Adding columns

Any post field can become a Bulk Editor column with the sheetline_columns filter. Put the code in a small custom plugin or your child theme's functions.php. Columns you add get everything the built-in ones have: keyboard editing, highlighted unsaved changes, errors on their cell, Screen Options, and with Sheetline Pro bulk changes, undo and CSV export and import.

A first column

// A "Subtitle" text column for posts, stored in post meta.
add_filter( 'sheetline_columns', function ( $columns, $post_type ) {
	if ( 'post' !== $post_type ) {
		return $columns;
	}
	$columns['subtitle'] = array(
		'label' => 'Subtitle',
		'group' => 'Extras',
		'type'  => 'text',
		'get'   => function ( WP_Post $post ) {
			return (string) get_post_meta( $post->ID, 'subtitle', true );
		},
		'set'   => function ( \Extendiment\Sheetline\Draft $draft, $value ) {
			$draft->meta( 'subtitle', sanitize_text_field( $value ) );
		},
		'sort'  => array( 'meta' => 'subtitle' ),
	);
	return $columns;
}, 10, 2 );

The key (subtitle) must be unique. The filter runs once per post type, with the post type as its second argument, so each Bulk Editor can have its own columns.

Setters record, they don't save

A column's set gets a Draft: the post's pending changes. Record the new value there and Sheetline writes everything once, after checking every cell of the post:

Draft method	What it does when the post is saved
$draft->field( 'post_title', $value )	Sets a wp_update_post() field (unslashed)
$draft->meta( $key, $value )	Updates post meta ('' or null deletes the key)
$draft->terms( $taxonomy, $ids )	Replaces the post's terms of a taxonomy
$draft->before( fn( $id ) => … )	Runs before the post is updated
$draft->after( fn( $id ) => … )	Runs after the post is updated

$draft->post is the post as loaded, and $draft->get( 'post_status' ) a field as it will be saved. Never write to the database in set yourself: Sheetline Pro calls the same setters to preview bulk changes and imports without saving.

The column format

Key	Required	What it is
label	yes	Shown in the header and in Screen Options
type	yes	How the value is shown and edited (see below)
get	yes	function ( WP_Post $post ) returning the value to edit
set	yes	function ( Draft $draft, $value ) recording a new value
group	no	Groups related columns (default "Other")
options	for select and terms	value => label pairs, or a function returning them (called only when needed)
applies	no	function ( WP_Post $post ) returning false where the field doesn't exist (the cell shows a dash)
can	no	function ( WP_Post $post ) returning false where the current user may not change it (the cell is read-only). Sheetline already checks edit_post for every post
hidden	no	true to hide the column until switched on in Screen Options
sort	no	Makes it sortable: a WP_Query orderby value (e.g. 'title'), or array( 'meta' => 'my_key', 'num' => true )
bulk	no	false keeps the column out of Sheetline Pro's bulk changes

Types

Type	Value	Edited with
text	string	a text box
longtext	HTML string	a larger text box over the cell
number	number as a string	a text box
date	Y-m-d string, '' for none	a date picker
datetime	Y-m-d H:i string	a date and time picker
select	one of the options keys	a dropdown
bool	'yes' or 'no'	a Yes/No dropdown
terms	array of term IDs	a checkbox list of the options
image	attachment ID as a string, '' for none	the media library
images	array of attachment IDs	the media library, several in order
readonly	string	shown, not editable

Values arrive in set as the grid sends them: strings, or arrays of IDs for terms and images. Sanitize them as you would any input.

Refusing a value

Throw an exception with a message for the editor. It appears under the cell in red, and that post isn't saved:

'set' => function ( \Extendiment\Sheetline\Draft $draft, $value ) {
	$value = trim( (string) $value );
	if ( '' !== $value && ! preg_match( '/^\d{4}$/', $value ) ) {
		throw \Extendiment\Sheetline\Columns::invalid( 'Enter a year, such as 2026.' );
	}
	$draft->meta( 'year', $value );
},

Columns::invalid() returns an InvalidArgumentException; any InvalidArgumentException works.

Helpers

Extendiment\Sheetline\Columns has the helpers the built-in columns use:

• Columns::option( $value, $options ): one of the options' keys; refuses anything else.
• Columns::bool( $value ): true for "yes", "1", "true" or "on".
• Columns::integer( $value ), Columns::number( $value ): a whole number, or any number (a comma works as the decimal point).
• Columns::date( $value ), Columns::datetime( $value ): a valid date, or date and time, in the formats above.
• Columns::term_options( $taxonomy ): a taxonomy's terms as ID => 'Parent › Child', ready for options.
• Columns::term_ids( $value, $taxonomy ): the IDs, each an existing term of the taxonomy.
• Columns::statuses(), Columns::authors( $post_type ): the status and author options the grid uses.

// A taxonomy as a terms column, for a "book" post type.
add_filter( 'sheetline_columns', function ( $columns, $post_type ) {
	if ( 'book' === $post_type ) {
		$columns['series'] = array(
			'label'   => 'Series',
			'type'    => 'terms',
			'options' => fn() => \Extendiment\Sheetline\Columns::term_options( 'series' ),
			'can'     => fn() => current_user_can( get_taxonomy( 'series' )->cap->assign_terms ),
			'get'     => fn( $p ) => wp_get_object_terms( $p->ID, 'series', array( 'fields' => 'ids' ) ),
			'set'     => fn( $d, $v ) => $d->terms( 'series', \Extendiment\Sheetline\Columns::term_ids( $v, 'series' ) ),
		);
	}
	return $columns;
}, 10, 2 );

Taxonomies registered for a post type with show_ui already get a column of their own, so you only need this for something special.

Where the column goes

Columns appear in the array's order. Adding a key puts the column at the end; to place it elsewhere, rebuild the array:

add_filter( 'sheetline_columns', function ( $columns ) {
	$at  = array_search( 'title', array_keys( $columns ), true ) + 1;
	$new = array( 'kicker' => array( /* … */ ) );
	return array_slice( $columns, 0, $at, true ) + $new + array_slice( $columns, $at, null, true );
} );

Sheetline Pro adds its columns at priority 5, so columns added at the default priority 10 come after them.