plugins.md

Plugins

Micro supports creating plugins with a simple Lua system. Plugins are folders containing Lua files and possibly other source files placed in ~/.config/micro/plug. The plugin directory (within plug) should contain at least one Lua file and an info.json file. The info file provides additional information such as the name of the plugin, the plugin's website, dependencies, etc... Here is an example info file from the go plugin, which has the following file structure:

~/.config/micro/plug/go-plugin
    go.lua
    info.json

info.json:

{
    "name": "go",
    "description": "Go formatting and tool support",
    "website": "https://github.com/micro-editor/go-plugin",
	"install": "https://github.com/micro-editor/go-plugin",
    "version": "1.0.0",
    "require": [
        "micro >= 2.0.0"
    ]
}

All fields are simply interpreted as strings, so the version does not need to be a semantic version, and the dependencies are also only meant to be parsed by humans. The name should be an identifier, and the website should point to a valid website. The install field should provide info about installing the plugin, or point to a website that provides information.

Lua callbacks

Plugins use Lua but also have access to many functions both from micro and from the Go standard library. Many callbacks are also defined which are called when certain events happen. Here is the list of callbacks which micro defines:

• init(): this function should be used for your plugin initialization.

• onBufferOpen(buf): runs when a buffer is opened. The input contains the buffer object.

• onBufPaneOpen(bufpane): runs when a bufpane is opened. The input contains the bufpane object.

• onAction(bufpane): runs when Action is triggered by the user, where Action is a bindable action (see > help keybindings). A bufpane is passed as input and the function should return a boolean defining whether the view should be relocated after this action is performed.

• preAction(bufpane): runs immediately before Action is triggered by the user. Returns a boolean which defines whether the action should be canceled.

For example a function which is run every time the user saves the buffer would be:

function onSave(bp)
    ...
    return false
end

The bp variable is a reference to the bufpane the action is being executed within. This is almost always the current bufpane.

All available actions are listed in the keybindings section of the help.

For callbacks to mouse actions, you are also given the event info:

function onMousePress(view, event)
    local x, y = event:Position()

    return false
end

These functions should also return a boolean specifying whether the bufpane should be relocated to the cursor or not after the action is complete.

Accessing micro functions

Some of micro's internal information is exposed in the form of packages which can be imported by Lua plugins. A package can be imported in Lua and a value within it can be accessed using the following syntax:

local micro = import("micro")
micro.Log("Hello")

The packages and functions are listed below:

• micro
  • TermMessage(msg interface{}...)
  • TermError()
  • InfoBar()
  • Log(msg interface{}...)
  • SetStatusInfoFn
• micro/config
  • MakeCommand
  • FileComplete
  • HelpComplete
  • OptionComplete
  • OptionValueComplete
  • NoComplete
  • TryBindKey
  • Reload
  • AddRuntimeFilesFromDirectory
  • AddRuntimeFileFromMemory
  • AddRuntimeFile
  • ListRuntimeFiles
  • ReadRuntimeFile
  • RTColorscheme
  • RTSyntax
  • RTHelp
  • RTPlugin
  • RegisterCommonOption
  • RegisterGlobalOption
• micro/shell
  • ExecCommand
  • RunCommand
  • RunBackgroundShell
  • RunInteractiveShell
  • JobStart
  • JobSpawn
  • JobStop
  • JobStop
  • RunTermEmulator
  • TermEmuSupported
• micro/buffer
  • NewMessage
  • NewMessageAtLine
  • MTInfo
  • MTWarning
  • MTError
  • Loc
  • BTDefault
  • BTLog
  • BTRaw
  • BTInfo
  • NewBufferFromFile
  • ByteOffset
• micro/util
  • RuneAt
  • GetLeadingWhitespace
  • IsWordChar

This may seem like a small list of available functions but some of the objects returned by the functions have many methods. The Lua plugin may access any public methods of an object returned by any of the functions above. For example, with a BufPane object called bp, you could called the Save function in Lua with bp:Save().

Note that Lua uses the : syntax to call a function rather than Go's . syntax.

micro.InfoBar().Message()

turns to

micro.InfoBar():Message()

Accessing the Go standard library

It is possible for your lua code to access many of the functions in the Go standard library.

Simply import the package you'd like and then you can use it. For example:

local ioutil = import("io/ioutil")
local fmt = import("fmt")
local micro = import("micro")

local data, err = ioutil.ReadFile("SomeFile.txt")

if err ~= nil then
    micro.InfoBar():Error("Error reading file: SomeFile.txt")
else
    -- Data is returned as an array of bytes
    -- Using Sprintf will convert it to a string
    local str = fmt.Sprintf("%s", data)

    -- Do something with the file you just read!
    -- ...
end

Here are the packages from the Go standard library that you can access. Nearly all functions from these packages are supported. For an exact list of which functions are supported you can look through lua.go (which should be easy to understand).

fmt
io
io/ioutil
net
math
math/rand
os
runtime
path
filepath
strings
regexp
errors
time

For documentation for each of these functions, you can simply look through the Go standard library documentation.

Adding help files, syntax files, or colorschemes in your plugin

You can use the AddRuntimeFile(name, type, path string) function to add various kinds of files to your plugin. For example, if you'd like to add a help topic to your plugin called test, you would create a test.md file, and call the function:

AddRuntimeFile("test", "help", "test.md")

Use AddRuntimeFilesFromDirectory(name, type, dir, pattern) to add a number of files to the runtime. To read the content of a runtime file use ReadRuntimeFile(fileType, name string) or ListRuntimeFiles(fileType string) for all runtime files.

Autocomplete command arguments

See this example to learn how to use MakeCompletion and MakeCommand

local function StartsWith(String,Start)
    String = String:upper()
    Start = Start:upper() 
    return string.sub(String,1,string.len(Start))==Start
end

function complete(input)
    local allCompletions = {"Hello", "World", "Foo", "Bar"}
    local result = {}

    for i,v in pairs(allCompletions) do
        if StartsWith(v, input) then
            table.insert(result, v)
        end
    end
    return result
end

function foo(arg)
    messenger:Message(arg)
end

MakeCommand("foo", "example.foo", MakeCompletion("example.complete"))

Default plugins

For examples of plugins, see the default autoclose and linter plugins (stored in the normal micro core repo under runtime/plugins) as well as any plugins that are stored in the official channel here.

Plugin Manager

Micro also has a built in plugin manager which you can invoke with the > plugin ... command.

For the valid commands you can use, see the commands help topic.

The manager fetches plugins from the channels (which is simply a list of plugin metadata) which it knows about. By default, micro only knows about the official channel which is located at github.com/micro-editor/plugin-channel but you can add your own third-party channels using the pluginchannels option and you can directly link third-party plugins to allow installation through the plugin manager with the pluginrepos option.

If you'd like to publish a plugin you've made as an official plugin, you should upload your plugin online (to Github preferably) and add a repo.json file. This file will contain the metadata for your plugin. Here is an example:

[{
  "Name": "pluginname",
  "Description": "Here is a nice concise description of my plugin",
  "Tags": ["python", "linting"],
  "Versions": [
    {
      "Version": "1.0.0",
      "Url": "https://github.com/user/plugin/archive/v1.0.0.zip",
      "Require": {
        "micro": ">=1.0.3"
      }
    }
  ]
}]

Then open a pull request at github.com/micro-editor/plugin-channel adding a link to the raw repo.json that is in your plugin repository. To make updating the plugin work, the first line of your plugins lua code should contain the version of the plugin. (Like this: VERSION = "1.0.0") Please make sure to use semver for versioning.