Rg Manual

rg.el is an Emacs search package based on the ripgrep command line tool. It allows you to interactively create searches, doing automatic searches based on the editing context, refining and modifying search results and much more. It is also highly configurable to be able to fit different users’ needs.

Throughout this manual this emacs package will be referred to as rg while the command line utility will be referred to as ripgrep.

If you are used to built-in Emacs rgrep command, transitioning to rg should be simple. rg provides a lot of extra features but the basics are similar.

The big benefit of using ripgrep instead of grep as a backend is speed. Especially when searching large source code repositories where ripgrep really shines. Please read this blog post for some speed comparisons with other tools.

Usage

Installation

This version of rg is supported on GNU Emacs 25.1 or later on Linux systems. It might work on older Emacsen and on other systems but such configurations are not tested. Patches for other OS:es are welcome.

MELPA

Packages are published on MELPA Stable and MELPA. From within Emacs, run M-x package-install [RET] rg [RET] to install from those sources.

Enable default key bindings:

(rg-enable-default-bindings)

The above will enable the default key map rg-menu under the default prefix key C-c s.

Manual

Releases can alternatively be downloaded from GitHub and installed manually. Put all elisp files in main directory in your load path and require the package in your init file.

(require 'rg)
(rg-enable-default-bindings)

You would also need to make sure all package requirements are met. For this version these are:

  • wgrep 2.1.10
  • transient 0.3.0
  • emacs 25.1

rg is using autoloaded symbols which means it’s also possible to defer loading if you have autoloading setup. That usually comes out of the box with package-install.

Lazy loading

For lazy loading you don’t want to call directly into the package during startup. Use a setup similar to this instead:

(global-set-key (kbd "C-c s") #'rg-menu)
(with-eval-after-load 'rg
   ;; Your settings goes here.
)

If you don’t want to use the transient menu interface, the following is needed to achieve lazy loading:

;; Workaround for emacs' lack of autoloaded keymaps.
;; This is essentially what use-package do.
(defun rg-autoload-keymap ()
  (interactive)
  (if (not (require 'rg nil t))
      (user-error (format "Cannot load rg"))
    (let ((key-vec (this-command-keys-vector)))
      (global-set-key key-vec rg-global-map)
      (setq unread-command-events
        (mapcar (lambda (ev) (cons t ev))
                (listify-key-sequence key-vec))))))

(global-set-key (kbd "C-c s") #'rg-autoload-keymap)
(with-eval-after-load 'rg
   ;; Your settings goes here.
)

wgrep

This package use wgrep for editing capabilities in the rg results buffer. No setup is needed.

Isearch integration

Optional isearch integration can be enabled to allow you to extend isearch to trigger ripgrep searching. Enable it in your configuration with:

(require 'rg-isearch)
(define-key isearch-mode-map "\M-sr" 'rg-isearch-menu)

For the evil use case where isearch-mode is exited after first search hit, users would also want to add the binding to the global-map or similar.

Interaction with the ripgrep configuration file

The ripgrep binary allows using a configuration file to set default values for command line flags. This package requires specific command line flags to function correctly and using a ripgrep configuration may conflict with these requirements. Therefore the configuration file is ignored by default. This can be changed by the rg-ignore-ripgreprc setting.

Note

Using the ripgrep configuration file may break functionality of this package if you are not careful.

Searching

Searching is done by invoking one of the different frontend commands. This package is built around recursive search based on three parameters; a single directory, file type filter, and a search pattern. These three parameters can interactively be selected or figured out automatically by the package, depending on which command that is used.

The underlying ripgrep binary has the file type filter concept built in. You have a high level of control over which files to search and which to ignore. This is partly what makes it so fast, ignoring uninteresting files.

In addition to the base parameters there are a lot of options that control how a search is done. These are typically selected from the rg-menu interface.

Case sensitivity

Considering case when searching is an important feature of any search tool. This package gives you a lot of control over how to handle case sensitive and case insensitive search. It can be forced to on or off and set to smart case. The latter is similar to the ripgrep --smart-case flag but is not using the flag directly. One thing to note about this is that the case insensitive setting controls the behavior when starting a new search. In the results buffer the setting is fixed to on or off but can be toggled easily with a key binding. See rg-ignore-case customization for the details of the configuration.

Do what I mean

The DWIM family of search commands tries to be smart by figure out the search parameters from the context without prompting. Thanks to ripgrep’s speed, this allows for new ways of searching by invoking a dwim command and then refine the search from the results buffer.

These commands use the word (with the definition of word depending on context) under cursor as the query string. The file type parameter is taken from the type of the currently visited file. If the current file type can not be identified all file types known to ripgrep are used. The fallback can be customized with rg-default-alias-fallback. The directory parameter varies between these commands.

M-x rg-dwim-project-dir

Do a DWIM search in the current project.

M-x rg-dwim-current-dir

Do a DWIM search in the current directory.

M-x rg-dwim-current-file

Do a DWIM search in the current file. The current file in this context is actually a file pattern exactly matching the current file name in a search starting from current directory. Most of the time this means a single file but if there are multiple files with the same name in a sub directory, those will be searched as well.

C-c s d (rg-dwim)

This command combines all the DWIM commands to one. The default search is in the project dir. With one universal argument current directory is used and with double universal arguments a file search is done.

File type aliases

File type aliases are used in ripgrep to filter out the files to search in. The ripgrep binary comes with a default set of aliases that can be extended or overridden from this package by customizing rg-custom-type-aliases.

