Compiler plugin for Bitty Engine

This repository demonstrates how to implement a custom compiler/transpiler plugin for Bitty Engine with a BF example.

Installing

1. Clone or download this repository.

2. Click "Project", "Browse Data Directory..." from the menu bar.

3. Ensure there is a "plugins" directory under that directory.

4. Put the "plugin.bit" into the new created "plugins" directory. And name it properly.

5. Reopen Bitty Engine.

Injecting

1. Create a new asset, select the registered asset type.

2. Click "Install" to inject necessary assets to the target project.

3. Write and run BF code.

Principles

Bitty Engine loads plugin to extend its features once it's installed. It loads a BF compiler in this example which can inject the compiler to a target project. And the injected compiler/transpiler runs as regular Bitty code that translates BF code to runnable Lua chunk.

require 'bf/compiler'               -- Require the compiler.

local f = compile('hello world.bf') -- Compile something.
f()                                 -- Run the compiled chunk.

Write your own compiler plugin

A compiler plugin contains three parts.

1. Meta info

Similar to regular Bitty projects, it has an "info.json", define it as you want.

2. Main entry

Bitty Engine doesn't run a plugin project directly, it must be installed before running. The execution entry is also named as "main.lua".

But the entry functions are different from regular project. Eg.

-- Which assets are supposed to be injected from this plugin to target project.
local assets = {
  'bf/compiler.lua',
  'bf/README.txt'
}

-- Tips and example code.
local tips = 'Usage:\n  require \'bf/compiler\'\n  f = compile(\'source.bf\')\n  f()'
local code = 'require \'bf/compiler\'\nf = compile(\'source.bf\')\nf()\n'

-- Plugin entry, called to determine the usage of this plugin.
function usage()
  return { 'compiler' } -- This plugin is a compiler.
end

-- Plugin entry, called to determine the schema of this plugin.
function schema()
  return {
    -- Common.
    name = 'BF',      -- Asset name registered for this plugin.
    extension = 'bf', -- Asset extension registered for this plugin.

    -- List of string.
    keywords = { },
    identifiers = { },
    quotes = { '\'', '"' },
    -- String.
    multiline_comment_start = nil,
    multiline_comment_end = nil,
    -- C++ regex.
    comment_patterns = { '\\#.*' },
    number_patterns = { },
    identifier_patterns = { },
    punctuation_patterns = { '[\\<\\>\\+\\-\\.\\,\\[\\]]' },
    -- Boolean.
    case_sensitive = true,
    -- List of string.
    assets = assets
  }
end

-- Plugin entry, called to install necessary assets to your target project.
function compiler()
  print('Install BF compiler to the current project.')

  waitbox('Installing')
    :thus(function (rsp)
      local install = function (name)
        local data = Project.main:read(name)
        data:poke(1)
        Project.editing:write(name, data) -- Write into the target project.
      end

      for _, asset in ipairs(assets) do -- Install all necessary assets.
        install(asset)
      end

      print('Done.')

      msgbox(tips)
        :thus(function ()
          Platform.setClipboardText(code) -- Put example code to clipboard.
        end)
    end)
end

3. Assets to be injected

The plugin project also contains assets to be injected. See the plugin in this repository for details.