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* Taxy: (taxy).         Programmable taxonomical grouping for arbitrary objects.
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File: README.info,  Node: Top,  Next: Examples,  Up: (dir)

taxy.el
*******

https://elpa.gnu.org/packages/taxy.svg
(https://elpa.gnu.org/packages/taxy.html)

   _Now, where did I put that..._

   This library provides a programmable way to classify arbitrary
objects into a hierarchical taxonomy.  (That's a lot of fancy words to
say that this lets you automatically put things in nested groups.)

   Helpful features include:

Dynamic taxonomies
     Objects may be classified into hierarchies automatically defined at
     runtime based on their attributes.
Reusable taxonomies
     Taxonomy definitions may be stored in variables and reused in other
     taxonomies' descendant groups.
Classification domain-specific language
     Easily define a custom DSL used to classify items dynamically
     (which can be extended by users).
Flexible table view
     Based on ‘magit-section’, with easily defined columns (also
     extendable by users).

* Menu:

* Examples::
* Installation::
* Usage::
* Changelog::
* Development::
* Credits::
* License::

-- The Detailed Node Listing --

Examples

* Numbery (starting basically)::
* Lettery (filling incrementally)::
* Sporty (understanding completely)::
* Applications::

Usage

* Reusable taxys::
* Threading macros::
* Modifying filled taxys::
* Dynamic taxys::
* Magit section::
* Reference::

Dynamic taxys

* Multi-level dynamic taxys::
* "Chains" of independent, multi-level dynamic taxys: "Chains" of independent multi-level dynamic taxys.
* Defining a classification domain-specific language::

Reference

* Functions::
* Macros::

Changelog

* v0.11-pre: v011-pre.
* 0.10.2: 0102.
* 0.10.1: 0101.
* 0.10: 010.
* 0.9: 09.
* 0.8: 08.
* 0.7: 07.
* 0.6: 06.
* 0.5: 05.
* 0.4: 04.
* 0.3: 03.
* 0.2: 02.
* 0.1: 01.

0.9

* Changes::

0.8

* Additions::
* Fixes::

0.7

* Additions: Additions (1).

0.6

* Additions: Additions (2).

0.5

* Additions: Additions (3).
* Fixes: Fixes (1).

0.3

* Changes: Changes (1).
* Fixes: Fixes (2).

0.2

* Changes: Changes (2).
* Additions: Additions (4).
* Fixes: Fixes (3).

Development

* Copyright assignment::



File: README.info,  Node: Examples,  Next: Installation,  Prev: Top,  Up: Top

1 Examples
**********

   • • • • 
   May these examples help you classify your understanding.

* Menu:

* Numbery (starting basically)::
* Lettery (filling incrementally)::
* Sporty (understanding completely)::
* Applications::


File: README.info,  Node: Numbery (starting basically),  Next: Lettery (filling incrementally),  Up: Examples

1.1 Numbery (starting basically)
================================

Let's imagine a silly taxonomy of numbers below 100:

     ("Numbery" "A silly taxonomy of numbers."
      (("< 10" "Numbers below 10"
        ;; These numbers are leftovers from the sub-taxys below.
        (0 2 4 6 8)
        ;; These sub-taxys further classify the numbers below 10 into odd
        ;; and even.  The odd taxy "consumes" numbers, while the even one
        ;; doesn't, leaving them to reappear in the parent taxy's items.
        (("Odd" "(consuming)"
          (1 3 5 7 9))
         ("Even" "(non-consuming)"
          (0 2 4 6 8))))
       (">= 10" "Numbers above 9"
        ;; Like in the "< 10" taxy, these numbers are leftovers from this
        ;; taxy's sub-taxys, three of which are non-consuming.
        (10 11 13 14 17 19 22 23 25 26 29 31 34 35 37 38 41 43 46 47 49 50 53 55 58
            59 61 62 65 67 70 71 73 74 77 79 82 83 85 86 89 91 94 95 97 98)
        (("Divisible by 3" "(non-consuming)"
          (12 15 18 21 24 27 30 33 36 39 42 45 48 51 54 57 60 63 66 69 72 75 78 81 84
              87 90 93 96 99))
         ("Divisible by 4" "(non-consuming)"
          (12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72 76 80 84 88 92 96))
         ("Divisible by 3 or 4" "(consuming)"
          ;; This taxy consumes numbers it takes in, but since these
          ;; numbers have already been taken in (without being consumed) by
          ;; the previous two sibling taxys, they may also appear in them.
          (12 15 16 18 20 21 24 27 28 30 32 33 36 39 40 42 44 45 48 51 52 54 56 57 60
              63 64 66 68 69 72 75 76 78 80 81 84 87 88 90 92 93 96 99))
         ("Divisible by 5" "(non-consuming)"
          (10 25 35 50 55 65 70 85 95))))))

   You might think about how to produce that by writing some imperative
code, but ‘taxy’ allows you to do so in a more declarative and
functional manner:

     (require 'taxy)

     (defvar numbery
       (make-taxy
        :name "Numbery"
        :description "A silly taxonomy of numbers."
        :taxys (list (make-taxy
                      :name "< 10"
                      :description "Numbers below 10 (consuming)"
                      :predicate (lambda (n) (< n 10))
                      :taxys (list
                              ;; These sub-taxys further classify the numbers below 10 into odd
                              ;; and even.  The odd taxy "consumes" numbers, while the even one
                              ;; doesn't, leaving them to reappear in the parent taxy's items.
                              (make-taxy :name "Odd"
                                         :description "(consuming)"
                                         :predicate #'oddp)
                              (make-taxy :name "Even"
                                         :description "(non-consuming)"
                                         :predicate #'evenp
                                         :then #'identity)))
                     (make-taxy
                      :name ">= 10"
                      :description "Numbers above 9 (consuming)"
                      :predicate (lambda (n) (>= n 10))
                      :taxys (list
                              ;; Like in the "< 10" taxy, these sub-taxys further classify
                              ;; the numbers, but only one of them consumes numbers it
                              ;; takes in, leaving the rest to reappear in the parent taxy.
                              (make-taxy :name "Divisible by 3"
                                         :description "(non-consuming)"
                                         :predicate (lambda (n) (zerop (mod n 3)))
                                         :then #'identity)
                              (make-taxy :name "Divisible by 4"
                                         :description "(non-consuming)"
                                         :predicate (lambda (n) (zerop (mod n 4)))
                                         :then #'identity)
                              (make-taxy :name "Divisible by 3 or 4"
                                         :description "(consuming)"
                                         ;; Since this taxy's `:then' function is unset,
                                         ;; it defaults to `ignore', which causes it to
                                         ;; consume numbers it takes in.  Since these
                                         ;; numbers have already been taken in (without
                                         ;; being consumed) by the previous two sibling
                                         ;; taxys, they also appear in them.
                                         :predicate (lambda (n) (or (zerop (mod n 3))
                                                                    (zerop (mod n 4)))))
                              (make-taxy :name "Divisible by 5"
                                         :description "(non-consuming)"
                                         :predicate (lambda (n) (zerop (mod n 5)))
                                         :then #'identity))))))