An alias is a mapping between a name and a list of glob patterns matching the files of interest. Selecting an alias when searching is done with completing read of the defined aliases. It is also possible to enter a custom glob pattern if there is no suitable alias defined for the file type.

rg defines some internal aliases:

Name Meaning
all all defined types including rg-custom-type-aliases
everything all files. No filtering on type is done.
custom used internally in this package for mapping custom glob patterns.

Warning

Do not use any of the internal aliases in rg-custom-type-aliases. That would interfere with the package internal usage.

The menu

The global prefix key may be bound to a transient prefix command, which means that the key binding will popup a menu. This package is using the same popup menu backend called transient as the magit package. If you are familiar with magit this should feels like home.

The menu is mostly interesting when you want to give specific command line flags to the ripgrep binary. When you just want to do a quick search based on the defaults the menu basically acts as a normal keymap.

Pressing the rg-menu prefix key will popup the menu where command line flags can be selected before triggering the wanted search function. The menu can be customized via the transient API as usual. This package contains some shortcuts to directly add a new command to the menu when defining the command via the rg-define-search macro.

(rg-define-search rg-word
  :format literal
  :flags ("--word-regexp")
  :menu ("Custom" "w" "Word"))

The :menu keyword in the above invocation will trigger insertion of a new menu item bound to key w with description Word. The new menu item will be put under the Custom group. This group is not available in the original menu so it will be created.

The menu can be triggered from the results buffer with the m key. The commands in the menu differs, depending on from where it’s triggered but the available options are the same. The menu does not show all options by default.

The visible options can be controlled by the transient suffix levels documented here. To modify what is enabled at the default level 4 press C-x l to enter edit mode when the menu is visible. Then select the option by pressing the key sequence that activates the option and choose the level 4 for that option. It’s also possible to use the transient edit mode for modifying the overall level of the menu to enable more options at once.

Results buffer

The results of a search is shown in the results buffer. This buffer displays search parameters, the full command line and the output of the ripgrep binary. It supports basic navigation between search results editing of the file contents directly from the search buffer and also modification of the current search. The results buffer is a modified compilation buffer and some key bindings and functionality is inherited from the parent and from grep mode.

History navigation

Each search result is stored in the search history, which is a per results buffer property. History can be navigated back and forward, the forward history is cleared when a new search is done.

C-c < (rg-back-history)

Navigate back in history.

C-c > (rg-forward-history)

Navigate forward in history.

Tip

The key bindings here are slightly inconvenient so invoking this via the menu by pressing m b and m w is more ergonomic.

Edit and apply (wgrep)

The results buffer supports inline editing via the wgrep package. This is setup automatically when rg is loaded.

e (wgrep-change-to-wgrep-mode)

Make the search results editable by enabling wgrep mode. When done press C-c C-c to commit your changes to the underlying files or C-c C-k to drop the changes.

Search management

The result buffer is named *rg* and rg reuse the same result buffer for new searches. If you want to store a search while continuing doing new searches there are two ways of doing that.

Save the search buffer by renaming it to a unique new name. This is available both outside and inside a result buffer. Outside of the result buffer it’s bound to C-c s s.

If you want to keep all search buffers until manually killed you can use this snippet in your init file.

(defadvice rg-run (before rg-run-before activate)
  (rg-save-search))
S (rg-save-search-as-name)

Save the search buffer and interactively give it a specific name. This is available both outside and inside a result buffer. Outside of the result buffer it’s bound to C-c s S.

The default buffer name can be customized with rg-buffer-name. This setting considers dir local variables and it’s even possible to use a function to get a really dynamic setup.

Having a lot of search buffers floating around can easily get messy. To help keeping this under control there is a search manager. The manager is simply a modified ibuffer that lists all the results buffers, shows some data about the searches and make it possible to kill of some unused etc.

L (rg-list-searches)

Open the search manager. This is available both in result buffer and globally bound to C-c s l.

C-c s k (rg-kill-saved-searches)

Kill all saved searches except for the one that matches rg-buffer-name. This is available both in result buffer and globally bound to C-c s k.

Warning

If you have a dynamic rg-buffer-name setup, only one buffer that matches your current criteria (dir locals or project for instance) will be kept. So be careful when killing saved searches to avoid losing important search results.

Configuration

Customization

Customization is done via the Emacs customization system. The group rg is the main group of the package.

M-x customize-group [RET] rg [RET]
rg-executable [(executable-find "rg")]

The ripgrep executable to use. Could be an absolute path or just the base name if the executable is in the path. The default is using executable-find to locate the command. If you want to use this package with tramp it might be better to set it to just “rg” in order to let the OS find the binary where it’s invoked. From Emacs 27.1, the tramp use case is by default handled automatically. See rg-executable-per-connection for details.

rg-executable-per-connection [t]

This setting only has effect in Emacs 27.1 or later. Handle the rg-executable automatically for different hosts if used with tramp. executable-find for “rg” binary will be invoked on remote hosts to determine the path to ripgrep. The result is stored per connection.

rg-custom-type-aliases [(("gyp" . "\*.gyp \*.gypi"))]

An association list that maps file type aliases to a space delimited string with file globs. These are combined with the ripgrep builtin file aliases.

Example:

(setq rg-custom-type-aliases
  '(("foo" .    "*.foo *.bar")
    ("baz" .    "*.baz *.qux")))

You may also add lambdas to rg-custom-type-aliases to add aliases dynamically based on mode, directory, project, etc.

(add-to-list
 'rg-custom-type-aliases
 (lambda ()
   (when (in-frontend-app)
     (cons "ui" "*.js *.hbs *.json"))))
rg-default-alias-fallback ["everything"]

This setting controls the default alias used when no alias can be recognized for the current buffer. all or everything are reasonable values for this variable.

rg-command-line-flags [nil]

A list of command line flags that will be appended to the ripgrep command line. Must either be a list of flags or a function that returns a list of flags.

rg-group-result [t]

Controls the layout of the results buffer. If non nil, each file name is displayed once and matches are grouped under that filename instead of repeating the filename on each match. This is essentially the layout of the --no-heading ripgrep command line flag.

rg-show-columns [nil]

Controls if column numbers are used in the search result.

rg-ignore-case [case-fold-search]

Setting that controls if case sensitive search is made or not. It can essentially be on, off or smart. The smart setting will trigger an analyze of the search string and if it’s all lower case, the search will be case insensitive, otherwise it will be case sensitive. The following values are valid:

  • case-fold-search - A non nil value of case-fold-search will trigger smart case behavior.
  • smart - Smart case behavior.
  • force - Always ignore case.
  • nil - Always consider case.
rg-hide-command [t]

Hide most of command line by default. This is enabled by default and can be set to nil to show full command line. This can be toggled in the results buffer by clicking on the command line.

rg-keymap-prefix ["C-c s"]

This variable sets the default prefix used for the global key bindings. Note that rg-enable-default-bindings needs to be invoked for the bindings to be enabled.

rg-use-transient-menu [t]

Controls whether rg-menu will be used by default or not. It’s also possible to enable the menu explicitly with

(rg-enable-menu)
rg-show-header [t]

Controls if the search info header is shown in the result buffer. This is enabled by default but can be disabled by setting this variable to nil.

rg-buffer-name ["rg"]

Controls the name of the results buffer. It may be string or function. This name will be surrounded by * to yield the final buffer name so if this setting is foo the buffer name will be *foo*. One useful case of using it is to have separate result buffers per project. One can set this variable in `dir-locals` file or set it to function.

Example, this function will set results buffer name based on `project-current`:

(defun my-rg-buffer-name ()
  (let ((p (project-current)))
    (if p
 (format "rg %s" (abbreviate-file-name (cdr p)))
      "rg"))))
rg-ignore-ripgreprc [t]

Controls if the ripgreprc file should be ignored or not. If nil, the config file will be used, otherwise it will be ignored. The default is to ignore this file in order to avoid that conflicting settings have impact on this package’s behavior. Setting this to nil may affect core functionality of this package. Especially changing colors can affect parsing of the output and result in a broken results buffer.

Position numbers alignment

When operating rg in grouped output mode (rg-group-result is non nil), it’s possible to control how the line and column numbers are displayed in the result buffer.

Example settings:

(setq rg-align-position-numbers t)
(setq rg-align-line-number-field-length 3)
(setq rg-align-column-number-field-length 3)
(setq rg-align-line-column-separator "#")
(setq rg-align-position-content-separator "|")

Will yield the following format:

File: matched_file.foo
  1#  2|match1
888# 10|match2
rg-align-position-numbers [t]

Setting this to t will align line and column numbers in columns padded with white space.

rg-align-line-number-field-length [4]

Defines the length of the line number field.

rg-align-column-number-field-length [3]

Defines the length of the column number field.

rg-align-line-column-separator [" "]

Separator string used between line and column numbers. nil means use default separator from ripgrep.

rg-align-position-content-separator [" "]

Separator string used between the position numbers and matched content. nil means use default separator from ripgrep.

Faces

All faces are in the subgroup rg-face of the main group rg.

M-x customize-group [RET] rg-face [RET]

Results buffer

rg-match-face [match]

Face used to highlight matches in result.

rg-error-face [compilation-error]

Face used to highlight errors when invoking ripgrep.

rg-context-face [shadow]

Face used to highlight context lines in ripgrep output when --context-lines flag is used.

rg-info-face [compilation-info]

Face used to highlight general info in results buffer. For instance the number of matches found.

rg-warning-face [compilation-warning]

Face used to highlight warnings in the ripgrep output.

rg-filename-face [rg-info-face]

Face used to highlight filenames in the output.

rg-file-tag-face [rg-info-face]

Face used for the File: tag in grouped results output.

rg-line-number-face [compilation-line-number]

Face used on line numbers.

rg-column-number-face [compilation-column-number]

Face used on column numbers.

rg-match-position-face [default]

Face added to file positions. This is the start of a matching line and depending on configuration may be, file name, column number and line number.

Header line

rg-toggle-on-face [rg-file-tag-face]

Face used for flags that are toggled on.

rg-toggle-off-face [rg-error-face]

Face used for flags that are toggled off.

rg-literal-face [rg-filename-face]

Face used the on the literal marker in the header line.

rg-regexp-face [compilation-line-number]

Face used the on the regexp marker in the header line.

Configuration functions

(rg-enable-default-bindings &optional, prefix)

Enable the default keyboard bindings for the package with prefix key. If rg-use-transient-menu is on this will enable the menu instead of activating the global bindings. If prefix is not provided rg-keymap-prefix will be used.

(rg-enable-menu &optional, prefix)

Enable the rg-menu with prefix key. This bypass rg-use-transient-menu setting. If prefix is not provided rg-keymap-prefix will be used.

(rg-use-old-defaults)

This function is provided to keep backwards compatibility with versions older than 2.0.0. In this version default settings as well as key bindings changed and to bring back the old defaults call this function in your init file.

Configuration macros

(rg-define-toggle flag, &optional, key, default)

This is a macro that can be used to define custom ripgrep flag toggling functions in the result buffer. The macro takes the flag (and potential value) as an argument and optionally binds the toggle function to a key. If default is non nil the flag is used by default.

The function defined by this macro will be named as the flag name stripped with leading dashes and prefixed with rg-custom-toggle-flag-.

(rg-define-toggle "-uu" "I" t)

Creates a function named rg-custom-toggle-flag-uu that is on by default and bound to I in rg result buffer.

(rg-define-toggle "--context 3" (kbd "C-c c"))

Creates a function named rg-custom-toggle-flag-context that is off by default and bound to C-c c in rg result buffer.

This macro can be used to define custom search functions in a declarative style. Default implementations for common behavior is available and custom forms can also be used.

It optionally starts with a string that is used as the docstring for the defined function. The rest of the arguments contain key value pairs according to the specification below. All keys are optional with specified default if left out.

  • :query - Method for retrieving the search string. Allowed values are point which means extract thing at point and ask which means prompt the user for a string. Any form that evaluates to a string is allowed. Default is ask.
  • :format - Specifies if :query is interpreted literally (literal) or as a regexp (regexp). If it is a form, eg. (not current-prefix-arg), and is non-nil the :query is interpreted literally, otherwise as a regexp. Default is regexp.
  • :files - Form that evaluates to a file alias or custom file glob. current means extract alias from current buffer file name, ask will prompt the user. Default is ask.
  • :dir - Root search directory. Allowed values are ask for user prompt, current for current dir and project for project root. Any form that evaluates to a directory string is also allowed. Default is ask.
  • :confirm - never, always, or prefix are allowed values. Specifies if the the final search command line string can be modified and confirmed the user. Default is never.
  • :flags - ask or a list of command line flags that will be used when invoking the search.
  • :menu - Bind the command into rg-menu. Must be a list with three items in it. The first item is the description of the group in witch the new command will appear. If the group does not exist a new will be created. The second item is the key binding for this new command (ether a key vector or a key description string) and the third item is the description of the command that will appear in the menu.

Examples:

(rg-define-search search-everything-at-home
  "Search files including hidden in home directory"
  :query ask
  :format literal
  :files "everything"
  :flags ("--hidden")
  :dir (getenv "HOME")
  :menu ("Search" "h" "Home"))

(rg-define-search rg-emacs
  "Search the emacs lisp source code."
  :dir "/usr/share/emacs/25.2/lisp/"
  :flags '("-z")
  :files "*.{el,el.gz}"
  :menu ("Custom" "L" "lisp"))

Use with evil-mode

Some key bindings clash with evil-mode. Recommendation is to use evil motion state for the results buffer and then switch to evil normal mode when editing in wgrep-mode. Some adjustments need to be done to avoid the clashes though.

This is a start of a configuration. This let rg-mode’s key bindings override the motion state map bindings based on that these motion keys are not important in an rg results buffer. Adjust this to your preferred use case:

(with-eval-after-load 'rg
  (advice-add 'wgrep-change-to-wgrep-mode :after
          #'evil-normal-state)
  (advice-add 'wgrep-to-original-mode :after
          #'evil-motion-state)
  (defvar rg-mode-map)
  (add-to-list 'evil-motion-state-modes 'rg-mode)
  (evil-add-hjkl-bindings rg-mode-map 'motion
    "e" #'wgrep-change-to-wgrep-mode
    "g" #'rg-recompile
    "t" #'rg-rerun-change-literal))

Customizing the menu

The menu can be modified from the emacs configuration file.

To add a new switch before the option triggered by -n at suffix level 3:

(transient-insert-suffix 'rg-menu "-n" '(3 "-o" "Only print matches" "--only-matching"))

To add a new option before the option triggered by -g at suffix level 4:

(transient-insert-suffix 'rg-menu "-g" '(4 "-f" "Pattern file" "--file="))

The = in --file= triggers argument input for the flag.

To remove an item from the menu specify the trigger key in the transient remove command. For example, to remove the Search hidden files switch use the following:

(transient-remove-suffix 'rg-menu "-h")

Please refer to the transient documentation for details on customizing the menu.

This package also adds a convenience function for appending new commands to the menu in the groups at the bottom.

(rg-menu-transient-insert group, key, description, command)

This inserts a new command under group if it exists, otherwise a new group is created. key, description and command is as for the transient-insert-suffix function.

For example to insert a new command under Search group:

(rg-menu-transient-insert "Search" "m" "My search" 'my-search-command)

It’s usually better to use the :menu key of the rg-define-search macro to define a search function and adding it to the menu in one go.

Contribute

Contributions are very welcome. Development is done in the GitHub repository. If you find a bug, please report it in the issue tracker.

Pull requests

If you want to submit a patch, please submit a GitHub pull request. If you want to submit any larger code changes, please create an issue first for discussion. Some features does not fit well into this package and there is also good to agree on the general design before doing any major work.

The minimum requirements for a pull request to be accepted is that all existing tests pass and test coverage should not decrease. Often a patch also needs additional tests, new/changed documentation etc.

Don’t strive to submit a perfect pull request directly. It’s often better to submit something simple that shows the main direction of the new code in order to discuss the best way to proceed and what additions are needed.

Tests

Cask is used for testing. The tests are written using the Emacs built in ERT framework and executed with ert runner. There are also compilation tests, style check, package verification etc.

Setup

  • Install cask

  • Install all developer dependencies:

    make deps

Running

  • Run the whole test suite:

    make test

  • Run only the unit/integration tests:

    make ert-test

  • Manually test the package with Emacs:

    cask emacs -Q -L . --eval="(progn (require 'rg) (enable-default-bindings))"

Documentation

The documentation is written in org mode. The export target is restructured text suitable for the Sphinx documentation generator. Sphinx is used to export the output from org mode to info and HTML documentation. The resulting .rst files are used for the online documentation on https://readthedocs.io.

The end user documentation is generated after committing to the main repository. It’s advisable to build both html and info documentation locally and verify the output to make sure the changes looks as expected.

Setup

  • Install Sphinx

    sudo apt install python3-sphinx python3-sphinx-rtd-theme

  • Install makeinfo

    sudo apt install texinfo

Building

  • HTML documentation

    make html

    Open docs/rst/_build/html/index.html in a browser.

  • Info documentation

    make info

    To view in emacs:

    C-u M-x info [RET]

    Then select the docs/rst/_build/info/rgel.info file.

License

rg is free software; you can redistribute it 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.

rg 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.

GNU General Public License

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  0. Definitions.

  "This License" refers to version 3 of the GNU General Public License.

  "Copyright" also means copyright-like laws that apply to other kinds of
works, such as semiconductor masks.

  "The Program" refers to any copyrightable work licensed under this
License.  Each licensee is addressed as "you".  "Licensees" and
"recipients" may be individuals or organizations.

  To "modify" a work means to copy from or adapt all or part of the work
in a fashion requiring copyright permission, other than the making of an
exact copy.  The resulting work is called a "modified version" of the
earlier work or a work "based on" the earlier work.

  A "covered work" means either the unmodified Program or a work based
on the Program.

  To "propagate" a work means to do anything with it that, without
permission, would make you directly or secondarily liable for
infringement under applicable copyright law, except executing it on a
computer or modifying a private copy.  Propagation includes copying,
distribution (with or without modification), making available to the
public, and in some countries other activities as well.

  To "convey" a work means any kind of propagation that enables other
parties to make or receive copies.  Mere interaction with a user through
a computer network, with no transfer of a copy, is not conveying.

  An interactive user interface displays "Appropriate Legal Notices"
to the extent that it includes a convenient and prominently visible
feature that (1) displays an appropriate copyright notice, and (2)
tells the user that there is no warranty for the work (except to the
extent that warranties are provided), that licensees may convey the
work under this License, and how to view a copy of this License.  If
the interface presents a list of user commands or options, such as a
menu, a prominent item in the list meets this criterion.

  1. Source Code.

  The "source code" for a work means the preferred form of the work
for making modifications to it.  "Object code" means any non-source
form of a work.

  A "Standard Interface" means an interface that either is an official
standard defined by a recognized standards body, or, in the case of
interfaces specified for a particular programming language, one that
is widely used among developers working in that language.

  The "System Libraries" of an executable work include anything, other
than the work as a whole, that (a) is included in the normal form of
packaging a Major Component, but which is not part of that Major
Component, and (b) serves only to enable use of the work with that
Major Component, or to implement a Standard Interface for which an
implementation is available to the public in source code form.  A
"Major Component", in this context, means a major essential component
(kernel, window system, and so on) of the specific operating system
(if any) on which the executable work runs, or a compiler used to
produce the work, or an object code interpreter used to run it.

  The "Corresponding Source" for a work in object code form means all
the source code needed to generate, install, and (for an executable
work) run the object code and to modify the work, including scripts to
control those activities.  However, it does not include the work's
System Libraries, or general-purpose tools or generally available free
programs which are used unmodified in performing those activities but
which are not part of the work.  For example, Corresponding Source
includes interface definition files associated with source files for
the work, and the source code for shared libraries and dynamically
linked subprograms that the work is specifically designed to require,
such as by intimate data communication or control flow between those
subprograms and other parts of the work.

  The Corresponding Source need not include anything that users
can regenerate automatically from other parts of the Corresponding
Source.

  The Corresponding Source for a work in source code form is that
same work.

  2. Basic Permissions.

  All rights granted under this License are granted for the term of
copyright on the Program, and are irrevocable provided the stated
conditions are met.  This License explicitly affirms your unlimited
permission to run the unmodified Program.  The output from running a
covered work is covered by this License only if the output, given its
content, constitutes a covered work.  This License acknowledges your
rights of fair use or other equivalent, as provided by copyright law.

  You may make, run and propagate covered works that you do not
convey, without conditions so long as your license otherwise remains
in force.  You may convey covered works to others for the sole purpose
of having them make modifications exclusively for you, or provide you
with facilities for running those works, provided that you comply with
the terms of this License in conveying all material for which you do
not control copyright.  Those thus making or running the covered works
for you must do so exclusively on your behalf, under your direction
and control, on terms that prohibit them from making any copies of
your copyrighted material outside their relationship with you.

  Conveying under any other circumstances is permitted solely under
the conditions stated below.  Sublicensing is not allowed; section 10
makes it unnecessary.

  3. Protecting Users' Legal Rights From Anti-Circumvention Law.

  No covered work shall be deemed part of an effective technological
measure under any applicable law fulfilling obligations under article
11 of the WIPO copyright treaty adopted on 20 December 1996, or
similar laws prohibiting or restricting circumvention of such
measures.

  When you convey a covered work, you waive any legal power to forbid
circumvention of technological measures to the extent such circumvention
is effected by exercising rights under this License with respect to
the covered work, and you disclaim any intention to limit operation or
modification of the work as a means of enforcing, against the work's
users, your or third parties' legal rights to forbid circumvention of
technological measures.

  4. Conveying Verbatim Copies.

  You may convey verbatim copies of the Program's source code as you
receive it, in any medium, provided that you conspicuously and
appropriately publish on each copy an appropriate copyright notice;
keep intact all notices stating that this License and any
non-permissive terms added in accord with section 7 apply to the code;
keep intact all notices of the absence of any warranty; and give all
recipients a copy of this License along with the Program.

  You may charge any price or no price for each copy that you convey,
and you may offer support or warranty protection for a fee.

  5. Conveying Modified Source Versions.

  You may convey a work based on the Program, or the modifications to
produce it from the Program, in the form of source code under the
terms of section 4, provided that you also meet all of these conditions:

    a) The work must carry prominent notices stating that you modified
    it, and giving a relevant date.

    b) The work must carry prominent notices stating that it is
    released under this License and any conditions added under section
    7.  This requirement modifies the requirement in section 4 to
    "keep intact all notices".

    c) You must license the entire work, as a whole, under this
    License to anyone who comes into possession of a copy.  This
    License will therefore apply, along with any applicable section 7
    additional terms, to the whole of the work, and all its parts,
    regardless of how they are packaged.  This License gives no
    permission to license the work in any other way, but it does not
    invalidate such permission if you have separately received it.

    d) If the work has interactive user interfaces, each must display
    Appropriate Legal Notices; however, if the Program has interactive
    interfaces that do not display Appropriate Legal Notices, your
    work need not make them do so.

  A compilation of a covered work with other separate and independent
works, which are not by their nature extensions of the covered work,
and which are not combined with it such as to form a larger program,
in or on a volume of a storage or distribution medium, is called an
"aggregate" if the compilation and its resulting copyright are not
used to limit the access or legal rights of the compilation's users
beyond what the individual works permit.  Inclusion of a covered work
in an aggregate does not cause this License to apply to the other
parts of the aggregate.

  6. Conveying Non-Source Forms.

  You may convey a covered work in object code form under the terms
of sections 4 and 5, provided that you also convey the
machine-readable Corresponding Source under the terms of this License,
in one of these ways:

    a) Convey the object code in, or embodied in, a physical product
    (including a physical distribution medium), accompanied by the
    Corresponding Source fixed on a durable physical medium
    customarily used for software interchange.

    b) Convey the object code in, or embodied in, a physical product
    (including a physical distribution medium), accompanied by a
    written offer, valid for at least three years and valid for as
    long as you offer spare parts or customer support for that product
    model, to give anyone who possesses the object code either (1) a
    copy of the Corresponding Source for all the software in the
    product that is covered by this License, on a durable physical
    medium customarily used for software interchange, for a price no
    more than your reasonable cost of physically performing this
    conveying of source, or (2) access to copy the
    Corresponding Source from a network server at no charge.

    c) Convey individual copies of the object code with a copy of the
    written offer to provide the Corresponding Source.  This
    alternative is allowed only occasionally and noncommercially, and
    only if you received the object code with such an offer, in accord
    with subsection 6b.

    d) Convey the object code by offering access from a designated
    place (gratis or for a charge), and offer equivalent access to the
    Corresponding Source in the same way through the same place at no
    further charge.  You need not require recipients to copy the
    Corresponding Source along with the object code.  If the place to
    copy the object code is a network server, the Corresponding Source
    may be on a different server (operated by you or a third party)
    that supports equivalent copying facilities, provided you maintain
    clear directions next to the object code saying where to find the
    Corresponding Source.  Regardless of what server hosts the
    Corresponding Source, you remain obligated to ensure that it is
    available for as long as needed to satisfy these requirements.

    e) Convey the object code using peer-to-peer transmission, provided
    you inform other peers where the object code and Corresponding
    Source of the work are being offered to the general public at no
    charge under subsection 6d.

  A separable portion of the object code, whose source code is excluded
from the Corresponding Source as a System Library, need not be
included in conveying the object code work.

  A "User Product" is either (1) a "consumer product", which means any
tangible personal property which is normally used for personal, family,
or household purposes, or (2) anything designed or sold for incorporation
into a dwelling.  In determining whether a product is a consumer product,
doubtful cases shall be resolved in favor of coverage.  For a particular
product received by a particular user, "normally used" refers to a
typical or common use of that class of product, regardless of the status
of the particular user or of the way in which the particular user
actually uses, or expects or is expected to use, the product.  A product
is a consumer product regardless of whether the product has substantial
commercial, industrial or non-consumer uses, unless such uses represent
the only significant mode of use of the product.

  "Installation Information" for a User Product means any methods,
procedures, authorization keys, or other information required to install
and execute modified versions of a covered work in that User Product from
a modified version of its Corresponding Source.  The information must
suffice to ensure that the continued functioning of the modified object
code is in no case prevented or interfered with solely because
modification has been made.

  If you convey an object code work under this section in, or with, or
specifically for use in, a User Product, and the conveying occurs as
part of a transaction in which the right of possession and use of the
User Product is transferred to the recipient in perpetuity or for a
fixed term (regardless of how the transaction is characterized), the
Corresponding Source conveyed under this section must be accompanied
by the Installation Information.  But this requirement does not apply
if neither you nor any third party retains the ability to install
modified object code on the User Product (for example, the work has
been installed in ROM).

  The requirement to provide Installation Information does not include a
requirement to continue to provide support service, warranty, or updates
for a work that has been modified or installed by the recipient, or for
the User Product in which it has been modified or installed.  Access to a
network may be denied when the modification itself materially and
adversely affects the operation of the network or violates the rules and
protocols for communication across the network.

  Corresponding Source conveyed, and Installation Information provided,
in accord with this section must be in a format that is publicly
documented (and with an implementation available to the public in
source code form), and must require no special password or key for
unpacking, reading or copying.

  7. Additional Terms.

  "Additional permissions" are terms that supplement the terms of this
License by making exceptions from one or more of its conditions.
Additional permissions that are applicable to the entire Program shall
be treated as though they were included in this License, to the extent
that they are valid under applicable law.  If additional permissions
apply only to part of the Program, that part may be used separately
under those permissions, but the entire Program remains governed by
this License without regard to the additional permissions.

  When you convey a copy of a covered work, you may at your option
remove any additional permissions from that copy, or from any part of
it.  (Additional permissions may be written to require their own
removal in certain cases when you modify the work.)  You may place
additional permissions on material, added by you to a covered work,
for which you have or can give appropriate copyright permission.

  Notwithstanding any other provision of this License, for material you
add to a covered work, you may (if authorized by the copyright holders of
that material) supplement the terms of this License with terms:

    a) Disclaiming warranty or limiting liability differently from the
    terms of sections 15 and 16 of this License; or

    b) Requiring preservation of specified reasonable legal notices or
    author attributions in that material or in the Appropriate Legal
    Notices displayed by works containing it; or

    c) Prohibiting misrepresentation of the origin of that material, or
    requiring that modified versions of such material be marked in
    reasonable ways as different from the original version; or

    d) Limiting the use for publicity purposes of names of licensors or
    authors of the material; or

    e) Declining to grant rights under trademark law for use of some
    trade names, trademarks, or service marks; or

    f) Requiring indemnification of licensors and authors of that
    material by anyone who conveys the material (or modified versions of
    it) with contractual assumptions of liability to the recipient, for
    any liability that these contractual assumptions directly impose on
    those licensors and authors.

  All other non-permissive additional terms are considered "further
restrictions" within the meaning of section 10.  If the Program as you
received it, or any part of it, contains a notice stating that it is
governed by this License along with a term that is a further
restriction, you may remove that term.  If a license document contains
a further restriction but permits relicensing or conveying under this
License, you may add to a covered work material governed by the terms
of that license document, provided that the further restriction does
not survive such relicensing or conveying.

  If you add terms to a covered work in accord with this section, you
must place, in the relevant source files, a statement of the
additional terms that apply to those files, or a notice indicating
where to find the applicable terms.

  Additional terms, permissive or non-permissive, may be stated in the
form of a separately written license, or stated as exceptions;
the above requirements apply either way.

  8. Termination.

  You may not propagate or modify a covered work except as expressly
provided under this License.  Any attempt otherwise to propagate or
modify it is void, and will automatically terminate your rights under
this License (including any patent licenses granted under the third
paragraph of section 11).

  However, if you cease all violation of this License, then your
license from a particular copyright holder is reinstated (a)
provisionally, unless and until the copyright holder explicitly and
finally terminates your license, and (b) permanently, if the copyright
holder fails to notify you of the violation by some reasonable means
prior to 60 days after the cessation.

  Moreover, your license from a particular copyright holder is
reinstated permanently if the copyright holder notifies you of the
violation by some reasonable means, this is the first time you have
received notice of violation of this License (for any work) from that
copyright holder, and you cure the violation prior to 30 days after
your receipt of the notice.

  Termination of your rights under this section does not terminate the
licenses of parties who have received copies or rights from you under
this License.  If your rights have been terminated and not permanently
reinstated, you do not qualify to receive new licenses for the same
material under section 10.

  9. Acceptance Not Required for Having Copies.

  You are not required to accept this License in order to receive or
run a copy of the Program.  Ancillary propagation of a covered work
occurring solely as a consequence of using peer-to-peer transmission
to receive a copy likewise does not require acceptance.  However,
nothing other than this License grants you permission to propagate or
modify any covered work.  These actions infringe copyright if you do
not accept this License.  Therefore, by modifying or propagating a
covered work, you indicate your acceptance of this License to do so.

  10. Automatic Licensing of Downstream Recipients.

  Each time you convey a covered work, the recipient automatically
receives a license from the original licensors, to run, modify and
propagate that work, subject to this License.  You are not responsible
for enforcing compliance by third parties with this License.

  An "entity transaction" is a transaction transferring control of an
organization, or substantially all assets of one, or subdividing an
organization, or merging organizations.  If propagation of a covered
work results from an entity transaction, each party to that
transaction who receives a copy of the work also receives whatever
licenses to the work the party's predecessor in interest had or could
give under the previous paragraph, plus a right to possession of the
Corresponding Source of the work from the predecessor in interest, if
the predecessor has it or can get it with reasonable efforts.

  You may not impose any further restrictions on the exercise of the
rights granted or affirmed under this License.  For example, you may
not impose a license fee, royalty, or other charge for exercise of
rights granted under this License, and you may not initiate litigation
(including a cross-claim or counterclaim in a lawsuit) alleging that
any patent claim is infringed by making, using, selling, offering for
sale, or importing the Program or any portion of it.

  11. Patents.

  A "contributor" is a copyright holder who authorizes use under this
License of the Program or a work on which the Program is based.  The
work thus licensed is called the contributor's "contributor version".

  A contributor's "essential patent claims" are all patent claims
owned or controlled by the contributor, whether already acquired or
hereafter acquired, that would be infringed by some manner, permitted
by this License, of making, using, or selling its contributor version,
but do not include claims that would be infringed only as a
consequence of further modification of the contributor version.  For
purposes of this definition, "control" includes the right to grant
patent sublicenses in a manner consistent with the requirements of
this License.

  Each contributor grants you a non-exclusive, worldwide, royalty-free
patent license under the contributor's essential patent claims, to
make, use, sell, offer for sale, import and otherwise run, modify and
propagate the contents of its contributor version.

  In the following three paragraphs, a "patent license" is any express
agreement or commitment, however denominated, not to enforce a patent
(such as an express permission to practice a patent or covenant not to
sue for patent infringement).  To "grant" such a patent license to a
party means to make such an agreement or commitment not to enforce a
patent against the party.

  If you convey a covered work, knowingly relying on a patent license,
and the Corresponding Source of the work is not available for anyone
to copy, free of charge and under the terms of this License, through a
publicly available network server or other readily accessible means,
then you must either (1) cause the Corresponding Source to be so
available, or (2) arrange to deprive yourself of the benefit of the
patent license for this particular work, or (3) arrange, in a manner
consistent with the requirements of this License, to extend the patent
license to downstream recipients.  "Knowingly relying" means you have
actual knowledge that, but for the patent license, your conveying the
covered work in a country, or your recipient's use of the covered work
in a country, would infringe one or more identifiable patents in that
country that you have reason to believe are valid.

  If, pursuant to or in connection with a single transaction or
arrangement, you convey, or propagate by procuring conveyance of, a
covered work, and grant a patent license to some of the parties
receiving the covered work authorizing them to use, propagate, modify
or convey a specific copy of the covered work, then the patent license
you grant is automatically extended to all recipients of the covered
work and works based on it.

  A patent license is "discriminatory" if it does not include within
the scope of its coverage, prohibits the exercise of, or is
conditioned on the non-exercise of one or more of the rights that are
specifically granted under this License.  You may not convey a covered
work if you are a party to an arrangement with a third party that is
in the business of distributing software, under which you make payment
to the third party based on the extent of your activity of conveying
the work, and under which the third party grants, to any of the
parties who would receive the covered work from you, a discriminatory
patent license (a) in connection with copies of the covered work
conveyed by you (or copies made from those copies), or (b) primarily
for and in connection with specific products or compilations that
contain the covered work, unless you entered into that arrangement,
or that patent license was granted, prior to 28 March 2007.

  Nothing in this License shall be construed as excluding or limiting
any implied license or other defenses to infringement that may
otherwise be available to you under applicable patent law.

  12. No Surrender of Others' Freedom.

  If conditions are imposed on you (whether by court order, agreement or
otherwise) that contradict the conditions of this License, they do not
excuse you from the conditions of this License.  If you cannot convey a
covered work so as to satisfy simultaneously your obligations under this
License and any other pertinent obligations, then as a consequence you may
not convey it at all.  For example, if you agree to terms that obligate you
to collect a royalty for further conveying from those to whom you convey
the Program, the only way you could satisfy both those terms and this
License would be to refrain entirely from conveying the Program.

  13. Use with the GNU Affero General Public License.

  Notwithstanding any other provision of this License, you have
permission to link or combine any covered work with a work licensed
under version 3 of the GNU Affero General Public License into a single
combined work, and to convey the resulting work.  The terms of this
License will continue to apply to the part which is the covered work,
but the special requirements of the GNU Affero General Public License,
section 13, concerning interaction through a network will apply to the
combination as such.

  14. Revised Versions of this License.

  The Free Software Foundation may publish revised and/or new versions of
the GNU General Public License from time to time.  Such new versions will
be similar in spirit to the present version, but may differ in detail to
address new problems or concerns.

  Each version is given a distinguishing version number.  If the
Program specifies that a certain numbered version of the GNU General
Public License "or any later version" applies to it, you have the
option of following the terms and conditions either of that numbered
version or of any later version published by the Free Software
Foundation.  If the Program does not specify a version number of the
GNU General Public License, you may choose any version ever published
by the Free Software Foundation.

  If the Program specifies that a proxy can decide which future
versions of the GNU General Public License can be used, that proxy's
public statement of acceptance of a version permanently authorizes you
to choose that version for the Program.

  Later license versions may give you additional or different
permissions.  However, no additional obligations are imposed on any
author or copyright holder as a result of your choosing to follow a
later version.

  15. Disclaimer of Warranty.

  THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
APPLICABLE LAW.  EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE.  THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
IS WITH YOU.  SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
ALL NECESSARY SERVICING, REPAIR OR CORRECTION.

  16. Limitation of Liability.

  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
SUCH DAMAGES.

  17. Interpretation of Sections 15 and 16.

  If the disclaimer of warranty and limitation of liability provided
above cannot be given local legal effect according to their terms,
reviewing courts shall apply local law that most closely approximates
an absolute waiver of all civil liability in connection with the
Program, unless a warranty or assumption of liability accompanies a
copy of the Program in return for a fee.

                     END OF TERMS AND CONDITIONS

            How to Apply These Terms to Your New Programs

  If you develop a new program, and you want it to be of the greatest
possible use to the public, the best way to achieve this is to make it
free software which everyone can redistribute and change under these terms.

  To do so, attach the following notices to the program.  It is safest
to attach them to the start of each source file to most effectively
state the exclusion of warranty; and each file should have at least
the "copyright" line and a pointer to where the full notice is found.

    <one line to give the program's name and a brief idea of what it does.>
    Copyright (C) <year>  <name of author>

    This program is free software: you can redistribute it 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 program 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.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.

Also add information on how to contact you by electronic and paper mail.

  If the program does terminal interaction, make it output a short
notice like this when it starts in an interactive mode:

    <program>  Copyright (C) <year>  <name of author>
    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
    This is free software, and you are welcome to redistribute it
    under certain conditions; type `show c' for details.

The hypothetical commands `show w' and `show c' should show the appropriate
parts of the General Public License.  Of course, your program's commands
might be different; for a GUI interface, you would use an "about box".

  You should also get your employer (if you work as a programmer) or school,
if any, to sign a "copyright disclaimer" for the program, if necessary.
For more information on this, and how to apply and follow the GNU GPL, see
<http://www.gnu.org/licenses/>.

  The GNU General Public License does not permit incorporating your program
into proprietary programs.  If your program is a subroutine library, you
may consider it more useful to permit linking proprietary applications with
the library.  If this is what you want to do, use the GNU Lesser General
Public License instead of this License.  But first, please read
<http://www.gnu.org/philosophy/why-not-lgpl.html>.