#+TITLE: Magit-Popup User Manual
#+AUTHOR: Jonas Bernoulli
#+EMAIL: jonas@bernoul.li
#+DATE: 2015-2018
#+LANGUAGE: en

#+TEXINFO_DIR_CATEGORY: Emacs
#+TEXINFO_DIR_TITLE: Magit-Popup: (magit-popup).
#+TEXINFO_DIR_DESC: Infix arguments with feedback
#+SUBTITLE: for version 2.12.2 (v2.12.2-6-gbd04ebd+1)
#+BIND: ox-texinfo+-before-export-hook ox-texinfo+-update-version-strings

#+TEXINFO_DEFFN: t
#+OPTIONS: H:4 num:4 toc:2

Taking inspiration from regular prefix commands and prefix arguments,
this library implements a similar abstraction; a new kind of prefix
command that is associated with a specific set of infix arguments and
suffix commands.

#+TEXINFO: @noindent
This manual is for Magit-Popup version 2.12.2 (v2.12.2-6-gbd04ebd+1).

#+BEGIN_QUOTE
Copyright (C) 2015-2018 Jonas Bernoulli <jonas@bernoul.li>

You can redistribute this document and/or modify it under the terms
of the GNU General Public License as published by the Free Software
Foundation, either version 3 of the License, or (at your option) any
later version.

This document is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.
#+END_QUOTE

* Introduction

Taking inspiration from regular prefix commands and prefix arguments,
this library implements a similar abstraction; a new kind of prefix
command that is associated with a specific set of infix arguments and
suffix commands.

Invoking such a prefix command displays a popup buffer which lists the
associated infix arguments and suffix commands.  In that buffer each
argument is prefixed with the key sequence that can be used to toggle
it or change its value.  Likewise each suffix command is prefixed with
the key used to invoke it.  Such a popup buffer might look like this:

#+BEGIN_EXAMPLE
,-----------------------------------------
|Switches
| -l Show graph (--graph)
| -d Show refnames (--decorate)
|
|Options
| =m Search messages (--grep="popup")
| =p Search patches (-G)
|
|Action
| l Show log for current branch
| o Show log for another branch
'-----------------------------------------
#+END_EXAMPLE

The user could then for example type ~-l~ to toggle the ~--graph~ *switch*
(when it is on then it is shown in green, otherwise in gray), or ~=m~ to
change the value of the *option* ~--grep~.

Once all arguments are as desired one invokes a suffix command, which
causes the popup buffer to disappear.  The suffix command should then
retrieve the infix arguments in its ~interactive~ form like this is done
for prefix arguments.

While such "prefix-infix-suffix" combos were inspired by regular
prefix commands and prefix arguments, they are also quite different.
This should illustrate the most basic differences:

- A regular prefix command

  #+BEGIN_EXAMPLE
          /- command1
  prefix --- command2
          \- command3
  #+END_EXAMPLE

- Prefix arguments

  #+BEGIN_EXAMPLE
           /- command1
  C-u ... --- command2
           \- well any command
  #+END_EXAMPLE

- A Prefix-Infix-Suffix combo

  #+BEGIN_EXAMPLE
           /- argument1 -\ /- suffix1
  prefix----- argument2 --+-- suffix2
         ^ \- argument3 -/
         |        |
         '--------'
      (refresh buffer)
   #+END_EXAMPLE

This library was written as a replacement for ~magit-key-mode~, which
was used in Magit releases before 2.1.0.  It is used to implement all
"popups" in the current Magit release but a future release will switch
to yet another implementation.

This library does not depend on any other Magit libraries and it is
distributed as a separate package, which makes it possible to use it
in packages that are not related to Magit.  But keep in mind that it
will be deprecated eventually.

* Usage
** _ :ignore:

Every popup buffers created with a prefix command contains a section
named "Actions" listing the available suffix commands.  Most buffers
also contain a "Switches" and/or an "Options" section which list the
two types of infix arguments separately.

Switches are arguments that can be toggled on or off.  When a switch
is active then it is shown in color, when it is off then it is shown
in gray (of course the details depend on the color theme in use).

