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Luke edited this page Sep 16, 2024 · 23 revisions

Introduction

Ox uses Lua as a configuration language.

You can find an example configuration file (which is probably the easiest way to learn how to configure).

As standard, your configuration file is located in ~/.oxrc.

Ox will not install this for you as standard, and instead will use built-in defaults.

You will need to create this ~/.oxrc file yourself. I recommend pulling the default configuration file found in the config folder in the main repository and copying it to ~/.oxrc.

You can use the following commands to do this:

cd ~
curl -O https://github.com/curlpipe/ox/raw/master/config/.oxrc

Then, feel free to play around with this configuration file.

See the Configuration section below to see more details on how the configuration file is structured

Configuration

You can change many aspects of Ox:

  • Mouse behaviour
  • Colours of the editor
  • Colours of the syntax highlighter
  • Line numbers
  • Status line contents and padding / alignment
  • Contents and visibility of the greeting message

Mouse

This is enabled by default.

This feature will enable you to click on parts of the document and select / copy / paste text natively.

Note that you can change the selection colour as in the following example:

colors.selection_bg = "black"
colors.selection_fg = "white"

You can disable it by including the following line:

terminal.mouse_enabled = false

Format of Colours

This is a very important part to understand

Colours in the ox configuration file can be of the following form:

{RED, GREEN, BLUE} for rgb colours

"HEX CODE" for hex codes (be sure to include the #)

"COLOUR NAME" for various colour names e.g. red, green, darkblue, magenta etc

Editor Colours

Be sure to check out the Format of Colours section above to learn how to structure colours

In the configuration file, the colors table is in charge of storing the colours the editor should be.

You can change the colours of the editor by setting the following variables:

Note foreground is equivalent to text colour and background is the background colour of the text.

Editor

background found in colors.editor_bg

it can be set (for example) like colors.editor_bg = "black"

foreground found in colors.editor_fg

it can be set (for example) like colors.editor_fg = "black"

Line Numbers

background found in colors.line_number_bg

it can be set (for example) like colors.line_number_bg = "black"

foreground found in colors.line_number_fg

it can be set (for example) like colors.line_number_fg = "black"

Status Line

background found in colors.status_bg

it can be set (for example) like colors.status_bg = "black"

foreground found in colors.status_fg

it can be set (for example) like colors.status_fg = "black"

Highlight

found in colors.highlight

it can be set (for example) like colors.highlight = "black"

Active Tabs

found in colors.active_tab_bg and colors.active_tab_fg

it can be set (for example) like colors.active_tab_fg = "black"

Inactive Tabs

found in colors.inactive_tab_bg and colors.inactive_tab_fg

it can be set (for example) like colors.inactive_tab_bg = "black"

Info Message

background found in colors.info_bg

it can be set (for example) like colors.info_bg = "black"

foreground found in colors.info_fg

it can be set (for example) like colors.info_fg = "black"

Warning Message

background found in colors.warning_bg

it can be set (for example) like colors.warning_bg = "black"

foreground found in colors.warning_fg

it can be set (for example) like colors.warning_fg = "black"

Error Message Background

background found in colors.error_bg

it can be set (for example) like colors.error_bg = "black"

foreground found in colors.error_fg

it can be set (for example) like colors.error_fg = "black"

Line Numbers

You can enable or disable line numbers by setting line_numbers.enabled

E.g. line_numbers.enabled = false disables line numbers, line_numbers.enabled = true enables line numbers

Status Line

A status line is made up of "parts" these are groups of information.

For example, if you want some of the status line on the left (e.g. file name, file type) and some of the status line on the right (e.g. cursor position), then you must create two parts.

To create parts, you can use the status:add_part method to add a part to the status line.

E.g. status:add_part("PART FORMAT STRING")

An example part format string is as follows: This is my file: {file_name}

If you look at the file text.txt This will show This is my file: test.txt

Anything between { and } is used to bring data from the editor and interpolate it into the status line.

The following options are available:

  • {file_name} - The name of the file that is currently open
  • {modified} - Will show [+] if the current file differs from the file on the disk and will show nothing if not
  • {file_type} - This shows the type of file i.e. Rust for files with the rs extension
  • {cursor_y} - The line the cursor is on
  • {cursor_x} - The character the cursor is on (horizontally)
  • {line_count} - The number of lines in the document currently open

Anything outside of these {} will be put in as is, which allows you to put separators or static text

After adding your parts to the status line, the next thing you can set is the alignment / padding

There are two modes to pad / align status parts:

  • around - this will place padding to the left, right and between parts
  • between - this will place padding only between parts

You're probably going to want to use between, unless you want a more unique look to your status line.

The best way to understand what these look like is to experiment with them.

To set the alignment mode, you can set the status_line.alignment variable as such:

status_line.alignment = "around"
-- OR --
status_line.alignment = "between"

Greeting Message

You can enable / disable the greeting message by setting greeting_message.enabled:

-- For enabling the greeting message: --
greeting_message.enabled = true

-- For disabling the greeting message: --
greeting_message.enabled = false

You can also set the actual contents of the greeting message as such:

greeting_message.format = [[
Ox editor version {version}
]]

Here, if you are running version 0.3.3 of the editor, then the greeting message will show Ox editor version 0.3.3

As with status lines, anything between { and } will be replaced with information from the editor.

The following options are available:

  • {version} - the version of the editor that is running
  • {highlight_start} - starts the highlight colour from being used as text colour
  • {highlight_end} - stops the highlight colour from being used as text colour

NOTE: when using {highlight_start} or {highlight_end}, it is best practice to put these on their own line as not doing so can mess with the alignment of the greeting message.

Plug-ins

If there is a feature you would like to integrate into Ox that doesn't currently come as standard, then the plug-in API may allow you to implement this feature.

As with the rest of the configuration, the language used is Lua and plug-ins are defined in the same configuration file (~/.oxrc)

You can also use other people's plug-ins. See the plugins folder in the repository to see some pre-made plugins, including auto bracket pairs and automatic indentation. To enable these plug-ins, please see the Plugin Distribution section below.

Editor API

You are very likely going to want to interact with the editor somehow, whether it's displaying a message to the user, or writing some text for them. The way to interact with the editor is through the API. There are a wide range of methods available for you to call, attached to an editor table.

Here are all the commands that you can run that may come in handy:

Command Description Example usage
editor:display_error This command will display an error message to the user (red by default) editor:display_error("file not found") which will display an error message saying "file not found"
editor:display_warning This command will display a warning message to the user (yellow by default) editor:display_warning("backup failed") which will show a warning message saying "backup failed"
editor:display_info This command will display an information message to the user (blue by default) editor:display_info("time to take a break") which will show info to the user asking them to take a break
editor:prompt This command will ask the user for something and return what they entered name = editor:prompt("What's your name") which will ask the user their name and store their answer in the name variable
editor:insert This command will insert specified text at the place where the cursor currently is in the document editor:insert("3.141") which will insert PI (the number) where the user's cursor currently is
editor:remove This command will essentially just simulate the user pressing the backspace key, and will delete whatever is behind the cursor editor:remove() which will simulate the user pressing backspace
editor:insert_line This command will insert a line at the current position of the cursor, it essentially simulates the user pressing the enter key editor:insert_line() which will simulate the user pressing enter
editor:remove_line This command will delete the line that the cursor is currently on editor:remove_line() which will remove the line where the cursor is, e.g. line 3 if the cursor is on line 3
editor:move_to This command will move the cursor to a specified x and y coordinate in the document editor:move_to(3, 1) which will move the cursor to the third character (x coordinate) on the first line (y coordinate)
editor:move_up This command will move the cursor one upwards editor:move_up() which will move the cursor to the line above where it currently is
editor:move_down This command will move the cursor one downwards editor:move_down() which will move the cursor to the line below where it currently is
editor:move_left This command will move the cursor one to the left editor:move_left() which will move the cursor to the left
editor:move_right This command will move the cursor one to the right editor:move_right() which will move the cursor to the right
editor:move_home This command will move the cursor to the beginning of the current line editor:move_home() which will move the cursor to the beginning of the line it is currently on
editor:move_end This command will move the cursor to the end of the current line editor:move_end() which will move the cursor to the very end of the line it is currently on
editor:move_page_up This command will scroll up a page e.g. if the viewport is 20 lines in height, then it will scroll 20 lines upwards editor:move_page_up() which will move up one page
editor:move_page_down This command will scroll down a page e.g. if the viewport is 20 lines in height, then it will scroll 20 lines downwards editor:move_page_down() which will move down one page
editor:move_top This command will move the cursor to the first line in the document editor:move_top() which will move to the top of the document
editor:move_bottom This command will move the cursor to the last line in the document editor:move_bottom() which will move to the bottom of the document
editor:move_previous_word This command will move the cursor to the previous word (separated by spaces) editor:move_previous_word() which will move the cursor to the previous word
editor:move_next_word This command will move the cursor to the next word (separated by spaces) editor:move_next_word() which will move the cursor to the next word
editor:insert_at This command will insert text at a certain x and y location editor:insert_at("Hello", 2, 3) which will insert the text "hello" at the 2nd character of the 3rd line
editor:remove_at This command will remove the a character at a certain x and y location editor:remove_at(4, 1) which will remove the 4th character on the 1st line
editor:insert_line_at This command will insert a line at a certain line number editor:insert_line_at("new line", 4) which will create a new line on line 4 of the document with the text "new line"
editor:remove_line_at This command will remove the line at a certain index editor:remove_line_at(4) which will remove the 4th line in the document
editor:open_command_line This command will open the command line editor:open_command_line() which will open the command line
editor:previous_tab This command will move to the previous document that is currently opened in the editor editor:previous_tab() which will move focus to the previous document that is currently opened
editor:next_tab This command will move to the next document that is currently opened in the editor editor:next_tab() which will move focus to the next document that is currently opened
editor:new This command will create and open a new document for the user to write in editor:new() which will create a new document
editor:open This command will ask the user for a file name and then open that file editor:open() which will ask the user for a file to open, and then open it
editor:save This command will save the document the user is currently on editor:save() which will save the current document
editor:save_as This command will ask the user for a file name and save the current document to that path editor:save_as() which will ask the user for a path to save the current document to
editor:save_all This command will save all currently opened documents editor:() which will save all opened documents
editor:quit This command will quit the current document (and the whole editor if all documents are quit out of) editor:quit() which will close the current document (and the whole editor if all documents have been closed)
editor:undo This command will trigger an undo action editor:undo() which will undo the last change the user made
editor:redo This command will trigger a redo action editor:redo() which will redo the last change the user made
editor:search This command will trigger the search wizard editor:search() which will ask the user for what they wish to search for and move the cursor along all matches
editor:replace This command will open the replace wizard editor:replace() which will ask the user what they want to replace and what to replace with, and then provide options to replace certain instances or all instances
editor:get_character This command will get the character that the cursor is currently over editor:get_character() which will return e, for example, if the cursor in the editor is next to the letter e in the document
editor:get_character_at This command will get a character at a certain location within the document editor:get_character_at(3, 1) which will get the 3rd character on the first line
editor:get_line This command will get the line the cursor is currently on in the document editor:get_line() which will get line 2, for example, if the cursor in the document is currently at line 2
editor:get_line_at This command will get the line at a certain index editor:get_line_at(5) which will get the fifth line in the document
editor:move_to_document This command will move to a document that is currently open editor:move_to_document(0) which will move to the first document that is open in the editor
editor:move_previous_match This command will move to a previous instance of a certain string editor:move_previous_match("self") which will search backwards until it finds the text self, and then move the cursor to where that text is in the document
editor:move_next_match This command will move to the next instance of a certain string editor:move_next_match("bar") which will search forwards until it finds the text bar, and then move the cursor to where that text is in the document
editor:hide_help_message This command will hide the in-editor help message editor:hide_help_message() which will hide the help message
editor:show_help_message This command will show the in-editor help message editor:show_help_message() which will show the help message
editor:set_read_only This command will set the file's read only status editor:set_read_only(true) which will make the file that is currently open read only
editor:set_file_type This command will set the file type of the file that is currently open editor:set_file_type("py") which will set the file type of the file currently open to a python file, and enable language-specific features such as syntax highlighting
editor.cursor This command will return the current cursor position of the document editor.cursor.x which will return the x coordinate of the cursor (the character) and editor.cursor.y which will return the y position of the cursor (line number)
editor.document_name This command will return the name of the document editor.document_name which will return the name of the document that is currently being looked at
editor.document_length This command will return the number of lines in the document currently open editor.document_length which will return 300 if the document currently being looked at is 300 lines in length
editor.document_type This command will return the type of document you're looking at editor.document_type which will return "Python", for example, if you are looking at a .py file
editor.version This command will return the version of the editor editor.version which will return "0.4.3" if you're using version 0.4.3 of Ox
editor.current_document_id This command will give the ID of the document that the user is currently looking at editor.current_document_id which will return 1 for example, if the user is looking at the second document open and 0 if the user is looking at the first one
editor.document_count This command will return the number of documents currently open editor.document_count which will return 5 if there are 5 documents currently open in the editor
editor.help_visible This command will return true if the in-editor help message is showing, and false if not editor.help_visible which will return false, for example, if the in-editor help message is hidden

Now you know how to interact and control the editor from your plug-ins, you can get to work writing them.

Please note that you can use all APIs available in the standard library of Lua, e.g. shell commands.

Examples of Plug-ins

Displaying the date and time to the user in the editor
handle = io.popen("date") -- run the "date" command to get the date and time
date = handle:read("*a") -- read the result of the command
handle:close()

-- Now display to the user the date and time
editor:display_info("The date and time is currently: " .. date)
Auto HTML tags

Here, we ask the user for their HTML tag name e.g. body or h1 and then insert both the starting and ending tags for them to use

tag_name = editor:prompt("Tag name")
editor:insert("<" .. tag_name .. ">\n\n</" .. tag_name .. ">" )

For example, if the user puts in style, it would write:

<style>

</style>

in their document (at the location of where the cursor currently is)

This would be a quick way to write HTML tags without having to repeat yourself all the time

Running your plug-ins

Now you've been able to understand how to write your plug-ins, we must go over how to start them when in the editor.

There are two main ways to trigger plug-ins:

  1. On key press
  2. When a command is run (by default, you can access the command line by using the key combination Ctrl + K and then typing in a command there)

Key Bindings

The format of keys

In the configuration file, key presses are represented with strings.

Modifiers, such as ctrl, alt and shift come first, followed by key codes e.g. backspace or z or 4

Here are some examples:

  • a - the a key on the keyboard is pressed
  • ctrl_a - the control key is held down, followed by the a key being pressed
  • ctrl_alt_s - the control key is held down, then the alt key is held, then the s key is pressed
  • esc - the escape key is pressed
Mapping key bindings to plug-ins

When the user presses a key, Ox will send that key press through to your configuration file. It will check in a table called event_mapping for a key combination corresponding to the key the user pressed and then run the function that was attached to that key combination.

It's probably better demonstrated with an example:

event_mapping = {
    ["ctrl_h"] = function()
        editor:display_info("You pressed CTRL and H")
    end,
}

here you can see the binding of ctrl h to a function which will display an info message to the user.

in the default config file (in config/.oxrc in the repository) you can see a list of all the key bindings that are used by default.

You are free to use any key binding for whatever purpose you please.

Custom Commands

So, perhaps you don't want to run a plugin on a key press, or you would like your plug-in to act differently depending on what the user inputs. This can be done through custom commands.

Just like with key bindings, you can add custom commands into the configuration file at ~/.oxrc.

When a command is run, it is shown to the configuration file, which can then determine how to deal with that command.

The command table defines how to handle various commands to the user. The keys are the command name, and the values are functions.

Here is an example:

commands = {
    ["greet"] = function(arguments)
        editor:display_info("Hello, " .. arguments[1] .. ", nice to meet you")
    end,
}

When the user writes a command that starts with greet, followed by some arguments (separated by spaces), it will take the first argument the user provided, and display a message to greet the user.

For example, if I were to open the command line using Ctrl + K (which is the default key binding for opening the command line), and run the command greet James then the first argument would be James, and the editor would display Hello, James, nice to meet you. Arguments are a list of what the user has put in (after the initial command name, which is greet in this case)

You could extend on this (to demonstrate multiple arguments) as such:

commands = {
    ["greet"] = function(arguments)
        first_name = arguments[1]
        surname = arguments[2]
        editor:display_info("Nice to meet you, " .. first_name .. " " .. surname)
    end,
}

where we use the first argument as the first name and the second as the surname.

E.g. greet James Smith would display Nice to meet you, James Smith to the console (here using both the first and second argument)

Distribution of Plug-ins

There may come a time where you want to distribute your plug-in or download someone else's plug-in.

Downloading a Plug-in

You can see a list of plug-ins you might want to use in the plugins folder in the repository. This includes plug-ins such as auto bracket pairs (for quick editing) and auto indentation in code files.

You may also find another plug-in elsewhere, such as on github.

Plug-ins should be in a single lua file (or multiple lua files with a central one that imports the others).

Download all lua files and place them in your ~/.config/ox/ folder (on unix based systems) or in an ox folder in your user's home directory on windows (e.g. C:/Users/Boris/ox/).

Then, in your configuration file, you can import plugins by using the load_plugin function.

Example

Say you want to install the pairs.lua plug-in, which is included in the plugins folder.

  1. Download it and put it in the ~/.config/ox/ folder as ~/.config/ox/pairs.lua
  2. Load it in your configuration file (it is best to put it at the bottom of the config file) 
    load_plugin("pairs.lua")
    Ox will look in the directory for the plug-in pairs.lua, which we downloaded in step 1
  3. Now when the editor is opened, the plugin should be up and running

Packaging a Plug-in

If you want to override or set key bindings in your plug-in, you can do it, for example, like this:

event_mapping["ctrl_h"] = function()
    -- Your plugin code goes here
end

This just adds to the same event_mapping object the user has in their config file.

Similarly, to add in a command, you can do the following:

commands["name"] = function(arguments)
    -- Your plugin code goes here
end

To package a plug-in, simply take the lua files where you have written your plug-in and then you are free to distribute them on github or through other means where users can download and import them.

Syntax Highlighting Configuration

Theme

The syntax object is in charge of all things syntax highlighting.

Use the set method to set the colour of certain tokens.

Note "tokens" refers to the different snippets of programs that should be highlighted. For example "return" is a keyword in many languages, and therefore, all keywords found in a source file will become "keyword tokens" and will all share a common colour. For example, in Rust, keyword tokens include "return", "fn", "if" etc, and it makes sense that all these should be the same colour. These all become keyword tokens.

So to set the colour of these tokens, which themselves are groups of certain snippets of text (e.g. "return"), you can do the following:

syntax:set("TOKEN NAME", COLOUR)

where TOKEN NAME becomes the name of the token and COLOUR is the corresponding colour (see the Format of Colours section above to see how to write colours into the configuration file)

So for example, if we wanted to make keywords orange, we should include the following in the configuration file:

syntax:set("keyword", {255, 165, 0})

Here, the RGB value of orange is provided.

If you want a full list of the tokens that are provided to ox with explanations of what they cover, here you go:

  • string refers to strings in various programming languages
  • comment refers to comments in various programming languages
  • digit refers to digits in various programming languages
  • keyword refers to keywords in various programming languages
  • attribute refers to attributes in various programming languages
  • character refers to characters in various programming languages
  • type refers to types in various programming languages
  • function refers to function names in various programming languages
  • header refers to headers in various programming language
  • macro refers to macro names in various programming languages
  • namespace refers to namespaces in various programming languages
  • struct refers to the names of structs, classes, enums in various programming languages
  • operator refers to operators in various programming languages e.g. +, -, * etc
  • boolean refers to booleans in various programming langauges e.g. true / false
  • table refers to tables in various programming languages
  • reference refers to references in various programming languages
  • tag refers to tags in various markup langauges e.g. HTML <p> tags
  • heading refers to headings in various markup languages e.g. # in markdown
  • link refers to links in various markup languages e.g. URLs
  • key refers to keys in various markup languages
  • quote refers to quotes in various markup languages e.g. > in markdown
  • bold refers to quotes in various markup languages e.g. ** in markdown
  • italic refers to quotes in various markup languages e.g. * in markdown
  • block refers to code blocks in various markup languages e.g. ``` ``` in markdown
  • list refers to bullet lists in various markup languages e.g. lines starting with - in markdown

You can set each of these tokens individually. I recommend using the default configuration file and tweaking it from there

Rules

Ox, by default, comes with a wide variety of syntax highlighting support for various languages, but it isn't an exhaustive list and there will always be languages that aren't included by default (as there are so many of them).

If you really want to support a certain file type in syntax highlighting, then you have the power to manually add it in via the configuration file at ~/.oxrc (you will need to create this file first if you haven't already)

It is a good idea to understand what I mean when I say "token". See the Theme section above for more information on what tokens are, and what tokens are included by default in the editor.

First, it is worth going into the theory of how the syntax highlighting system in Ox works, below is a brief explanation of how it is designed.

Please note, this is quite wordy and may be quite hard to understand without an example. It might be worth jumping back and forth between the example below and the theory, just to really make sure it "clicks" for you.

  • tokens - These are snippets of text that should be highlighted. For example "return" is a keyword in many languages, and therefore, all keywords found in a source file ought to become "keyword tokens" and will all share a common colour. For example, in Rust, keyword tokens include "return", "fn", "if" etc, and it makes sense that all these should be the same colour. These all become keyword tokens.
  • patterns - These are how we define what these snippets are. Ox uses regular expressions to define and identify different snippets of text. For example, if we want to make every single instance of a number a token of "digit", then the pattern we can use (in regex) is [0-9], where all digits 0 through 9 are captured and can assigned as a "digit token".
  • rules - These are a group of patterns for a certain token, rules can come together to highlight a language. E.g. rules that each include their token and patterns of strings, digits, keywords etc etc to highlight a Python file.

There are also different types of tokens:

  • keyword - Not to be confused with a keyword token! This is a type of token that will take a single pattern and assign all instances as a specified token. Tokens with the keyword type can not travel across multiple lines.
  • bounded - This will take two patterns, one starting pattern and one ending pattern. This is ideal for multi-line tokens, such as comments or strings.

Creating keyword tokens can be done like this: syntax:keyword(NAME, PATTERN)

You can also create multiple keyword tokens like this: syntax:keywords(NAME, {PATTERN1, PATTERN2, ...})

where

  • NAME is the name you want to assign to the token e.g. digit or comment.
  • PATTERN are the patterns that you want to attach to that token (as there is often more than one way of making a token, e.g. strings could be made up of "" or '')

Creating bounded tokens can be done like this: syntax:bounded(NAME, START_PATTERN, END_PATTERN, ESCAPE)

where

  • NAME is the name you want to assign to the token e.g. string or comment
  • START_PATTERN is the pattern you want to start the token with e.g. /* for multiline comments
  • END_PATTERN is the pattern you want to end the token with e.g. */ for multiline comments
  • ESCAPE is true if you want to be able to escape the end pattern, and false if not e.g. "here is a quote: \" but the string continues"

To attach these tokens you've made to the syntax highlighter, you must use the syntax:new method, which uses the following syntax: syntax:new(FILE_EXTENSIONS, RULES)

where

  • FILE_EXTENSIONS is a list of file extensions that will trigger this syntax highlighting e.g. {"c", "h"} if you're writing syntax highlighting rules for C files, which have .c and .h extensions.
  • RULES is a list of rules that you would have defined (using the keyword and bounded methods)

Examples

Now it's time to bring it all together with an example, where we write very basic syntax highlighting for a python file:

syntax:new(
    -- File extensions of python files can be .py or .pyw
    {"py", "pyw"},
    -- Now let's define some rules
    {
        -- Adding in tokens of type keyword to highlight keywords in the language
        syntax:keywords("keyword", {"def", "return", "print", "if", "else", "elif", "import"}),
        -- Adding in a token of type keyword to highlight digits in the language
        syntax:keyword("digit", "[0-9]+"),
        -- Adding in a bounded token for strings
        -- We allow escaping strings by passing true in 
        -- (e.g. "a quote is \" not going to end the string")
        -- Using a bounded token allows strings to be on multiple lines
        syntax:bounded("string", "\"", "\"", true),
    }
)

This is a small example that is far from complete, but hopefully, it gives you an idea of how to write syntax highlighting rules for your own files.

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