https://github.com/melisgl/mgl-pax.git
git clone 'https://github.com/melisgl/mgl-pax.git'
(ql:quickload :mgl-pax)
Here is the official repository and the HTML documentation for the latest version.
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and out of date, so I tend to stay in the editor and explore the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 @mgl-pax-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 PAX was born.
PAX 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.
In typical use, PAX packages have no :EXPORT's defined. Instead the
DEFINE-PACKAGE form gets a docstring which may mention section
names (defined with DEFSECTION). 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:
(mgl-pax:define-package :foo-random
(:documentation "This package provides various utilities for
random. See FOO-RANDOM:@FOO-RANDOM-MANUAL.")
(:use #:common-lisp #:mgl-pax))
(in-package :foo-random)
(defsection @foo-random-manual (:title "Foo Random manual")
"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)
(state (reader foo-random-state))
"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 ()
((state :reader state)))
(defmethod print-object ((object foo-random-state) stream)
(print-unreadable-object (object stream :type t)))
(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."
nil)
(defun gaussian-random (stddev &key (random-state *foo-state*))
"Return a random number from a zero mean normal distribution with
STDDEV."
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:
(describe @foo-random-manual)For this example, the generated markdown would look like this:
# Foo Random manual
###### \[in package FOO-RANDOM\]
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.
- [class] FOO-RANDOM-STATE
- [reader] STATE FOO-RANDOM-STATE
Hey we can also print states!
- [method] PRINT-OBJECT (OBJECT FOO-RANDOM-STATE) STREAM
- [variable] *FOO-STATE* #<FOO-RANDOM-STATE >
Much like *RANDOM-STATE* but uses the FOO algorithm.
- [function] GAUSSIAN-RANDOM STDDEV &KEY (RANDOM-STATE *FOO-STATE*)
Return a random number from a zero mean normal distribution with
STDDEV.
- [function] UNIFORM-RANDOM LIMIT &KEY (RANDOM-STATE *FOO-STATE*)
Return a random number from the between 0 and LIMIT (exclusive)
uniform distribution.
## 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 >
```
More fancy markdown or HTML output with automatic markup and linking
of uppercase symbol names found in docstrings, section numbering,
table of contents, etc is possible by calling the DOCUMENT function.
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. For a complete example of how to generate
HTML with multiple pages, see src/doc.lisp.
Note how (VARIABLE *FOO-STATE*) in the DEFSECTION form both
exports *FOO-STATE* and 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.
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.
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):
;;; MGL-PAX M-. integration
(defun slime-edit-locative-definition (name &optional where)
(or (slime-locate-definition name (slime-locative-before))
(slime-locate-definition name (slime-locative-after))
(slime-locate-definition name (slime-locative-after-in-brackets))
;; support "foo function" and "function foo" syntax in
;; interactive use
(let ((pos (cl-position ?\s name)))
(when pos
(or (slime-locate-definition (cl-subseq name 0 pos)
(cl-subseq name (1+ pos)))
(slime-locate-definition (cl-subseq name (1+ pos))
(cl-subseq name 0 pos)))))))
(defun slime-locative-before ()
(ignore-errors (save-excursion
(slime-beginning-of-symbol)
(slime-last-expression))))
(defun slime-locative-after ()
(ignore-errors (save-excursion
(slime-end-of-symbol)
(slime-forward-sexp)
(slime-last-expression))))
(defun slime-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 slime-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)))))
(add-hook 'slime-edit-definition-hooks 'slime-edit-locative-definition)Now let's examine the most important pieces in detail.
[macro] DEFSECTION NAME (&KEY (PACKAGE ‘*PACKAGE*) (READTABLE ’*READTABLE*) (EXPORT T) TITLE (DISCARD-DOCUMENTATION-P *DISCARD-DOCUMENTATION-P*)) &BODY ENTRIES
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
form:
(symbol 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 a reference, typically with different locatives, but this is not required.
The references are not looked up (see RESOLVE in the
Extension API) until documentation is generated, so it is
allowed to refer to things yet to be defined.
If EXPORT is true (the default), the referenced symbols and NAME are
candidates for exporting. A candidate symbol is exported if
it is accessible in PACKAGE (it's not OTHER-PACKAGE:SOMETHING)
and
there is a reference to it in the section being defined with a
locative whose type is approved by EXPORTABLE-LOCATIVE-TYPE-P.
See DEFINE-PACKAGE if you use the export feature. The idea with
confounding documentation and exporting is to force documentation of
all exported symbols.
When DISCARD-DOCUMENTATION-P (defaults to *DISCARD-DOCUMENTATION-P*)
is true, ENTRIES will not be recorded to save memory.
[variable] *DISCARD-DOCUMENTATION-P* 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.
[macro] DEFINE-PACKAGE PACKAGE &REST OPTIONS
This is like CL:DEFPACKAGE but silences warnings and errors
signaled when the redefined package is at variance with the current
state of the package. Typically this situation occurs when symbols
are exported by calling EXPORT (as is the case with DEFSECTION) as
opposed to adding :EXPORT forms to the DEFPACKAGE form and the
package definition is reevaluated. See the section on package
variance in the SBCL
manual.
The bottom line is that if you rely on DEFSECTION to do the
exporting, then you'd better use DEFINE-PACKAGE.
[function] DOCUMENT OBJECT &KEY STREAM PAGES (FORMAT :MARKDOWN)
Write OBJECT in FORMAT to STREAM diverting some output to PAGES.
FORMAT can be anything 3BMD supports which is
currently :MARKDOWN, :HTML and :PLAIN. STREAM may be a stream
object, T or NIL as with CL:FORMAT.
Most often, this function is called on section objects
like (DOCUMENT @MGL-PAX-MANUAL), but it supports all kinds of
objects for which DOCUMENT-OBJECT is defined. To look up the
documentation of function DOCUMENT:
(document #'document)
To generate the documentation for separate libraries with automatic cross-links:
(document (list @cube-manual @mat-manual))
Note that not only first class objects can have documentation. For
instance, variables and deftypes are not represented by objects.
That's why CL:DOCUMENTATION has a DOC-TYPE argument. DOCUMENT does
not have anything like that, instead it relies on REFERENCE objects
to carry the extra information. We are going to see later how
references and locatives work. Until then, here is an example on how
to look up the documentation of type FOO:
(document (locate 'foo 'type))
One can call DESCRIBE on SECTION objects to get
documentation in markdown format with less markup than the default.
See DESCRIBE-OBJECT (METHOD () (SECTION T)).
There are quite a few special variables that affect how output is generated, see Documentation Printer Variables.
The rest of this description deals with how to generate multiple pages.
The PAGES argument is to create multi-page documents by routing some
of the generated output to files, strings or streams. PAGES is a
list of page specification elements. A page spec is a plist with
keys :OBJECTS, :OUTPUT, :URI-FRAGMENT, :SOURCE-URI-FN, :HEADER-FN
and :FOOTER-FN. OBJECTS is a list of objects (references are allowed
but not required) whose documentation is to be sent to OUTPUT.
OUTPUT can be a number things:
If it's a list whose first element is a string or a pathname, then
output will be sent to the file denoted by that and the rest of
the elements of the list are passed on as arguments to CL:OPEN.
One extra keyword argument is :ENSURE-DIRECTORIES-EXIST. If it's
true, ENSURE-DIRECTORIES-EXIST will be called on the pathname
before it's opened.
If it's NIL, then output will be collected in a string.
If it's T, then output will be sent to *STANDARD-OUTPUT*.
If it's a stream, then output will be sent to that stream.
If some pages are specified, DOCUMENT returns a list of designators
for generated output. If a page whose OUTPUT refers to a file that
was created (which doesn't happen if nothing would be written to
it), then the corresponding pathname is included in the list. For
strings the string itself, while for streams the stream object is
included in the list. This way it's possible to write some pages to
files and some to strings and have the return value indicate what
was created. The output designators in the returned list are ordered
by creation time.
If no PAGES are specified, DOCUMENT returns a single pathname,
string or stream object according to the value of the STREAM
argument.
Note that even if PAGES is specified, STREAM acts as a catch all
taking the generated documentation for references not claimed by any
pages. Also, the filename, string or stream corresponding to STREAM
is always the first element in list of generated things that is the
return value.
HEADER-FN, if not NIL, is a function of a single stream argument
which is called just before the first write to the page.
Since :FORMAT :HTML only generates HTML fragments, this makes it
possible to print arbitrary headers, typically setting the title,
css stylesheet, or charset.
FOOTER-FN is similar to HEADER-FN, but it's called after the last
write to the page. For HTML, it typically just closes the body.
URI-FRAGMENT is a string such as "doc/manual.html" that specifies
where the page will be deployed on a webserver. It defines how links
between pages will look. If it's not specified and OUTPUT refers
to a file, then it defaults to the name of the file. If URI-FRAGMENT
is NIL, then no links will be made to or from that page.
Finally, SOURCE-URI-FN is a function of a single, REFERENCE
argument. If it returns a value other than NIL, then it must be a
string representing an URI. If FORMAT is :HTML and
*DOCUMENT-MARK-UP-SIGNATURES* is true, then the locative as
displayed in the signature will be a link to this uri. See
MAKE-GITHUB-SOURCE-URI-FN.
PAGES may look something like this:
`((;; The section about SECTIONs and everything below it ...
:objects (,@mgl-pax-sections)
;; ... is so boring that it's not worth the disk space, so
;; send it to a string.
:output (nil)
;; Explicitly tell other pages not to link to these guys.
:uri-fragment nil)
;; Send the @MGL-PAX-EXTENSIONS section and everything reachable
;; from it ...
(:objects (,@mgl-pax-extension-api)
;; ... to build/tmp/pax-extension-api.html.
:output ("build/tmp/pax-extension-api.html")
;; However, on the web server html files will be at this
;; location relative to some common root, so override the
;; default:
:uri-fragment "doc/dev/pax-extension-api.html"
;; Set html page title, stylesheet, charset.
:header-fn 'write-html-header
;; Just close the body.
:footer-fn 'write-html-footer)
(:objects (,@mgl-pax-manual)
:output ("build/tmp/manual.html")
;; Links from the extension api page to the manual page will
;; be to ../user/pax-manual#<anchor>, while links going to
;; the opposite direction will be to
;; ../dev/pax-extension-api.html#<anchor>.
:uri-fragment "doc/user/pax-manual.html"
:header-fn 'write-html-header
:footer-fn 'write-html-footer))The Markdown in docstrings is processed with the 3BMD library.
Docstrings can be indented in any of the usual styles. PAX normalizes indentation by converting:
(defun foo ()
"This is
indented
differently")
to
(defun foo ()
"This is
indented
differently")
See DOCUMENT-OBJECT for the details.
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. Copy doc/style.css
from PAX and you are set. The language tag, elisp in this example,
is optional and defaults to common-lisp.
See the documentation of 3BMD and colorize for the details.
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 pain. Pythonic String Reader can help with that.
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.
[variable] *DOCUMENT-UPPERCASE-IS-CODE* 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 *DOCUMENT-LINK-CODE*. For example, this docstring:
"`FOO` and FOO."
is equivalent to this:
"`FOO` and `FOO`."
iff FOO is an interned symbol. To suppress this behavior, add a
backslash to the beginning of the symbol or right after the leading
* if it would otherwise be parsed as markdown emphasis:
"\\MGL-PAX *\\DOCUMENT-NORMALIZE-PACKAGES*"
The number of backslashes is doubled above because that's how the
example looks in a docstring. Note that the backslash is discarded
even if *DOCUMENT-UPPERCASE-IS-CODE* is false.
[variable] *DOCUMENT-LINK-CODE* T
When true, during the process of generating documentation for a
SECTION, 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 in PAX with SECTION(0 1) which is both a class (see
SECTION) and a locative type denoted by a symbol (see
SECTION). 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
*DOCUMENT-UPPERCASE-IS-CODE* to have links generated for
uppercase names with no quoting required.
[variable] *DOCUMENT-LINK-SECTIONS* T
When true, HTML anchors are generated before the heading of
sections which allows the table of contents to contain links and
also code-like references to sections (like @FOO-MANUAL) to be
translated to links with the section title being the name of the
link.
[variable] *DOCUMENT-MIN-LINK-HASH-LENGTH* 4
Recall that markdown reference style links (like [label][id]) are
used for linking to sections and code. It is desirable to have ids
that are short to maintain legibility of the generated markdown, but
also stable to reduce the spurious diffs in the generated
documentation which can be a pain in a version control system.
Clearly, there is a tradeoff here. This variable controls how many characters of the md5 sum of the full link id (the reference as a string) are retained. If collisions are found due to the low number of characters, then the length of the hash of the colliding reference is increased.
This variable has no effect on the HTML generated from markdown, but it can make markdown output more readable.
[variable] *DOCUMENT-MARK-UP-SIGNATURES* T
When true, some things such as function names and arglists are
rendered as bold and italic. In :HTML output, locative types become
links to sources (if :SOURCE-URI-FN is provided, see DOCUMENT), and
the symbol becomes a self-link for your permalinking pleasure.
For example, a reference is rendered in markdown roughly as:
- [function] foo x y
With this option on, the above becomes:
- [function] **foo** *x y*
Also, in HTML **foo** will be a link to that very entry and
[function] may turn into a link to sources.
[variable] *DOCUMENT-MAX-NUMBERING-LEVEL* 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.
[variable] *DOCUMENT-MAX-TABLE-OF-CONTENTS-LEVEL* 3
A non-negative integer. Top-level sections are given a table of
contents which includes a nested tree of section titles whose depth
is limited by this value. Setting it to 0 turns generation of the
table of contents off. If *DOCUMENT-LINK-SECTIONS* is true, then the
table of contents will link to the sections.
[variable] *DOCUMENT-TEXT-NAVIGATION* NIL
If true, then before each heading a line is printed with links to
the previous, parent and next section. Needs
*DOCUMENT-LINK-SECTIONS* to be on to work.
[variable] *DOCUMENT-FANCY-HTML-NAVIGATION* T
If true and the output format is HTML, then headings get a
navigation component that consists of links to the previous, parent,
next section and a permalink. This component is normally hidden, it
is visible only when the mouse is over the heading. Needs
*DOCUMENT-LINK-SECTIONS* to be on to work.
[variable] *DOCUMENT-NORMALIZE-PACKAGES* T
If true, symbols are printed relative to SECTION-PACKAGE of the
innermost containing section or with full package names if there is
no containing section. To eliminate ambiguity [in package ...]
messages are printed right after the section heading if necessary.
If false, symbols are always printed relative to the current
package.
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.
[locative] ASDF/SYSTEM: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.
[locative] SECTION
Refers to a section defined by DEFSECTION.
[locative] 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.
[locative] CONSTANT &OPTIONAL INITFORM
Refers to a DEFCONSTANT. INITFORM, or if not specified,
the value of the constant is included in the documentation.
[locative] FUNCTION
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.
[locative] METHOD 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)))
[locative] ACCESSOR CLASS-NAME
To refer to an accessor named FOO-SLOT of class
FOO:
(foo-slot (accessor foo))
[locative] READER CLASS-NAME
To refer to a reader named FOO-SLOT of class
FOO:
(foo-slot (reader foo))
[locative] WRITER CLASS-NAME
To refer to a writer named FOO-SLOT of class
FOO:
(foo-slot (writer foo))
[locative] STRUCTURE-ACCESSOR
This is a synonym of FUNCTION with the difference that the often
ugly and certainly uninformative lambda list will not be printed.
[locative] TYPE
TYPE can refer to classes as well, but it's better style to use the
more specific CLASS locative type for that. Another difference to
CLASS is that an attempt is made at printing the arguments of type
specifiers.
[locative] DISLOCATED
Refers to a symbol in a non-specific context. Useful for preventing
autolinking. For example, if there is a function called FOO then
`FOO`
will be linked to (if *DOCUMENT-LINK-CODE*) its definition. However,
[`FOO`][dislocated]
will not be. On a dislocated locative LOCATE always fails with a
LOCATE-ERROR condition.
[locative] LOCATIVE 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 (DEFINE-LOCATIVE-TYPE VARIABLE ...) form.
Similarly, (LOCATIVE LOCATIVE) leads to this very definition.
[locative] INCLUDE SOURCE &KEY LINE-PREFIX HEADER FOOTER HEADER-NL FOOTER-NL
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 :mgl-pax "src/pax.el")
:header-nl "```elisp" :footer-nl "```"))
(foo-example (include (:start (foo function)
:end (end-of-foo-example variable))
:header-nl "```commonlisp"
:footer-nl "```"))
(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 surrounded by the strings given as
HEADER-NL and FOOTER-NL (if any). The trailing newline character is
assumed implicitly. If that's undesirable, then use HEADER and
FOOTER instead. 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.
Finally, if specified LINE-PREFIX is a string that's prepended to
each line included in the documentation. For example, a string of
four spaces makes markdown think it's a code block.
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). (MAKE-REFERENCE 'FOO 'VARIABLE) constructs a 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 (MAKE-REFERENCE 'FOO
'VARIABLE). Operations need to know how to deal with references
which we will see in LOCATE-AND-COLLECT-REACHABLE-OBJECTS,
LOCATE-AND-DOCUMENT and LOCATE-AND-FIND-SOURCE.
Naturally, (LOCATE 'FOO 'FUNCTION) will simply return #'FOO, no
need to muck with references when there is a perfectly good object.
[function] LOCATE OBJECT LOCATIVE &KEY (ERRORP T)
Follow LOCATIVE from OBJECT and return the object it leads to or a
REFERENCE if there is no first class object corresponding to the
location. If ERRORP, then a LOCATE-ERROR condition is signaled when
lookup fails.
[condition] LOCATE-ERROR ERROR
Signaled by LOCATE when lookup fails and ERRORP is
true.
[function] RESOLVE REFERENCE &KEY (ERRORP T)
A convenience function to LOCATE REFERENCE's object with its
locative.
[class] REFERENCE
A REFERENCE represents a path (REFERENCE-LOCATIVE)
to take from an object (REFERENCE-OBJECT).
[function] LOCATIVE-TYPE 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.
[function] LOCATIVE-ARGS LOCATIVE
The REST of LOCATIVE if it's a list. If it's a symbol then
it's ().
One may wish to make the DOCUMENT function and M-. navigation
work with new object types. Extending DOCUMENT can be done by
defining a DOCUMENT-OBJECT method. To allow these objects to be
referenced from DEFSECTION a LOCATE-OBJECT method is to be defined.
Finally, for M-. FIND-SOURCE can be specialized. Finally,
EXPORTABLE-LOCATIVE-TYPE-P 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))
(make-reference (asdf/find-system:primary-system-name system) 'asdf:system))
(defmethod document-object ((system asdf:system) stream)
(with-heading (stream system
(format nil "~A ASDF System Details"
(asdf/find-system:primary-system-name system)))
(flet ((foo (name fn &key type)
(let ((value (funcall fn system)))
(when value
(case type
((:link)
(format stream "- ~A: [~A](~A)~%" name value value))
((:mailto)
(format stream "- ~A: [~A](mailto:~A)~%"
name value value))
((nil)
(format stream "- ~A: ~A~%" name value)))))))
(foo "Version" 'asdf/component:component-version)
(foo "Description" 'asdf/system:system-description)
(foo "Licence" 'asdf/system:system-licence)
(foo "Author" 'asdf/system:system-author)
(foo "Maintainer" 'asdf/system:system-maintainer)
(foo "Mailto" 'asdf/system:system-mailto :type :mailto)
(foo "Homepage" 'asdf/system:system-homepage :type :link)
(foo "Bug tracker" 'asdf/system:system-bug-tracker)
(foo "Long description" 'asdf/system:system-long-description))))
(defmethod find-source ((system asdf:system))
`(:location
(:file ,(namestring (asdf/system:system-source-file system)))
(:position 1)
(:snippet "")))
[macro] DEFINE-LOCATIVE-TYPE 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.
[generic-function] EXPORTABLE-LOCATIVE-TYPE-P LOCATIVE-TYPE
Return true iff symbols in references with
LOCATIVE-TYPE are to be exported by default when they occur in a
DEFSECTION. The default method returns T, while the methods for
PACKAGE, ASDF:SYSTEM and METHOD return NIL.
DEFSECTION calls this function to decide what symbols to export when
its EXPORT argument is true.
[generic-function] LOCATE-OBJECT OBJECT LOCATIVE-TYPE LOCATIVE-ARGS
Return the object OBJECT + locative refers to. For
example, if LOCATIVE-TYPE is the symbol PACKAGE, this
returns (FIND-PACKAGE SYMBOL). Signal a LOCATE-ERROR condition by
calling the LOCATE-ERROR function if lookup fails. Signal other
errors if the types of the argument are bad, for instance
LOCATIVE-ARGS is not the empty list in the package example. If a
REFERENCE is returned then it must be canonical in the sense that
calling CANONICAL-REFERENCE on it will return the same reference.
For extension only, don't call this directly.
[function] LOCATE-ERROR &REST FORMAT-AND-ARGS
Call this function to signal a LOCATE-ERROR condition from a
LOCATE-OBJECT method. 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.
[generic-function] CANONICAL-REFERENCE OBJECT
Return a REFERENCE that resolves to OBJECT.
[generic-function] COLLECT-REACHABLE-OBJECTS OBJECT
Return a list of objects representing all things
that would be documented in a (DOCUMENT OBJECT) call. For sections
this is simply the union of references reachable from references in
SECTION-ENTRIES. The returned objects can be anything provided that
CANONICAL-REFERENCE works on them. The list need not include OBJECT
itself.
One only has to specialize this for new container-like objects.
[method] COLLECT-REACHABLE-OBJECTS OBJECT
This default implementation returns the empty list. This means that
nothing is reachable from OBJECT.
[generic-function] DOCUMENT-OBJECT OBJECT STREAM
Write OBJECT (and its references recursively) in
FORMAT to STREAM.
The DOCUMENT function calls this generic function with LEVEL 0,
passing FORMAT on. Add methods specializing on OBJECT to customize
how objects of that type are presented in the documentation.
[method] DOCUMENT-OBJECT (STRING STRING) STREAM
Print STRING verbatim to STREAM after cleaning up indentation.
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.
[generic-function] FIND-SOURCE 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 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")Let's see how to extend DOCUMENT and M-. navigation if there is
no first class object to represent the thing of interest. Recall
that LOCATE returns a REFERENCE object in this case. DOCUMENT-OBJECT
and FIND-SOURCE defer to LOCATE-AND-DOCUMENT and
LOCATE-AND-FIND-SOURCE 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:
(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))
(make-reference symbol (cons locative-type locative-args)))
(defmethod locate-and-document (symbol (locative-type (eql 'variable))
locative-args stream)
(destructuring-bind (&optional (initform nil initformp)) locative-args
(locate-and-print-bullet locative-type locative-args symbol stream)
(write-char #\Space stream)
(multiple-value-bind (value unboundp) (symbol-global-value symbol)
(print-arglist (prin1-to-string (cond (initformp initform)
(unboundp "-unbound-")
(t value)))
stream))
(terpri stream)
(with-dislocated-symbols ((list symbol))
(maybe-print-docstring symbol locative-type stream))))
(defmethod locate-and-find-source (symbol (locative-type (eql 'variable))
locative-args)
(declare (ignore locative-args))
(find-one-location (swank-backend:find-definitions symbol)
'("variable" "defvar" "defparameter"
"special-declaration")))
[method] COLLECT-REACHABLE-OBJECTS (REFERENCE REFERENCE)
If REFERENCE can be resolved to a non-reference, call
COLLECT-REACHABLE-OBJECTS with it, else call
LOCATE-AND-COLLECT-REACHABLE-OBJECTS on the object, locative-type,
locative-args of REFERENCE
[generic-function] LOCATE-AND-COLLECT-REACHABLE-OBJECTS OBJECT LOCATIVE-TYPE LOCATIVE-ARGS
Called by COLLECT-REACHABLE-OBJECTS on REFERENCE
objects, this function has essentially the same purpose as its
caller but it has different arguments to allow specializing on
LOCATIVE-TYPE.
[method] LOCATE-AND-COLLECT-REACHABLE-OBJECTS OBJECT LOCATIVE-TYPE LOCATIVE-ARGS
This default implementation returns the empty list. This means that nothing is reachable from the reference.
[method] DOCUMENT-OBJECT (REFERENCE REFERENCE) STREAM
If REFERENCE can be resolved to a non-reference, call
DOCUMENT-OBJECT with it, else call LOCATE-AND-DOCUMENT-OBJECT on the
object, locative-type, locative-args of REFERENCE
[generic-function] LOCATE-AND-DOCUMENT OBJECT LOCATIVE-TYPE LOCATIVE-ARGS STREAM
Called by DOCUMENT-OBJECT on REFERENCE objects,
this function has essentially the same purpose as DOCUMENT-OBJECT
but it has different arguments to allow specializing on
LOCATIVE-TYPE.
[method] FIND-SOURCE (REFERENCE REFERENCE)
If REFERENCE can be resolved to a non-reference, call FIND-SOURCE
with it, else call LOCATE-AND-FIND-SOURCE on the object,
locative-type, locative-args of REFERENCE
[generic-function] LOCATE-AND-FIND-SOURCE OBJECT LOCATIVE-TYPE LOCATIVE-ARGS
Called by FIND-SOURCE on REFERENCE objects, this
function has essentially the same purpose as FIND-SOURCE but it has
different arguments to allow specializing on LOCATIVE-TYPE.
[method] LOCATE-AND-FIND-SOURCE OBJECT LOCATIVE-TYPE LOCATIVE-ARGS
This default implementation simply calls FIND-SOURCE with OBJECT
which should cover the common case of a macro expanding to, for
instance, a defun but having its own locative type.
We have covered the basic building blocks of reference based
extensions. Now let's see how the obscure
DEFINE-SYMBOL-LOCATIVE-TYPE and
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.
[macro] DEFINE-SYMBOL-LOCATIVE-TYPE LOCATIVE-TYPE LAMBDA-LIST &BODY DOCSTRING
Similar to 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 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 how 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.
[macro] DEFINE-DEFINER-FOR-SYMBOL-LOCATIVE-TYPE 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 DEFINE-SYMBOL-LOCATIVE-TYPE.
Section objects rarely need to be dissected since
DEFSECTION and DOCUMENT cover most needs. However, it is plausible
that one wants to subclass them and maybe redefine how they are
presented.
[class] SECTION
DEFSECTION stores its NAME, TITLE and ENTRIES in
SECTION objects.
[reader] SECTION-NAME SECTION (:NAME)
The name of the global variable whose value is this section object.
[reader] SECTION-PACKAGE SECTION (:PACKAGE)
*PACKAGE* will be bound to this package when
generating documentation for this section.
[reader] SECTION-READTABLE SECTION (:READTABLE)
*READTABLE* will be bound to this when generating
documentation for this section.
[reader] SECTION-TITLE SECTION (:TITLE)
Used in generated documentation.
[reader] SECTION-ENTRIES SECTION (:ENTRIES)
A list of strings and REFERENCE objects in the
order they occurred in DEFSECTION.
[method] DESCRIBE-OBJECT (SECTION SECTION) STREAM
SECTION objects are printed by calling DOCUMENT on them
with all Documentation Printer Variables, except for
*DOCUMENT-NORMALIZE-PACKAGES*, turned off to reduce clutter.
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)
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 elisp function mgl-pax-transcribe 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 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
TRANSCRIPTION-CONSISTENCY-ERROR 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 elisp function mgl-pax-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 mgl-pax-transcribe will emit commented markup:
(values (princ :hello) (list 1 2))
;.. HELLO
;=> :HELLO
;=> (1 2)
C-u 0 mgl-pax-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 MGL-PAX:*SYNTAXES*. Without a
prefix argument mgl-pax-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 src/transcribe.el):
;;; MGL-PAX transcription
(defun mgl-pax-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 MGL-PAX:TRANSCRIBE. Use a numeric prefix
argument as in index to select one of the Common Lisp
MGL-PAX:*SYNTAXES* as the SYNTAX argument to MGL-PAX: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))))
(mgl-pax-transcribe start end (mgl-pax-transcribe-syntax-arg)
nil nil nil)))))
(defun mgl-pax-retranscribe-region (start end)
"Updates the transcription in the current region (as in calling
MGL-PAX:TRANSCRIBE with :UPDATE-ONLY T). Use a numeric prefix
argument as in index to select one of the Common Lisp
MGL-PAX:*SYNTAXES* as the SYNTAX argument to MGL-PAX:TRANSCRIBE.
Without a prefix argument, the syntax of the input will not be
changed."
(interactive "r")
(let* ((point-at-start-p (= (point) start))
(point-at-end-p (= (point) end))
(transcript (mgl-pax-transcribe start end
(mgl-pax-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 mgl-pax-transcribe-syntax-arg ()
(if current-prefix-arg
(prefix-numeric-value current-prefix-arg)
nil))
(defun mgl-pax-transcribe (start end syntax update-only echo
first-line-special-p)
(let ((transcription
(slime-eval
`(cl:if (cl:find-package :mgl-pax)
(cl:funcall
(cl:find-symbol
(cl:symbol-name :transcribe-for-emacs) :mgl-pax)
,(buffer-substring-no-properties start end)
',syntax ',update-only ',echo ',first-line-special-p)
t))))
(if (eq transcription t)
(error "MGL-PAX is not loaded.")
transcription)))[function] TRANSCRIBE 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 (iff 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 valuewhere 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)Unreadable Values
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)
(print-unreadable-object (obj stream :type t)
(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.
[variable] *SYNTAXES* ((:DEFAULT (:OUTPUT “..”) (:NO-VALUE “⇒ ; No value”) (:READABLE “⇒”) (:UNREADABLE “=⇒”) (:UNREADABLE-CONTINUATION “–>”)) (:COMMENTED-1 (:OUTPUT “;..”) (:NO-VALUE “;⇒ ; No value”) (:READABLE “;⇒”) (:READABLE-CONTINUATION “;→”) (:UNREADABLE “;=⇒”) (:UNREADABLE-CONTINUATION “;–>”)) (:COMMENTED-2 (:OUTPUT “;;..”) (:NO-VALUE “;;⇒ ; No value”) (:READABLE “;;⇒”) (:READABLE-CONTINUATION “;;→”) (:UNREADABLE “;;=⇒”) (:UNREADABLE-CONTINUATION “;;–>”)))
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")
(:readable ";=>")
(:readable-continuation ";->")
(:unreadable ";==>")
(: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.
[condition] TRANSCRIPTION-ERROR ERROR
Represents syntactic errors in the SOURCE argument
of TRANSCRIBE and also serves as the superclass of
TRANSCRIPTION-CONSISTENCY-ERROR.
[condition] TRANSCRIPTION-CONSISTENCY-ERROR TRANSCRIPTION-ERROR
A common superclass for
TRANSCRIPTION-OUTPUT-CONSISTENCY-ERROR and
TRANSCRIPTION-VALUES-CONSISTENCY-ERROR.
[condition] TRANSCRIPTION-OUTPUT-CONSISTENCY-ERROR TRANSCRIPTION-CONSISTENCY-ERROR
Signaled (with CERROR) by TRANSCRIBE when invoked
with :CHECK-CONSISTENCY and the output of a form is not the same as
what was parsed.
[condition] TRANSCRIPTION-VALUES-CONSISTENCY-ERROR TRANSCRIPTION-CONSISTENCY-ERROR
Signaled (with CERROR) by TRANSCRIBE when invoked
with :CHECK-CONSISTENCY and the values of a form are inconsistent
with their parsed representation.
[function] MAKE-GITHUB-SOURCE-URI-FN ASDF-SYSTEM GITHUB-URI &KEY GIT-VERSION
Return a function suitable as :SOURCE-URI-FN of a page spec (see
the PAGES argument of DOCUMENT). 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.
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.
*