Options are arguments that have a value.  When an option has a value
then that is shown after the option itself.  Because for some options
the empty string is a valid value, options are additionally colorized
like switches to indicate whether they are active or not.

The events bound to suffix commands are always single alphabetic
characters.  The bindings for arguments are always two events long.
For switches the first key is always ~-~, for options it is always ~=~.
The second key is always an alphabetic character.

By default popup buffers also feature a section listing commands
common to all popups.  To avoid conflicts with suffix commands, the
bindings of these common commands are not alphabetic characters.  This
section is shown by default so that documentation-resistant users get
a chance to notice them.

- User Option: magit-popup-show-common-commands

  This option controls whether the section that lists the commands
  that are common to all popups is initially shown.

  By default this is not the case, but note that you can temporarily
  show this section using ~C-t~, which therefore is the only common
  command you actually have to memorize.

- Key: C-t, magit-popup-toggle-show-common-commands

  Show or hide the section listing the commands shared by all popups.

- Key: C-g, magit-popup-quit

  Quit popup buffer without invoking a suffix command.

Without further action, setting arguments only affects the next suffix
command.  Invoking the same prefix command again resets the arguments
to their default value, but the defaults can be changed directly from
the popup buffer itself.  For a prefix command named ~NAME-popup~ the
default values are stored as the value of the custom option named
~NAME-arguments~.  While this option can be customized using the Custom
interface, it is better to do so directly from the popup buffer.

- Key: C-c C-c, magit-popup-set-default-arguments

  This sets the default value for the arguments for the current popup.

  Then the popup buffer is closed without invoking a suffix command;
  unless a prefix argument is used in which case the popup remains
  open.

- Key: C-x C-s, magit-popup-save-default-arguments

  This sets the default value for the arguments for the current popup
  and saves it for future Emacs sessions.

  Then the popup buffer is closed without invoking an action; unless a
  prefix argument is used in which case the popup remains open.

It is also possible to add additional arguments and commands to an
existing popup, but that cannot be done directly from the popup (or
the Custom interface).  See [[*Customizing Existing Popups]].

Documentation about a popup's arguments and commands can be shown
directly from the popup.

- Key: C-h i, magit-popup-info

  Show this manual.

- Key: ?, magit-popup-help

  This command reads a key sequence and then shows the documentation
  of the argument or command that sequence is bound to.  In other
  words type the same keys that you would use to invoke the argument
  or command, but prefix the sequence with ~?~.

  For suffix commands this shows the doc-string.  For arguments this
  command can only show something for popups that have an associated
  man-page.  If the man-page is set, then this command displays it in
  a separate buffer and puts point on the entry about the argument in
  question.

  The buffer which is used to display the documentation is selected.
  Simply press ~q~ to leave that buffer and restore the old window
  configuration.

While it isn't very useful, it is possible to move around in a popup
buffer using ~C-p~ and ~C-n~, and to invoke the argument or command at
point using ~RET~.  But it is much more efficient to use the dedicated
key bindings instead, so these commands are not listed in popup
buffers along with the other common commands.

** Customizing Existing Popups

It is possible to define additional infix arguments and suffix
commands to an existing popup using the following functions.

You can find some examples which use the below commands at
https://github.com/magit/magit/wiki/Additional-proposed-infix-arguments-and-suffix-commands.

- Function: magit-define-popup-switch popup key desc switch &optional enable at prepend

  In POPUP, define KEY as SWITCH.

  POPUP is a popup command defined using ~magit-define-popup~.  SWITCH
  is a string representing an argument that takes no value.  KEY is a
  character representing the second event in the sequence of
  keystrokes used to toggle the argument.  (The first event, the
  prefix, is shared among all switches, defaults to ~-~, and can be
  changed in ~magit-popup-mode-keymap~).

  DESC is a string describing the purpose of the argument, it is
  displayed in the popup.

  If optional ENABLE is non-nil then the switch is on by default.

