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 <path> <highlighter_name> <highlighter_parameters> ...

and

remove-highlighter <path>/<highlighter_id>

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

highlighter_id is a name generated by the highlighter specified with highlighter_name, possibly dependent on the parameters. Use command completion in a prompt on the remove-highlighter command to see the existing highlighters ids.

Convenient highlighters

show_matching

highlight matching char of the character under the selections' cursor using MatchingChar face

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

-spc <separator>

a one character long separator that will replace spaces

-nbsp <separator>

a one character long separator that will replace non-breakable spaces

-tab <separator>

a one character long separator that will replace tabulations

-tabpad <separator>

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

number_lines [options]

show line numbers, 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 with the rest of the buffer (default is '|')

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.

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

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 typos. 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 a display line to display 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> group <name>

That group is then accessible using the <path>/<name> path

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 group -passes colorize|move|wrap <name>

Regions highlighters

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

name

user defined, used to identify the region

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

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

%sh{ ... }

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

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

This region can be defined with:

shell_expand %sh\{ \} \{

Regions are used in the region highlighters which can take any number of regions.

The following command:

add-highlighter <path> regions <name> \
    <region_name1> <opening1> <closing1> <recurse1> \
    <region_name2> <opening2> <closing2> <recurse2>...

defines multiple regions in which other highlighters can be added as follows:

add-highlighter <path>/<name>/<region_name> ...

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.

Regions also supports a -default <default_region> switch to define the default region, when no other region matches the current buffer range.

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

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

add-highlighter <path> regions -default code <lang> \
    string <str_opening> <str_closing> <str_recurse> \
    comment <comment_opening> <comment_closing> <comment_recurse>

add-highlighter <path>/<lang>/code ...
add-highlighter <path>/<lang>/string ...
add-highlighter <path>/<lang>/comment ...

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/<group_name> ...

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

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

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

add-highlighter ref <name>

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