emacs/runtime/doc/textprop.txt

*textprop.txt*  For Vim version 9.0.  Last change: 2022 Nov 18


		  VIM REFERENCE MANUAL    by Bram Moolenaar


Displaying text with properties attached.	*textprop* *text-properties*


1. Introduction			|text-prop-intro|
2. Functions			|text-prop-functions|
3. When text changes		|text-prop-changes|


{not able to use text properties when the |+textprop| feature was
disabled at compile time}

==============================================================================
1. Introduction						*text-prop-intro*

Text properties can be attached to text in a buffer.  They will move with the
text: If lines are deleted or inserted the properties move with the text they
are attached to.  Also when inserting/deleting text in the line before the
text property.  And when inserting/deleting text inside the text property, it
will increase/decrease in size.

The main use for text properties is to highlight text.  This can be seen as a
replacement for syntax highlighting.  Instead of defining patterns to match
the text, the highlighting is set by a script, possibly using the output of an
external parser.  This only needs to be done once, not every time when
redrawing the screen, thus can be much faster, after the initial cost of
attaching the text properties.

Text properties can also be used for other purposes to identify text.  For
example, add a text property on a function name, so that a search can be
defined to jump to the next/previous function.

A text property is attached at a specific line and column, and has a specified
length.  The property can span multiple lines.

A text property has these fields:
	"id"		a number to be used as desired
	"type"		the name of a property type


Property Types ~
							*E971*
A text property normally has the name of a property type, which defines
how to highlight the text.  The property type can have these entries:
	"highlight"	name of the highlight group to use
	"combine"	when omitted or TRUE the text property highlighting is
			combined with any syntax highlighting; when FALSE the
			text property highlighting replaces the syntax
			highlighting
	"priority"	when properties overlap, the one with the highest
			priority will be used.
	"start_incl"	when TRUE inserts at the start position will be
			included in the text property
	"end_incl"    	when TRUE inserts at the end position will be
			included in the text property


Example ~

Suppose line 11 in a buffer has this text (excluding the indent):

	The number 123 is smaller than 4567.

To highlight the numbers in this text: >
	call prop_type_add('number', {'highlight': 'Constant'})
	call prop_add(11, 12, {'length': 3, 'type': 'number'})
	call prop_add(11, 32, {'length': 4, 'type': 'number'})

Try inserting or deleting lines above the text, you will see that the text
properties stick to the text, thus the line number is adjusted as needed.

Setting "start_incl" and "end_incl" is useful when white space surrounds the
text, e.g. for a function name.  Using false is useful when the text starts
and/or ends with a specific character, such as the quote surrounding a string.

	func FuncName(arg) ~
	     ^^^^^^^^        property with start_incl and end_incl set

	var = "text"; ~
	      ^^^^^^	     property with start_incl and end_incl not set

Nevertheless, when text is inserted or deleted the text may need to be parsed
and the text properties updated.  But this can be done asynchronously.


Internal error *E967*

If you see E967, please report the bug.  You can do this at Github:
https://github.com/vim/vim/issues/new

==============================================================================
2. Functions						*text-prop-functions*

Manipulating text property types:

prop_type_add({name}, {props})		define a new property type
prop_type_change({name}, {props})	change an existing property type
prop_type_delete({name} [, {props}])	delete a property type
prop_type_get({name} [, {props}])	get property type values
prop_type_list([{props}])		get list of property types


Manipulating text properties:

prop_add({lnum}, {col}, {props})  	add a text property
prop_add_list({props}, [[{lnum}, {col}, {end-lnum}, {end-col}], ...])
					add a text property at multiple
					positions.
prop_clear({lnum} [, {lnum-end} [, {bufnr}]])
					remove all text properties
prop_find({props} [, {direction}])	search for a text property
prop_list({lnum} [, {props}])  		text properties in {lnum}
prop_remove({props} [, {lnum} [, {lnum-end}]])
					remove a text property

						*prop_add()* *E965*
prop_add({lnum}, {col}, {props})
		Attach a text property at position {lnum}, {col}.  {col} is
		counted in bytes, use one for the first column.
		If {lnum} is invalid an error is given. *E966*
		If {col} is invalid an error is given. *E964*