  SWITCH is inserted after all other switches already defined for
  POPUP, unless optional PREPEND is non-nil, in which case it is
  placed first.  If optional AT is non-nil then it should be the KEY
  of another switch already defined for POPUP, the argument is then
  placed before or after AT, depending on PREPEND.

- Function: magit-define-popup-option popup key desc option &optional reader value at prepend

  In POPUP, define KEY as OPTION.

  POPUP is a popup command defined using ~magit-define-popup~.  OPTION
  is a string representing an argument that takes a value.  KEY is a
  character representing the second event in the sequence of
  keystrokes used to set the argument's value.  (The first event, the
  prefix, is shared among all options, defaults to ~=~, and can be
  changed in ~magit-popup-mode-keymap~).

  DESC is a string describing the purpose of the argument, it is
  displayed in the popup.

  If optional VALUE is non-nil then the option is on by default, and
  VALUE is its default value.

  READER is used to read a value from the user when the option is
  invoked and does not currently have a value.  It should take one
  argument and use it as the prompt.  If this is nil, then
  ~read-from-minibuffer~ is used.

  OPTION is inserted after all other options already defined for
  POPUP, unless optional PREPEND is non-nil, in which case it is
  placed first.  If optional AT is non-nil then it should be the KEY
  of another option already defined for POPUP, the argument is then
  placed before or after AT, depending on PREPEND.

- Function: magit-define-popup-action popup key desc command &optional at prepend

  In POPUP, define KEY as COMMAND.

  POPUP is a popup command defined using ~magit-define-popup~.  COMMAND
  can be any command but should usually consume the popup arguments in
  its ~interactive~ form.  KEY is a character representing the event
  used invoke the action, i.e. to interactively call the COMMAND.

  DESC is a string describing the purpose of the action, it is
  displayed in the popup.

  COMMAND is inserted after all other commands already defined for
  POPUP, unless optional PREPEND is non-nil, in which case it is
  placed first.  If optional AT is non-nil then it should be the KEY
  of another command already defined for POPUP, the command is then
  placed before or after AT, depending on PREPEND.

- Function: magit-define-popup-sequence-action popup key desc command &optional at prepend

  Like ~magit-define-popup-action~, but modifies the value of the
  ~:sequence-actions~ property instead of ~:actions~.

- Function: magit-define-popup-variable popup key desc command formatter &optional at prepend

  In POPUP, define KEY as COMMAND.

  POPUP is a popup command defined using ~magit-define-popup~.  COMMAND
  is a command which calls ~magit-popup-set-variable~.  FORMATTER is a
  function which calls ~magit-popup-format-variable~.  These two
  functions have to be called with the same arguments.

  KEY is a character representing the event used interactively call
  the COMMAND.

  DESC is the variable or a representation thereof.  It's not actually
  used for anything.

  COMMAND is inserted after all other commands already defined for
  POPUP, unless optional PREPEND is non-nil, in which case it is
  placed first.  If optional AT is non-nil then it should be the KEY
  of another command already defined for POPUP, the command is then
  placed before or after AT, depending on PREPEND."

- Function: magit-change-popup-key popup type from to

  In POPUP, bind TO to what FROM was bound to.  TYPE is one of
  ~:action~, ~:sequence-action~, ~:switch~, or ~:option~.  Bind TO and unbind
  FROM, both are characters.

- Function: magit-remove-popup-key popup type key

  In POPUP, remove KEY's binding of TYPE.  POPUP is a popup command
  defined using ~magit-define-popup~.  TYPE is one of ~:action~,
  ~:sequence-action~, ~:switch~, or ~:option~.  KEY is the character which
  is to be unbound.

It is also possible to change other aspects of a popup by setting a
property using ~plist-put~.  See [[*Defining Prefix Commands]] for valid
properties.  The most likely change Magit users might want to make
is:

#+BEGIN_SRC emacs-lisp
  (plist-put magit-show-refs-popup :use-prefix nil)
#+END_SRC

** Other Options

- User Option: magit-popup-use-prefix-argument

  This option controls the effect that the use of a prefix argument
  before entering a popup has.

  - ~default~

    With a prefix argument directly invoke the popup's
    default action (an Emacs command), instead of bringing
    up the popup.

  - ~popup~

    With a prefix argument bring up the popup, otherwise
    directly invoke the popup's default action.

  - ~nil~

    Ignore prefix arguments.

  This option can be overridden for individual popups.
  ~magit-show-refs-popup~ for example defaults to invoking the default
  action directly.  It only shows the popup buffer when a prefix
  argument is used.  See [[*Customizing Existing Popups]].

- User Option: magit-popup-manpage-package

  The Emacs package used to display man-pages, one of ~man~ or ~woman~.

- User Option: magit-popup-display-buffer-action

  The option controls how the window used to display a popup buffer is
  created.  Popup buffers are displayed using ~display-buffer~ with the
  value of this option as ACTION argument.  You can also set this to
  nil and instead add an entry to ~display-buffer-alist~.

To emphasize the default action by making it bold use this:

#+BEGIN_SRC emacs-lisp
  (button-type-put 'magit-popup-action-button 'format " %k %D")
#+END_SRC

* Defining Prefix and Suffix Commands
** _ :ignore:

If you write an extension for Magit then you should use this library
now and later when ~transient~ is released port to that.

If you are considering using this library to define popups for
packages not related to Magit, then keep in mind that it will be
superseded eventually.  Once ~transient~ has been released I will only
fix bugs in ~magit-popup~ but not implement any new features.

Also consider using ~hydra~ instead.  To some extend ~magit-popup~ and
~hydra~ are similar but have a different focus.  The main purpose of
~magit-popup~ is to pass infix arguments to suffix commands.  If all you
need is a command dispatcher then you are better of using ~hydra~.  Of
course ~hydra~ may also be a better fit not only because of the features
it lacks, but also because of the features it provides, which are in
turn missing from ~magit-popup~.

Here is an example of how one defines a prefix command along with its
infix arguments, and then also one of its suffix commands.

#+BEGIN_SRC emacs-lisp
  ;;;###autoload (autoload 'magit-tag-popup "magit" nil t)
  (magit-define-popup magit-tag-popup
    "Show popup buffer featuring tagging commands."
    'magit-commands
    :man-page "git-tag"
    :switches '((?a "Annotate" "--annotate")
                (?s "Sign"     "--sign")
                (?f "Force"    "--force"))
    :actions  '((?t "Create"   magit-tag)
                (?k "Delete"   magit-tag-delete)
                (?p "Prune"    magit-tag-prune))
    :default-action 'magit-tag)

  ;;;###autoload
  (defun magit-tag (name rev &optional args)
    "Create a new tag with the given NAME at REV."
    (interactive (list (magit-read-tag "Tag name")
                       (magit-read-branch-or-commit "Place tag on")
                       (magit-tag-arguments)))
    (magit-run-git-with-editor "tag" args name rev))
#+END_SRC

** Defining Prefix Commands

Prefix commands and their infix arguments are defined using the macro
~magit-define-popup~.  The key bindings and descriptions of suffix
commands are also defined using that macro, but the actual interactive
commands have to be defined separately using plain ~defun~.

- Macro: magit-define-popup name doc [group [mode [option]]] :keyword value...

  This macro defines a popup named NAME.  The NAME should begin with
  the package prefix and by convention end with ~-popup~, it is used
  as the name of the command which shows the popup and for an internal
  variable (whose value is used to store information about the popup
  and should not be accessed directly).  DOC is the doc-string of the
  popup command.

  This macro also defines an option and a function both named
  ~SHORTNAME-arguments~, where SHORTNAME is NAME with the trailing
  ~-popup~ removed.  The name of this option and this function can be
  overwritten using the optional argument OPTION, but that is rarely
  advisable. As a special case if OPTION is specified but ~nil~, then
  this option and this function are not defined at all, which is
  useful for popups that are used as simple dispatchers that offer no
  arguments.

  The option ~SHORTNAME-arguments~ holds the value for the popup
  arguments.  It can be customized from within the popup or using the
  Custom interface.  It can also have a buffer local value in any
  non-popup buffer.  The local value for the buffer from which the
  popup command was invoked, can be set from within the popup buffer.

  The function ~SHORTNAME-arguments~ returns the currently effective
  value of the variable by the same name.  See below for more
  information.

  Optional argument GROUP specifies the Custom group into which the
  option is placed.  If omitted then the option is placed into some
  group the same way it is done when directly using ~defcustom~ and
  omitting the group, except when NAME begins with "magit-", in
  which case the group ~magit-git-arguments~ is used.

  The optional argument MODE specifies the mode used by the popup
  buffer.  If it is omitted or ~nil~ then ~magit-popup-mode~ is used.

  The remaining arguments should have the form ~[KEYWORD VALUE]...~.

  The following keywords are meaningful (and by convention are
  usually specified in that order):

  - ~:actions~

    The actions which can be invoked from the popup.  VALUE is a list
    whose members have the form (KEY DESC COMMAND), see
    ~magit-define-popup-action~ for details.

    Actions are regular Emacs commands, which usually have an
    ~interactive~ form setup to consume the values of the popup
    ~:switches~ and ~:options~ when invoked from the corresponding popup,
    else when invoked as the default action or directly without using
    the popup, the default value of the variable ~SHORTNAME-arguments~.
    This is usually done by calling the function ~SHORTNAME-arguments~.

    Members of VALUE may also be strings and functions, assuming the
    first member is a string or function.  In that case the members
    are split into sections and these special elements are used as
    headings.  If such an element is a function then it is called with
    no arguments and must return either a string, which is used as the
    heading, or nil, in which case the section is not inserted.

    Members of VALUE may also be nil.  This should only be used
    together with ~:max-action-columns~ and allows having gaps in the
    action grit, which can help arranging actions sensibly.

  - ~:default-action~

    The default action of the popup which is used directly instead of
    displaying the popup buffer, when the popup is invoked with a
    prefix argument.  Also see ~magit-popup-use-prefix-argument~ and
    ~:use-prefix~, which can be used to inverse the meaning of the
    prefix argument.

  - ~:use-prefix~

    Controls when to display the popup buffer and when to invoke the
    default action (if any) directly.  This overrides the global
    default set using ~magit-popup-use-prefix-argument~.  The value, if
    specified, should be one of ~default~ or ~prefix~, or a function that
    is called with no arguments and returns one of these symbols.

  - ~:max-action-columns~

    The maximum number of actions to display on a single line, a
    number or a function that return a number and takes the name of
    the section currently being inserted as argument.  If there isn't
    enough room to display as many columns as specified here, then
    fewer are used.

  - ~:switches~

    The popup arguments which can be toggled on and off.  VALUE is a
    list whose members have the form ~(KEY DESC SWITCH)~, see
    ~magit-define-popup-switch~ for details.

    Members of VALUE may also be strings and functions, assuming the
    first member is a string or function.  In that case the members
    are split into sections and these special elements are used as
    headings.  If such an element is a function then it is called with
    no arguments and must return either a string, which is used as the
    heading, or nil, in which case the section is not inserted.

  - ~:options~

    The popup arguments which take a value, as in "--opt~OPTVAL".
    VALUE is a list whose members have the form ~(KEY DESC OPTION
    READER)~, see ~magit-define-popup-option~ for details.

    Members of VALUE may also be strings and functions, assuming the
    first member is a string or function.  In that case the members
    are split into sections and these special elements are used as
    headings.  If such an element is a function then it is called with
    no arguments and must return either a string, which is used as the
    heading, or nil, in which case the section is not inserted.

  - ~:default-arguments~

    The default arguments, a list of switches (which are then enabled
    by default) and options with there default values, as in
    ~"--OPT=OPTVAL"~.

  - ~:variables~

    Git variables which can be set from the popup.  VALUE is a list
    whose members have the form ~(KEY DESC COMMAND FORMATTER)~, see
    ~magit-define-popup-variable~ for details.

    Members of VALUE may also be strings and functions, assuming the
    first member is a string or function.  In that case the members
    are split into sections and these special elements are used as
    headings.  If such an element is a function then it is called with
    no arguments and must return either a string, which is used as the
    heading, or nil, in which case the section is not inserted.

    Members of VALUE may also be actions as described above for
    ~:actions~.

    VALUE may also be a function that returns a list as describe
    above.

  - ~:sequence-predicate~

    When this function returns non-nil, then the popup uses
    ~:sequence-actions~ instead of ~:actions~, and does not show the
    ~:switches~ and ~:options~.

  - ~:sequence-actions~

    The actions which can be invoked from the popup, when
    ~:sequence-predicate~ returns non-nil.

  - ~:setup-function~

    When this function is specified, then it is used instead of
    ~magit-popup-default-setup~.

  - ~:refresh-function~

    When this function is specified, then it is used instead of
    calling ~magit-popup-insert-section~ three times with symbols
    ~magit-popup-switch-button~, ~magit-popup-option-button~, and finally
    ~magit-popup-action-button~ as argument.

  - ~:man-page~

    The name of the manpage to be displayed when the user requests
    help for an argument.

** Defining Suffix Commands

Commands intended to be invoked from a particular popup should
determine the currently effective arguments by calling the function
~SHORTNAME-arguments~ inside their ~interactive~ form.  This function
is created by the ~magit-define-popup~ macro.  For a popup named
~prefix-foo-popup~ the name of this function is ~prefix-foo-arguments~.

When the command was invoked as an action in the respective popup,
then this function returns the arguments that were set in the popup.
Otherwise when the command was invoked as the default of the popup (by
calling the popup command with a prefix argument), or without using
the popup command at all, then this function returns the buffer-local
or global value of the variable ~SHORTNAME-arguments~.

Internally arguments are handled as a list of strings.  This might not
be appropriate for the intended use inside commands, or it might be
necessary to manipulate that list somehow, i.e. to split "--ARG=VAL"
into "--ARG""VAL".  This should be done by advising or redefining the
function ~SHORTNAME-arguments~.

Internally ~SHORNAME-arguments~ used following variables and function.
Except when redefining the former, you should not use these directly.

- Variable: magit-current-popup

  The popup from which this editing command was invoked.

- Variable: magit-current-popup-args

  The value of the popup arguments for this editing command.

  If the current command was invoked from a popup, then this is a list
  of strings of all the set switches and options.  This includes
  arguments which are set by default not only those explicitly set
  during this invocation.

  When the value is nil, then that can be because no argument is set,
  or because the current command wasn't invoked from a popup at all.

- Function: magit-current-popup-args &rest args

  This function returns the value of the popup arguments for this
  editing command.  The value is the same as that of the variable by
  the same name, except that FILTER is applied.  FILTER is a list of
  regexps; only arguments that match one of them are returned.  The
  first element of FILTER may also be ~:not~ in which case only
  arguments that don't match any of the regexps are returned, or ~:only~
  which doesn't change the behavior.

* _ Copying
:PROPERTIES:
:COPYING:    t
:END:

#+BEGIN_QUOTE
Copyright (C) 2015-2018 Jonas Bernoulli <jonas@bernoul.li>

You can redistribute this document and/or modify it under the terms
of the GNU General Public License as published by the Free Software
Foundation, either version 3 of the License, or (at your option) any
later version.

This document is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.
#+END_QUOTE

* _ :ignore:

#  LocalWords:  ARG DESC KEY's LocalWords Magit OPTVAL POPUP PREPEND
#  LocalWords:  Popup SHORTNAME args desc magit manpage popup popup's
#  LocalWords:  popups pre prepend

# IMPORTANT: Also update ORG_ARGS and ORG_EVAL in the Makefile.
# Local Variables:
# eval: (require 'magit-utils nil t)
# eval: (require 'org-man     nil t)
# eval: (require 'ox-extra    nil t)
# eval: (require 'ox-texinfo+ nil t)
# eval: (and (featurep 'ox-extra) (ox-extras-activate '(ignore-headlines)))
# indent-tabs-mode: nil
# org-src-preserve-indentation: nil
# End:
