Magit-Popup User Manual

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Magit-Popup User Manual

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.

Copyright (C) 2015-2017 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.


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1 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 prefixes 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:

,-----------------------------------------
|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
'-----------------------------------------

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 disappears. 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:

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.


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2 Usage

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.

C-t     (magit-popup-toggle-show-common-commands)

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

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.

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.

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.

C-h i     (magit-popup-info)

Show this manual.

?     (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.


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2.1 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.

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:

(plist-put magit-show-refs-popup :use-prefix nil)

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2.2 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.

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:

(button-type-put 'magit-popup-action-button 'format " %k %D")

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3 Defining Prefix and Suffix Commands

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.

;;;###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))

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3.1 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):


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3.2 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.