		{props} is a dictionary with these fields:
		   type		name of the text property type
		   length	length of text in bytes, can only be used
				for a property that does not continue in
				another line; can be zero
		   end_lnum	line number for the end of text (inclusive)
		   end_col	column just after the text; not used when
				"length" is present; when {col} and "end_col"
				are equal, and "end_lnum" is omitted or equal
				to {lnum}, this is a zero-width text property
		   bufnr	buffer to add the property to; when omitted
				the current buffer is used
		   id		user defined ID for the property; must be a
				number, should be positive; when using "text"
				then "id" must not be present and will be set
				automatically to a negative number; otherwise
				zero is used
							*E1305*
		   text		text to be displayed before {col}, or
				above/below the line if {col} is zero; prepend
				and/or append spaces for padding with
				highlighting; cannot be used with "length",
				"end_lnum" and "end_col"
				See |virtual-text| for more information.
		   					*E1294*
		   text_align	when "text" is present and {col} is zero;
				specifies where to display the text:
				   after   after the end of the line
				   right   right aligned in the window (unless
					   the text wraps to the next screen
					   line)
				   below   in the next screen line
				   above   just above the line
				When omitted "after" is used.  Only one
				"right" property can fit in each line, if
				there are two or more these will go in a
				separate line (still right aligned).
		   text_padding_left				*E1296*
				used when "text" is present and {col} is zero;
				padding between the end of the text line
				(leftmost column for "below") and the virtual
				text, not highlighted
		   text_wrap	when "text" is present and {col} is zero,
				specifies what happens if the text doesn't
				fit:
				   wrap      wrap the text to the next line
				   truncate  truncate the text to make it fit
		   		When omitted "truncate" is used.
				Note that this applies to the individual text
				property, the 'wrap' option sets the overall
				behavior
		All fields except "type" are optional.

		It is an error when both "length" and "end_lnum" or "end_col"
		are given.  Either use "length" or "end_col" for a property
		within one line, or use "end_lnum" and "end_col" for a
		property that spans more than one line.
		When neither "length" nor "end_col" are given the property
		will be zero-width.  That means it will move with the text, as
		a kind of mark.  One character will be highlighted, if the
		type specifies highlighting.
		The property can end exactly at the last character of the
		text, or just after it.  In the last case, if text is appended
		to the line, the text property size will increase, also when
		the property type does not have "end_incl" set.

		"type" will first be looked up in the buffer the property is
		added to. When not found, the global property types are used.
		If not found an error is given.
							*virtual-text*
		When "text" is used and the column is non-zero then this text
		will be displayed at the specified start location of the text
		property.  The text of the buffer line will be shifted to make
		room.  This is called "virtual text".
		When the column is zero the virtual text will appear above,
		after or below the buffer text.  The "text_align" and
		"text_wrap" arguments determine how it is displayed.
		To separate the virtual text from the buffer text prepend
		and/or append spaces to the "text" field or use the
		"text_padding_left" value.

		Make sure to use a highlight that makes clear to the user that
		this is virtual text, otherwise it will be very confusing that
		the text cannot be edited.  When using "above" you need to
		make clear this text belongs to the text line below it, when
		using "below" you need to make sure it belongs to the text
		line above it.

		The text will be displayed but it is not part of the actual
		buffer line, the cursor cannot be placed on it.  A mouse click
		in the text will move the cursor to the first character after
		the text, or the last character of the line.
		Any Tab and other control character in the text will be
		changed to a space (Rationale: otherwise the size of the text
		is difficult to compute).
		A negative "id" will be chosen and is returned.  Once a
		property with "text" has been added for a buffer then using a
		negative "id" for any other property will give an error:
		*E1293*

		Can also be used as a |method|: >
			GetLnum()->prop_add(col, props)
<
						*prop_add_list()*
prop_add_list({props}, [{item}, ...])
		Similar to prop_add(), but attaches a text property at
		multiple positions in a buffer.

		{props} is a dictionary with these fields:
		   bufnr	buffer to add the property to; when omitted
				the current buffer is used
		   id		user defined ID for the property; must be a
				number; when omitted zero is used
		   type		name of the text property type
		All fields except "type" are optional.

		The second argument is a List of items, where each {item} is a
		list that specifies the starting and ending position of the
		text: [{lnum}, {col}, {end-lnum}, {end-col}]
		or:   [{lnum}, {col}, {end-lnum}, {end-col}, {id}]

		The first two items {lnum} and {col} specify the starting
		position of the text where the property will be attached.
		The next two items {end-lnum} and {end-col} specify the
		position just after the text.
		An optional fifth item {id} can be used to give a different ID
		to a property.  When omitted the ID from {props} is used,
		falling back to zero if none are present.

