feat: 初始提交 LeonOS 实现

添加 LeonOS 的基本实现，包括：
- 核心 API 模块（colors, disk, gps, keys, multishell, parallel, rednet, redstone, settings, vector）
- 命令行程序（about, alias, bg, clear, copy, delete, edit, fg, help, list, lua, mkdir, move, paint, peripherals, programs, reboot, set, shutdown, threads）
- 系统启动脚本和包管理
- 文档（README.md, LICENSE）
- 开发工具（devbin）和更新程序

实现功能：
- 完整的线程管理系统
- 兼容 ComputerCraft 的 API 设计
- 改进的 shell 和命令补全系统
- 多标签终端支持
- 设置管理系统

data/computercraft/lua/rom/modules/main/rc/copy.lua

@@ -0,0 +1,36 @@
+-- rc.copy - table copier
+
+-- from https://lua-users.org/wiki/CopyTable
+local function deepcopy(orig, copies, dont_copy)
+  copies = copies or {}
+  local orig_type = type(orig)
+  local copy
+
+  if orig_type == 'table' and not dont_copy[orig] then
+    if copies[orig] then
+      copy = copies[orig]
+    else
+      copy = {}
+      copies[orig] = copy
+
+      for orig_key, orig_value in next, orig, nil do
+        copy[deepcopy(orig_key, copies, dont_copy)] = deepcopy(orig_value,
+          copies, dont_copy)
+      end
+
+      setmetatable(copy, deepcopy(getmetatable(orig), copies, dont_copy))
+    end
+  else -- number, string, boolean, etc
+    copy = orig
+  end
+
+  return copy
+end
+
+return { copy = function(original, ...)
+  local dont_copy = {}
+  for _, thing in pairs({...}) do
+    dont_copy[thing] = true
+  end
+  return deepcopy(original, nil, dont_copy)
+end }

data/computercraft/lua/rom/modules/main/rc/io.lua

@@ -0,0 +1,231 @@
+-- rc.io
+
+local expect = require("cc.expect").expect
+local thread = require("rc.thread")
+local colors = require("colors")
+local term = require("term")
+local fs = require("fs")
+local rc = require("rc")
+
+local io = {}
+
+local _file = {}
+function _file:read(...)
+  local args = table.pack(...)
+  local ret = {}
+
+  if args.n == 0 then
+    args[1] = "l"
+    args.n = 1
+  end
+
+  if not (self.handle.read and pcall(self.handle.read, 0)) then
+    return nil, "bad file descriptor"
+  end
+
+  if self.handle.flush then self.handle.flush() end
+
+  for i=1, args.n, 1 do
+    local format = args[i]
+    if format:sub(1,1) == "*" then
+      format = format:sub(2)
+    end
+
+    if format == "a" then
+      ret[#ret+1] = self.handle.readAll()
+
+    elseif format == "l" or format == "L" then
+      ret[#ret+1] = self.handle.readLine(format == "L")
+
+    elseif type(format) == "number" then
+      ret[#ret+1] = self.handle.read(format)
+
+    else
+      error("invalid format '"..format.."'", 2)
+    end
+  end
+
+  return table.unpack(ret, 1, args.n)
+end
+
+function _file:lines(...)
+  local formats = {...}
+  if #formats == 0 then
+    formats[1] = "l"
+  end
+  return function()
+    return self:read(table.unpack(formats))
+  end
+end
+
+function _file:write(...)
+  local args = table.pack(...)
