This file documents the GNU vtable.el package.

Copyright © 2022–2024 Free Software Foundation, Inc.

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, with the Front-Cover Texts being “A GNU Manual,” and with the Back-Cover Texts as in (a) below. A copy of the license is included in the section entitled “GNU Free Documentation License.”

(a) The FSF’s Back-Cover Text is: “You have the freedom to copy and modify this GNU manual.”

Table of Contents

1 Introduction and Tutorial

Most modes that display tabular data in Emacs use tabulated-list-mode, but it has some limitations: It assumes that the text it’s displaying is monospaced, which makes it difficult to mix fonts and images in a single list. The vtable (“variable pitch tables”) package tackles this instead.

tabulated-list-mode is a major mode, and assumes that it controls the entire buffer. A vtable doesn’t assume that—you can have a vtable in the middle of other data, or have several vtables in the same buffer.

Here’s just about the simplest vtable that can be created:

 :objects '(("Foo" 1034)
            ("Gazonk" 45)))

By default, vtable uses the vtable face (which inherits from the variable-pitch face), and right-aligns columns that have only numerical data (and left-aligns the rest).

You’d normally want to name the columns:

 :columns '("Name" "ID")
 :objects '(("Foo" 1034)
            ("Gazonk" 45)))

Clicking on the column names will sort the table based on the data in each column (which, in this example, corresponds to an element in a list).

By default, the data is displayed “as is”, that is, the way ‘(format "%s" ...)’ would display it, but you can override that.

 :columns '("Name" "ID")
 :objects '(("Foo" 1034)
            ("Gazonk" 45))
 :formatter (lambda (value column &rest _)
              (if (= column 1)
                  (file-size-human-readable value)

In this case, that ‘1034’ will be displayed as ‘1k’—but will still sort after ‘45’, because sorting is done on the actual data, and not the displayed data.

Alternatively, instead of having a general formatter for the table, you can put the formatter in the column definition:

 :columns '("Name"
            (:name "ID" :formatter file-size-human-readable))
 :objects '(("Foo" 1034)
            ("Gazonk" 45)))

The data doesn’t have to be simple lists—you can give any type of object to vtable, but then you also have to write a function that returns the data for each column. For instance, here’s a very simple version of M-x list-buffers:

 :columns '("Name" "Size" "File")
 :objects (buffer-list)
 :actions '("k" kill-buffer
            "RET" display-buffer)
 :getter (lambda (object column vtable)
           (pcase (vtable-column vtable column)
             ("Name" (buffer-name object))
             ("Size" (buffer-size object))
             ("File" (or (buffer-file-name object) "")))))

objects in this case is a list of buffers. To get the data to be displayed, vtable calls the getter function, which is called for each column of every object, and which should return the data that will eventually be displayed.

Also note the actions: These are simple commands that will be called with the object under point. So hitting RET on a line will result in display-buffer being called with a buffer object as the parameter. (You can also supply a keymap to be used, but then you have to write commands that call vtable-current-object to get at the object.)

Note that the actions aren’t called with the data displayed in the buffer—they’re called with the original objects.

Finally, here’s an example that uses just about all the features:

 :columns `(( :name "Thumb" :width "500px"
              ,(lambda (value max-width table)
                 (propertize "*" 'display
                             (create-image value nil nil
                                           :max-width max-width))))
            (:name "Size" :width 10
                   :formatter file-size-human-readable)
            (:name "Time" :width 10 :primary ascend)
 :objects-function (lambda ()
                     (directory-files "/tmp/" t "\\.jpg\\'"))
 :actions '("RET" find-file)
 :getter (lambda (object column table)
           (pcase (vtable-column table column)
             ("Name" (file-name-nondirectory object))
             ("Thumb" object)
             ("Size" (file-attribute-size (file-attributes object)))
             ("Time" (format-time-string
                      "%F" (file-attribute-modification-time
                            (file-attributes object))))))
 :separator-width 5
 :keymap (define-keymap
           "q" #'kill-buffer))

This vtable implements a simple image browser that displays image thumbnails (that change sizes dynamically depending on the width of the column), human-readable file sizes, date and file name. The separator width is 5 typical characters wide. Hitting RET on a line will open the image in a new window, and hitting q will kill a buffer.