		It is not possible to add a text property with a "text" field
		here.

		Example:
			call prop_add_list(#{type: 'MyProp', id: 2},
					\ [[1, 4, 1, 7],
					\  [1, 15, 1, 20],
					\  [2, 30, 3, 30]]

		Can also be used as a |method|: >
			GetProp()->prop_add_list([[1, 1, 1, 2], [1, 4, 1, 8]])


prop_clear({lnum} [, {lnum-end} [, {props}]])		*prop_clear()*
		Remove all text properties from line {lnum}.
		When {lnum-end} is given, remove all text properties from line
		{lnum} to {lnum-end} (inclusive).

		When {props} contains a "bufnr" item use this buffer,
		otherwise use the current buffer.

		Can also be used as a |method|: >
			GetLnum()->prop_clear()
<
							*prop_find()*
prop_find({props} [, {direction}])
		Search for a text property as specified with {props}:
		   id		property with this ID
		   type		property with this type name
		   both		"id" and "type" must both match
		   bufnr	buffer to search in; when present a
				start position with "lnum" and "col"
				must be given; when omitted the
				current buffer is used
		   lnum		start in this line (when omitted start
				at the cursor)
		   col		start at this column (when omitted
				and "lnum" is given: use column 1,
				otherwise start at the cursor)
		   skipstart	do not look for a match at the start
				position

		A property matches when either "id" or "type" matches.
		{direction} can be "f" for forward and "b" for backward.  When
		omitted forward search is performed.

		If a match is found then a Dict is returned with the entries
		as with prop_list(), and additionally an "lnum" entry.
		If no match is found then an empty Dict is returned.


prop_list({lnum} [, {props}])				*prop_list()*
		Returns a List with all the text properties in line {lnum}.

		The following optional items are supported in {props}:
		   bufnr	use this buffer instead of the current buffer
		   end_lnum	return text properties in all the lines
				between {lnum} and {end_lnum} (inclusive).
				A negative value is used as an offset from the
				last buffer line; -1 refers to the last buffer
				line.
		   types	List of property type names. Return only text
				properties that match one of the type names.
		   ids		List of property identifiers. Return only text
				properties with one of these identifiers.

		The properties are ordered by starting column and priority.
		Each property is a Dict with these entries:
		   lnum		starting line number. Present only when
				returning text properties between {lnum} and
				{end_lnum}.
		   col		starting column
		   length	length in bytes, one more if line break is
				included
		   id		property ID
		   type		name of the property type, omitted if
				the type was deleted
		   type_bufnr	buffer number for which this type was defined;
				0 if the type is global
		   start	when TRUE property starts in this line
		   end		when TRUE property ends in this line

		When "start" is zero the property started in a previous line,
		the current one is a continuation.
		When "end" is zero the property continues in the next line.
		The line break after this line is included.

		Returns an empty list on error.

		Examples:
		   " get text properties placed in line 5
		   echo prop_list(5)
		   " get text properties placed in line 20 in buffer 4
		   echo prop_list(20, {'bufnr': 4})
		   " get all the text properties between line 1 and 20
		   echo prop_list(1, {'end_lnum': 20})
		   " get all the text properties of type 'myprop'
		   echo prop_list(1, {'types': ['myprop'],
						\ 'end_lnum': -1})
		   " get all the text properties of type 'prop1' or 'prop2'
		   echo prop_list(1, {'types': ['prop1', 'prop2'],
						\ 'end_lnum': -1})
		   " get all the text properties with ID 8
		   echo prop_list(1, {'ids': [8], 'end_lnum': line('$')})
		   " get all the text properties with ID 10 and 20
		   echo prop_list(1, {'ids': [10, 20], 'end_lnum': -1})
		   " get text properties with type 'myprop' and ID 100
		   " in buffer 4.
		   echo prop_list(1, {'bufnr': 4, 'types': ['myprop'],
					\ 'ids': [100], 'end_lnum': -1})

		Can also be used as a |method|: >
			GetLnum()->prop_list()
<
						*prop_remove()* *E968* *E860*
prop_remove({props} [, {lnum} [, {lnum-end}]])
		Remove a matching text property from line {lnum}.  When
		{lnum-end} is given, remove matching text properties from line
		{lnum} to {lnum-end} (inclusive).
		When {lnum} is omitted remove matching text properties from
		all lines (this requires going over all lines, thus will be a
		bit slow for a buffer with many lines).