+
+  if not (self.handle.write and pcall(self.handle.write, "")) then
+    return nil, "bad file descriptor"
+  end
+
+  for i=1, args.n, 1 do
+    self.handle.write(args[i])
+  end
+
+  return self
+end
+
+function _file:seek(whence, offset)
+  expect(1, whence, "string", "nil")
+  expect(2, offset, "number", "nil")
+  if self.handle.seek then
+    return self.handle.seek(whence, offset)
+  else
+    return nil, "bad file descriptor"
+  end
+end
+
+function _file:flush()
+  if self.handle.flush then self.handle.flush() end
+  return self
+end
+
+function _file:close()
+  self.closed = true
+  pcall(self.handle.close)
+end
+
+local function iofile(handle)
+  return setmetatable({handle = handle, closed = false}, {__index = _file})
+end
+
+local stdin_rbuf = ""
+io.stdin = iofile {
+  read = function(n)
+    while #stdin_rbuf < n do
+      stdin_rbuf = stdin_rbuf .. term.read() .. "\n"
+    end
+    local ret = stdin_rbuf:sub(1, n)
+    stdin_rbuf = stdin_rbuf:sub(#ret+1)
+    return ret
+  end,
+
+  readLine = function(trail)
+    local nl = stdin_rbuf:find("\n")
+
+    if nl then
+      local ret = stdin_rbuf:sub(1, nl+1)
+      if not trail then ret = ret:sub(1, -2) end
+      stdin_rbuf = stdin_rbuf:sub(#ret+1)
+      return ret
+
+    else
+      return stdin_rbuf .. term.read() .. (trail and "\n" or "")
+    end
+  end
+}
+
+io.stdout = iofile {
+  write = rc.write
+}
+
+io.stderr = iofile {
+  write = function(text)
+    local old = term.getTextColor()
+    term.setTextColor(colors.red)
+    rc.write(text)
+    term.setTextColor(old)
+  end
+}
+
+function io.open(file, mode)
+  expect(1, file, "string")
+  expect(2, mode, "string", "nil")
+
+  mode = (mode or "r"):match("[rwa]") .. "b"
+
+  local handle, err = fs.open(file, mode)
+  if not handle then
+    return nil, err
+  end
+
+  return iofile(handle)
+end
+
+function io.input(file)
+  expect(1, file, "string", "table", "nil")
+  local vars = thread.vars()
+  if type(file) == "string" then file = assert(io.open(file, "r")) end
+  if file then vars.input = file end
+  return vars.input or io.stdin
+end
+
+function io.output(file)
+  expect(1, file, "string", "table", "nil")
+  local vars = thread.vars()
+  if type(file) == "string" then file = assert(io.open(file, "w")) end
+  if file then vars.output = file end
+  return vars.output or io.stdout
+end
+
+function io.read(...)
+  return io.input():read(...)
+end
+
+function io.write(...)
+  return io.output():write(...)
+end
+
+function io.flush(file)
+  expect(1, file, "table", "nil")
+  return (file or io.output):flush()
+end
+
+function io.close(file)
+  expect(1, file, "table", "nil")
+  return (file or io.output):close()
+end
+
+function io.lines(file, ...)
+  expect(1, file, "string", "nil")
+  if file then file = assert(io.open(file, "r")) end
+  local formats = table.pack(...)
+  return (file or io.stdin):lines(table.unpack(formats, 1, formats.n))
+end
+
+function io.type(obj)
+  if type(obj) == "table" then
+    local is_file = true
+    for k, v in pairs(_file) do
+      if (not obj[k]) or v ~= obj[k] then
+        is_file = false
+      end
+    end
+
+    if is_file then
+      return obj.closed and "closed file" or "file"
+    end
+  end
+end
+
+-- loadfile and dofile here as well
+function _G.loadfile(file, mode, env)
+  expect(1, file, "string")
+  expect(2, mode, "string", "nil")
+  expect(3, env, "table", "nil")
+  local handle, err = io.open(file, "r")
+  if not handle then
+    return nil, file .. ": " .. err
+  end
+  local data = handle:read("a")
+  handle:close()
+  return load(data, "="..file, mode or "bt", env)
+end
+
+function _G.dofile(file, ...)
+  expect(1, file, "string")
+  local func, err = loadfile(file)
+  if not func then
+    error(err)
+  end
+  return func(...)
+end
+
+return io

data/computercraft/lua/rom/modules/main/rc/json.lua

@@ -0,0 +1,388 @@
+--
+-- json.lua
+--
+-- Copyright (c) 2020 rxi
+--
+-- Permission is hereby granted, free of charge, to any person obtaining a copy of
+-- this software and associated documentation files (the "Software"), to deal in
+-- the Software without restriction, including without limitation the rights to
+-- use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+-- of the Software, and to permit persons to whom the Software is furnished to do
+-- so, subject to the following conditions:
+--
+-- The above copyright notice and this permission notice shall be included in all
+-- copies or substantial portions of the Software.
+--
+-- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+-- IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+-- FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+-- AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+-- LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+-- OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+-- SOFTWARE.
+--
+
+local json = { _version = "0.1.2" }
+
+-------------------------------------------------------------------------------
+-- Encode
+-------------------------------------------------------------------------------
+
+local encode
+
+local escape_char_map = {
+  [ "\\" ] = "\\",
+  [ "\"" ] = "\"",
+  [ "\b" ] = "b",
+  [ "\f" ] = "f",
+  [ "\n" ] = "n",
+  [ "\r" ] = "r",
+  [ "\t" ] = "t",
+}
+
+local escape_char_map_inv = { [ "/" ] = "/" }
+for k, v in pairs(escape_char_map) do
+  escape_char_map_inv[v] = k
+end
+
+
+local function escape_char(c)
+  return "\\" .. (escape_char_map[c] or string.format("u%04x", c:byte()))
+end
+
+
+local function encode_nil(val)
+  return "null"
+end
+
+
+local function encode_table(val, stack)
+  local res = {}
+  stack = stack or {}
+
+  -- Circular reference?
+  if stack[val] then error("circular reference") end
+
+  stack[val] = true
+
+  if rawget(val, 1) ~= nil or next(val) == nil then
+    -- Treat as array -- check keys are valid and it is not sparse
+    local n = 0
+    for k in pairs(val) do
+      if type(k) ~= "number" then
+        error("invalid table: mixed or invalid key types")
+      end
+      n = n + 1
+    end
+    if n ~= #val then
+      error("invalid table: sparse array")
+    end
+    -- Encode
+    for i, v in ipairs(val) do
+      table.insert(res, encode(v, stack))
+    end
+    stack[val] = nil
+    return "[" .. table.concat(res, ",") .. "]"
+
+  else
+    -- Treat as an object
+    for k, v in pairs(val) do
+      if type(k) ~= "string" then
+        error("invalid table: mixed or invalid key types")
+      end
+      table.insert(res, encode(k, stack) .. ":" .. encode(v, stack))
+    end
+    stack[val] = nil
+    return "{" .. table.concat(res, ",") .. "}"
+  end
+end
+
+
+local function encode_string(val)
+  return '"' .. val:gsub('[%z\1-\31\\"]', escape_char) .. '"'
+end
+
+
+local function encode_number(val)
+  -- Check for NaN, -inf and inf
+  if val ~= val or val <= -math.huge or val >= math.huge then
+    error("unexpected number value '" .. tostring(val) .. "'")
+  end
+  return string.format("%.14g", val)
+end
+
+
+local type_func_map = {
+  [ "nil"     ] = encode_nil,
+  [ "table"   ] = encode_table,
+  [ "string"  ] = encode_string,
+  [ "number"  ] = encode_number,
+  [ "boolean" ] = tostring,
+}
+
+
+encode = function(val, stack)
+  local t = type(val)
+  local f = type_func_map[t]
+  if f then
+    return f(val, stack)
+  end
+  error("unexpected type '" .. t .. "'")
+end
+
+
+function json.encode(val)
+  return ( encode(val) )
+end
+
+
+-------------------------------------------------------------------------------
+-- Decode
+-------------------------------------------------------------------------------
+
+local parse
+
+local function create_set(...)
+  local res = {}
+  for i = 1, select("#", ...) do
+    res[ select(i, ...) ] = true
+  end
+  return res
+end
+
+local space_chars   = create_set(" ", "\t", "\r", "\n")
+local delim_chars   = create_set(" ", "\t", "\r", "\n", "]", "}", ",")
+local escape_chars  = create_set("\\", "/", '"', "b", "f", "n", "r", "t", "u")
+local literals      = create_set("true", "false", "null")
+
+local literal_map = {
+  [ "true"  ] = true,
+  [ "false" ] = false,
+  [ "null"  ] = nil,
+}
+
+
+local function next_char(str, idx, set, negate)
+  for i = idx, #str do
+    if set[str:sub(i, i)] ~= negate then
+      return i
+    end
+  end
+  return #str + 1
+end
+
+
+local function decode_error(str, idx, msg)
+  local line_count = 1
+  local col_count = 1
+  for i = 1, idx - 1 do
+    col_count = col_count + 1
+    if str:sub(i, i) == "\n" then
+      line_count = line_count + 1
+      col_count = 1
+    end
+  end
+  error( string.format("%s at line %d col %d", msg, line_count, col_count) )
+end
+
+
+local function codepoint_to_utf8(n)
+  -- http://scripts.sil.org/cms/scripts/page.php?site_id=nrsi&id=iws-appendixa
+  local f = math.floor
+  if n <= 0x7f then
+    return string.char(n)
+  elseif n <= 0x7ff then
+    return string.char(f(n / 64) + 192, n % 64 + 128)
+  elseif n <= 0xffff then
+    return string.char(f(n / 4096) + 224, f(n % 4096 / 64) + 128, n % 64 + 128)
+  elseif n <= 0x10ffff then
+    return string.char(f(n / 262144) + 240, f(n % 262144 / 4096) + 128,
+                       f(n % 4096 / 64) + 128, n % 64 + 128)
+  end
+  error( string.format("invalid unicode codepoint '%x'", n) )
+end
+
+
+local function parse_unicode_escape(s)
+  local n1 = tonumber( s:sub(1, 4),  16 )
+  local n2 = tonumber( s:sub(7, 10), 16 )
+   -- Surrogate pair?
+  if n2 then
+    return codepoint_to_utf8((n1 - 0xd800) * 0x400 + (n2 - 0xdc00) + 0x10000)
+  else
+    return codepoint_to_utf8(n1)
+  end
+end
+
+
+local function parse_string(str, i)
+  local res = ""
+  local j = i + 1
+  local k = j
+
+  while j <= #str do
+    local x = str:byte(j)
+
+    if x < 32 then
+      decode_error(str, j, "control character in string")
+
+    elseif x == 92 then -- `\`: Escape
+      res = res .. str:sub(k, j - 1)
+      j = j + 1
+      local c = str:sub(j, j)
+      if c == "u" then
+        local hex = str:match("^[dD][89aAbB]%x%x\\u%x%x%x%x", j + 1)
+                 or str:match("^%x%x%x%x", j + 1)
+                 or decode_error(str, j - 1, "invalid unicode escape in string")
+        res = res .. parse_unicode_escape(hex)
+        j = j + #hex
+      else
+        if not escape_chars[c] then
+          decode_error(str, j - 1, "invalid escape char '" .. c .. "' in string")
+        end
+        res = res .. escape_char_map_inv[c]
+      end
+      k = j + 1
+
+    elseif x == 34 then -- `"`: End of string
+      res = res .. str:sub(k, j - 1)
+      return res, j + 1
+    end
+
+    j = j + 1
+  end
+
+  decode_error(str, i, "expected closing quote for string")
+end
+
+
+local function parse_number(str, i)
+  local x = next_char(str, i, delim_chars)
+  local s = str:sub(i, x - 1)
+  local n = tonumber(s)
+  if not n then
+    decode_error(str, i, "invalid number '" .. s .. "'")
+  end
+  return n, x
+end
+
+
+local function parse_literal(str, i)
+  local x = next_char(str, i, delim_chars)
+  local word = str:sub(i, x - 1)
+  if not literals[word] then
+    decode_error(str, i, "invalid literal '" .. word .. "'")
+  end
+  return literal_map[word], x
+end
+
+
+local function parse_array(str, i)
+  local res = {}
+  local n = 1
+  i = i + 1
+  while 1 do
+    local x
+    i = next_char(str, i, space_chars, true)
+    -- Empty / end of array?
+    if str:sub(i, i) == "]" then
+      i = i + 1
+      break
+    end
+    -- Read token
+    x, i = parse(str, i)
+    res[n] = x
+    n = n + 1
+    -- Next token
+    i = next_char(str, i, space_chars, true)
+    local chr = str:sub(i, i)
+    i = i + 1
+    if chr == "]" then break end
+    if chr ~= "," then decode_error(str, i, "expected ']' or ','") end
+  end
+  return res, i
+end
+
+
+local function parse_object(str, i)
+  local res = {}
+  i = i + 1
+  while 1 do
+    local key, val
+    i = next_char(str, i, space_chars, true)
+    -- Empty / end of object?
+    if str:sub(i, i) == "}" then
+      i = i + 1
+      break
+    end
+    -- Read key
+    if str:sub(i, i) ~= '"' then
+      decode_error(str, i, "expected string for key")
+    end
+    key, i = parse(str, i)
+    -- Read ':' delimiter
+    i = next_char(str, i, space_chars, true)
+    if str:sub(i, i) ~= ":" then
+      decode_error(str, i, "expected ':' after key")
+    end
+    i = next_char(str, i + 1, space_chars, true)
+    -- Read value
+    val, i = parse(str, i)
+    -- Set
+    res[key] = val
+    -- Next token
+    i = next_char(str, i, space_chars, true)
+    local chr = str:sub(i, i)
+    i = i + 1
+    if chr == "}" then break end
+    if chr ~= "," then decode_error(str, i, "expected '}' or ','") end
+  end
+  return res, i
+end
+
+
+local char_func_map = {
+  [ '"' ] = parse_string,
+  [ "0" ] = parse_number,
+  [ "1" ] = parse_number,
+  [ "2" ] = parse_number,
+  [ "3" ] = parse_number,
+  [ "4" ] = parse_number,
+  [ "5" ] = parse_number,
+  [ "6" ] = parse_number,
+  [ "7" ] = parse_number,
+  [ "8" ] = parse_number,
+  [ "9" ] = parse_number,
+  [ "-" ] = parse_number,
+  [ "t" ] = parse_literal,
+  [ "f" ] = parse_literal,
+  [ "n" ] = parse_literal,
+  [ "[" ] = parse_array,
+  [ "{" ] = parse_object,
+}
+
+
+parse = function(str, idx)
+  local chr = str:sub(idx, idx)
+  local f = char_func_map[chr]
+  if f then
+    return f(str, idx)
+  end
+  decode_error(str, idx, "unexpected character '" .. chr .. "'")
+end
+
+
+function json.decode(str)
+  if type(str) ~= "string" then
+    error("expected argument of type string, got " .. type(str))
+  end
+  local res, idx = parse(str, next_char(str, 1, space_chars, true))
+  idx = next_char(str, idx, space_chars, true)
+  if idx <= #str then
+    decode_error(str, idx, "trailing garbage")
+  end
+  return res
+end
+
+
+return json

data/computercraft/lua/rom/modules/main/rc/thread.lua

@@ -0,0 +1,398 @@
+-- New scheduler.
+-- Tabs are integral to the design of this scheduler;  Multishell cannot
+-- be disabled.
+
+local rc = require("rc")
+local fs = require("fs")
+local keys = require("keys")
+local term = require("term")
+local colors = require("colors")
+local window = require("window")
+local expect = require("cc.expect")
+local copy = require("rc.copy").copy
+
+local getfenv
+if rc.lua51 then
+  getfenv = rc.lua51.getfenv
+else
+  getfenv = function() return _ENV or _G end
+end
+
+local tabs = { {} }
+local threads = {}
+local current, wrappedNative
+
+local focused = 1
+
+local api = {}
+
+function api.launchTab(x, name)
+  expect(1, x, "string", "function")
+  name = expect(2, name, "string", "nil") or tostring(x)
+
+  local newTab = {
+    term = window.create(wrappedNative, 1, 1, wrappedNative.getSize()),
+    id = #tabs + 1
+  }
+
+  tabs[newTab.id] = newTab
+
+  local _f = focused
+  focused = newTab.id
+  local id = (type(x) == "string" and api.load or api.spawn)(x, name)
+  focused = _f
+
+  return newTab.id, id
+end
+
+function api.setFocusedTab(f)
+  expect(1, f, "number")
+  if tabs[focused] then focused = f end
+  return not not tabs[f]
+end
+
+function api.getFocusedTab()
+  return focused
+end
+
+function api.getCurrentTab()
+  return current.tab.id
+end
+
+function api.load(file, name)
+  expect(1, file, "string")
+  name = expect(2, name, "string", "nil") or file
+
+  local env = copy(current and current.env or _ENV or _G, package.loaded)
+
+  local func, err = loadfile(file, "t", env)
+  if not func then
+    return nil, err
+  end
+
+  return api.spawn(func, name, tabs[focused])
+end
+
+function api.spawn(func, name, _)
+  expect(1, func, "function")
+  expect(2, name, "string")
+
+  local new = {
+    name = name,
+    coro = coroutine.create(function()
+      assert(xpcall(func, debug.traceback))
+    end),
+    vars = setmetatable({}, {__index = current and current.vars}),
+    env = getfenv(func) or _ENV or _G,
+    tab = _ or tabs[focused],
+    id = #threads + 1,
+    dir = current and current.dir or "/"
+  }
+
+  new.tab[new.id] = true
+  threads[new.id] = new
+
+  new.tab.name = name
+
+  return new.id
+end
+
+function api.exists(id)
+  expect(1, id, "number")
+  return not not threads[id]
+end
+
+function api.id()
+  return current.id
+end
+
+function api.dir()
+  return current.dir or "/"
+end
+
+function api.setDir(dir)
+  expect(1, dir, "string")
+
+  if not fs.exists(dir) then
+    return nil, "that directory does not exist"
+
+  elseif not fs.isDir(dir) then
+    return nil, "not a directory"
+  end
+
+  current.dir = dir
+
+  return true
+end
+
+function api.vars()
+  return current.vars
+end
+
+function api.getTerm()
+  return current and current.tab and current.tab.term or term.native()
+end
+
+function api.setTerm(new)
+  if tabs[focused] then
+    local old = tabs[focused].term
+    tabs[focused].term = new
+    return old
+  end
+end
+
+local w, h
+local function getName(tab)
+  local highest = 0
+
+  for k in pairs(tab) do
+    if type(k) == "number" then highest = math.max(highest, k) end
+  end
+
+  return threads[highest] and threads[highest].name or "???"
+end
+
+function api.info()
+  local running = {}
+  for i, thread in pairs(threads) do
+    running[#running+1] = { id = i, name = thread.name, tab = thread.tab.id }
+  end
+
+  table.sort(running, function(a,b) return a.id < b.id end)
+
+  return running
+end
+
+function api.remove(id)
+  expect(1, id, "number", "nil")
+  threads[id or current.id] = nil
+end
+
+local scroll = 0
+local totalNameLength = 0
+local function redraw()
+  w, h = wrappedNative.getSize()
+
+  wrappedNative.setVisible(false)
+
+  local names = {}
+  totalNameLength = 0
+  for i=1, #tabs, 1 do
+    names[i] = " " .. getName(tabs[i]) .. " "
+    totalNameLength = totalNameLength + #names[i]
+  end
+
+  if #tabs > 1 then
+    local len = -scroll + 1
+    wrappedNative.setCursorPos(1, 1)
+    wrappedNative.setTextColor(colors.black)
+    wrappedNative.setBackgroundColor(colors.gray)
+    wrappedNative.clearLine()
+
+    for i=1, #tabs, 1 do
+      local tab = tabs[i]
+      local name = names[i]
+
+      wrappedNative.setCursorPos(len, 1)
+      len = len + #name
+
+      if i == focused then
+        wrappedNative.setTextColor(colors.yellow)
+        wrappedNative.setBackgroundColor(colors.black)
+        wrappedNative.write(name)
+
+      else
+        wrappedNative.setTextColor(colors.black)
+        wrappedNative.setBackgroundColor(colors.gray)
+        wrappedNative.write(name)
+      end
+
+      tab.term.setVisible(false)
+      tab.term.reposition(1, 2, w, h - 1)
+    end
+
+    if totalNameLength > w-2 then
+      wrappedNative.setTextColor(colors.black)
+      wrappedNative.setBackgroundColor(colors.gray)
+      if scroll > 0 then
+        wrappedNative.setCursorPos(1, 1)
+        wrappedNative.write("<")
+      end
+      if totalNameLength - scroll > w-1 then
+        wrappedNative.setCursorPos(w, 1)
+        wrappedNative.write(">")
+      end
+    end
+
+    tabs[focused].term.setVisible(true)
+
+  elseif #tabs > 0 then
+    local tab = tabs[1]
+    tab.term.reposition(1, 1, w, h)
+    tab.term.setVisible(true)
+  end
+
+  wrappedNative.setVisible(true)
+end
+
+local inputEvents = {
+  key = true,
+  char = true,
