentation for your library!

• Added a warning mechanism, which will issue such warnings on words which looks like a symbol, but when real symbol or reference is absent:

 WARNING: Unable to find target for reference #<XREF "FIND-SOURCE" GENERIC-FUNCTION> mentioned at 40Ants Doc Manual / Extension API / Reference Based Extensions 

• Documentation processing now uses CommonDoc as intermediate format, and markup languages other than Markdown can be supported.

• Added a JS search index which will work when you are hosting pages on a static website like GitHub pages.

• It is possible to render pages in multiple formats and having cross references between them. See Multiple Formats.

I'm planning to extend this fork even more. Read todo section to learn about proposed features or start a new discussion on the GitHub to suggest a new feature.

See full list of changes in the ChangeLog section.

## 40ANTS-DOC-FULL ASDF System Details

Here is the official repository and the HTML documentation for the latest version.

This system is a fork of the MGL-PAX. Because of massive refactoring, it is incompatible with original repository.

## Background ¶

Here is the story behind the MGL-PAX, precursor of 40ants-doc, written by Gábor Melis.

As a user, I frequently run into documentation that's incomplete and out of date, so I tend to stay in the editor and explore the code by jumping around with SLIME's M-.. As a library author, I spend a great deal of time polishing code, but precious little writing documentation.

In fact, I rarely write anything more comprehensive than docstrings for exported stuff. Writing docstrings feels easier than writing a separate user manual and they are always close at hand during development. The drawback of this style is that users of the library have to piece the big picture together themselves.

That's easy to solve, I thought, let's just put all the narrative that holds docstrings together in the code and be a bit like a Literate Programming weenie turned inside out. The original prototype which did almost everything I wanted was this:

(defmacro defsection (name docstring)
(defun ,name () ,docstring))

Armed with defsection, I soon found myself organizing code following the flow of user level documentation and relegated comments to implementational details entirely. However, some portions of defsection docstrings were just listings of all the functions, macros and variables related to the narrative, and this list was effectively repeated in the DEFPACKAGE form complete with little comments that were like section names. A clear violation of OAOO, one of them had to go, so defsection got a list of symbols to export.

That was great, but soon I found that the listing of symbols is ambiguous if, for example, a function, a compiler macro and a class are named by the same symbol. This did not concern exporting, of course, but it didn't help readability. Distractingly, on such symbols, M-. was popping up selection dialogs. There were two birds to kill, and the symbol got accompanied by a type which was later generalized into the concept of locatives:

(defsection @introduction ()
"A single line for one man ..."
(foo class)
(bar function))

After a bit of elisp hacking, M-. was smart enough to disambiguate based on the locative found in the vicinity of the symbol and everything was good for a while.

Then I realized that sections could refer to other sections if there were a section locative. Going down that path, I soon began to feel the urge to generate pretty documentation as all the necessary information was manifest in the defsection forms. The design constraint imposed on documentation generation was that following the typical style of upcasing symbols in docstrings there should be no need to explicitly mark up links: if M-. works, then the documentation generator shall also be able find out what's being referred to.

I settled on Markdown as a reasonably non-intrusive format, and a few thousand lines later MGL-PAX was born.

## Tutorial¶

40ants-doc provides an extremely poor man's Explorable Programming environment. Narrative primarily lives in so called sections that mix markdown docstrings with references to functions, variables, etc, all of which should probably have their own docstrings.

The primary focus is on making code easily explorable by using SLIME's M-. (slime-edit-definition). See how to enable some fanciness in Emacs Integration. Generating documentation from sections and all the referenced items in Markdown or HTML format is also implemented.

With the simplistic tools provided, one may accomplish similar effects as with Literate Programming, but documentation is generated from code, not vice versa and there is no support for chunking yet. Code is first, code must look pretty, documentation is code.

When the code is loaded into the lisp, pressing M-. in SLIME on the name of the section will take you there. Sections can also refer to other sections, packages, functions, etc and you can keep exploring.

Here is an example of how it all works together:

(uiop:define-package #:foo-random
(:documentation "This package provides various utilities for
random. See @FOO-RANDOM-MANUAL.")
(:use #:common-lisp
#:40ants-doc)
(:import-from #:40ants-doc/ignored-words
#:ignore-words-in-package)
(:export #:foo-random-state
#:state
#:*foo-state*
#:gaussian-random
#:uniform-random))

(in-package foo-random)

(defsection @foo-random-manual (:title "Foo Random manual"
:ignore-words ("FOO"))
"Here you describe what's common to all the referenced (and
exported) functions that follow. They work with *FOO-STATE*,
and have a :RANDOM-STATE keyword arg. Also explain when to
choose which."
(foo-random-state class)

"Hey we can also print states!"

(print-object (method () (foo-random-state t)))
(*foo-state* variable)
(gaussian-random function)
(uniform-random function)
;; this is a subsection
(@foo-random-examples section))

(defclass foo-random-state ()
:documentation "Returns random foo's state.")))

(defmethod print-object ((object foo-random-state) stream)

(defvar *foo-state* (make-instance 'foo-random-state)
"Much like *RANDOM-STATE* but uses the FOO algorithm.")

(defun uniform-random (limit &key (random-state *foo-state*))
"Return a random number from the between 0 and LIMIT (exclusive)
uniform distribution."
(declare (ignore limit random-state))
nil)

(defun gaussian-random (stddev &key (random-state *foo-state*))
"Return not a random number from a zero mean normal distribution with
STDDEV."
(declare (ignore stddev random-state))
nil)

(defsection @foo-random-examples (:title "Examples")
"Let's see the transcript of a real session of someone working
with FOO:

cl-transcript
(values (princ :hello) (list 1 2))
.. HELLO
=> :HELLO
=> (1 2)

(make-instance 'foo-random-state)
==> #<FOO-RANDOM-STATE >
")



Generating documentation in a very stripped down markdown format is easy:

(40ants-doc/builder:render-to-string
@foo-random-manual
:format :markdown)

For this example, the generated markdown would look like this:

<a id="x-28FOO-RANDOM-3A-3A-40FOO-RANDOM-MANUAL-2040ANTS-DOC-2FLOCATIVES-3ASECTION-29"></a>

# Foo Random manual

Here you describe what's common to all the referenced (and
exported) functions that follow. They work with [*foo-state*][2133],
and have a :RANDOM-STATE keyword arg. Also explain when to
choose which.

<a id="x-28FOO-RANDOM-3AFOO-RANDOM-STATE-20CLASS-29"></a>

## [class](cea4) foo-random:foo-random-state ()

## [reader](6a02) foo-random:state (foo-random-state) ()

Returns random foo's state.

Hey we can also print states!

<a id="x-28PRINT-OBJECT-20-28METHOD-20NIL-20-28FOO-RANDOM-3AFOO-RANDOM-STATE-20T-29-29-29"></a>

## [method](8792) common-lisp:print-object (object foo-random-state) stream

<a id="x-28FOO-RANDOM-3A-2AFOO-STATE-2A-20-28VARIABLE-29-29"></a>

## [variable](0537) foo-random:*foo-state* #<foo-random-state >

Much like *RANDOM-STATE* but uses the FOO algorithm.

<a id="x-28FOO-RANDOM-3AGAUSSIAN-RANDOM-20FUNCTION-29"></a>

## [function](c92b) foo-random:gaussian-random stddev &key (random-state \*foo-state\*)

Return not a random number from a zero mean normal distribution with
STDDEV.

<a id="x-28FOO-RANDOM-3AUNIFORM-RANDOM-20FUNCTION-29"></a>

## [function](6ec3) foo-random:uniform-random limit &key (random-state \*foo-state\*)

Return a random number from the between 0 and LIMIT (exclusive)
uniform distribution.

<a id="x-28FOO-RANDOM-3A-3A-40FOO-RANDOM-EXAMPLES-2040ANTS-DOC-2FLOCATIVES-3ASECTION-29"></a>

## Examples

Let's see the transcript of a real session of someone working
with FOO:

cl-transcript
(values (princ :hello) (list 1 2))
.. HELLO
=> :HELLO
=> (1 2)

(make-instance 'foo-random-state)
==> #<FOO-RANDOM-STATE >


[2133]: #x-28FOO-RANDOM-3A-2AFOO-STATE-2A-20-28VARIABLE-29-29
[cea4]: https://github.com/40ants/doc/blob/8de59028c489a62cf0a4cb528749a19a523c7bea/tutorial.lisp#L34
[6a02]: https://github.com/40ants/doc/blob/8de59028c489a62cf0a4cb528749a19a523c7bea/tutorial.lisp#L35
[8792]: https://github.com/40ants/doc/blob/8de59028c489a62cf0a4cb528749a19a523c7bea/tutorial.lisp#L38
[0537]: https://github.com/40ants/doc/blob/8de59028c489a62cf0a4cb528749a19a523c7bea/tutorial.lisp#L41
[6ec3]: https://github.com/40ants/doc/blob/8de59028c489a62cf0a4cb528749a19a523c7bea/tutorial.lisp#L44
[c92b]: https://github.com/40ants/doc/blob/8de59028c489a62cf0a4cb528749a19a523c7bea/tutorial.lisp#L50

MGL-PAX supported the plain text format which was more readble when viewed from a simple text editor, but I've dropped support for plain text in this fork because most time documentation are read in the browser these days.

To render into the files, use 40ants-doc/builder:render-to-files and 40ants-doc/builder:update-asdf-system-docs functions.

Last one can even generate documentation for different, but related libraries at the same time with the output going to different files, but with cross-page links being automatically added for symbols mentioned in docstrings. See Generating Documentation for some convenience functions to cover the most common cases.

Note how (*FOO-STATE* VARIABLE) in the defsection form includes its documentation in @FOO-RANDOM-MANUAL. The symbols variable and function are just two instances of 'locatives' which are used in defsection to refer to definitions tied to symbols. See Locative Types.

The transcript in the code block tagged with cl-transcript is automatically checked for up-to-dateness. See Transcripts.

## Emacs Integration ¶

Integration into SLIME's M-. (slime-edit-definition) allows one to visit the source location of the thing that's identified by a symbol and the locative before or after the symbol in a buffer. With this extension, if a locative is the previous or the next expression around the symbol of interest, then M-. will go straight to the definition which corresponds to the locative. If that fails, M-. will try to find the definitions in the normal way which may involve popping up an xref buffer and letting the user interactively select one of possible definitions.

Note that the this feature is implemented in terms of SWANK-BACKEND:FIND-SOURCE-LOCATION and SWANK-BACKEND:FIND-DEFINITIONS whose support varies across the Lisp implementations. Sadly, but this integration does not with SLY because it does not support hooks on finding definition.

In the following examples, pressing M-. when the cursor is on one of the characters of FOO or just after FOO, will visit the definition of function FOO:

function foo
foo function
(function foo)
(foo function)


In particular, references in a defsection form are in (SYMBOL locative) format so M-. will work just fine there.

Just like vanilla M-., this works in comments and docstrings. In this example pressing M-. on FOO will visit FOO's default method:

;;;; See FOO (method () (t t t)) for how this all works.
;;;; But if the locative has semicolons inside: FOO (method
;;;; () (t t t)), then it won't, so be wary of line breaks
;;;; in comments.

With a prefix argument (C-u M-.), one can enter a symbol plus a locative separated by whitespace to preselect one of the possibilities.

The M-. extensions can be enabled by adding this to your Emacs initialization file (or loading src/pax.el):

;;; M-. integration

(defun 40ants-doc-edit-locative-definition (name &optional where)
(or (40ants-doc-locate-definition name (40ants-doc-locative-before))
(40ants-doc-locate-definition name (40ants-doc-locative-after))
(40ants-doc-locate-definition name (40ants-doc-locative-after-in-brackets))
;; support "foo function" and "function foo" syntax in
;; interactive use
(let ((pos (cl-position ?\s name)))
(when pos
(or (40ants-doc-locate-definition (cl-subseq name 0 pos)
(cl-subseq name (1+ pos)))
(40ants-doc-locate-definition (cl-subseq name (1+ pos))
(cl-subseq name 0 pos)))))))

(defun 40ants-doc-locative-before ()
(ignore-errors (save-excursion
(slime-beginning-of-symbol)
(slime-last-expression))))

(defun 40ants-doc-locative-after ()
(ignore-errors (save-excursion
(slime-end-of-symbol)
(slime-forward-sexp)
(slime-last-expression))))

(defun 40ants-doc-locative-after-in-brackets ()
(ignore-errors (save-excursion
(slime-end-of-symbol)
(skip-chars-forward "" (+ (point) 1))
(when (and (= 1 (skip-chars-forward "\\]" (+ (point) 1)))
(= 1 (skip-chars-forward "\\[" (+ (point) 1))))
(buffer-substring-no-properties
(point)
(progn (search-forward "]" nil (+ (point) 1000))
(1- (point))))))))

(defun 40ants-doc-locate-definition (name locative)
(when locative
(let ((location
(slime-eval
;; Silently fail if mgl-pax is not loaded.
(cl:when (cl:find-package :mgl-pax)
(cl:funcall
(cl:find-symbol
(cl:symbol-name :locate-definition-for-emacs) :mgl-pax)
,name ,locative)))))
(when (and (consp location)
(not (eq (car location) :error)))
(slime-edit-definition-cont
(list (make-slime-xref :dspec (,name)
:location location))
"dummy name"
where)))))

(when (boundp 'slime-edit-definition-hooks)

• name locative-string

Note, there is also another part of Emacs code, related to transcription blocks. It is described in Transcripts section.

## Basics¶

Now let's examine the most important pieces in detail.

### Defining Sections ¶

Define a documentation section and maybe export referenced symbols. A bit behind the scenes, a global variable with NAME is defined and is bound to a section object. By convention, section names start with the character @. See Tutorial for an example.

ENTRIES consists of docstrings and references. Docstrings are arbitrary strings in markdown format, references are defined in the forms:

(symbol locative) or ((symbol1 symbol2 ... symboln) locative)


For example, (FOO FUNCTION) refers to the function FOO, (@BAR SECTION) says that @BAR is a subsection of this one. (BAZ (METHOD () (T T T))) refers to the default method of the three argument generic function BAZ. (FOO FUNCTION) is equivalent to (FOO (FUNCTION)).

A locative in a reference can either be a symbol or it can be a list whose CAR is a symbol. In either case, the symbol is the called the type of the locative while the rest of the elements are the locative arguments. See Locative Types for the list of locative types available out of the box.

The same symbol can occur multiple times in ENTRIES, typically with different locatives, but this is not required.

The references are not looked up (see 40ants-doc/reference:resolve in the Extension API) until documentation is generated, so it is allowed to refer to things yet to be defined.

If you set :EXPORT to true, the referenced symbols and NAME are candidates for exporting. A candidate symbol is exported if

The original idea with confounding documentation and exporting is to force documentation of all exported symbols. However when forking MGL-PAX into 40ants-doc I've decided explicit imports make code more readable, and changed the default for :EXPORT argument to NIL and added automatic warnings to help find exported symbols not referenced from the documention.

If you decide to use :EXPORT t argument, note it will cause package variance error on SBCL. To prevent it, use UIOP:DEFINE-PACKAGE instead of CL:DEFPACKAGE.

:TITLE is a non-marked-up string or NIL. If non-nil, it determines the text of the heading in the generated output. :LINK-TITLE-TO is a reference given as an (OBJECT LOCATIVE) pair or NIL, to which the heading will link when generating HTML. If not specified, the heading will link to its own anchor.

When :DISCARD-DOCUMENTATION-P (defaults to *discard-documentation-p*) is true, ENTRIES will not be recorded to save memory.

EXTERNAL-DOCS argument can be a list of URLs leading to documentation of other libraries. These libraries should be documented using 40ants-doc and you'll be able to mention symbols from them and have automatic cross-links.

EXTERNAL-LINKS argument could contain an alist of ("name" . "URL") pairs. These pairs will be tranformed to name: URL text and appended to each markdown part of the defined chapter. This argument is useful when you are having more than one text part in the chapter and want to reference same URL from all of them using short markdown links.

:IGNORE-WORDS allows to pass a list of strings which should not cause warnings. Usually these are uppercased words which are not symbols in the current package, like SLIME, LISP, etc.

• name section

When you use DOCS-BUILDER, you might want to define a @readme variable to make README.md file with the same content as your main documentation. This case might be popular for libraries having a short documentation.

To define @readme as a copy of the main doc, export @readme symbol and do this in the code:

(defparameter @readme (40ants-doc:copy-section @index))
• nil

The default value of defsection's DISCARD-DOCUMENTATION-P argument. One may want to set *DISCARD-DOCUMENTATION-P* to true before building a binary application.

• obj

Returns a list of words or symbols to ignore in OBJ's documentation.

• &rest symbols-or-strings

Adds given symbols or string to ignore list bound to the current package.

You will not be warned when one of these symbols is not documented or documented and not exported from the package.

### Cross-referencing ¶

You can cross-reference entries from different documentation parts be it content of the defsection or a documentation string of some lisp entity.

The simples form of cross reference is uppercased name of the entity, like: 40ants-doc/reference:make-reference. But if there are more than one locative bound to the name, then all these links will be rendered in a parenthesis. For example, docstring:

See 40ANTS-DOC/SOURCE-API:FIND-SOURCE.

will be rendered as "See 40ants-doc/source-api:find-source (1 2)." because there is a generic-function and a method called FIND-SOURCE.

But you can mention a locative type in a docstring before or after a symbol name:

See 40ANTS-DOC/SOURCE-API:FIND-SOURCE generic-function.

and it will be rendered as: See 40ants-doc/source-api:find-source generic-function.

In case if you don't want locative type to appear in the resulting documentation or if locative type is complex, then you can use in a docstring markdown reference:

See [40ANTS-DOC/SOURCE-API:FIND-SOURCE][(method () (40ants-doc/reference:reference))].

and link will lead to the specified method: See 40ants-doc/source-api:find-source.

## Generating Documentation ¶

To make documentation builder work, you need to load 40ants-doc-full asdf system.

There are two core functions which render documentation to a string or files:

• object &key (format :html) (source-uri-fn 40ants-doc/reference-api:\*source-uri-fn\*) (full-package-names t)

Renders given CommonDoc node into the string using specified format. Supported formats are :HTML and :MARKDOWN.

This function is useful for debugging 40ants-doc itself.

• sections &key (theme '40ants-doc/themes/default:default-theme) (base-dir #p"./") (base-url nil) (source-uri-fn 40ants-doc/reference-api:\*source-uri-fn\*) (warn-on-undocumented-packages 40ants-doc/commondoc/page::\*warn-on-undocumented-packages\*) (clean-urls 40ants-doc/rewrite::\*clean-urls\*) (downcase-uppercase-code 40ants-doc/builder/vars::\*downcase-uppercase-code\*) (format :html) highlight-languages highlight-theme (full-package-names t)

Renders given sections or pages into a files on disk.

By default, it renders in to HTML, but you can specify FORMAT argument. Supported formats are :HTML and :MARKDOWN.

Returns an absolute pathname to the output directory as the first value and pathnames corresponding to each of given sections.

When WARN-ON-UNDOCUMENTED-PACKAGES is true, then builder will check if there are other packages of the package-inferred system with external but not documented symbols. Otherwise, external symbols are searched only in packages with at least one documented entity.

If CLEAN-URLS is true, then builder rewrites filenames and urls to make it possible to host files on site without showing .html files inside. Also, you need to specify a BASE-URL, to make urls absolute if you are rendering markdown files together with HTML.

If DOWNCASE-UPPERCASE-CODE is true, then all references to symbols will be downcased.

THEME argument should be a theme class name. By default it is 40ants-doc/themes/default:default-theme. See Defining a Custom Theme to learn how to define themes.

HIGHLIGHT-LANGUAGES and HIGHLIGHT-THEME arguments allow to redefine theme's settings for Highlight.js. Languages should be a list of strings where each item is a language name, supported by Highlight.js. Theme should be a name of a supported theme. You can preview different highlighting themes here

When FULL-PACKAGE-NAMES is true (default), then all symbols in documentation headers are rendered in their fully qualified form. This helps a lot when you are documenting a package inferred ASDF system.

When building HTML documentation, this function also renders and index file references.json with references to all documented entities. You can give a list of urls to such reference files as EXTERNAL-DOCS argument of defsection macro if you want to reference entities from other libraries.

Besides render-to-string and render-to-files a convenience function is provided to serve the common case of having an ASDF system with a readme and a directory for the HTML documentation.

• SECTIONS-OR-PAGES ASDF-SYSTEM &KEY (README-SECTIONS NIL) (CHANGELOG-SECTIONS NIL) (THEME '40ANTS-DOC/THEMES/DEFAULT:DEFAULT-THEME) (WARN-ON-UNDOCUMENTED-PACKAGES 40ANTS-DOC/COMMONDOC/PAGE::\*WARN-ON-UNDOCUMENTED-PACKAGES\*) (BASE-URL NIL) (DOCS-DIR #P"docs/") (CLEAN-URLS 40ANTS-DOC/REWRITE::\*CLEAN-URLS\*) (DOWNCASE-UPPERCASE-CODE 40ANTS-DOC/BUILDER/VARS::\*DOWNCASE-UPPERCASE-CODE\*) HIGHLIGHT-LANGUAGES HIGHLIGHT-THEME (FULL-PACKAGE-NAMES T)

Generate pretty HTML documentation for a single ASDF system, possibly linking to github. If you are migrating from MGL-PAX, then note, this function replaces UPDATE-ASDF-SYSTEM-HTML-DOCS and UPDATE-ASDF-SYSTEM-README while making it possible to generate a crosslinks between README.md and HTML docs. The same way you can generate a ChangeLog.md file using :CHANGELOG-SECTIONS argument. See Changelog Generation section to learn about 40ants-doc/changelog:defchangelog helper.

Both :README-SECTIONS and :CHANGELOG-SECTIONS arguments may be a single item or a list.

See docs on render-to-files function to learn about meaning of BASE-DIR, BASE-URL, SOURCE-URI-FN, WARN-ON-UNDOCUMENTED-PACKAGES, CLEAN-URLS, DOWNCASE-UPPERCASE-CODE, THEME, HIGHLIGHT-LANGUAGES and HIGHLIGHT-THEME arguments.

Example usage:

(40ants-doc/builder:update-asdf-system-docs 40ants-doc/doc:@index
:40ants-doc
:readme-sections 40ants-doc/doc:@readme)

This is just a shorthand to call render-to-files for ASDF system.

All sections, listed in :README-SECTIONS argment will be concantenated into the README.md. Some symbols, referenced in the :README-SECTIONS but not documented there will be linked to the HTML documentation. To make this work for a hosted static sites, then provide :BASE-URL of the site, otherwise, links will be relative.

In MGL-PAX this function supported such parameters as :UPDATE-CSS-P and :PAGES, but in 40ants-doc javascript and CSS files are updated automatically. See documentation on render-to-files to learn how does page separation and other parameters work.

If you want a more generic wrapper for building documentation for your projects, take a look at DOCS-BUILDER.

• Returns an ASDF system currently documented by call to update-asdf-system-docs.

This function can be used by your extensions to do add some additional features like github stripe "Fork Me".

• nil

A list of blocks of links to be display on the sidebar on the left, above the table of contents. A block is of the form (&KEY TITLE ID LINKS), where TITLE will be displayed at the top of the block in a HTML div with id, followed by the links. LINKS is a list of (URI LABEL) elements.

Is not supported yet.

### Multiple Formats ¶

With 40ants-doc you can render HTML and Markdown documentation simultaneously. This way, you can cross-reference entities from the README.md or ChangeLog.md to HTML docs.

To render documents in multiple formats, you have to pass to function render-to-files not 40ants-doc:section objects, but PAGE objects. Page object consists of one or more sections and additional information such as document format. A section can belong to a multiple pages usually having different formats. This allows you to include "tutorial" section into both HTML docs and README.

Here is an example of rendering the full documentation and a README with only introduction and tutorial:

(defsection @full-manual (:title "Manual")
(@introduction)
(@tutorial)
(@api)
(@changelog))

(render-to-files
(list @full-manual
(40ants-doc/page:make-page (list @introduction
@tutorial)
:format :markdown
(40ants-doc/page:make-page @changelog
:format :markdown
:base-filename "ChangeLog")))

The same approach works with the update-asdf-system-docs function.

### Changelog Generation ¶

• (&KEY (TITLE "ChangeLog") IGNORE-WORDS EXTERNAL-DOCS EXTERNAL-LINKS) &BODY VERSIONS

This macro might be used to define a ChangeLog in a structured way. With defchangelog you specify a body where each sublist starts with a version number and the rest is it's description in the markdown format. You can mention symbols from the rest of the documentation and they will be cross-linked automatically if you are using 40ants-doc/builder:update-asdf-system-docs function.

Here is an example:

(defchangelog ()
(0.2.0
"- Feature B implemented.
- Bug was fixed in function FOO.")

(0.1.0
"- Project forked from [MGL-PAX](https://github.com/melisgl/mgl-pax).
- Feature A implemented."))

### Github Workflow ¶

It is generally recommended to commit generated readmes (see 40ants-doc/builder:update-asdf-system-docs) so that users have something to read without reading the code and sites like github can display them.

HTML documentation can also be committed, but there is an issue with that: when linking to the sources (see make-github-source-uri-fn), the commit id is in the link. This means that code changes need to be committed first, then HTML documentation regenerated and committed in a followup commit.

To serve static documentation, use gh-pages. You can use a separate branch gh-pages, or point GitHub Pages to a docs folder inside the main branch. Good description of this process is http://sangsoonam.github.io/2019/02/08/using-git-worktree-to-deploy-github-pages.html. Two commits needed still, but it is somewhat less painful.

This way the HTML documentation will be available at http://<username>.github.io/<repo-name>. It is probably a good idea to add section like the Links section to allow jumping between the repository and the gh-pages site.

• asdf-system &key github-uri git-version

Return a function suitable as :SOURCE-URI-FN of the 40ants-doc/builder:render-to-files function. The function looks the source location of the reference passed to it, and if the location is found, the path is made relative to the root directory of ASDF-SYSTEM and finally an URI pointing to github is returned. The URI looks like this:

https://github.com/melisgl/mgl-pax/blob/master/src/pax-early.lisp#L12


"master" in the above link comes from GIT-VERSION.

If GIT-VERSION is NIL, then an attempt is made to determine to current commit id from the .git in the directory holding ASDF-SYSTEM. If no .git directory is found, then no links to github will be generated.

If GITHUB-URI argument is not given, function will try to get URL from ASDF system's description. To make this work, your system description should look like this:

(defsystem 40ants-doc
...
:source-control (:git "https://github.com/40ants/doc")
...))))

A separate warning is signalled whenever source location lookup fails or if the source location points to a directory not below the directory of ASDF-SYSTEM.

### PAX World¶

MGL-PAX supported a "World" which was a registry of documents, which can generate cross-linked HTML documentation pages for all the registered documents.

But I decided to drop this feature for now, because usually build libraries documentation separately as part of their CI pipline.

If somebody want's cross referencing between different libraries, then instead of building their docs simultaneously, I'd suggest to create an index of entities, provided by libraries and to store them as a JSON file along with a library documentation.

This way it will be possible to enumerate such sources of cross references as usual URLs.

Such feature is not implemented in the 40ants-doc system yet, but probably it will be useful for libraries built around the Weblocks. If you want to help and implement the feature, please, let me know.

## Markdown Support ¶

The Markdown in docstrings is processed with the 3BMD library.

### Indentation ¶

Docstrings can be indented in any of the usual styles. 40ants-doc normalizes indentation by converting:

(defun foo ()
"This is
indented
differently")

to

(defun foo ()
"This is
indented
differently")

Docstrings in sources are indented in various ways which can easily mess up markdown. To handle the most common cases leave the first line alone, but from the rest of the lines strip the longest run of leading spaces that is common to all non-blank lines."

### Syntax highlighting ¶

For syntax highlighting, github's fenced code blocks markdown extension to mark up code blocks with triple backticks is enabled so all you need to do is write:

elisp
(defun foo ())



to get syntactically marked up HTML output. The language tag, elisp in this example, is optional and defaults to commonlisp.

Originally MGL-PAX used colorize for the syntax highlighting, but 40ants-doc uses Highlight.js which is able to guess code block language if it is not specified. To minimize HTML document's static size, Hightlight.js is configured to support only these languages:

• bash

• css

• json

• yaml

• plain-text

• html

• markdown

• lisp

There is a separate README where you will find instructions on how to support other languages.

Besides an automatic language detection, the other cool feature of Highlight.js is it's support for different color themes. Here you can view all available themes: https://highlightjs.org/static/demo/. There is no easy way to choose color theme yet, but probably this will be a nice feature for 40ants-doc.

### MathJax ¶

Displaying pretty mathematics in TeX format is supported via MathJax. It can be done inline with $ like this: $\int_0^\infty e^{-x^2} dx=\frac{\sqrt{\pi}}{2}$ which is diplayed as$\int_0^\infty e^{-x^2} dx=\frac{\sqrt{\pi}}{2}$, or it can be delimited by $$ like this: $$\int_0^\infty e^{-x^2} dx=\frac{\sqrt{\pi}}{2}$$ to get:$$\int_0^\infty e^{-x^2} dx=\frac{\sqrt{\pi}}{2}$$MathJax will leave code blocks (including those inline with backticks) alone. Outside code blocks, escape $ by prefixing it with a backslash to scare MathJax off.

Escaping all those backslashes in TeX fragments embedded in Lisp strings can be a pain. Pythonic String Reader can help with that.

## Documentation Printer Variables ¶

Docstrings are assumed to be in markdown format and they are pretty much copied verbatim to the documentation subject to a few knobs described below.

Note, some of these variables might be not supported yet in this fork.

• t

When true, words with at least three characters and no lowercase characters naming an interned symbol are assumed to be code as if they were marked up with backticks which is especially useful when combined with 40ants-doc/link:*document-link-code*. For example, this docstring:

"FOO and FOO."


is equivalent to this:

"FOO and FOO."


if FOO is an interned symbol.

• t

When true, during the process of generating documentation for a 40ants-doc:section class, HTML anchors are added before the documentation of every reference that's not to a section. Also, markdown style reference links are added when a piece of inline code found in a docstring refers to a symbol that's referenced by one of the sections being documented. Assuming BAR is defined, the documentation for:

(defsection @foo
(foo function)
(bar function))

(defun foo (x)
"Calls BAR on X."
(bar x))

would look like this:

- [function] FOO X

Calls [BAR][1] on X.


Instead of BAR, one can write [bar][] or [bar][] as well. Since symbol names are parsed according to READTABLE-CASE, character case rarely matters.

Now, if BAR has references with different locatives:

(defsection @foo
(foo function)
(bar function)
(bar type))

(defun foo (x)
"Calls BAR on X."
(bar x))

then documentation would link to all interpretations:

- [function] FOO X

Calls BAR([1][link-id-1] [2][link-id-2]) on X.


This situation occurs with 40ants-doc:section which is both a class (see 40ants-doc:section class) and a locative type denoted by a symbol (see 40ants-doc/locatives:section locative). Back in the example above, clearly, there is no reason to link to type BAR, so one may wish to select the function locative. There are two ways to do that. One is to specify the locative explicitly as the id of a reference link:

"Calls [BAR][function] on X."


However, if in the text there is a locative immediately before or after the symbol, then that locative is used to narrow down the range of possibilities. This is similar to what the M-. extension does. In a nutshell, if M-. works without questions then the documentation will contain a single link. So this also works without any markup:

"Calls function BAR on X."


This last option needs backticks around the locative if it's not a single symbol.

Note that *DOCUMENT-LINK-CODE* can be combined with 40ants-doc/builder/printer:*document-uppercase-is-code* to have links generated for uppercase names with no quoting required.

• 3

A non-negative integer. In their hierarchy, sections on levels less than this value get numbered in the format of 3.1.2. Setting it to 0 turns numbering off.

Is not supported yet.

## Locative Types ¶

These are the locatives type supported out of the box. As all locative types, they are symbols and their names should make it obvious what kind of things they refer to. Unless otherwise noted, locatives take no arguments.

• This package holds all symbols denoting 40ants-doc locatives.

It serves for a forward declaration of supported locatives. To build documentation you'll need to load the 40ants-doc-full system which includes methods supporting these locatives.

• Refers to an asdf system. The generated documentation will include meta information extracted from the system definition. This also serves as an example of a symbol that's not accessible in the current package and consequently is not exported.

• &optional initform

Refers to a global special variable. INITFORM, or if not specified, the global value of the variable is included in the documentation.

• &optional initform

Refers to a DEFCONSTANT. INITFORM, or if not specified, the value of the constant is included in the documentation.

• Note that the arglist in the generated documentation depends on the quality of SWANK-BACKEND:ARGLIST. It may be that default values of optional and keyword arguments are missing.

• method-qualifiers method-specializers

See CL:FIND-METHOD for the description of the arguments. To refer to the default method of the three argument generic function FOO:

(foo (method () (t t t)))
• class-name

To refer to an accessor named FOO-SLOT of class FOO:

(foo-slot (accessor foo))
• class-name

To refer to a reader named FOO-SLOT of class FOO:

(foo-slot (reader foo))
• class-name

To refer to a writer named FOO-SLOT of class FOO:

(foo-slot (writer foo))
• This is a synonym of function with the difference that the often ugly and certainly uninformative lambda list will not be printed.

• An alias for 40ants-doc/locatives:dislocated, so the one can refer to an argument of a macro without accidentally linking to a class that has the same name as that argument. In the following example, FORMAT may link to CL:FORMAT (if we generated documentation for it):

"See the FORMAT in DOCUMENT."

Since argument is a locative, we can prevent that linking by writing:

"See the FORMAT argument of DOCUMENT."
• lambda-list

This is the locative for locatives. When M-. is pressed on variable in (VARIABLE LOCATIVE), this is what makes it possible to land at the (40ANTS-DOC/LOCATIVES/BASE:DEFINE-LOCATIVE-TYPE VARIABLE ...) form. Similarly, (LOCATIVE LOCATIVE) leads to this very definition.

• source &key lang

Refers to a region of a file. SOURCE can be a string or a pathname in which case the whole file is being pointed to or it can explicitly supply START, END locatives. include is typically used to include non-lisp files in the documentation (say markdown or elisp as in the next example) or regions of lisp source files. This can reduce clutter and duplication.

(defsection example-section ()
(pax.el (include #.(asdf:system-relative-pathname :40ants-doc "elisp/pax.el")
:lang "elisp"))
(foo-example (include (:start (foo function)
:end (end-of-foo-example variable))
:lang "commonlisp")))

(defun foo (x)
(1+ x))

;;; Since file regions are copied verbatim, comments survive.
(defmacro bar ())

;;; This comment is the last thing in FOO-EXAMPLE's
;;; documentation since we use the dummy END-OF-FOO-EXAMPLE
;;; variable to mark the end location.
(defvar end-of-foo-example)

;;; More irrelevant code follows.

In the above example, pressing M-. on pax.el will open the src/pax.el file and put the cursor on its first character. M-. on FOO-EXAMPLE will go to the source location of the (asdf:system locative) locative.

When documentation is generated, the entire pax.el file is included in the markdown as a code block. The documentation of FOO-EXAMPLE will be the region of the file from the source location of the START locative (inclusive) to the source location of the END locative (exclusive). START and END default to the beginning and end of the file, respectively.

Note that the file of the source location of :START and :END must be the same. If SOURCE is pathname designator, then it must be absolute so that the locative is context independent.

• form &key lang

Creates a block containing output of a given form. Also, an optional :LANG argument may be specified. This could be useful when you want to show the results of some code's evaluation.

Here is an example of the usage:

(defsection @example ()
(describe-output (stdout-of (format t "Hello World!"))))

Resulting block, rendered to Markdown format will look like:

markdown
Hello World!


• symbol lambda-list &body docstring

A definer macro to hang the documentation of a restart on a symbol.

(define-restart my-ignore-error ()
"Available when MY-ERROR is signalled, MY-IGNORE-ERROR unsafely continues.")

Note that while there is a CL:RESTART class, there is no corresponding source location or docstring like for conditions.

Define a global variable with NAME and set it to a glossary term object. A glossary term is just a symbol to hang a docstring on. It is a bit like a 40ants-doc:section in that, when linked to, its TITLE will be the link text instead of the name of the symbol. Unlike sections though, glossary terms are not rendered with headings, but in the more lightweight bullet + locative + name/title style.

When DISCARD-DOCUMENTATION-P (defaults to 40ants-doc:*discard-documentation-p*) is true, DOCSTRING will not be recorded to save memory.

There is also a helper function to compare locatives:

• left right

Compares two locatives.

Each locative may be a symbol or a locative with arugments in a list form.

## Extension API ¶

### Defining a Custom Theme ¶

Out of the box, 40ants-doc system supports three color themes:

You can pass these names as THEME argument to the 40ants-doc/builder:render-to-files function. Or you can define your own theme.

Theme allows to control HTML page rendering, colors and code highlighting.

#### Changing Colors

The simplest way to customize theme is to redefine some colors using CSS. Here is how to set orange page background:

(defclass my-theme (default-theme)
())

(defmethod 40ants-doc/themes/api:render-css ((theme my-theme))
(concatenate
'string
(call-next-method)

(lass:compile-and-write
(body
:background orange))))

Also you might want to redefine a color theme for code highlighter:

(defmethod 40ants-doc/themes/api:highlight-theme ((theme my-theme))
"atom-one-light")

Talking about code highlighting, you can also redefine a list of languages to highlight:

(defmethod 40ants-doc/themes/api:highlight-languages ((theme my-theme))
(list "lisp"
"python"
"bash"))

#### Changing Page Layout

The main entry-point for page rendering is render-page generic-function. It calls all other rendering functions.

If you are inheriting your theme class from 40ants-doc/themes/default:default-theme, then rendering functions will be called in the following order:

On this page stripes on the right demonstrate order in which different rendering functions will be called:

Some of these methods might call render-toc and render-search-form to display a table of content and a table form. Also, you might want to redefine render-html-head generic-function to change html page metadata such as included stylesheets and js files, page title, etc.

If you want to introduce changes, it is better to inherit from existing theme class and to define a few methods to change only needed properties. For example, here is a theme I've made for all 40Ants projects. I've added header, footer and made colors match the main site.

#### Theme Definition Protocol

• theme

Returns a list of languages to highlight in snippets. Each language should be supported by Highlight.js.

• theme

Returns a string with CSS.

• theme uri title &key toc content

Renders whole page using theme and callable CONTENT-FUNC.

• theme uri title

Renders content of the HTML HEAD tag.

• theme uri title

Renders whole page header. Does nothing by default.

• theme uri

Renders whole page footer. Does nothing by default.

• theme uri toc content-func

Renders page's content. It can wrap content into HTML tags and should funcall CONTENT-FUNC without arguments.

• theme uri toc

Renders page's sidebar

• theme uri toc

Renders sidebar's header. Usually it contains a search input.

• theme uri toc

Renders documentation TOC.

• theme uri toc

Renders a search form.

### Locatives and References ¶

While Common Lisp has rather good introspective abilities, not everything is first class. For example, there is no object representing the variable defined with (DEFVAR FOO). (40ANTS-DOC/REFERENCE:MAKE-REFERENCE 'FOO 'VARIABLE) constructs a 40ants-doc/reference:reference that captures the path to take from an object (the symbol FOO) to an entity of interest (for example, the documentation of the variable). The path is called the locative. A locative can be applied to an object like this:

(locate 'foo 'variable)

which will return the same reference as (40ANTS-DOC/REFERENCE:MAKE-REFERENCE 'FOO 'VARIABLE). Operations need to know how to deal with references which we will see in 40ants-doc/locatives/base:locate-and-find-source (1 2).

Naturally, (40ANTS-DOC/LOCATIVES/BASE:LOCATE 'FOO 'FUNCTION) will simply return #'FOO, no need to muck with references when there is a perfectly good object.

• object locative &key (errorp t)

Follow LOCATIVE from OBJECT and return the object it leads to or a 40ants-doc/reference:reference if there is no first class object corresponding to the location. If ERRORP, then a locate-error (1 2) condition is signaled when the lookup fails.

• (:message)
• (:object)
• (:locative)
• (:object)
• (:locative)
• object locative
• locative

The first element of LOCATIVE if it's a list. If it's a symbol then it's that symbol itself. Typically, methods of generic functions working with locatives take locative type and locative args as separate arguments to allow methods have eql specializers on the type symbol.

• locative

The REST of LOCATIVE if it's a list. If it's a symbol then it's ().

### Adding New Object Types ¶

If you wish to make it possible to render documentation for a new object type, then you have to define a method for the 40ants-doc/commondoc/builder:to-commondoc generic function. And to make M-. navigation work with new object types, a methods of 40ants-doc/locatives/base:locate-object generic-function and 40ants-doc/source-api:find-source generic-function are to be defined. Also, additional method for 40ants-doc/reference-api:canonical-reference generic-function need to be defined to make an opposite to 40ants-doc/locatives/base:locate-object's action.

Finally, 40ants-doc:exportable-locative-type-p generic-function may be overridden if exporting does not makes sense. Here is a stripped down example of how all this is done for asdf:system:

(define-locative-type asdf:system ()
"Refers to an asdf system. The generated documentation will include
meta information extracted from the system definition. This also
serves as an example of a symbol that's not accessible in the
current package and consequently is not exported.")

(defmethod locate-object (symbol (locative-type (eql 'asdf:system))
locative-args)
(assert (endp locative-args))
;; FIXME: This is slow as hell.
(or (asdf:find-system symbol nil)
(locate-error)))

(defmethod canonical-reference ((system asdf:system))
(40ants-doc/reference:make-reference (asdf:primary-system-name system)
'asdf:system))

(defmethod find-source ((system asdf:system))
(:location
(:file ,(namestring (asdf/system:system-source-file system)))
(:position 1)
(:snippet "")))

(defmethod to-commondoc ((system asdf:system))
(let ((title (format nil "~A ASDF System Details"
(string-upcase
(asdf:primary-system-name system)))))
(flet ((item (name getter &key type)
(let* ((value (funcall getter system))
(href nil))
(when value
(case type
(:mailto (setf href (format nil "mailto:~A"
value)))
(:source-control (psetf value (format nil "~A"
(first value))
href (second value))))
(make-list-item
(make-paragraph
(if href
(make-content
(list (make-text
(format nil "~A: "
name))
(make-text value))))
(make-text
(format nil "~A: ~A"
name
value)))))))))

(let* ((items (list (item "Version" 'asdf/component:component-version)
(item "Description" 'asdf/system:system-description)
(item "Licence" 'asdf/system:system-licence)
(item "Author" 'asdf/system:system-author)
(item "Maintainer" 'asdf/system:system-maintainer)
(item "Mailto" 'asdf/system:system-mailto
:type :mailto)
(item "Homepage" 'asdf/system:system-homepage
(item "Bug tracker" 'asdf/system:system-bug-tracker
(item "Source control" 'asdf/system:system-source-control
:type :source-control)))
(children (make-unordered-list
(remove nil items)))
(reference (40ants-doc/reference-api:canonical-reference system)))
(make-section-with-reference title
children
reference)))))


• locative-type lambda-list &body docstring

Declare locative-type as a locative. One gets two things in return: first, a place to document the format and semantics of locative-type (in LAMBDA-LIST and DOCSTRING); second, being able to reference (LOCATIVE-TYPE LOCATIVE). For example, if you have:

(define-locative-type variable (&optional initform)
"Dummy docstring.")

then (VARIABLE LOCATIVE) refers to this form.

• &rest format-and-args

Call this function to signal a locate-error (1 2) condition from a locate-object generic-function. FORMAT-AND-ARGS contains a format string and args suitable for FORMAT from which the locate-error-message is constructed. If FORMAT-AND-ARGS is NIL, then the message will be NIL too.

The object and the locative are not specified, they are added by locate when it resignals the condition.

• object

Like SWANK:FIND-DEFINITION-FOR-THING, but this one is a generic function to be extensible. In fact, the default implementation simply defers to SWANK:FIND-DEFINITION-FOR-THING. This function is called by 40ants-doc/swank:locate-definition-for-emacs which lies behind the M-. extension (see Emacs Integration).

If successful, the return value looks like this:

(:location (:file "/home/mega/own/mgl/pax/test/test.lisp")
(:position 24) nil)

The NIL is the source snippet which is optional. Note that position 1 is the first character. If unsuccessful, the return values is like:

(:error "Unknown source location for SOMETHING")
• obj

Define methods for this generic function to render object's documentation into an intermediate CommonDoc format.

Function should return a COMMON-DOC:DOCUMENT-NODE.

To show a standard documentation item with locative, name and arguments, use 40ants-doc/commondoc/bullet:make-bullet function.

• reference &key arglist children name ignore-words dislocated-symbols

Creates a CommonDoc node to represent a documentation item.

Documentation item can have an ARGLIST. If NAME is not given, then it will be made from reference's object printed representation.

You can provide a CHILDREN arguments. It should be a list of CommonDoc nodes or a single node.

IGNORE-WORDS can be a list with the same meaning as 40ants-doc:defsection.

If you want to completely ignore some symbol inside the reference's documentation, then use DISPLOCATED-SYMBOLS argument.

### Reference Based Extensions ¶

Let's see how to extend 40ants-doc/builder:render-to-files and M-. navigation if there is no first class object to represent the thing of interest. Recall that 40ants-doc/locatives/base:locate returns a 40ants-doc/reference:reference object in this case:

(40ants-doc/locatives/base:locate
'variable)
==> #<40ANTS-DOC/REFERENCE:REFERENCE 40ANTS-DOC:*DISCARD-DOCUMENTATION-P* (VARIABLE)>

Some methods of 40ants-doc/source-api:find-source generic-function defer to 40ants-doc/locatives/base:locate-and-find-source generic-function, which have LOCATIVE-TYPE in their argument list for EQL specializing pleasure.

Here is a stripped down example of how the variable locative is defined. Pay attention how it defines a method of 40ants-doc/commondoc/builder:reference-to-commondoc generic-function instead of 40ants-doc/commondoc/builder:to-commondoc. This is because we have no a lisp object to represent a variable and have to specialize method on LOCATIVE-TYPE argument:

(define-locative-type variable (&optional initform)
"Refers to a global special variable. INITFORM, or if not specified,
the global value of the variable is included in the documentation.")

(defmethod locate-object (symbol (locative-type (eql 'variable)) locative-args)
(assert (<= (length locative-args) 1))
(40ants-doc/reference:make-reference symbol (cons locative-type locative-args)))

(defmethod 40ants-doc/commondoc/builder:reference-to-commondoc ((symbol symbol) (locative-type (eql 'variable)) locative-args)
(destructuring-bind (&optional (initform nil initformp)) locative-args
(let* ((reference (canonical-reference
(40ants-doc/reference:make-reference symbol
(cons locative-type
locative-args))))
(docstring (40ants-doc/docstring:get-docstring symbol 'variable))
(arglist (multiple-value-bind (value unboundp) (40ants-doc/utils::symbol-global-value symbol)
(cond (initformp
(prin1-to-string initform))
(unboundp "-unbound-")
(t
(prin1-to-string value)))))
(children (when docstring
(parse-markdown docstring))))

(40ants-doc/commondoc/bullet:make-bullet reference
:arglist arglist
:children children
:dislocated-symbols symbol))))

(defmethod locate-and-find-source (symbol (locative-type (eql 'variable))
locative-args)
(declare (ignore locative-args))
(40ants-doc/locatives/utils::find-one-location (swank-backend:find-definitions symbol)
'("variable" "defvar" "defparameter"
"special-declaration")))


• object locative-type locative-args

This default implementation simply calls 40ants-doc/source-api:find-source (1 2) with OBJECT which should cover the common case of a macro expanding to, for instance, a defun but having its own locative type.

• obj locative-type locative-args

Define a method for this generic function, when there is no a lisp object to represent an object of given locative type.

LOCATIVE-TYPE argument will be a symbol. OBJ argument also usually a symbol. LOCATIVE-ARGS argument is a list which will be non-nil in case if object is referenced in a 40ants-doc:defsection like this:

(40ants-doc/source-api:find-source (method () (40ants-doc/reference:reference)))

In this case LOCATIVE-ARGS argument will be '(NIL (40ANTS-DOC/REFERENCE:REFERENCE)).

We have covered the basic building blocks of reference based extensions. Now let's see how the obscure 40ants-doc/locatives/definers:define-symbol-locative-type and 40ants-doc/locatives/define-definer:define-definer-for-symbol-locative-type macros work together to simplify the common task of associating definition and documentation with symbols in a certain context.

• locative-type lambda-list &body docstring

Similar to 40ants-doc/locatives/base:define-locative-type but it assumes that all things locatable with LOCATIVE-TYPE are going to be just symbols defined with a definer defined with 40ants-doc/locatives/define-definer:define-definer-for-symbol-locative-type. It is useful to attach documentation and source location to symbols in a particular context. An example will make everything clear:

(define-symbol-locative-type direction ()
"A direction is a symbol. (After this M-. on DIRECTION LOCATIVE
works and it can also be included in DEFSECTION forms.)")

(define-definer-for-symbol-locative-type define-direction direction
"With DEFINE-DIRECTION one can document what a symbol means when
interpreted as a direction.")

(define-direction up ()
"UP is equivalent to a coordinate delta of (0, -1).")

After all this, (UP DIRECTION) refers to the DEFINE-DIRECTION form above.

• name locative-type &body docstring

Define a macro with NAME which can be used to attach documentation, a lambda-list and source location to a symbol in the context of LOCATIVE-TYPE. The defined macro's arglist is (SYMBOL LAMBDA-LIST &OPTIONAL DOCSTRING). LOCATIVE-TYPE is assumed to have been defined with 40ants-doc/locatives/definers:define-symbol-locative-type.

### Sections¶

40ants-doc:section objects rarely need to be dissected since 40ants-doc:defsection and 40ants-doc/builder:render-to-files cover most needs. However, it is plausible that one wants to subclass them and maybe redefine how they are presented.

• (:package)

*PACKAGE* will be bound to this package when generating documentation for this section.

*READTABLE* will be bound to this when generating documentation for this section.

• (:title)

STRING or NIL. Used in generated documentation.

• (:external-docs = nil)

A list of strings with URLs of other system's documentation.

• (:ignore-words = nil)

A list of strings to not warn about.

## Transcripts ¶

What are transcripts for? When writing a tutorial, one often wants to include a REPL session with maybe a few defuns and a couple of forms whose output or return values are shown. Also, in a function's docstring an example call with concrete arguments and return values speaks volumes. A transcript is a text that looks like a repl session, but which has a light markup for printed output and return values, while no markup (i.e. prompt) for lisp forms. The PAX transcripts may include output and return values of all forms, or only selected ones. In either case the transcript itself can be easily generated from the source code.

The main worry associated with including examples in the documentation is that they tend to get out-of-sync with the code. This is solved by being able to parse back and update transcripts. In fact, this is exactly what happens during documentation generation with PAX. Code sections tagged cl-transcript are retranscribed and checked for inconsistency (that is, any difference in output or return values). If the consistency check fails, an error is signalled that includes a reference to the object being documented.

Going beyond documentation, transcript consistency checks can be used for writing simple tests in a very readable form. For example:

(+ 1 2)
=> 3

(values (princ :hello) (list 1 2))
.. HELLO
=> :HELLO
=> (1 2)

All in all, transcripts are a handy tool especially when combined with the Emacs support to regenerate them and with PYTHONIC-STRING-READER and its triple-quoted strings that allow one to work with nested strings with less noise. The triple-quote syntax can be enabled with:

(in-readtable pythonic-string-syntax)


### Transcribing with Emacs ¶

Typical transcript usage from within Emacs is simple: add a lisp form to a docstring or comment at any indentation level. Move the cursor right after the end of the form as if you were to evaluate it with C-x C-e. The cursor is marked by #\^:

This is part of a docstring.

cl-transcript
(values (princ :hello) (list 1 2))^



Note that the use of fenced code blocks with the language tag cl-transcript is only to tell PAX to perform consistency checks at documentation generation time.

Now invoke the emacs command mgl-pax-transcribe-last-expression where the cursor is and the fenced code block from the docstring becomes:

(values (princ :hello) (list 1 2))
.. HELLO
=> :HELLO
=> (1 2)
^


Then you change the printed message to :HELLO-WORLD and add a comment to the second return value:

(values (princ :hello-world) (list 1 2))
.. HELLO
=> :HELLO
=> (1
;; This value is arbitrary.
2)


When generating the documentation you get a a warning:

WARNING:
Transcription error. Inconsistent output found.

Source:
"HELLO"

Output:
"HELLO-WORLD"

Form:
"(values (princ :hello-world) (list 1 2))"


because the printed output and the first return value changed so you regenerate the documentation by marking the region of bounded by | and the cursor at ^ in the example:

|(values (princ :hello-world) (list 1 2))
.. HELLO
=> :HELLO
=> (1
;; This value is arbitrary.
2)
^


then invoke the emacs command 40ants-doc-retranscribe-region to get:

(values (princ :hello-world) (list 1 2))
.. HELLO-WORLD
=> :HELLO-WORLD
=> (1
;; This value is arbitrary.
2)
^


Note how the indentation and the comment of (1 2) was left alone but the output and the first return value got updated.

Alternatively, C-u 1 40ants-doc-transcribe-last-expression will emit commented markup:

(values (princ :hello) (list 1 2))
;.. HELLO
;=> :HELLO
;=> (1 2)


This can be useful for producing results outside of the docstrings.

C-u 0 40ants-doc-retranscribe-region will turn commented into non-commented markup. In general, the numeric prefix argument is the index of the syntax to be used in 40ants-doc/transcribe:*syntaxes*. Without a prefix argument 40ants-doc-retranscribe-region will not change the markup style.

Finally, not only do both functions work at any indentation level, but in comments too:

;;;; (values (princ :hello) (list 1 2))
;;;; .. HELLO
;;;; => :HELLO
;;;; => (1 2)


Transcription support in emacs can be enabled by adding this to your Emacs initialization file (or loading elisp/transcribe.el):

;;; Code transcription

(defun 40ants-doc-lisp-eval (form)
(cond
((and (fboundp 'sly-connected-p)
(sly-connected-p))
(sly-eval form))
((and (fboundp 'slime-connected-p)
(slime-connected-p))
(slime-eval form))
(t
(error "Nor SLY, nor SLIME is connected to the Lisp."))))

(defun 40ants-doc-transcribe-last-expression ()
"A bit like C-u C-x C-e (slime-eval-last-expression) that
inserts the output and values of the sexp before the point, this
does the same but with 40ANTS-DOC/TRANSCRIBE:TRANSCRIBE. Use a numeric prefix
argument as in index to select one of the Common Lisp
40ANTS-DOC/TRANSCRIBE:*SYNTAXES* as the SYNTAX argument to 40ANTS-DOC/TRANSCRIBE:TRANSCRIBE.
Without a prefix argument, the first syntax is used."
(interactive)
(insert
(save-excursion
(let* ((end (point))
(start (progn (backward-sexp)
(move-beginning-of-line nil)
(point))))
(40ants-doc-transcribe start end (40ants-doc-transcribe-syntax-arg)
nil nil nil)))))

(defun 40ants-doc-retranscribe-region (start end)
"Updates the transcription in the current region (as in calling
40ANTS-DOC/TRANSCRIBE:TRANSCRIBE with :UPDATE-ONLY T). Use a numeric prefix
argument as in index to select one of the Common Lisp
40ANTS-DOC/TRANSCRIBE:*SYNTAXES* as the SYNTAX argument to 40ANTS-DOC/TRANSCRIBE:TRANSCRIBE.
Without a prefix argument, the syntax of the input will not be
changed."
(interactive "r")
(let ((point-at-start-p (= (point) start)))
;; We need to extend selection to the
;; beginning of line because otherwise
;; block's indentation might be wrong and
;; transcription parsing will fail
(goto-char start)
(move-beginning-of-line nil)
(setf start
(point))

(let ((transcript (40ants-doc-transcribe start end
(40ants-doc-transcribe-syntax-arg)
t t nil)))
(if point-at-start-p
(save-excursion
(goto-char start)
(delete-region start end)
(insert transcript))
(save-excursion
(goto-char start)
(delete-region start end))
(insert transcript)))))

(defun 40ants-doc-transcribe-syntax-arg ()
(if current-prefix-arg
(prefix-numeric-value current-prefix-arg)
nil))

(defun 40ants-doc-transcribe (start end syntax update-only echo
first-line-special-p)
(let ((transcription
(40ants-doc-lisp-eval
(cl:if (cl:find-package :40ants-doc/transcribe)
(uiop:symbol-call :40ants-doc/transcribe :transcribe-for-emacs
,(buffer-substring-no-properties start end)
',syntax ',update-only ',echo ',first-line-special-p)
t))))
(if (eq transcription t)
transcription)))



### Transcript API ¶

• input output &key update-only (include-no-output update-only) (include-no-value update-only) (echo t) check-consistency default-syntax (input-syntaxes \*syntaxes\*) (output-syntaxes \*syntaxes\*)

Read forms from INPUT and write them (if ECHO) to OUTPUT followed by any output and return values produced by calling EVAL on the form. INPUT can be a stream or a string, while OUTPUT can be a stream or NIL in which case transcription goes into a string. The return value is the OUTPUT stream or the string that was constructed.

A simple example is this:

(transcribe "(princ 42) " nil)
=> "(princ 42)
.. 42
=> 42
"

However, the above may be a bit confusing since this documentation uses transcribe markup syntax in this very example, so let's do it differently. If we have a file with these contents:

(values (princ 42) (list 1 2))

it is transcribed to:

(values (princ 42) (list 1 2))
.. 42
=> 42
=> (1 2)

Output to all standard streams is captured and printed with the :OUTPUT prefix (".."). The return values above are printed with the :READABLE prefix ("=>"). Note how these prefixes are always printed on a new line to facilitate parsing.

Updating

transcribe is able to parse its own output. If we transcribe the previous output above, we get it back exactly. However, if we remove all output markers, leave only a placeholder value marker and pass :UPDATE-ONLY T with source:

(values (princ 42) (list 1 2))
=>

we get this:

(values (princ 42) (list 1 2))
=> 42
=> (1 2)

With UPDATE-ONLY, printed output of a form is only transcribed if there were output markers in the source. Similarly, with UPDATE-ONLY, return values are only transcribed if there were value markers in the source.

No Output/Values

If the form produces no output or returns no values, then whether or not output and values are transcribed is controlled by INCLUDE-NO-OUTPUT and INCLUDE-NO-VALUE, respectively. By default, neither is on so:

(values)
..
=>

is transcribed to

(values)

With UPDATE-ONLY true, we probably wouldn't like to lose those markers since they were put there for a reason. Hence, with UPDATE-ONLY, INCLUDE-NO-OUTPUT and INCLUDE-NO-VALUE default to true. So with UPDATE-ONLY the above example is transcribed to:

(values)
..
=> ; No value

where the last line is the :NO-VALUE prefix.

Consistency Checks

If CHECK-CONSISTENCY is true, then transcribe signals a continuable transcription-output-consistency-error whenever a form's output as a string is different from what was in INPUT, provided that INPUT contained the output. Similary, for values, a continuable transcription-values-consistency-error is signalled if a value read from the source does not print as the as the value returned by EVAL. This allows readable values to be hand-indented without failing consistency checks:

(list 1 2)
=> (1
2)

The above scheme involves READ, so consistency of unreadable values cannot be treated the same. In fact, unreadable values must even be printed differently for transcribe to be able to read them back:

(defclass some-class () ())

(defmethod print-object ((obj some-class) stream)
(format stream \"~%~%end\")))

(make-instance 'some-class)
==> #<SOME-CLASS
-->
--> end>

where "==>" is the :UNREADABLE prefix and "-->" is the :UNREADABLE-CONTINUATION prefix. As with outputs, a consistency check between an unreadable value from the source and the value from EVAL is performed with STRING=. That is, the value from EVAL is printed to a string and compared to the source value. Hence, any change to unreadable values will break consistency checks. This is most troublesome with instances of classes with the default PRINT-OBJECT method printing the memory address. There is currently no remedy for that, except for customizing PRINT-OBJECT or not transcribing that kind of stuff.

Syntaxes

Finally, a transcript may employ different syntaxes for the output and values of different forms. When INPUT is read, the syntax for each form is determined by trying to match all prefixes from all syntaxes in INPUT-SYNTAXES against a line. If there are no output or values for a form in INPUT, then the syntax remains undetermined.

When OUTPUT is written, the prefixes to be used are looked up in DEFAULT-SYNTAX of OUTPUT-SYNTAXES, if DEFAULT-SYNTAX is not NIL. If DEFAULT-SYNTAX is NIL, then the syntax used by the same form in the INPUT is used or (if that could not be determined) the syntax of the previous form. If there was no previous form, then the first syntax if OUTPUT-SYNTAXES is used.

To produce a transcript that's executable Lisp code, use :DEFAULT-SYNTAX :COMMENTED-1:

(make-instance 'some-class)
;==> #<SOME-CLASS
;-->
;--> end>

(list 1 2)
;=> (1
;->    2)

To translate the above to uncommented syntax, use :DEFAULT-SYNTAX :DEFAULT. If DEFAULT-SYNTAX is NIL (the default), the same syntax will be used in the output as in the input as much as possible.

The default syntaxes used by transcribe for reading and writing lines containing output and values of an evaluated form.

A syntax is a list of of the form (SYNTAX-ID &REST PREFIXES) where prefixes is a list of (PREFIX-ID PREFIX-STRING) elements. For example the syntax :COMMENTED-1 looks like this:

(:commented-1
(:output ";..")
(:no-value ";=>  No value")
(:unreadable-continuation ";-->"))

All of the above prefixes must be defined for every syntax except for :READABLE-CONTINUATION. If that's missing (as in the :DEFAULT syntax), then the following value is read with READ and printed with PRIN1 (hence no need to mark up the following lines).

When writing, an extra space is added automatically if the line to be prefixed is not empty. Similarly, the first space following the prefix discarded when reading.

See transcribe for how the actual syntax to be used is selected.

• Signaled (with CERROR) by transcribe when invoked with :CHECK-CONSISTENCY and the output of a form is not the same as what was parsed.

• Signaled (with CERROR) by transcribe when invoked with :CHECK-CONSISTENCY and the values of a form are inconsistent with their parsed representation.

## TODO¶

• Refactor code and make a core package with only a few dependencies.

• Add warnings on UPPERCASED symbols in docstrings which aren't found in the package and can't be cross referenced.

• Support SLY and make both SLIME and SLY integrations optional.

• Add a search facility which will build an index for static file like Sphinx does.

• Separate markup parsing and result rendering code to support markups other than Markdown and HTML.

• Add a new section type to render ChangeLog.

• Support custom HTML themes.

• Generate RSS or Atom feed out of changelog items, defined with 40ants-doc/changelog:defchangelog` macro.

• Make some warnings compile-time for defsection and show them in the Emacs, if possible.