     (let ((numbers (cl-loop for i below 100 collect i))
           ;; Since `numbery' is stored in a variable, we use an emptied
           ;; copy of it to avoid mutating the original taxy.
           (taxy (taxy-emptied numbery)))
       (taxy-plain (taxy-fill (reverse numbers) taxy)))

   The ‘taxy-fill’ function applies the numbers in a "cascade" down the
hierarchy of "taxys", and the ‘taxy-plain’ function returns a meaningful
subset of the taxys' slots, suitable for display.


File: README.info,  Node: Lettery (filling incrementally),  Next: Sporty (understanding completely),  Prev: Numbery (starting basically),  Up: Examples

1.2 Lettery (filling incrementally)
===================================

You can also add more items after the hierarchy has been filled.  In
this example we'll make a comprehensive taxonomy of letters.  The first
sub-taxy collects vowels, and the second, by leaving its predicate at
the default value, ‘identity’, collects all letters not collected by the
first taxy, i.e.  non-vowels.

     (defvar lettery
       (make-taxy
        :name "Lettery"
        :description "A comprehensive taxonomy of letters."
        :taxys (list (make-taxy
                      :name "Vowels"
                      :description "You know what those are."
                      :predicate (lambda (l)
                                   (member-ignore-case l '("a" "e" "i" "o" "u"))))
                     (make-taxy
                      :name "Consonants"
                      :description "Well, if they aren't vowels..."))))

     (taxy-plain
      (taxy-fill (reverse
                  (cl-loop for l from ?a to ?n
                           collect (upcase (char-to-string l))))
                 lettery))

   That produces:

     ("Lettery" "A comprehensive taxonomy of letters."
      (("Vowels" "You know what those are."
        ("A" "E" "I"))
       ("Consonants" "Well, if they aren't vowels..."
        ("B" "C" "D" "F" "G" "H" "J" "K" "L" "M" "N"))))

   Oops, we forgot the letters after N!  Let's add them, too:

     (taxy-plain
      (taxy-fill (reverse
                  (cl-loop for l from ?n to ?z
                           collect (upcase (char-to-string l))))
                 lettery))

   Which gives us:

     ("Lettery" "A comprehensive taxonomy of letters."
      (("Vowels" "You know what those are."
        ("O" "U" "A" "E" "I"))
       ("Consonants" "Well, if they aren't vowels..."
        ("N" "P" "Q" "R" "S" "T" "V" "W" "X" "Y" "Z" "B" "C" "D" "F" "G" "H" "J" "K" "L" "M" "N"))))

   Oh, they're out of order, now.  That won't do.  Let's fix that:

     (taxy-plain
      (taxy-sort #'string< #'identity lettery))

   That's better:

     ("Lettery" "A comprehensive taxonomy of letters."
      (("Vowels" "You know what those are."
        ("A" "E" "I" "O" "U"))
       ("Consonants" "Well, if they aren't vowels..."
        ("B" "C" "D" "F" "G" "H" "J" "K" "L" "M" "N" "N" "P" "Q" "R" "S" "T" "V" "W" "X" "Y" "Z"))))


File: README.info,  Node: Sporty (understanding completely),  Next: Applications,  Prev: Lettery (filling incrementally),  Up: Examples

1.3 Sporty (understanding completely)
=====================================

Let's try to understand a few things about sports.  First we'll define a
struct to make them easier to grasp:

     (cl-defstruct sport
       name uses venue fun)

   Now we'll make a list of sports:

     (defvar sports
       (list (make-sport :name "Baseball"
                         :uses '(bat ball glove)
                         :venue 'outdoor
                         :fun t)
             (make-sport :name "Football"
                         :uses '(ball)
                         :venue 'outdoor
                         :fun t)
             (make-sport :name "Basketball"
                         :uses '(ball hoop)
                         :venue 'indoor
                         :fun t)
             (make-sport :name "Tennis"
                         :uses '(ball racket)
                         :venue 'outdoor
                         :fun t)
             (make-sport :name "Racquetball"
                         :uses '(ball racket)
                         :venue 'indoor
                         :fun t)
             (make-sport :name "Handball"
                         :uses '(ball glove)
                         :venue 'indoor
                         :fun t)
             (make-sport :name "Soccer"
                         :uses '(ball)
                         :venue 'outdoor
                         :fun nil)
             (make-sport :name "Disc golf"
                         :uses '(disc basket)
                         :venue 'outdoor
                         :fun t)
             (make-sport :name "Ultimate"
                         :uses '(disc)
                         :venue 'outdoor
                         :fun t)
             (make-sport :name "Volleyball"
                         :uses '(ball)
                         :venue 'indoor
                         :fun t)))

   And finally we'll define a taxy to organize them.  In this, we use a
helper macro to make the ‘member’ function easier to use in the list of
key functions:

     (defvar sporty
       (cl-macrolet ((in (needle haystack)
                         `(lambda (item)
                            (when (member ,needle (funcall ,haystack item))
                              ,needle))))
         (make-taxy
          :name "Sporty"
          :take (lambda (item taxy)
                  (taxy-take-keyed
                    (list #'sport-venue
                          (in 'ball 'sport-uses)
                          (in 'disc 'sport-uses)
                          (in 'glove 'sport-uses)
                          (in 'racket 'sport-uses))
                    item taxy
                    ;; We set the `:then' function of the taxys
                    ;; created by `taxy-take-keyed' to `identity'
                    ;; so they will not consume their items.
                    :then #'identity)))))

   Now let's fill the taxy with the sports and format it:

     (thread-last sporty
       taxy-emptied
       (taxy-fill sports)
       (taxy-mapcar #'sport-name)
       taxy-plain)

     ((("Sporty"
        ((indoor
          ((ball
            ("Volleyball" "Basketball")
            ((glove
              ("Handball"))
             (racket
              ("Racquetball"))))))
         (outdoor
          ((disc
            ("Ultimate" "Disc golf"))
           (ball
            ("Soccer" "Football")
            ((racket
              ("Tennis"))
             (glove
              ("Baseball"))))))))))

   That's pretty sporty.  But classifying them by venue first makes the
racket and glove sports not be listed together.  Let's swap the key
functions around so the venue is classified at the deepest level of the
hierarchy:

     (defvar sporty
       (cl-macrolet ((in (needle haystack)
                         `(lambda (item)
                            (when (member ,needle (funcall ,haystack item))
                              ,needle))))
         (make-taxy
          :name "Sporty"
          :take (lambda (item taxy)
                  (taxy-take-keyed
                    (list (in 'ball 'sport-uses)
                          (in 'disc 'sport-uses)
                          (in 'glove 'sport-uses)
                          (in 'racket 'sport-uses)
                          #'sport-venue)
                    item taxy
                    :then #'identity)))))

     (thread-last sporty
       taxy-emptied
       (taxy-fill sports)
       (taxy-mapcar #'sport-name)
       taxy-plain)

     ((("Sporty"
        ((disc
          ((outdoor
            ("Ultimate" "Disc golf"))))
         (ball
          ((racket
            ((indoor
              ("Racquetball"))
             (outdoor
              ("Tennis"))))
           (indoor
            ("Volleyball" "Basketball"))
           (outdoor
            ("Soccer" "Football"))
           (glove
            ((indoor
              ("Handball"))
             (outdoor
              ("Baseball"))))))))))

   That's better.  But I'd also like to see a very simple classification
to help me decide what to play:

     (thread-last
         (make-taxy
          :name "Funny"
          :take (lambda (item taxy)
                  (taxy-take-keyed
                    (list (lambda (sport)
                            (if (sport-fun sport)
                                'fun 'boring))
                          #'sport-venue)
                    item taxy)))
       taxy-emptied
       (taxy-fill sports)
       (taxy-mapcar #'sport-name)
       taxy-plain)

     ((("Funny"
        ((boring
          ((outdoor
            ("Soccer"))))
         (fun
          ((indoor
            ("Volleyball" "Handball" "Racquetball" "Basketball"))
           (outdoor
            ("Ultimate" "Disc golf" "Tennis" "Football" "Baseball"))))))))

   Ah, now I understand.


File: README.info,  Node: Applications,  Prev: Sporty (understanding completely),  Up: Examples

1.4 Applications
================

Some example applications may be found in the examples directory
(examples/):

   • Deffy shows top-level definitions and forms in an Elisp project or
     file:
   • Diredy rearranges a Dired buffer into groups by file size and type:
   • Musicy shows a music library with tracks categorized by genre,
     artist, year, album, etc:


File: README.info,  Node: Installation,  Next: Usage,  Prev: Examples,  Up: Top

2 Installation
**************

‘taxy’ is distributed in GNU ELPA (https://elpa.gnu.org/), which is
available in Emacs by default.  Use ‘M-x package-install RET taxy RET’,
then ‘(require 'taxy)’ in your Elisp project.


File: README.info,  Node: Usage,  Next: Changelog,  Prev: Installation,  Up: Top

3 Usage
*******

   • • • • • • 
   A taxy is defined with the ‘make-taxy’ constructor, like:

     (make-taxy :name "Numbery"
                :description "A silly taxonomy of numbers."
                :predicate #'numberp
                :then #'ignore
                :taxys (list ...))

   The ‘:predicate’ function determines whether an object fits into that
taxy.  If it does, ‘taxy-fill’ adds the object to that taxy's descendant
‘:taxys’, if present, or to its own ‘:items’.  The function defaults to
‘identity’, so a taxy "takes in" any object by default (i.e.  if you
only apply objects you want to classify, there's no need to test them at
the top-level taxy).

   The ‘:then’ function determines what happens to an object after being
taken in to the taxy's ‘:items’: if the function, called with the
object, returns a non-nil value, that value is applied to other taxys at
the same level until one of their ‘:then’ functions returns nil or no
more taxys remain.  The function defaults to ‘ignore’, which makes a
taxy "consume" its items by default.  Setting the function to, e.g.
‘identity’, makes it not consume them, leaving them eligible to also be
taken into subsequent taxys, or to appear in the parent taxy's items.

   After defining a taxy, call ‘taxy-fill’ with it and a list of objects
to fill the taxy's hierarchy.  *Note:* ‘taxy-fill’ modifies the taxy
given to it (filling its ‘:items’ and those of its ‘:taxys’), so when
using a statically defined taxy (e.g.  one defined with ‘defvar’), you
should pass ‘taxy-fill’ a taxy copied with ‘taxy-emptied’, which
recursively copies a taxy without ‘:items’.

   To return a taxy in a more human-readable format (with only relevant
fields included), use ‘taxy-plain’.  You may also use ‘taxy-mapcar’ to
replace items in a taxy with, e.g.  a more useful representation.

* Menu:

* Reusable taxys::
* Threading macros::
* Modifying filled taxys::
* Dynamic taxys::
* Magit section::
* Reference::


File: README.info,  Node: Reusable taxys,  Next: Threading macros,  Up: Usage

3.1 Reusable taxys
==================

Since taxys are structs, they may be stored in variables and used in
other structs (being sure to copy the root taxy with ‘taxy-emptied’
before filling).  For example, this shows using ‘taxy’ to classify
Matrix rooms in Ement.el (https://github.com/alphapapa/ement.el):

     (defun ement-roomy-buffer (room)
       (alist-get 'buffer (ement-room-local room)))

     (defvar ement-roomy-unread
       (make-taxy :name "Unread"
                  :predicate (lambda (room)
                               (buffer-modified-p (ement-roomy-buffer room)))))

     (defvar ement-roomy-opened
       (make-taxy :name "Opened"
                  :description "Rooms with buffers"
                  :predicate #'ement-roomy-buffer
                  :taxys (list ement-roomy-unread
                               (make-taxy))))

     (defvar ement-roomy-closed
       (make-taxy :name "Closed"
                  :description "Rooms without buffers"
                  :predicate (lambda (room)
                               (not (ement-roomy-buffer room)))))

     (defvar ement-roomy
       (make-taxy
        :name "Ement Rooms"
        :taxys (list (make-taxy
                      :name "Direct"
                      :description "Direct messaging rooms"
                      :predicate (lambda (room)
                                   (ement-room--direct-p room ement-session))
                      :taxys (list ement-roomy-opened
                                   ement-roomy-closed))
                     (make-taxy
                      :name "Non-direct"
                      :description "Group chat rooms"
                      :taxys (list ement-roomy-opened
                                   ement-roomy-closed)))))

   Note how the taxys defined in the first three variables are used in
subsequent taxys.  As well, the ‘ement-roomy-opened’ taxy has an
"anonymous" taxy, which collects any rooms that aren't collected by its
sibling taxy (otherwise those objects would be collected into the
parent, "Opened" taxy, which may not always be the most useful way to
present the objects).

   Using those defined taxys, we then fill the ‘ement-roomy’ taxy with
all of the rooms in the user's session, and then use ‘taxy-mapcar’ to
replace the room structs with useful representations for display:

     (taxy-plain
      (taxy-mapcar (lambda (room)
                     (list (ement-room--room-display-name room)
                           (ement-room-id room)))
        (taxy-fill (ement-session-rooms ement-session)
                   (taxy-emptied ement-roomy))))

   This produces:

     ("Ement Rooms"
      (("Direct" "Direct messaging rooms"
        (("Opened" "Rooms with buffers"
          (("Unread"
            (("Lars Ingebrigtsen" "!nope:gnus.org")))))
         ("Closed" "Rooms without buffers"
          (("John Wiegley" "!not-really:newartisans.com")
           ("Eli Zaretskii" "!im-afraid-not:gnu.org")))))
       ("Non-direct" "Group chat rooms"
        (("Opened" "Rooms with buffers"
          (("Unread"
            (("Emacs" "!WfZsmtnxbxTdoYPkaT:greyface.org")
             ("#emacs" "!KuaCUVGoCiunYyKEpm:libera.chat")))
           ;; The non-unread buffers in the "anonymous" taxy.
           ((("magit/magit" "!HZYimOcmEAsAxOcgpE:gitter.im")
             ("Ement.el" "!NicAJNwJawmHrEhqZs:matrix.org")
             ("#emacsconf" "!UjTTDnYmSAslLTtMCF:libera.chat")
             ("Emacs Matrix Client" "!ZrZoyXEyFrzcBZKNis:matrix.org")
             ("org-mode" "!rUhEinythPhVTdddsb:matrix.org")
             ("This Week in Matrix (TWIM)" "!xYvNcQPhnkrdUmYczI:matrix.org")))))
         ("Closed" "Rooms without buffers"
          (("#matrix-spec" "!NasysSDfxKxZBzJJoE:matrix.org")
           ("#commonlisp" "!IiGsrmKRHzpupHRaKS:libera.chat")
           ("Matrix HQ" "!OGEhHVWSdvArJzumhm:matrix.org")
           ("#lisp" "!czLxhhEegTEGNKUBgo:libera.chat")
           ("Emacs" "!gLamGIXTWBaDFfhEeO:matrix.org")
           ("#matrix-dev:matrix.org" "!jxlRxnrZCsjpjDubDX:matrix.org")))))))


File: README.info,  Node: Threading macros,  Next: Modifying filled taxys,  Prev: Reusable taxys,  Up: Usage

3.2 Threading macros
====================

If you happen to like macros, ‘taxy’ works well with threading (i.e.
‘thread-last’ or ‘->>’):

     (thread-last ement-roomy
       taxy-emptied
       (taxy-fill (ement-session-rooms ement-session))
       (taxy-mapcar (lambda (room)
                      (list (ement-room--room-display-name room)
                            (ement-room-id room))))
       taxy-plain)


File: README.info,  Node: Modifying filled taxys,  Next: Dynamic taxys,  Prev: Threading macros,  Up: Usage

3.3 Modifying filled taxys
==========================

Sometimes it's necessary to modify a taxy after filling it with objects,
e.g.  to sort the items and/or the sub-taxys.  For this, use the
function ‘taxy-mapc-taxys’ (a.k.a.  ‘taxy-mapc*’).  For example, in the
sample application musicy.el (examples/musicy.el), the taxys and their
items are sorted after filling, like so:

     (defun musicy-files (files)
       (thread-last musicy-taxy
         taxy-emptied
         (taxy-fill files)
         ;; Sort sub-taxys by their name.
         (taxy-sort* #'string< #'taxy-name)
         ;; Sort sub-taxys' items by name.
         (taxy-sort #'string< #'identity)
         taxy-magit-section-pp))


File: README.info,  Node: Dynamic taxys,  Next: Magit section,  Prev: Modifying filled taxys,  Up: Usage

3.4 Dynamic taxys
=================

   • • • 
   You may not always know in advance what taxonomy a set of objects
fits into, so ‘taxy’ lets you add taxys dynamically by using the ‘:take’
function to add a taxy when an object is "taken into" a parent taxy's
items.  For example, you could dynamically classify buffers by their
major mode like so:

     (defun buffery-major-mode (buffer)
       (buffer-local-value 'major-mode buffer))

     (defvar buffery
       (make-taxy
        :name "Buffers"
        :taxys (list
                (make-taxy
                 :name "Modes"
                 :take (apply-partially #'taxy-take-keyed (list #'buffery-major-mode))))))

     ;; Note the use of `taxy-emptied' to avoid mutating the original taxy definition.
     (taxy-plain
      (taxy-fill (buffer-list)
                 (taxy-emptied buffery)))

   The taxy's ‘:take’ function is set to the ‘taxy-take-keyed’ function,
partially applied with the ‘buffery-major-mode’ function as its list of
‘key-fns’ (‘taxy-fill’ supplies the buffer and the taxy as arguments),
and it produces this taxonomy of buffers:

     ("Buffers"
      (("Modes"
        ((magit-process-mode
          (#<buffer magit-process: taxy.el> #<buffer magit-process: > #<buffer magit-process: notes>))
         (messages-buffer-mode
          (#<buffer *Messages*>))
         (special-mode
          (#<buffer *Warnings*> #<buffer *elfeed-log*>))
         (dired-mode
          (#<buffer ement.el<emacs>>))
         (Custom-mode
          (#<buffer *Customize Apropos*>))
         (fundamental-mode
          (#<buffer  *helm candidates:Bookmarks*> #<buffer *Backtrace*>))
         (magit-diff-mode
          (#<buffer magit-diff: taxy.el> #<buffer magit-diff: notes> #<buffer magit-diff: ement.el>))
         (compilation-mode
          (#<buffer *compilation*> #<buffer *Compile-Log*>))
         (Info-mode
          (#<buffer  *helm info temp buffer*> #<buffer *info*>))
         (help-mode
          (#<buffer *Help*>))
         (emacs-lisp-mode
          (#<buffer ement.el<ement.el>> #<buffer ement-room-list.el> #<buffer *scratch*>
                    #<buffer ement-room.el> #<buffer init.el> #<buffer bufler.el>
                    #<buffer dash.el> #<buffer *Pp Eval Output*> #<buffer taxy.el> #<buffer scratch.el>))))))

* Menu:

* Multi-level dynamic taxys::
* "Chains" of independent, multi-level dynamic taxys: "Chains" of independent multi-level dynamic taxys.
* Defining a classification domain-specific language::


File: README.info,  Node: Multi-level dynamic taxys,  Next: "Chains" of independent multi-level dynamic taxys,  Up: Dynamic taxys

3.4.1 Multi-level dynamic taxys
-------------------------------

Of course, the point of taxonomies is that they aren't restricted to a
single level of depth, so you may also use the function
‘taxy-take-keyed’ to dynamically make multi-level taxys.

   Expanding on the previous example, we use ‘cl-labels’ to define
functions which are used in the taxy's definition, which are used in the
‘:take’ function, which calls ‘taxy-take-keyed’ (rather than using
‘apply-partially’ like in the previous example, we use a lambda
function, which performs better than partially applied functions).  Then
when the taxy is filled, a multi-level hierarchy is created dynamically,
organizing buffers first by their directory, and then by mode in each
directory.

     (defvar buffery
       (cl-labels ((buffer-mode (buffer) (buffer-local-value 'major-mode buffer))
                   (buffer-directory (buffer) (buffer-local-value 'default-directory buffer)))
         (make-taxy
          :name "Buffers"
          :taxys (list
                  (make-taxy
                   :name "Directories"
                   :take (lambda (item taxy)
                           (taxy-take-keyed (list #'buffer-directory #'buffer-mode) item taxy)))))))

     (taxy-plain
      (taxy-fill (buffer-list)
                 (taxy-emptied buffery)))

   That produces a list like:

     ("Buffers"
      (("Directories"
        (("~/src/emacs/ement.el/"
          ((dired-mode
            (#<buffer ement.el<emacs>))
           (emacs-lisp-mode
            (#<buffer ement.el<ement.el> #<buffer ement-room-list.el> #<buffer ement-room.el>))
           (magit-diff-mode
            (#<buffer magit-diff: ement.el>))))
         ("~/src/emacs/taxy.el/"
          ((dired-mode
            (#<buffer taxy.el<emacs>))
           (Info-mode
            (#<buffer *info*>))
           (magit-status-mode
            (#<buffer magit: taxy.el>))
           (emacs-lisp-mode
            (#<buffer taxy-magit-section.el> #<buffer taxy.el<taxy.el> #<buffer scratch.el>))))))))


File: README.info,  Node: "Chains" of independent multi-level dynamic taxys,  Next: Defining a classification domain-specific language,  Prev: Multi-level dynamic taxys,  Up: Dynamic taxys

3.4.2 "Chains" of independent, multi-level dynamic taxys
--------------------------------------------------------

_Naming things is hard._

   Going a step further, each element in the ‘taxy-take-keyed’
function's ‘KEY-FNS’ argument may be a list of functions (or a list of
lists of functions, etc.), which creates a "chain" of "independent"
dynamic taxys.  Each such chain may be said to "short-circuit" the
filling process in that, when an object is "taken" by the first key
function in a chain, the object is not "offered" to other functions
outside that chain.  This allows each dynamic sub-taxy to have its own
set of sub-taxys, rather than sharing the same "global" set.  In effect,
this creates multiple, unique taxonomies that share a single root taxy.

   Building on the ‘sporty’ example, let's define a taxy in which
outdoor sports are classified only by whether they involve a disc, but
indoor sports are additionally classified by whatever equipment they may
use:

     (defvar sporty-dynamic
       (cl-macrolet ((in (needle haystack)
                         `(lambda (item)
                            (when (member ,needle (funcall ,haystack item))
                              ,needle))))
         (cl-labels ((outdoor-p
                      (sport) (when (eq 'outdoor (sport-venue sport))
                                "Outdoor"))
                     (indoor-p
                      (sport) (when (eq 'indoor (sport-venue sport))
                                "Indoor"))
                     (disc-p
                      (sport) (if (funcall (in 'disc 'sport-uses) sport)
                                  'disc
                                'non-disc)))
           (make-taxy
            :name "Sporty (dynamic)"
            :take (lambda (item taxy)
                    (taxy-take-keyed
                      (list (list #'outdoor-p #'disc-p)
                            (list #'indoor-p
                                  (in 'ball 'sport-uses)
                                  (in 'disc 'sport-uses)
                                  (in 'glove 'sport-uses)
                                  (in 'racket 'sport-uses)))
                      item taxy))))))

   Now let's fill the taxy with the sports and format it:

     (thread-last sporty-dynamic
       taxy-emptied
       (taxy-fill sports)
       (taxy-mapcar #'sport-name)
       taxy-plain)

     ("Sporty (dynamic)"
      (("Indoor"
        ((ball
          ("Volleyball" "Basketball")
          ((glove
            ("Handball"))
           (racket
            ("Racquetball"))))))
       ("Outdoor"
        ((disc
          ("Ultimate" "Disc golf"))
         (non-disc
          ("Soccer" "Tennis" "Football" "Baseball"))))))


File: README.info,  Node: Defining a classification domain-specific language,  Prev: "Chains" of independent multi-level dynamic taxys,  Up: Dynamic taxys

3.4.3 Defining a classification domain-specific language
--------------------------------------------------------

When writing a larger Taxy-based application, it may be necessary to
define a number of key functions that would be unwieldy to manage in a
‘cl-labels’ form.  For this case, Taxy provides the macro
‘taxy-define-key-definer’ to easily define Taxy key functions in an
application library.  Those functions are then passed to the function
‘taxy-make-take-function’ at runtime, along with a list of keys being
used to classify items.  Using these allows key functions to be defined
in top-level forms, and it allows an application to be extended by users
by defining additional key functions in their configurations.

   Extending the previous ‘sporty’ example, let's redefine its key
functions using ‘taxy-define-key-definer’:

     (taxy-define-key-definer sporty-define-key
       sporty-keys "sporty"
       "Define a `sporty' key function.")

     (sporty-define-key disc-based ()
       (if (member 'disc (sport-uses item))
           "Disc-based"
         "Non-disc-based"))

     (sporty-define-key uses (&optional thing)
       (pcase thing
         (`nil (sport-uses item))
         (_ (when (cl-typecase (sport-uses item)
                    (symbol (equal thing (sport-uses item)))
                    (list (member thing (sport-uses item))))
              thing))))

     (sporty-define-key venue (&optional place)
       (pcase place
         (`nil (sport-venue item))
         (_ (when (equal place (sport-venue item))
              (sport-venue item)))))

   Now we'll define the default keys to use when classifying items.
This list is equivalent to the one passed to ‘taxy-take-keyed’ in the
previous, "Chains" example.

     (defvar sporty-default-keys
       '(
         ((venue 'outdoor)
          disc-based)

         ((venue 'indoor)
          (uses 'ball)
          (uses 'disc)
          (uses 'glove)
          (uses 'racket))))

   Finally, rather than using a pre-made taxy struct, we make one at
runtime, making the ‘:take’ function with ‘taxy-make-take-function’.

     (let ((taxy (make-taxy
                  :name "Sporty (DSL)"
                  :take (taxy-make-take-function sporty-default-keys
                                                 sporty-keys))))
       (thread-last taxy
         (taxy-fill sports)
         (taxy-mapcar #'sport-name)
         taxy-plain))

   Which gives us:

     ("Sporty (DSL)"
      ((indoor
        ((ball
          ("Volleyball" "Basketball")
          ((glove
            ("Handball"))
           (racket
            ("Racquetball"))))))
       (outdoor
        (("Disc-based"
          ("Ultimate" "Disc golf"))
         ("Non-disc-based"
          ("Soccer" "Tennis" "Football" "Baseball"))))))

   As you can see, the result is the same as that in the previous
example, but we've defined a kind of DSL for grouping sports in a
modular, extendable way.

   This also allows the grouping keys to be easily changed at runtime,
producing a different result.  For example, we could group sports by,
first, whether they use a ball, and then by venue.  Let's do this in a
function so that users can pass their own list of keys:

     (cl-defun sporty-classify (sports &key (keys sporty-default-keys))
       (declare (indent defun))
       (let* ((taxy (make-taxy
                     :name "Sporty (DSL)"
                     :take (taxy-make-take-function keys
                                                    sporty-keys))))
         (thread-last taxy
           (taxy-fill sports)
           (taxy-mapcar #'sport-name)
           taxy-plain)))

     (sporty-classify sports
       :keys '((uses 'ball) venue))

   And this produces:

     ("Sporty (DSL)"
      ((outdoor
        ("Ultimate" "Disc golf"))
       (ball
        ((indoor
          ("Volleyball" "Handball" "Racquetball" "Basketball"))
         (outdoor
          ("Soccer" "Tennis" "Football" "Baseball"))))))


File: README.info,  Node: Magit section,  Next: Reference,  Prev: Dynamic taxys,  Up: Usage

3.5 Magit section
=================

Showing a ‘taxy’ with ‘magit-section’ is easy using the library
taxy-magit-section
(https://github.com/alphapapa/taxy.el/tree/package/taxy-magit-section),
which is packaged separately:

     (require 'taxy-magit-section)

     ;; Using the `numbery' taxy defined in earlier examples:
     (thread-last numbery
       taxy-emptied ;; Get an empty copy of the taxy, since it's defined in a variable.
       (taxy-fill (reverse (cl-loop for i below 30 collect i)))
       taxy-magit-section-pp)

   That shows a buffer like this:


File: README.info,  Node: Reference,  Prev: Magit section,  Up: Usage

3.6 Reference
=============

In Emacs 28+, see also ‘M-x shortdoc-display-group RET taxy RET’.

* Menu:

* Functions::
* Macros::


File: README.info,  Node: Functions,  Next: Macros,  Up: Reference

3.6.1 Functions
---------------

taxy-flatten (taxy)
     Return a list of items in ‘taxy’ and its sub-taxys.

taxy-emptied (taxy)
     Return a copy of ‘taxy’ without items.  Omits =taxy=’s items and
     those of its descendant taxys.  Useful when reusing taxy
     definitions.

taxy-fill (items taxy)
     Fill ‘taxy’ with ‘items’ according to its definition.

taxy-lift (taxy)
     Return ‘taxy’ having "lifted" its sub-taxys.  That is, a sub-taxy
     which has fewer items than ‘taxy-lift-min-items’ will have its
     items \"lifted\" into its parent taxy's items, and the sub-taxy
     itself will be removed from its parent taxy's taxys.  This operates
     recursively within ‘taxy’'s sub-taxys.

taxy-make-take-function (keys aliases)
     Return a taxy "take" function for ‘keys’.  Each of ‘keys’ should be
     a function alias defined in ‘aliases’, or a list of such ‘key-fns’
     (recursively, ad infinitum, approximately).  ‘aliases’ should be an
     alist mapping aliases to functions (such as defined with a definer
     defined by ‘taxy-define-key-definer’).

taxy-mapc-taxys (fn taxy)
     *Alias:* ‘taxy-mapc*’

     Return ‘taxy’ having applied ‘fn’ to it and its descendants.  Does
     not copy ‘taxy’.  Destructively modifies ‘taxy’, if ‘fn’ does.

taxy-mapcar-items (fn taxy)
     *Alias:* ‘taxy-mapcar’

     Return copy of ‘taxy’, having replaced its items with the value of
     ‘fn’ on each.  Replaces every item in ‘taxy’ and its descendants.
     Useful to replace items with a more useful form after
     classification.

taxy-plain (taxy)
     Return a list of the human-readable parts of ‘taxy’.

taxy-size (taxy)
     Return the number of items ‘taxy’ holds.  Includes items in ‘taxy’
     ’s sub-taxys.

taxy-sort-items (pred key taxy)
     *Alias:* ‘taxy-sort’

     Sort ‘taxy’ ’s items by ‘pred’ and ‘key’.  Sorts items in ‘taxy’
     and its sub-taxys.  ‘key’ is passed to ‘cl-sort’, which see.

taxy-sort-taxys (pred key taxy)
     *Alias:* ‘taxy-sort*’

     Sort ‘taxy’ ’s sub-taxys by ‘pred’ and ‘key’.  ‘key’ is passed to
     ‘cl-sort’, which see.