+  key_up = true,
+  mouse_up = true,
+  mouse_drag = true,
+  mouse_click = true,
+  mouse_scroll = true,
+  terminate = true,
+}
+
+local altIsDown
+
+local function processEvent(event)
+  if inputEvents[event[1]] then
+    if #event > 3 then -- mouse event
+
+      if #tabs > 1 then
+        if event[4] == 1 then
+          local curX = -scroll
+
+          if event[1] == "mouse_scroll" then
+            scroll = math.max(0, math.min(totalNameLength-w+1,
+              scroll - event[2]))
+            return false
+          end
+
+          for i=1, #tabs, 1 do
+            local tab = tabs[i]
+            curX = curX + #getName(tab) + 2
+
+            if event[3] <= curX then
+              focused = i
+              redraw()
+              break
+            end
+          end
+
+          return false
+
+        else
+          event[4] = event[4] - 1
+        end
+      end
+
+    elseif event[1] == "key" then
+      if event[2] == keys.rightAlt then
+        altIsDown = event[2]
+        return false
+
+      elseif altIsDown then
+        local num = tonumber(keys.getName(event[2]))
+        if num then
+          if tabs[num] then
+            focused = num
+            redraw()
+            return false
+          end
+
+        elseif event[2] == keys.left then
+          focused = math.max(1, focused - 1)
+          redraw()
+          return false
+
+        elseif event[2] == keys.right then
+          focused = math.min(#tabs, focused + 1)
+          redraw()
+          return false
+
+        elseif event[2] == keys.up then
+          scroll = math.max(0, math.min(totalNameLength-w+1,
+            scroll + 1))
+          return false
+
+        elseif event[2] == keys.down then
+          scroll = math.max(0, math.min(totalNameLength-w+1,
+            scroll - 1))
+          return false
+        end
+      end
+
+    elseif event[1] == "key_up" then
+      if event[2] == keys.rightAlt then
+        altIsDown = false
+        return false
+      end
+
+    end
+  end
+
+  return true
+end
+
+local function cleanTabs()
+  for t=#tabs, 1, -1 do
+    local tab = tabs[t]
+
+    local count, removed = 0, 0
+    for i in pairs(tab) do
+      if type(i) == "number" then
+        count = count + 1
+        if not threads[i] then
+          removed = removed + 1
+          tab[i] = nil
+        end
+      end
+    end
+
+    if count == removed then
+      table.remove(tabs, t)
+    end
+  end
+
+  for i=1, #tabs, 1 do
+    tabs[i].id = i
+  end
+
+  focused = math.max(1, math.min(#tabs, focused))
+end
+
+function api.start()
+  api.start = nil
+
+  local _native = term.native()
+  wrappedNative = window.create(_native, 1, 1, _native.getSize())
+  api.launchTab("/rc/programs/shell.lua", "shell")
+
+  rc.pushEvent("init")
+
+  while #tabs > 0 and next(threads) do
+    cleanTabs()
+    redraw()
+    local event = table.pack(coroutine.yield())
+
+    if event[1] == "term_resize" then
+      wrappedNative.reposition(1, 1, _native.getSize())
+    end
+
+    if processEvent(event) then
+      for tid, thread in pairs(threads) do
+        if thread.tab == tabs[focused] or not inputEvents[event[1]] then
+          current = thread
+          local result = table.pack(coroutine.resume(thread.coro,
+            table.unpack(event, 1, event.n)))
+
+          if not result[1] then
+            io.stderr:write(result[2].."\n")
+            threads[tid] = nil
+
+          elseif coroutine.status(thread.coro) == "dead" then
+            threads[tid] = nil
+          end
+        end
+      end
+    end
+  end
+
+  rc.shutdown()
+end
+
+return api