2 Concepts

A vtable lists data about a number of objects. Each object can be a list or a vector, but it can also be anything else.

To get the value for a particular column, the getter function is called on the object. If no getter function is defined, the default is to try to index the object as a sequence. In any case, we end up with a value that is then used for sorting.

This value is then formatted via a formatter function, which is called with the value as the argument. The formatter commonly makes the value more reader friendly.

Finally, the formatted value is passed to the displayer function, which is responsible for putting the table face on the formatted value, and also ensuring that it’s not wider than the column width. The displayer will commonly truncate too-long strings and scale image sizes.

All these three transforms, the getter, the formatter and the display functions, can be defined on a per-column basis, and also on a per-table basis. (The per-column transform takes precedence over the per-table transform.)

User commands that are defined on a table does not work on the displayed data. Instead they are called with the original object as the argument.

3 Making A Table

The interface function for making (and optionally inserting a table into a buffer) is make-vtable. It returns a table object.

The keyword parameters are described below.

There are many callback interface functions possible in make-vtable, and many of them take a object argument (an object from the :objects list), a column index argument (an integer starting at zero), and a table argument (the object returned by make-vtable).


This is a list of objects to be displayed. It should either be a list of strings (which will then be displayed as a single-column table), or a list where each element is a sequence containing a mixture of strings, numbers, and other objects that can be displayed “simply”.

In the latter case, if :columns is non-nil and there’s more elements in the sequence than there is in :columns, only the :columns first elements are displayed.


It’s often convenient to generate the objects dynamically (for instance, to make reversion work automatically). In that case, this should be a function (which will be called with no arguments), and should return a value as accepted as an :objects list.


This is a list where each element is either a string (the column name), a plist of keyword/values (to make a vtable-column object), or a full vtable-column object. A vtable-column object has the following slots:


The name of the column.


The width of the column. This is either a number (the width of that many ‘x’ characters in the table’s face), or a string on the form ‘Xex’, where x is a number of ‘x’ characters, or a string on the form ‘Xpx’ (denoting a number of pixels), or a string on the form ‘X%’ (a percentage of the window’s width).


This uses the same format as width, but specifies the minimum width (and overrides width if width is smaller than this.


This uses the same format as width, but specifies the maximum width (and overrides width if width is larger than this. min-width/max-width can be useful if width is given as a percentage of the window width, and you want to ensure that the column doesn’t grow pointlessly large or unreadably narrow.


Whether this is the primary column—this will be used for initial sorting. This should be either ascend or descend to say in which order the table should be sorted.


If present, this function will be called to return the column value.

Function: column-getter object table

It’s called with two parameters: the object and the table.


If present, this function will be called to format the value.

Function: column-formatter value

It’s called with one parameter: the column value.


If present, this function will be called to prepare the formatted value for display. This function should return a string with the table face applied, and also limit the width of the string to the display width.

Function: column-displayer fvalue max-width table

fvalue is the formatted value; max-width is the maximum width (in pixels), and table is the table.


Should be either right or left.


If given, this is a function that should return the values to use in the table, and will be called once for each element in the table (unless overridden by a column getter function).

Function: getter object index table

For a simple object (like a sequence), this function will typically just return the element corresponding to the column index (zero-based), but the function can do any computation it wants. If it’s more convenient to write the function based on column names rather than the column index, the vtable-column function can be used to map from index to name.


If present, this is a function that should format the value, and it will be called on all values in the table (unless overridden by a column formatter).

Function: formatter value index table

This function is called with three parameters: the value (as returned by the getter); the column index, and the table. It can return any value.

This can be used to (for instance) format numbers in a human-readable form.


Before displaying an element, it’s passed to the displaying function (if any).

Function: displayer fvalue index max-width table

This is called with four arguments: the formatted value of the element (as returned by the formatter function); the column index; the display width (in pixels); and the table.

This function should return a string with the table face applied, and truncated to the display width.

This can be used to (for instance) change the size of images that are displayed in the table.


If non-nil (which is the default), display the column names on the header line. This is the most common use case, but if there’s other text in the buffer before the table, or there are several tables in the same buffer, then this should be nil.


The face to be used. This defaults to vtable. This face doesn’t override the faces in the data, or the faces supplied by the getter and formatter functions.


If present, this should be a list of color names to be used as the background color on the rows. If there are fewer colors here than there are rows, the rows will be repeated. The most common use case here is to have alternating background colors on the rows, so this would usually be a list of two colors. This can also be a list of faces to be used.


If present, this should be a list of color names to be used as the background color on the columns. If there are fewer colors here than there are columns, the colors will be repeated. The most common use case here is to have alternating background colors on the columns, so this would usually be a list of two colors. This can also be a list of faces to be used. If both :row-colors and :column-colors is present, the colors will be “blended” to produce the final colors in the table.


This uses the same syntax as define-keymap, but doesn’t refer to commands directly. Instead each key is bound to a command that picks out the current object, and then calls the function specified with that as the argument.


This is a keymap used on the table. The commands here are called as usual, and if they’re supposed to work on the object displayed on the current line, they can use the vtable-current-object function (see Interface Functions) to determine what that object is.


The width of the blank space between columns.


You can have a divider inserted between the columns. This can either be specified by using :divider, which should be a string to be displayed between the columns, or :divider-width, which specifies the width of the space to be used as the divider.


This should be a list of tuples, and specifies how the table is to be sorted. Each tuple should consist of an integer (the column index) and either ascend or descend.

The table is first sorted by the first element in this list, and then the next, until the end is reached.


By default, when shortening displayed values, an ellipsis will be shown. If this is nil, no ellipsis is shown. (The text to use as the ellipsis is determined by the truncate-string-ellipsis function.)


By default, make-vtable will insert the table at point. If this is nil, nothing is inserted, but the vtable object is returned, and you can insert it later with the vtable-insert function.

make-table returns a vtable object. You can access the slots in that object by using accessor functions that have names based on the keywords described above. For instance, to access the face, use vtable-face.

4 Commands

When point is placed on a vtable, the following keys are bound:


Sort the table by the current column (vtable-sort-by-current-column). Note that the table is sorted according to the data returned by the getter function (see Making A Table), not by how it’s displayed in the buffer. Columns that have only numerical data are sorted as numbers, the rest are sorted as strings.


Make the current column narrower (vtable-narrow-current-column).


Make the current column wider (vtable-widen-current-column).


Move to the previous column (vtable-previous-column).


Move to the next column (vtable-next-column).


Regenerate the table (vtable-revert-command). This command mostly makes sense if the table has a :objects-function that can fetch new data.

5 Interface Functions

If you need to write a mode based on vtable, you will have to interact with the table in various ways—for instance, you’ll need to write commands that updates an object and then displays the result. This chapter describes functions for such interaction.

Function: vtable-current-table

This function returns the table under point.

Function: vtable-current-object

This function returns the object on the current line. (Note that this is the original object, not the characters displayed in the buffer.)

Function: vtable-current-column

This function returns the column index of the column under point.

Function: vtable-goto-table table

Move point to the start of table and return the position. If table can’t be found in the current buffer, don’t move point and return nil.

Function: vtable-goto-object object

Move point to the start of the line where object is displayed in the current table and return the position. If object can’t be found, don’t move point and return nil.

Function: vtable-goto-column index

Move point to the start of the indexth column. (The first column is numbered zero.)

Function: vtable-beginning-of-table

Move to the beginning of the current table.

Function: vtable-end-of-table

Move to the end of the current table.

Function: vtable-remove-object table object

Remove object from table. This also updates the displayed table.

Function: vtable-insert-object table object &optional after-object

Insert object into table. If after-object, insert the object after this object; otherwise append to table. This also updates the displayed table.

Function: vtable-update-object table object old-object

Change old-object into object in table. This also updates the displayed table.

This has the same effect as calling vtable-remove-object and then vtable-insert-object, but is more efficient.

Function: vtable-column table index

Return the column name of the indexth column in table.

6 GNU Free Documentation License

Version 1.3, 3 November 2008
Copyright © 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc.

Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.

    The purpose of this License is to make a manual, textbook, or other functional and useful document free in the sense of freedom: to assure everyone the effective freedom to copy and redistribute it, with or without modifying it, either commercially or noncommercially. Secondarily, this License preserves for the author and publisher a way to get credit for their work, while not being considered responsible for modifications made by others.

    This License is a kind of “copyleft”, which means that derivative works of the document must themselves be free in the same sense. It complements the GNU General Public License, which is a copyleft license designed for free software.

    We have designed this License in order to use it for manuals for free software, because free software needs free documentation: a free program should come with manuals providing the same freedoms that the software does. But this License is not limited to software manuals; it can be used for any textual work, regardless of subject matter or whether it is published as a printed book. We recommend this License principally for works whose purpose is instruction or reference.


    This License applies to any manual or other work, in any medium, that contains a notice placed by the copyright holder saying it can be distributed under the terms of this License. Such a notice grants a world-wide, royalty-free license, unlimited in duration, to use that work under the conditions stated herein. The “Document”, below, refers to any such manual or work. Any member of the public is a licensee, and is addressed as “you”. You accept the license if you copy, modify or distribute the work in a way requiring permission under copyright law.

    A “Modified Version” of the Document means any work containing the Document or a portion of it, either copied verbatim, or with modifications and/or translated into another language.

    A “Secondary Section” is a named appendix or a front-matter section of the Document that deals exclusively with the relationship of the publishers or authors of the Document to the Document’s overall subject (or to related matters) and contains nothing that could fall directly within that overall subject. (Thus, if the Document is in part a textbook of mathematics, a Secondary Section may not explain any mathematics.) The relationship could be a matter of historical connection with the subject or with related matters, or of legal, commercial, philosophical, ethical or political position regarding them.

    The “Invariant Sections” are certain Secondary Sections whose titles are designated, as being those of Invariant Sections, in the notice that says that the Document is released under this License. If a section does not fit the above definition of Secondary then it is not allowed to be designated as Invariant. The Document may contain zero Invariant Sections. If the Document does not identify any Invariant Sections then there are none.

    The “Cover Texts” are certain short passages of text that are listed, as Front-Cover Texts or Back-Cover Texts, in the notice that says that the Document is released under this License. A Front-Cover Text may be at most 5 words, and a Back-Cover Text may be at most 25 words.

    A “Transparent” copy of the Document means a machine-readable copy, represented in a format whose specification is available to the general public, that is suitable for revising the document straightforwardly with generic text editors or (for images composed of pixels) generic paint programs or (for drawings) some widely available drawing editor, and that is suitable for input to text formatters or for automatic translation to a variety of formats suitable for input to text formatters. A copy made in an otherwise Transparent file format whose markup, or absence of markup, has been arranged to thwart or discourage subsequent modification by readers is not Transparent. An image format is not Transparent if used for any substantial amount of text. A copy that is not “Transparent” is called “Opaque”.

    Examples of suitable formats for Transparent copies include plain ASCII without markup, Texinfo input format, LaTeX input format, SGML or XML using a publicly available DTD, and standard-conforming simple HTML, PostScript or PDF designed for human modification. Examples of transparent image formats include PNG, XCF and JPG. Opaque formats include proprietary formats that can be read and edited only by proprietary word processors, SGML or XML for which the DTD and/or processing tools are not generally available, and the machine-generated HTML, PostScript or PDF produced by some word processors for output purposes only.

    The “Title Page” means, for a printed book, the title page itself, plus such following pages as are needed to hold, legibly, the material this License requires to appear in the title page. For works in formats which do not have any title page as such, “Title Page” means the text near the most prominent appearance of the work’s title, preceding the beginning of the body of the text.

    The “publisher” means any person or entity that distributes copies of the Document to the public.

    A section “Entitled XYZ” means a named subunit of the Document whose title either is precisely XYZ or contains XYZ in parentheses following text that translates XYZ in another language. (Here XYZ stands for a specific section name mentioned below, such as “Acknowledgements”, “Dedications”, “Endorsements”, or “History”.) To “Preserve the Title” of such a section when you modify the Document means that it remains a section “Entitled XYZ” according to this definition.

    The Document may include Warranty Disclaimers next to the notice which states that this License applies to the Document. These Warranty Disclaimers are considered to be included by reference in this License, but only as regards disclaiming warranties: any other implication that these Warranty Disclaimers may have is void and has no effect on the meaning of this License.


    You may copy and distribute the Document in any medium, either commercially or noncommercially, provided that this License, the copyright notices, and the license notice saying this License applies to the Document are reproduced in all copies, and that you add no other conditions whatsoever to those of this License. You may not use technical measures to obstruct or control the reading or further copying of the copies you make or distribute. However, you may accept compensation in exchange for copies. If you distribute a large enough number of copies you must also follow the conditions in section 3.

    You may also lend copies, under the same conditions stated above, and you may publicly display copies.


    If you publish printed copies (or copies in media that commonly have printed covers) of the Document, numbering more than 100, and the Document’s license notice requires Cover Texts, you must enclose the copies in covers that carry, clearly and legibly, all these Cover Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on the back cover. Both covers must also clearly and legibly identify you as the publisher of these copies. The front cover must present the full title with all words of the title equally prominent and visible. You may add other material on the covers in addition. Copying with changes limited to the covers, as long as they preserve the title of the Document and satisfy these conditions, can be treated as verbatim copying in other respects.

    If the required texts for either cover are too voluminous to fit legibly, you should put the first ones listed (as many as fit reasonably) on the actual cover, and continue the rest onto adjacent pages.

    If you publish or distribute Opaque copies of the Document numbering more than 100, you must either include a machine-readable Transparent copy along with each Opaque copy, or state in or with each Opaque copy a computer-network location from which the general network-using public has access to download using public-standard network protocols a complete Transparent copy of the Document, free of added material. If you use the latter option, you must take reasonably prudent steps, when you begin distribution of Opaque copies in quantity, to ensure that this Transparent copy will remain thus accessible at the stated location until at least one year after the last time you distribute an Opaque copy (directly or through your agents or retailers) of that edition to the public.

    It is requested, but not required, that you contact the authors of the Document well before redistributing any large number of copies, to give them a chance to provide you with an updated version of the Document.


    You may copy and distribute a Modified Version of the Document under the conditions of sections 2 and 3 above, provided that you release the Modified Version under precisely this License, with the Modified Version filling the role of the Document, thus licensing distribution and modification of the Modified Version to whoever possesses a copy of it. In addition, you must do these things in the Modified Version:

    1. Use in the Title Page (and on the covers, if any) a title distinct from that of the Document, and from those of previous versions (which should, if there were any, be listed in the History section of the Document). You may use the same title as a previous version if the original publisher of that version gives permission.
    2. List on the Title Page, as authors, one or more persons or entities responsible for authorship of the modifications in the Modified Version, together with at least five of the principal authors of the Document (all of its principal authors, if it has fewer than five), unless they release you from this requirement.
    3. State on the Title page the name of the publisher of the Modified Version, as the publisher.
    4. Preserve all the copyright notices of the Document.
    5. Add an appropriate copyright notice for your modifications adjacent to the other copyright notices.
    6. Include, immediately after the copyright notices, a license notice giving the public permission to use the Modified Version under the terms of this License, in the form shown in the Addendum below.
    7. Preserve in that license notice the full lists of Invariant Sections and required Cover Texts given in the Document’s license notice.
    8. Include an unaltered copy of this License.
    9. Preserve the section Entitled “History”, Preserve its Title, and add to it an item stating at least the title, year, new authors, and publisher of the Modified Version as given on the Title Page. If there is no section Entitled “History” in the Document, create one stating the title, year, authors, and publisher of the Document as given on its Title Page, then add an item describing the Modified Version as stated in the previous sentence.
    10. Preserve the network location, if any, given in the Document for public access to a Transparent copy of the Document, and likewise the network locations given in the Document for previous versions it was based on. These may be placed in the “History” section. You may omit a network location for a work that was published at least four years before the Document itself, or if the original publisher of the version it refers to gives permission.
    11. For any section Entitled “Acknowledgements” or “Dedications”, Preserve the Title of the section, and preserve in the section all the substance and tone of each of the contributor acknowledgements and/or dedications given therein.
    12. Preserve all the Invariant Sections of the Document, unaltered in their text and in their titles. Section numbers or the equivalent are not considered part of the section titles.
    13. Delete any section Entitled “Endorsements”. Such a section may not be included in the Modified Version.
    14. Do not retitle any existing section to be Entitled “Endorsements” or to conflict in title with any Invariant Section.
    15. Preserve any Warranty Disclaimers.

    If the Modified Version includes new front-matter sections or appendices that qualify as Secondary Sections and contain no material copied from the Document, you may at your option designate some or all of these sections as invariant. To do this, add their titles to the list of Invariant Sections in the Modified Version’s license notice. These titles must be distinct from any other section titles.

    You may add a section Entitled “Endorsements”, provided it contains nothing but endorsements of your Modified Version by various parties—for example, statements of peer review or that the text has been approved by an organization as the authoritative definition of a standard.

    You may add a passage of up to five words as a Front-Cover Text, and a passage of up to 25 words as a Back-Cover Text, to the end of the list of Cover Texts in the Modified Version. Only one passage of Front-Cover Text and one of Back-Cover Text may be added by (or through arrangements made by) any one entity. If the Document already includes a cover text for the same cover, previously added by you or by arrangement made by the same entity you are acting on behalf of, you may not add another; but you may replace the old one, on explicit permission from the previous publisher that added the old one.

    The author(s) and publisher(s) of the Document do not by this License give permission to use their names for publicity for or to assert or imply endorsement of any Modified Version.


    You may combine the Document with other documents released under this License, under the terms defined in section 4 above for modified versions, provided that you include in the combination all of the Invariant Sections of all of the original documents, unmodified, and list them all as Invariant Sections of your combined work in its license notice, and that you preserve all their Warranty Disclaimers.

    The combined work need only contain one copy of this License, and multiple identical Invariant Sections may be replaced with a single copy. If there are multiple Invariant Sections with the same name but different contents, make the title of each such section unique by adding at the end of it, in parentheses, the name of the original author or publisher of that section if known, or else a unique number. Make the same adjustment to the section titles in the list of Invariant Sections in the license notice of the combined work.

    In the combination, you must combine any sections Entitled “History” in the various original documents, forming one section Entitled “History”; likewise combine any sections Entitled “Acknowledgements”, and any sections Entitled “Dedications”. You must delete all sections Entitled “Endorsements.”


    You may make a collection consisting of the Document and other documents released under this License, and replace the individual copies of this License in the various documents with a single copy that is included in the collection, provided that you follow the rules of this License for verbatim copying of each of the documents in all other respects.

    You may extract a single document from such a collection, and distribute it individually under this License, provided you insert a copy of this License into the extracted document, and follow this License in all other respects regarding verbatim copying of that document.


    A compilation of the Document or its derivatives with other separate and independent documents or works, in or on a volume of a storage or distribution medium, is called an “aggregate” if the copyright resulting from the compilation is not used to limit the legal rights of the compilation’s users beyond what the individual works permit. When the Document is included in an aggregate, this License does not apply to the other works in the aggregate which are not themselves derivative works of the Document.

    If the Cover Text requirement of section 3 is applicable to these copies of the Document, then if the Document is less than one half of the entire aggregate, the Document’s Cover Texts may be placed on covers that bracket the Document within the aggregate, or the electronic equivalent of covers if the Document is in electronic form. Otherwise they must appear on printed covers that bracket the whole aggregate.


    Translation is considered a kind of modification, so you may distribute translations of the Document under the terms of section 4. Replacing Invariant Sections with translations requires special permission from their copyright holders, but you may include translations of some or all Invariant Sections in addition to the original versions of these Invariant Sections. You may include a translation of this License, and all the license notices in the Document, and any Warranty Disclaimers, provided that you also include the original English version of this License and the original versions of those notices and disclaimers. In case of a disagreement between the translation and the original version of this License or a notice or disclaimer, the original version will prevail.

    If a section in the Document is Entitled “Acknowledgements”, “Dedications”, or “History”, the requirement (section 4) to Preserve its Title (section 1) will typically require changing the actual title.


    You may not copy, modify, sublicense, or distribute the Document except as expressly provided under this License. Any attempt otherwise to copy, modify, sublicense, or distribute it is void, and will automatically terminate your rights under this License.

    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, receipt of a copy of some or all of the same material does not give you any rights to use it.


    The Free Software Foundation may publish new, revised versions of the GNU Free Documentation 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. See https://www.gnu.org/licenses/.

    Each version of the License is given a distinguishing version number. If the Document specifies that a particular numbered version of this License “or any later version” applies to it, you have the option of following the terms and conditions either of that specified version or of any later version that has been published (not as a draft) by the Free Software Foundation. If the Document does not specify a version number of this License, you may choose any version ever published (not as a draft) by the Free Software Foundation. If the Document specifies that a proxy can decide which future versions of this License can be used, that proxy’s public statement of acceptance of a version permanently authorizes you to choose that version for the Document.


    “Massive Multiauthor Collaboration Site” (or “MMC Site”) means any World Wide Web server that publishes copyrightable works and also provides prominent facilities for anybody to edit those works. A public wiki that anybody can edit is an example of such a server. A “Massive Multiauthor Collaboration” (or “MMC”) contained in the site means any set of copyrightable works thus published on the MMC site.

    “CC-BY-SA” means the Creative Commons Attribution-Share Alike 3.0 license published by Creative Commons Corporation, a not-for-profit corporation with a principal place of business in San Francisco, California, as well as future copyleft versions of that license published by that same organization.

    “Incorporate” means to publish or republish a Document, in whole or in part, as part of another Document.

    An MMC is “eligible for relicensing” if it is licensed under this License, and if all works that were first published under this License somewhere other than this MMC, and subsequently incorporated in whole or in part into the MMC, (1) had no cover texts or invariant sections, and (2) were thus incorporated prior to November 1, 2008.

    The operator of an MMC Site may republish an MMC contained in the site under CC-BY-SA on the same site at any time before August 1, 2009, provided the MMC is eligible for relicensing.

ADDENDUM: How to use this License for your documents

To use this License in a document you have written, include a copy of the License in the document and put the following copyright and license notices just after the title page:

  Copyright (C)  year  your name.
  Permission is granted to copy, distribute and/or modify this document
  under the terms of the GNU Free Documentation License, Version 1.3
  or any later version published by the Free Software Foundation;
  with no Invariant Sections, no Front-Cover Texts, and no Back-Cover
  Texts.  A copy of the license is included in the section entitled ``GNU
  Free Documentation License''.

If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts, replace the “with…Texts.” line with this:

    with the Invariant Sections being list their titles, with
    the Front-Cover Texts being list, and with the Back-Cover Texts
    being list.

If you have Invariant Sections without Cover Texts, or some other combination of the three, merge those two alternatives to suit the situation.

If your document contains nontrivial examples of program code, we recommend releasing these examples in parallel under your choice of free software license, such as the GNU General Public License, to permit their use in free software.