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chicken-doc is a tool for exploring Chicken documentation.


chicken-doc provides facilities to explore Chicken documentation from the command-line and from the REPL. It also provides an API to access this documentation from your own programs.

You need to obtain Chicken documentation separately. To generate a documentation database from a copy of the wiki, see the chicken-doc-admin egg. You can also use a pre-built documentation package, described below.

Documentation repository

The documentation database is located, by default, under (chicken-home) in the chicken-doc/ directory. If you have installed it in a different location, set the CHICKEN_DOC_REPOSITORY enviroment variable:

export CHICKEN_DOC_REPOSITORY=/path/to/repository

Pre-built packages

Documentation tarballs are provided in gzip, bzip2 and zip format at They are updated daily from the latest wiki documentation.

Download your preferred format and extract it into the default location (chicken-home) or into some other writable directory of your choice. For example, on UNIX:

$ cd `csi -p '(chicken-home)'`
$ curl | sudo tar zx

The tarball will be extracted into the directory chicken-doc/. If you installed into a non-default location, CHICKEN_DOC_REPOSITORY must include this entire path.

Cleaning up old repository crust

Occasionally, or when the repository format changes significantly, you should wipe out your repository before extracting a new one, to get rid of dead wood. Simply delete the directory shown by the following command:

$ csi -R chicken-doc -p "(locate-repository)"

If you have chicken-doc-admin installed, just do instead:

$ chicken-doc-admin -D


The documentation is arranged in a tree structure, where each node may contain descriptive text, a signature, and other nodes. Nodes may be searched for by name or specified by an absolute path through the tree, and you may request the text, signature or table of contents (children) for any node.

With the standard documentation install, each unit (posix, lolevel) and egg (9p, base64) is assigned a toplevel node whose text contains that unit or egg's full documentation. The identifiers in each become these nodes' children, and contain the signature and descriptive text just for that identifier. Core bindings in the chicken module are similar, but because they are divided into several manual pages, each page is placed in a separate node under the toplevel node chicken.

So in general, if you know the full path of an identifier, you can pull it into your program with (use NODE) or (import NODE) where NODE is the name of the toplevel node. For example,

 and-let* -> (chicken macros and-let*) -> (import chicken)
 find-files -> (posix find-files) -> (use posix)

Here's an abbreviated example of the tree structure:

|- 9p +- alloc-handle
|     |- call-with-input-file
|     |- call-with-output-file
|- base64 +- base64-decode
|         |- base64-encode
|- chicken +- macros +- and-let*
|          |         |- assert
|          |
|          |- parameters -- make-parameter
|- posix +- find-files
|        |- glob
|        |- open/rdonly

From the command-line

chicken-doc -s|-c|-i path
chicken-doc -f node
chicken-doc node | path

-s path        Show signature
-c path        Show table of contents (children)
-i path        Show documentation
-f node        Show all matching paths for node

where NODE is a single identifier and PATH is one or more node names comprising a path from the documentation root, separated by spaces.

-m re          Show all matching paths for RE

where RE is a POSIX regular expression. Similar to -f.

When no option is given, guess the user's intent. With a single node name, find the node (as with -f) and show its documentation (as with -i) or show all matching paths if multiple matches exist. If more than one node is provided, show documentation on the path (as if called with -i).


When output is sent to a terminal, chicken-doc pipes its output to the pager of your choice. It looks for a pager in the following places:

If an environment variable is set but empty, for example:


then the output is not paginated. Windows does not distinguish between an empty and unset variable, so you can use the special value cat instead:


Text wrapping

chicken-doc will wrap its output text nicely if it can determine how wide your terminal is. If it can't (e.g. on Windows) it will wrap at 76 columns. If you wish to fix the wrap column to, say, 120:


or to disable wrapping, which won't look very good:



Alpha-quality feature added in 0.4.3, adding ANSI bold and underline support rather than the usual ASCII chars. The attributes cannot currently be configured beyond enabling and disabling colorization.

To enable:


Colorization will then be enabled when output is directed to a terminal and your TERM variable is set (to anything other than "dumb"). Using chicken-doc's pager facility counts as a terminal; we assume your pager supports ANSI escape sequences, as in less -R.


Show matches for identifier file-open, which occurs in Unit posix and in the 9p egg:

$ chicken-doc -f file-open
(9p file-open)        (file-open connection path mode)
(posix file-open)     (file-open FILENAME FLAGS [MODE])

Show signature of open/rdonly in Unit posix:

$ chicken-doc -s posix open/rdonly
(posix open/rdonly)     open/rdonly

Show documentation for file-open in the 9p egg:

$ chicken-doc -i 9p open/rdonly
procedure: (file-open connection path mode)

Opens the file indicated by `path` on the `connection` with the given
`mode` and returns an opaque handle object which you can use for the [...]

Show table of contents (identifiers) in Unit posix:

$ chicken-doc -c posix
get-host-name        (get-host-name)
glob                 (glob PATTERN1 ...)
group-information    (group-information GROUP)

Show identifiers containing call-:

$ chicken-doc -m call-
(scheme call-with-values)      (call-with-values producer consumer)
(xml-rpc call-xml-rpc-proc)    (call-xml-rpc-proc call-sxml procedures)
(library get-call-chain)       (get-call-chain [START [THREAD]])

Show identifiers ending in -file:

$ chicken-doc -m -file$
(spiffy access-file)           (access-file [string])
(scheme call-with-input-file)  (call-with-input-file string proc)
(scheme call-with-output-file) (call-with-output-file string proc)

Show `with-...-port` identifiers:

$ chicken-doc -m with-.+-port
(ports with-error-output-to-port)  (with-error-output-to-port PORT THUNK)
(ports with-input-from-port)       (with-input-from-port PORT THUNK)
(ports with-output-to-port)        (with-output-to-port PORT THUNK)

Show documentation for use in chicken core:

$ chicken-doc use
path: (chicken macros use)
macro: (use ID ...)

`use` is just a shorter alias for `require-extension`.

Show full documentation for Unit posix:

$ chicken-doc posix

Show matches for open/rdonly, as with -f:

$ chicken-doc open/rdonly

Show documentation for open/rdonly in Unit posix:

$ chicken-doc posix open/rdonly

From the REPL

To load chicken-doc for REPL use:

(require-library chicken-doc)

The following csi commands then become available:

,doc node
,doc (node ...)

Show documentation for the identifier node or the absolute path (node ...). If a single node is given, a search is performed across all identifiers, and documentation will be shown if the node is unique --- otherwise, the matches are listed.

,toc node
,toc (node ...)

Show a table of contents for the identifier node or the path (node ...). As with ,doc, a search will be performed if a single node is given.

,wtf regex

The "where to find" command. Search identifiers using POSIX regular expression regex (like the -m command-line option) and display the matches.


Search for identifier define-foreign-type and display its documentation.

#;> ,doc define-foreign-type
path: (foreign access define-foreign-type)
macro: (define-foreign-type NAME TYPE [ARGCONVERT [RETCONVERT]])

Defines an alias for `TYPE` with the name `NAME` (a symbol).
`TYPE` may be a type-specifier or a string naming a C type. The

Search for identifier file-open and (as multiple matches occur) display the matches:

#;> ,doc file-open
Found 2 matches:
(9p file-open)        (file-open connection path mode)
(posix file-open)     (file-open FILENAME FLAGS [MODE])

Display TOC for absolute path (chicken macros). This should list all the core chicken macros from Non-standard macros and special forms.

#;> ,toc (chicken macros)
and-let*              (and-let* (BINDING ...) EXP1 EXP2 ...)
assert                (assert EXP [STRING ARG ...])
begin-for-syntax      (begin-for-syntax EXP ...)


This elisp snippet will look up the word at point and display its documentation (or matches) in your *scheme* window and display it in a split window unless it is already visible.

(defun chicken-doc (&optional obtain-function)
  (let ((func (funcall (or obtain-function 'current-word))))
    (when func
      (process-send-string (scheme-proc)
                           (format "(require-library chicken-doc) ,doc %S\n" func))
        (select-window (display-buffer (get-buffer scheme-buffer) t))
        (goto-char (point-max))))))
(eval-after-load 'cmuscheme
 '(define-key scheme-mode-map "\C-cd" 'chicken-doc))

Additionally, because multiple matches may be listed, this snippet will allow you to place your cursor at the beginning of the match s-expression and get the actual documentation:

(eval-after-load 'cmuscheme
 '(define-key inferior-scheme-mode-map "\C-cd"
    (lambda () (interactive) (chicken-doc 'sexp-at-point))))



[parameter] wrap-column [default: 76]

Wrap column for text output. 0 or #f for no wrapping.

[parameter] chicken-doc-warnings [default: #f]

For debugging. Controls emission of warnings from the text renderer.

When using the command-line tool, you can set the environment variable CHICKEN_DOC_WARNINGS to any value to enable warnings.


[procedure] (verify-repository)

Open the repository found in the standard location with (locate-repository) and set the (current-repository) for the thread. Throws an error if the open fails.

This is the standard way to open the chicken-doc repository, because the node lookup procedures require (current-repository) to be set.

[procedure] (open-repository base)

Open repository at pathname base and return a new repository object or throw an error if nonexistent or unknown format.

Generally, you will want to use verify-repository to open the repository instead.

