highlighters.asciidoc

Highlighters

Description

Manipulation of the displayed text is done through highlighters, which can be added or removed with the following commands:

add-highlighter [-override] <path>/<name> <type> <parameters> ...

and

remove-highlighter <path>/<name>

path is the name of a highlighter group, it is expressed as a / separated path starting with a scope. Scopes are global, buffer, window and shared

name is the name of the highlighter, if name is omitted in add-highlighter (the path ends with a /), it will be auto-generated from the remaining parameters.

if -override is specified and the given name already exists, that highlighter is replaced with the new one.

Convenient highlighters

show-matching

highlight matching char of the character under the selections' cursor using MatchingChar face, with the following options:

-previous

fall back to the character before the cursor when the cursor is not over a matching char

show-whitespaces [options]

display symbols on top of whitespaces to make them more explicit using the Whitespace face, with the following options:

-lf <separator>

a one character long separator that will replace line feeds, or an empty string to ignore them.

-spc <separator>

a one character long separator that will replace spaces, or an empty string to ignore them.

-nbsp <separator>

a one character long separator that will replace non-breakable spaces, or an empty string to ignore them.

-tab <separator>

a one character long separator that will replace tabulations, or an empty string to ignore them.

-tabpad <separator>

a one character long separator that will be appended to tabulations to honor the tabstop option

-indent <separator>

a one character long separator that will replace the first space in indentation according to the indentwidth option, or an empty string to ignore them. This will use the WhitespaceIndent face.

-only-trailing

only highlight whitespaces at the end of the line

number-lines [options]

show line numbers using the LineNumbers, LineNumberCursor and LineNumbersWrapped faces, with the following options:

-relative

show line numbers relative to the main cursor line

-hlcursor

highlight the cursor line with a separate face

-separator <separator text>

specify a string to separate the line numbers column from the rest of the buffer (default is '|')

-cursor-separator <separator text>

identical to -separator but applies only to the line of the cursor (default is the same value passed to -separator)

-min-digits <num>

always reserve room for at least num digits, so text doesn’t jump around as lines are added or removed (default is 2)

wrap [options]

soft wrap buffer text at window width, with the following options:

-word

wrap at word boundaries instead of codepoint boundaries.

-indent

preserve line indent when wrapping.

-width <max_width>

wrap text at max_width if the window is wider.

-marker <marker_text>

prefix wrapped lines with marker_text; if -indent was given, the marker_text is displayed into the indentation if possible.

General highlighters

fill <face>

fill using the given face, mostly useful with regions highlighters

column <number> <face>

highlight column number with face face

line <number> <face>

highlight line number with face face

regex <regex> <capture_id>:<face> …​

highlight a regex, takes the regex as first parameter, followed by any number of face parameters. This highlights C++ style comments in cyan, with an eventual 'TODO:' in yellow on red background:

add-highlighter window/ regex //\h*(TODO:)[^\n]* 0:cyan 1:yellow,red

capture_id can be either the capture number, or its name if a
named capture is used in the regex (See
<<regex#groups, `:doc regex groups`>>)

dynregex <expression> <capture_id>:<face> …​

similar to regex, but expand (like a command parameter would) the given expression before building a regex from the result. This highlights all the current search matches in italic:

add-highlighter window/ dynregex '%reg{/}' 0:+i

Specs highlighters

The following highlighters are useful to add indicators like lint warnings, git blame output or spelling mistakes. See :doc options types for the format of line-specs and range-specs.

flag-lines <face> <option_name>

add columns in front of the buffer, and display the flags specified in line-specs option, using <face>. In this example two words will be added in the gutter: a blue Foo at line 1 and a bold red/yellow Bar on line 3:

declare-option line-specs my_flags
set-option window my_flags %val{timestamp} '1|Foo' '3|{red,yellow+b}Bar'
add-highlighter window/ flag-lines blue my_flags

ranges <option_name>

use the data in the range-specs option of the given name to highlight the buffer. The string part of each tuple of the range-specs is interpreted as a face to apply to the range. In this example the 3 first chars of the buffer will be colored in red:

declare-option range-specs my_range
set-option window my_range %val{timestamp} '1.1,1.3|red'
add-highlighter window/ ranges my_range

replace-ranges <option_name>

use the data in the range-specs option of the given name to highlight the buffer. The string part of each tuple of the range-specs is interpreted as markup string (see :doc faces markup-strings) and displayed in place of the range. Here, the 3 first chars of the buffer will be replaced by the word 'red':

declare-option range-specs my_range
set-option window my_range %val{timestamp} '1.1,1.3|red'
add-highlighter window/ replace-ranges my_range

Highlighting Groups

The group highlighter is a container for other highlighters. A subgroup can be added to an existing group or scope using:

add-highlighter <path>/<name> group

Other highlighters can then be added to that group

add-highlighter <path>/<name> <type> <params>...

In order to specify which kinds of highlighters can be added to a given group, the -passes flag set can be passed along with the group name. Possible values for this option can be one or several (separated with a pipe sign) of colorize, move or wrap (default: colorize):

add-highlighter window/<name> group -passes colorize|move|wrap

Regions highlighters

A special highlighter provides a way to segment the buffer into regions, which are to be highlighted differently.

add-highlighter <path>/<name> regions

Individual region definitions can then be added to that highlighter

add-highlighter <path>/<name>/<region_name> region \
    [-match-capture] [-recurse <recurse>]          \
    <opening> <closing> <type> <params>...

opening

regex that defines the region start text

closing

regex that defines the region end text

recurse

regex that defines the text that matches recursively an end token into the region, every match of recurse will consume a following match of closing regex, preventing it from closing the region.

type and params

A highlighter type, and associated params, as they would be passed to add-highlighter if they were not applied as a region.

If the -match-capture switch is passed, then region closing and recurse regex matches are considered valid for a given region opening match only if they matched the same content for the capture 1 in the opening regex.

The recurse option is useful for regions that can be nested, for example the following construct:

%sh{ ... }

accepts nested braces scopes ('{ …​ }') so the following string is valid:

%sh{ ... { ... } ... }

This region can be defined with:

shell_expand -recurse \{ %sh\{ \}

Regions are matched using the left-most rule: the left-most region opening starts a new region. When a region closes, the closest next opening start another region.

That matches the rule governing most programming language parsing.

A default region, that will apply its given highlighter to the segments of the buffer that are not in any defined region, can be added with the default-region highlighter type.

add-highlighter <path>/<name>/<region_name> default-region <type> <params>...

Most programming languages can then be properly highlighted using a region highlighter as root:

add-highlighter <path>/<lang> regions
add-highlighter <path>/<lang>/string region '"' '"' fill string
add-highlighter <path>/<lang>/comment region '//' '$' fill comment
add-highlighter <path>/<lang>/code default-region group
add-highlighter <path>/<lang>/code/variable regex ...
add-highlighter <path>/<lang>/code/function regex ...

Shared Highlighters

Highlighters are often defined for a specific filetype, and it makes then sense to share the highlighters between all the windows on the same filetypes.

Highlighters can be put in the shared scope in order to make them reusable.

add-highlighter shared/<name> ...

The common case would be to create a named shared group, or regions and then fill it with highlighters:

add-highlighter shared/<name> group
add-highlighter shared/<name>/ regex ...

It can then be referenced in a window using the ref highlighter.

add-highlighter window/ ref <name>

The ref can reference any named highlighter in the shared scope.