File: README.info,  Node: Macros,  Prev: Functions,  Up: Reference

3.6.2 Macros
------------

taxy-define-key-definer (name variable prefix docstring)
     Define a macro ‘name’ that defines a key-function-defining macro.
     The defined macro, having string ‘docstring’, associates the
     defined key functions with their aliases in an alist stored in
     symbol ‘variable’.  The defined key functions are named having
     string ‘prefix’, which will have a hyphen appended to it.  The key
     functions take one or more arguments, the first of which is the
     item being tested, bound within the function to ‘item’.


File: README.info,  Node: Changelog,  Next: Development,  Prev: Usage,  Up: Top

4 Changelog
***********

* Menu:

* v0.11-pre: v011-pre.
* 0.10.2: 0102.
* 0.10.1: 0101.
* 0.10: 010.
* 0.9: 09.
* 0.8: 08.
* 0.7: 07.
* 0.6: 06.
* 0.5: 05.
* 0.4: 04.
* 0.3: 03.
* 0.2: 02.
* 0.1: 01.


File: README.info,  Node: v011-pre,  Next: 0102,  Up: Changelog

4.1 v0.11-pre
=============

*Additions*
   • Function ‘taxy-lift’, which "lifts" the items in sub-taxys which
     have fewer than a certain number of items into parent taxys
     (helping to reduce the number of taxys with only a few items in
     them).


File: README.info,  Node: 0102,  Next: 0101,  Prev: v011-pre,  Up: Changelog

4.2 0.10.2
==========

*Fixes*
   • Reduce potential length of macro-expanded docstrings to prevent
     byte-compiler warnings in downstream packages.


File: README.info,  Node: 0101,  Next: 010,  Prev: 0102,  Up: Changelog

4.3 0.10.1
==========

*Examples*
   • Fixed byte-compilation of ‘diredy.el’.


File: README.info,  Node: 010,  Next: 09,  Prev: 0101,  Up: Changelog

4.4 0.10
========

*Examples*
   • Deffy
        • Fix: Disambiguate forms with the same name.
   • Diredy: Various small improvements.


File: README.info,  Node: 09,  Next: 08,  Prev: 010,  Up: Changelog

4.5 0.9
=======

* Menu:

* Changes::


File: README.info,  Node: Changes,  Up: 09

4.5.1 Changes
-------------

   • Library ‘taxy-magit-section’ is now packaged separately
     (https://elpa.gnu.org/packages/taxy-magit-section.html) and
     maintained in a separate branch
     (https://github.com/alphapapa/taxy.el/tree/package/taxy-magit-section).
   • Minor fixes to documentation and examples.


File: README.info,  Node: 08,  Next: 07,  Prev: 09,  Up: Changelog

4.6 0.8
=======

* Menu:

* Additions::
* Fixes::


File: README.info,  Node: Additions,  Next: Fixes,  Up: 08

4.6.1 Additions
---------------

   • Short documentation group for Emacs 28+.


File: README.info,  Node: Fixes,  Prev: Additions,  Up: 08

4.6.2 Fixes
-----------

   • Require ‘map’ for ‘pcase’ pattern.


File: README.info,  Node: 07,  Next: 06,  Prev: 08,  Up: Changelog

4.7 0.7
=======

* Menu:

* Additions: Additions (1).


File: README.info,  Node: Additions (1),  Up: 07

4.7.1 Additions
---------------

   • Function ‘taxy-flatten’ returns a list of the items in a taxy and
     its sub-taxys.
   • Function/macro reference documentation.
   • Example application ‘bookmarky’ lists Emacs bookmarks grouped with
     Taxy.


File: README.info,  Node: 06,  Next: 05,  Prev: 07,  Up: Changelog

4.8 0.6
=======

* Menu:

* Additions: Additions (2).


File: README.info,  Node: Additions (2),  Up: 06

4.8.1 Additions
---------------

   • Sorting functions:
        • ‘taxy-sort-items’ (alias: ‘taxy-sort’) sorts the items in a
          taxy and its sub-taxys.
        • ‘taxy-sort-taxys’ (alias: ‘taxy-sort*’) sorts a taxy's
          sub-taxys.
   • Defining classification domain-specific languages:
        • Macro ‘taxy-define-key-definer’ defines a
          key-function-defining macro.
        • Function ‘taxy-make-take-function’ makes a ‘:take’ function
          using a list of key functions and a set of classification
          keys.
   • Table-like, column-based formatting system for
     ‘taxy-magit-section’:
        • Function ‘taxy-magit-section-format-items’, which formats
          items by columns.
        • Variable ‘taxy-magit-section-insert-indent-items’, which
          controls whether ‘taxy-magit-section-insert’ applies
          indentation to each item.  (Used to disable that behavior when
          items are pre-indented strings, e.g.  as formatted by
          ‘taxy-magit-section-format-items’.)
   • Example application ‘deffy’, which shows an overview of top-level
     definitions and forms in an Elisp project or file.  (Likely to be
     published as a separate package later.)


File: README.info,  Node: 05,  Next: 04,  Prev: 06,  Up: Changelog

4.9 0.5
=======

* Menu:

* Additions: Additions (3).
* Fixes: Fixes (1).


File: README.info,  Node: Additions (3),  Next: Fixes (1),  Up: 05

4.9.1 Additions
---------------

   • Function ‘taxy-magit-section-insert’ takes new arguments:
        • ‘:initial-depth’ sets the level at which the first level of
          hierarchy is considered to be at, for purposes of indentation.
          Setting it to a negative number prevents indentation of so
          many levels (i.e.  setting it to -1 causes the first two
          levels to be unindented, since the first level will be
          considered to be at depth -1, and the second at depth 0).
        • ‘:blank-between-depth’ sets the level up to which blank lines
          are inserted between sections (i.e.  setting it to 1 causes
          blank lines to be inserted between sections up to depth 1, but
          not between sections deeper than that).
   • Struct ‘taxy-magit-section’ has a new ‘heading-face’ slot, a
     function which takes a depth level argument and returns the face
     with which to propertize that section's heading.
   • New example ‘taxy-package-report’.


File: README.info,  Node: Fixes (1),  Prev: Additions (3),  Up: 05

4.9.2 Fixes
-----------

   • Example ‘diredy’ referred to an old function name.


File: README.info,  Node: 04,  Next: 03,  Prev: 05,  Up: Changelog

4.10 0.4
========

   • Incremented version to cause a new ELPA release (since removing a
     file that wasn't intended to be distributed on ELPA).


File: README.info,  Node: 03,  Next: 02,  Prev: 04,  Up: Changelog

4.11 0.3
========

* Menu:

* Changes: Changes (1).
* Fixes: Fixes (2).


File: README.info,  Node: Changes (1),  Next: Fixes (2),  Up: 03

4.11.1 Changes
--------------

   • Within the ‘taxy’ struct and related functions, the term ‘objects’
     is renamed to ‘items’, which is shorter and has the same meaning.
     This makes code a bit more concise (e.g.  ‘(taxy-objects taxy)’
     becomes ‘(taxy-items taxy)’).


File: README.info,  Node: Fixes (2),  Prev: Changes (1),  Up: 03

4.11.2 Fixes
------------

   • Function ‘taxy-fill’ always calls a taxy's ‘:take’ function if
     defined.  (Fixing "chains" of dynamic taxys.)
   • Function ‘taxy-magit-section-insert’ applies text properties from
     the inserted string to the indentation string (so commands that
     rely on text properties at the beginning of a line will work).


File: README.info,  Node: 02,  Next: 01,  Prev: 03,  Up: Changelog

4.12 0.2
========

* Menu:

* Changes: Changes (2).
* Additions: Additions (4).
* Fixes: Fixes (3).


File: README.info,  Node: Changes (2),  Next: Additions (4),  Up: 02

4.12.1 Changes
--------------

   • Function ‘taxy-take-keyed*’ is renamed to ‘taxy-take-keyed’,
     replacing the old function: it's more powerful, and there's little
     reason to maintain two versions.


File: README.info,  Node: Additions (4),  Next: Fixes (3),  Prev: Changes (2),  Up: 02

4.12.2 Additions
----------------

   • Struct ‘taxy’ now has a ‘:make’ slot, a function called to make new
     sub-taxys by ‘take-take-keyed’ (defaulting to ‘make-taxy’).  This
     is useful when defining structs specialized on ‘taxy’.
   • Struct ‘taxy-magit-section’ now has an ‘:indent’ slot, a number of
     characters by which to indent each level of sub-taxy, applied
     automatically by function ‘taxy-magit-section-insert’.
   • Each element of the new ‘taxy-take-keyed’'s ‘KEY-FNS’ argument may
     now be a function or a list of functions (or a list of a list of
     functions, etc.).  Lists of functions create "chains" of
     independent, dynamic taxys descending from a single root taxy.  See
     *note example: "Chains" of independent multi-level dynamic taxys.


File: README.info,  Node: Fixes (3),  Prev: Additions (4),  Up: 02

4.12.3 Fixes
------------

   • ‘taxy-magit-section’'s ‘insert-object’ function.
   • ‘taxy-fill’ now applies objects to the root taxy if no sub-taxys
     take them.


File: README.info,  Node: 01,  Prev: 02,  Up: Changelog

4.13 0.1
========

First tagged version.


File: README.info,  Node: Development,  Next: Credits,  Prev: Changelog,  Up: Top

5 Development
*************

Bug reports, feature requests, suggestions — _oh my_!

* Menu:

* Copyright assignment::


File: README.info,  Node: Copyright assignment,  Up: Development

5.1 Copyright assignment
========================

This package is part of GNU Emacs (https://www.gnu.org/software/emacs/),
being distributed in GNU ELPA (https://elpa.gnu.org/).  Contributions to
this project must follow GNU guidelines, which means that, as with other
parts of Emacs, patches of more than a few lines must be accompanied by
having assigned copyright for the contribution to the FSF.  Contributors
who wish to do so may contact emacs-devel@gnu.org
<mailto:emacs-devel@gnu.org> to request the assignment form.


File: README.info,  Node: Credits,  Next: License,  Prev: Development,  Up: Top

6 Credits
*********

   • Thanks to Stefan Monnier for his feedback, and for maintaining GNU
     ELPA.


File: README.info,  Node: License,  Prev: Credits,  Up: Top

7 License
*********

GPLv3



Tag Table:
Node: Top220
Node: Examples2332
Node: Numbery (starting basically)2651
Node: Lettery (filling incrementally)8408
Node: Sporty (understanding completely)10910
Node: Applications16879
Node: Installation17354
Node: Usage17667
Node: Reusable taxys19812
Node: Threading macros23961
Node: Modifying filled taxys24500
Node: Dynamic taxys25316
Node: Multi-level dynamic taxys27961
Node: "Chains" of independent multi-level dynamic taxys30150
Node: Defining a classification domain-specific language33075
Node: Magit section37230
Node: Reference37898
Node: Functions38106
Node: Macros40439
Node: Changelog41089
Node: v011-pre41374
Node: 010241705
Node: 010141940
Node: 01042100
Node: 0942316
Node: Changes42426
Node: 0842798
Node: Additions42919
Node: Fixes43063
Node: 0743201
Node: Additions (1)43326
Node: 0643645
Node: Additions (2)43770
Node: 0545118
Node: Additions (3)45263
Node: Fixes (1)46371
Node: 0446529
Node: 0346751
Node: Changes (1)46894
Node: Fixes (2)47263
Node: 0247702
Node: Changes (2)47873
Node: Additions (4)48163
Node: Fixes (3)49086
Node: 0149340
Node: Development49441
Node: Copyright assignment49647
Node: Credits50242
Node: License50432

End Tag Table


Local Variables:
coding: utf-8
End:
