Tabulated List Mode

Tabulated List mode is a major mode for displaying tabulated data, i.e., data consisting of entries, each entry occupying one row of text with its contents divided into columns. Tabulated List mode provides facilities for pretty-printing rows and columns, and sorting the rows according to the values in each column. It is derived from Special mode (see Basic Major Modes).

Tabulated List mode is intended to be used as a parent mode by a more specialized major mode. Examples include Process Menu mode (see Process Information) and Package Menu mode (see Package Menu).

Such a derived mode should use define-derived-mode in the usual way, specifying tabulated-list-mode as the second argument (see Derived Modes). The body of the define-derived-mode form should specify the format of the tabulated data, by assigning values to the variables documented below; optionally, it can then call the function tabulated-list-init-header, which will populate a header with the names of the columns.

The derived mode should also define a listing command. This, not the mode command, is what the user calls (e.g., M-x list-processes). The listing command should create or switch to a buffer, turn on the derived mode, specify the tabulated data, and finally call tabulated-list-print to populate the buffer.

— Variable: tabulated-list-format

This buffer-local variable specifies the format of the Tabulated List data. Its value should be a vector. Each element of the vector represents a data column, and should be a list (name width sort), where

name is the column's name (a string).
width is the width to reserve for the column (an integer). This is meaningless for the last column, which runs to the end of each line.
sort specifies how to sort entries by the column. If nil, the column cannot be used for sorting. If t, the column is sorted by comparing string values. Otherwise, this should be a predicate function for sort (see Rearrangement), which accepts two arguments with the same form as the elements of tabulated-list-entries (see below).

— Variable: tabulated-list-entries

This buffer-local variable specifies the entries displayed in the Tabulated List buffer. Its value should be either a list, or a function.
If the value is a list, each list element corresponds to one entry, and should have the form (id contents), where

id is either nil, or a Lisp object that identifies the entry. If the latter, the cursor stays on the same entry when re-sorting entries. Comparison is done with equal.
contents is a vector with the same number of elements as tabulated-list-format. Each vector element is either a string, which is inserted into the buffer as-is, or a list (label.properties), which means to insert a text button by calling insert-text-button with label and properties as arguments (see Making Buttons).
There should be no newlines in any of these strings.

Otherwise, the value should be a function which returns a list of the above form when called with no arguments.

— Variable: tabulated-list-revert-hook

This normal hook is run prior to reverting a Tabulated List buffer. A derived mode can add a function to this hook to recompute tabulated-list-entries.

— Variable: tabulated-list-printer

The value of this variable is the function called to insert an entry at point, including its terminating newline. The function should accept two arguments, id and contents, having the same meanings as in tabulated-list-entries. The default value is a function which inserts an entry in a straightforward way; a mode which uses Tabulated List mode in a more complex way can specify another function.

— Variable: tabulated-list-sort-key

The value of this variable specifies the current sort key for the Tabulated List buffer. If it is nil, no sorting is done. Otherwise, it should have the form (name . flip), where name is a string matching one of the column names in tabulated-list-format, and flip, if non-nil, means to invert the sort order.

— Function: tabulated-list-init-header

This function computes and sets header-line-format for the Tabulated List buffer (see Header Lines), and assigns a keymap to the header line to allow sorting entries by clicking on column headers.
Modes derived from Tabulated List mode should call this after setting the above variables (in particular, only after setting tabulated-list-format).

— Function: tabulated-list-print &optional remember-pos update

This function populates the current buffer with entries. It should be called by the listing command. It erases the buffer, sorts the entries specified by tabulated-list-entries according to tabulated-list-sort-key, then calls the function specified by tabulated-list-printer to insert each entry.
If the optional argument remember-pos is non-nil, this function looks for the id element on the current line, if any, and tries to move to that entry after all the entries are (re)inserted.
If the optional argument update is non-nil, this function will only erase or add entries that have changed since the last print. This is several times faster if most entries haven't changed since the last time this function was called. The only difference in outcome is that tags placed via tabulated-list-put-tag will not be removed from entries that haven't changed (normally all tags are removed).

— Function: tabulated-list-delete-entry

This function deletes the entry at point.
It returns a list (id cols), where id is the ID of the deleted entry and cols is a vector of its column descriptors. It moves point to the beginning of the current line. It returns nil if there is no entry at point.
Note that this function only changes the buffer contents; it does not alter tabulated-list-entries.

— Function: tabulated-list-get-id &optional pos

This defsubst returns the ID object from tabulated-list-entries (if that is a list) or from the list returned by tabulated-list-entries (if it is a function). If omitted or nil, pos defaults to point.

— Function: tabulated-list-get-entry &optional pos

This defsubst returns the entry object from tabulated-list-entries (if that is a list) or from the list returned by tabulated-list-entries (if it is a function). This will be a vector for the ID at pos. If there is no entry at pos, then the function returns nil.

— Function: tabulated-list-header-overlay-p &optional POS

This defsubst returns non-nil if there is a fake header at pos. A fake header is used if tabulated-list-use-header-line is nil to put the column names at the beginning of the buffer. If omitted or nil, pos defaults to point-min.

— Function: tabulated-list-put-tag tag &optional advance

This function puts tag in the padding area of the current line. The padding area can be empty space at the beginning of the line, the width of which is governed by tabulated-list-padding. tag should be a string, with a length less than or equal to tabulated-list-padding. If advance is non-nil, this function advances point by one line.

— Function: tabulated-list-set-col col desc &optional change-entry-data

This function changes the tabulated list entry at point, setting col to desc. col is the column number to change, or the name of the column to change. desc is the new column descriptor, which is inserted via tabulated-list-print-col.
If change-entry-data is non-nil, this function modifies the underlying data (usually the column descriptor in the list tabulated-list-entries) by setting the column descriptor of the vector to desc.

23.2.7 Tabulated List mode