[procedure] (close-repository r)

Close repository object r.

[parameter] current-repository

The current repository; used by the node lookup API. It is usually set by calling verify-repository.

[procedure] (locate-repository)

Return the standard location of the repository, according to the rules described in Documentation repository. Does not check if the repository actually exists.

Node lookup

[procedure] (lookup-node path)

Return node record at path, or throw an error if the record does not exist. path is a list of string or symbols which identify the node; for example '(posix open/rdonly).

[procedure] (match-nodes idre #!optional (limit #f))

Return a list of node records whose identifiers match idre, which may be an identifier symbol, identifier string or a regular expression object. limit is an optional integer limit on the number of nodes returned, or #f for no limit.

[procedure] (match-node-paths/re re #!optional (limit #f))

Return a list of node records whose full paths match re, a regular expression string or object. re matches against the string representation of the node path, which is composed of each node id joined with spaces. For example, '(chicken foreign access) becomes "chicken foreign access".

limit is an optional integer limit on the number of nodes returned, or #f for no limit.

[procedure] (match-ids/prefix str #!optional (limit #f))

Return a list of node records whose identifiers match the string prefix str. limit is an optional integer limit on the number of records returned, or #f for no limit.

[procedure] (match-paths/prefix str #!optional (limit #f))

Return a list of node records whose full paths match the string prefix str. This matches against the string representation of the node path, which is composed of each node id joined with spaces. For example, '(chicken foreign access) becomes "chicken foreign access". limit is an optional integer limit on the number of records returned, or #f for no limit.

Node description

The command-line utility is a thin wrapper around these procedures, which print descriptive information to current-output-port.

[procedure] (describe node)

Formats and displays the text contents of node. An error is thrown if no textual content is available.

[procedure] (describe-contents node)

Displays the names and signatures of all child nodes of node.

[procedure] (describe-signatures nodes)

Displays the signatures of all nodes in the list nodes.

[procedure] (doc-dwim pathspec)

This "do-what-I-mean" procedure is used by the command line when no options are provided.

If pathspec is a list, it is treated as a node path and the node at that path is looked up and described.

If it is a string or symbol, it is decomposed into a list of node identifiers by splitting at each #. If this results in one identifier, it is matched against and the node is described (if exactly one match) or all matched paths are displayed. Otherwise, the identifier list is treated as a node path and the node at that path is described.

[procedure] (search-only idre)

Search for all nodes matching the identifier or regular expression idre, and print a description of their signatures. Equivalent to

(describe-signatures (match-nodes idre))

Node information

[record] chicken-doc-node

The chicken-doc-node record represents an individual repository node, such as '(posix) or '(posix open/rdonly).

[procedure] (node-signature node)

Return the signature of node as a string. The signature is a node's short identifying description. For example, it may be a procedure signature, an identifier or the name of a manual page.

[procedure] (node-type node)

Return a symbol representing the type of node. The currently defined node types are: egg (egg documentation), unit (manual page), procedure, parameter, syntax, constant, read (read syntax), record, setter, class, and method.

Returns 'unknown if type information is not available for some reason; however, the current repository backend always provides type information.

[procedure] (node-sxml node)

Return the sxml contents of node (as a pair).

[procedure] (node-path node)

Return the full node path of node as a list of identifiers. Each returned identifier may be a symbol or a string (this may be tightened up in the future).

[procedure] (node-id node)

Return the node id of node, which is the last component in the full path. The return value may be a symbol or a string (this may be tightened up in the future).

[procedure] (node-timestamp node)

Return the timestamp of a node in seconds since the UNIX epoch, or #f if no timestamp is available. In general, the timestamp is that of the source document used to generate this node.

[procedure] (node-children node)

Return the children of node as a list of node records.

[procedure] (node-child node id)

Return the child of node record node having identifier id, as a node record. id is a symbol or string.

[procedure] (node-child-ids node)

Return a list of identifiers (symbols or strings) of the children of node. Semantically equivalent to (map node-id (node-children node)), but may be significantly less expensive than calling node-children.

[procedure] (node-definition-ids node)

Experimental. Returns a list of identifiers for the definition children of node. This is a subset of the identifiers returned by node-children.

[procedure] (node-definition-id? node id)

Experimental. Returns #t if id is a definition child of node.

About this egg


Jim Ursetto

Version history

Fix for letrec behavior change in 4.8.3
Use pre-post-order* to avoid apply limit
Add limit option to node matching API
Experimental ANSI bold/underline support; improve int-link display
Decrease pre and highlight indent from 4 to 2; depend on regex egg
Improve DL rendering; add chicken-doc-warnings
Repository version 3
POSIX regular expression search
SXML database, formatting improvements
Initial release