		{props} is a dictionary with these fields:
		   id		remove text properties with this ID
		   type		remove text properties with this type name
		   types	remove text properties with type names in this
				List
		   both		"id" and "type"/"types" must both match
		   bufnr	use this buffer instead of the current one
		   all		when TRUE remove all matching text properties,
				not just the first one
		Only one of "type" and "types" may be supplied. *E1295*

		A property matches when either "id" or one of the supplied
		types matches.
		If buffer "bufnr" does not exist you get an error message.
		If buffer "bufnr" is not loaded then nothing happens.

		Returns the number of properties that were removed.

		Can also be used as a |method|: >
			GetProps()->prop_remove()


prop_type_add({name}, {props})		*prop_type_add()* *E969* *E970*
		Add a text property type {name}.  If a property type with this
		name already exists an error is given.  Nothing is returned.
		{props} is a dictionary with these optional fields:
		   bufnr	define the property only for this buffer; this
				avoids name collisions and automatically
				clears the property types when the buffer is
				deleted.
		   highlight	name of highlight group to use
		   priority	when a character has multiple text
				properties the one with the highest priority
				will be used; negative values can be used, the
				default priority is zero
		   combine	when omitted or TRUE combine the highlight
				with any syntax highlight; when FALSE syntax
				highlight will not be used
		   override	when TRUE the highlight overrides any other,
				including 'cursorline' and Visual
		   start_incl	when TRUE inserts at the start position will
				be included in the text property
		   end_incl	when TRUE inserts at the end position will be
				included in the text property

		Can also be used as a |method|: >
			GetPropName()->prop_type_add(props)

prop_type_change({name}, {props})			*prop_type_change()*
		Change properties of an existing text property type.  If a
		property with this name does not exist an error is given.
		The {props} argument is just like |prop_type_add()|.

		Can also be used as a |method|: >
			GetPropName()->prop_type_change(props)

prop_type_delete({name} [, {props}])			*prop_type_delete()*
		Remove the text property type {name}.  When text properties
		using the type {name} are still in place, they will not have
		an effect and can no longer be removed by name.

		{props} can contain a "bufnr" item.  When it is given, delete
		a property type from this buffer instead of from the global
		property types.

		When text property type {name} is not found there is no error.

		Can also be used as a |method|: >
			GetPropName()->prop_type_delete()

prop_type_get({name} [, {props}])			*prop_type_get()*
		Returns the properties of property type {name}.  This is a
		dictionary with the same fields as was given to
		prop_type_add().
		When the property type {name} does not exist, an empty
		dictionary is returned.

		{props} can contain a "bufnr" item.  When it is given, use
		this buffer instead of the global property types.

		Can also be used as a |method|: >
			GetPropName()->prop_type_get()

prop_type_list([{props}])				*prop_type_list()*
		Returns a list with all property type names.

		{props} can contain a "bufnr" item.  When it is given, use
		this buffer instead of the global property types.


==============================================================================
3. When text changes				*text-prop-changes*

Vim will do its best to keep the text properties on the text where it was
attached.  When inserting or deleting text the properties after the change
will move accordingly.

When text is deleted and a text property no longer includes any text, it is
deleted.  However, a text property that was defined as zero-width will remain,
unless the whole line is deleted.
								*E275*
When a buffer is unloaded, all the text properties are gone.  There is no way
to store the properties in a file.  You can only re-create them.  When a
buffer is hidden the text is preserved and so are the text properties.  It is
not possible to add text properties to an unloaded buffer.

When using replace mode, the text properties stay on the same character
positions, even though the characters themselves change.

To update text properties after the text was changed, install a callback with
`listener_add()`.  E.g, if your plugin does spell checking, you can have the
callback update spelling mistakes in the changed text.  Vim will move the
properties below the changed text, so that they still highlight the same text,
thus you don't need to update these.


Text property columns are not updated or copied: ~

- When setting the line with |setline()| or through an interface, such as Lua,
  Tcl or Python.  Vim does not know what text got inserted or deleted.
- With a command like `:move`, which takes a line of text out of context.


 vim:tw=78:ts=8:noet:ft=help:norl: