commit 1b55bb0ba653c4df442c94c380f74beaed1291ec
Author: Er2 <er2@dismail.de>
Date:   Wed Feb 16 21:53:37 2022 +0300

    init

diff --git a/autoexec.lua b/autoexec.lua
new file mode 100644
index 0000000..40043e3
--- /dev/null
+++ b/autoexec.lua
@@ -0,0 +1,8 @@
+-- Autoexec for ErDOS
+--- (c) Er2 2022 <er2@dismail.de>
+--- Zlib License
+
+-- Load default shell
+
+loadapp 'ver'
+loadapp 'ersh'
diff --git a/license b/license
new file mode 100644
index 0000000..888e15d
--- /dev/null
+++ b/license
@@ -0,0 +1,19 @@
+Zlib License
+
+Copyright (c) 2022 Er2 <er2@dismail.de>
+
+This software is provided 'as-is', without any express or implied
+warranty. In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+1. The origin of this software must not be misrepresented; you must not
+   claim that you wrote the original software. If you use this software
+   in a product, an acknowledgement in the product documentation would be
+   appreciated but is not required.
+2. Altered source versions must be plainly marked as such, and must not be
+   misrepresented as being the original software.
+3. This notice may not be removed or altered from any source distribution.
diff --git a/main.lua b/main.lua
new file mode 100644
index 0000000..1e03e17
--- /dev/null
+++ b/main.lua
@@ -0,0 +1,8 @@
+-- Startup
+
+local con = require 'src.term.init'
+require 'src.os' (con)
+
+require 'autoexec'
+
+love.event.push 'quit'
diff --git a/src/async.lua b/src/async.lua
new file mode 100644
index 0000000..92702b2
--- /dev/null
+++ b/src/async.lua
@@ -0,0 +1,48 @@
+
+ACTIVE = true
+function __run()
+  if love.event then
+    love.event.pump()
+    for n, a,b,c,d,e,f in love.event.poll() do
+      if n == 'quit' or not ACTIVE then
+        if not love.quit or not love.quit() then
+          ACTIVE = false
+          return a or 0
+        end
+      end
+      love.handlers[n](a,b,c,d,e,f)
+    end
+  end
+
+  local dt = 0
+  if love.timer
+  then dt = love.timer.step() or love.timer.getDelta()
+  end
+
+  if love.update then love.update(dt) end
+  if love.graphics and love.graphics.isActive() then
+    love.graphics.origin()
+    love.graphics.clear(0, 0, 0)
+    if love.draw then love.draw() end
+    love.graphics.present()
+  end
+  if love.timer then love.timer.sleep(0.001) end
+end
+
+function await(fn)
+  while fn() ~= true do
+    if not ACTIVE then break end
+    __run()
+  end
+end
+
+function love.run()
+  if love.timer then love.timer.step() end
+  if love.getVersion() == 0
+  then
+    while ACTIVE do
+      __run()
+    end
+  else return __run
+  end
+end
diff --git a/src/baseshell.lua b/src/baseshell.lua
new file mode 100644
index 0000000..a9c7ccc
--- /dev/null
+++ b/src/baseshell.lua
@@ -0,0 +1,83 @@
+return function(con)
+
+local sh = {
+  prompt = function() return '>' end,
+  runs = true,
+  env = {
+    code = 0,
+    path = 'sysapps:apps',
+  }
+}
+
+function sh:which(cmd)
+  local file = cmd or ''
+  if file:sub(-4) ~= '.lua'
+  then file = file.. '.lua'
+  end
+  if fsHas(file)
+  then return '', file end
+  for path in self.env.path:gmatch '[^:]+' do
+    if fsHas(path..'/'..file)
+    then return path, '/'..file
+    end
+  end
+end
+
+function sh:parseArgs(ln)
+  local iq, buf, args = false, '', {}
+  local qt, esc = nil, false
+
+  ln = ln:gsub('%$(%S+)%s*=%s*(.*)$', function(k, v)
+    env[k] = self:parseArgs(v)[1]
+    return ''
+  end)
+
+  -- helper function
+  local function psh()
+    if buf:sub(1,1) == '$'
+    then buf = tostring(self.env[buf:sub(2)] or '') end
+    if #buf > 0 then table.insert(args, buf) end
+    buf, qt = '', nil
+  end
+
+  for i = 1, #ln + 1 do
+    local v = ln:sub(i, i)
+    if ((v == ' ' or v == '\n' or v == '\t') and not iq)
+    or v == ''
+    then psh()
+
+    elseif esc then esc, buf = false, buf.. v
+    elseif v == '\\' then esc = true
+
+    elseif (not qt or qt == v)
+    and (v == '"' or v == "'")
+    then psh()
+      qt, iq = v, not iq
+
+    else buf = buf.. v
+    end
+  end
+
+  return args
+end
+
+function sh:run()
+  return 'TODO'
+end
+
+function sh:loop()
+  await(function()
+    con.print(self:prompt())
+    local ln = con.getln()
+    con.down()
+
+    local res = self:run(ln)
+    if res then con.println(res) end
+
+    return not self.runs
+  end)
+end
+
+return sh
+
+end
diff --git a/src/draw.lua b/src/draw.lua
new file mode 100644
index 0000000..6e8f525
--- /dev/null
+++ b/src/draw.lua
@@ -0,0 +1,31 @@
+-- Drawing API
+--- (c) Er2 2021-2022
+--- Zlib License
+
+local comp = {
+  'system', 'transform',
+  'color', 'figures', 'font',
+  'line', 'picture', 'rcorn',
+  'rrect',
+}
+
+FILL, LINE = 1, 0
+
+local draw = {}
+draw.__index = draw
+
+function draw.new(w, h)
+  assert(w > 0 and h > 0, 'cr must be greater than 0')
+  local cr = setmetatable({}, draw)
+  cr._cr = love.graphics.newCanvas(w, h)
+  cr.w, cr.h = w, h
+  cr:newFont()
+  return cr
+end
+
+for _, v in pairs(comp) do
+  require('src.draw.'.. v)(draw)
+end
+
+draw:newFont()
+return setmetatable({}, draw)
diff --git a/src/draw/color.lua b/src/draw/color.lua
new file mode 100644
index 0000000..3e5c269
--- /dev/null
+++ b/src/draw/color.lua
@@ -0,0 +1,32 @@
+
+local f = (love.getVersion or
+  function() return love._version_major
+end)() == 0 and 1 or 255
+
+return function(draw)
+
+function draw:color(r, g, b, a)
+  a = a or 255
+  love.graphics.setColor(r / f, g / f, b / f, a / f)
+  return self
+end
+
+function draw:colorT(t)
+  return self:color(t[1], t[2], t[3], t[4])
+end
+
+function draw:colorH(hex)
+  hex = (tostring(hex) or ''):lower()
+  local r, g, b, a = hex:match '#?(%x%x?)(%x%x?)(%x%x?)'
+  r = #r == 1 and r..r or r
+  g = #g == 1 and g..g or g
+  b = #b == 1 and b..b or b
+  if a then a = #a == 1 and a..a or a end
+  return self:color(
+    tonumber(r, 16), tonumber(g, 16),
+    tonumber(b, 16),
+    not a and 255 or tonumber(a, 16)
+  )
+end
+
+end
diff --git a/src/draw/figures.lua b/src/draw/figures.lua
new file mode 100644
index 0000000..50adaac
--- /dev/null
+++ b/src/draw/figures.lua
@@ -0,0 +1,44 @@
+
+local function gm(m)
+  return m == FILL and 'fill' or 'line'
+end
+
+return function(draw)
+
+function draw:rect(m, x, y, w, h)
+  love.graphics.rectangle(gm(m), x, y, w, h)
+  return self
+end
+
+function draw:ellipse(m, x, y, rx, ry)
+  love.graphics.ellipse(gm(m), x, y, rx, ry)
+  if m == FILL then
+    self:ellipse(LINE, x, y, rx, ry)
+  end
+  return self
+end
+
+function draw:circle(m, x, y, r)
+  return self:ellipse(m, x, y, r, r)
+end
+
+function draw:triang(m, x, y, ox1, oy1, ox2, oy2)
+  if m == FILL then self:triang(LINE, x, y, ox1, oy1, ox2, oy2) end
+  love.graphics.polygon(gm(m), x, y, x + ox1, y + oy1, x + ox2, y + oy2)
+  return self
+end
+
+function draw:arc(m, cx, cy, r, sa, ea)
+  love.graphics.arc(gm(m), m == FILL and 'pie' or 'open',
+    cx, cy, r, sa, ea)
+  if m == FILL then self:arc(LINE, cx, cy, r, sa, ea) end
+  return self
+end
+
+function draw:text(t, x, y)
+  love.graphics.setFont(self.f)
+  love.graphics.print(t, x, y)
+  return self
+end
+
+end
diff --git a/src/draw/font.lua b/src/draw/font.lua
new file mode 100644
index 0000000..7d6f78b
--- /dev/null
+++ b/src/draw/font.lua
@@ -0,0 +1,16 @@
+return function(draw)
+
+function draw:font(f)
+  if f then self.f = f end
+  return self
+end
+
+function draw:newFont(...)
+  return self:font(love.graphics.newFont(...))
+end
+
+function draw:getFText(t)
+  return self.f:getWidth(t), self.f:getHeight(t)
+end
+
+end
diff --git a/src/draw/line.lua b/src/draw/line.lua
new file mode 100644
index 0000000..7ead00d
--- /dev/null
+++ b/src/draw/line.lua
@@ -0,0 +1,13 @@
+return function(draw)
+
+function draw:lineWidth(w)
+  love.graphics.setLineWidth(w)
+  return self
+end
+
+function draw:line(x1, y1, x2, y2)
+  love.graphics.line(x1, y1, x2, y2)
+  return self
+end
+
+end
diff --git a/src/draw/picture.lua b/src/draw/picture.lua
new file mode 100644
index 0000000..5830287
--- /dev/null
+++ b/src/draw/picture.lua
@@ -0,0 +1,13 @@
+return function(draw)
+
+function draw:img(im, x, y, r, sx, sy)
+  love.graphics.draw(im, x, y, r, sx, sy)
+  return self
+end
+
+function draw:cr(cr, x, y, r, sx, sy)
+  if cr.fr then return end
+  return self:img(cr._cr, x, y, r, sx, sy)
+end
+
+end
diff --git a/src/draw/rcorn.lua b/src/draw/rcorn.lua
new file mode 100644
index 0000000..e4935ec
--- /dev/null
+++ b/src/draw/rcorn.lua
@@ -0,0 +1,33 @@
+return function(draw)
+
+function draw:rcorn(x, y, d, p)
+  p = p or 1
+  if p == 1 then self -- bot-right
+
+  :arc(LINE, x - d, y - d, d, 0, math.pi / 2)
+  :triang(FILL, x, y - d, 0, d, -d/2, d)
+  :triang(FILL, x - d, y, d / 1.5, -d / 4, d, 0)
+
+  elseif p == 2 then self -- bot-left
+
+  :arc(LINE, x + d, y - d, d, math.pi / 2, math.pi)
+  :triang(FILL, x, y - d, 0, d, d/2, d)
+  :triang(FILL, x, y, d / 1.5, -d / 4, d, 0)
+
+  elseif p == 3 then self -- top-right
+
+  :arc(LINE, x - d, y + d, d, math.pi * 1.5, math.pi * 2)
+  :triang(FILL, x, y, 0, d, -d/2, 0)
+  :triang(FILL, x - d, y, d / 1.5, d / 4, d, 0)
+
+  elseif p == 4 then self -- top-left
+
+  :arc(LINE, x + d, y + d, d, math.pi, math.pi * 1.5)
+  :triang(FILL, x, y, 0, d, d/2, 0)
+  :triang(FILL, x, y, d / 1.5, d / 4, d, 0)
+
+  end
+  return self
+end
+
+end
diff --git a/src/draw/rrect.lua b/src/draw/rrect.lua
new file mode 100644
index 0000000..4358a08
--- /dev/null
+++ b/src/draw/rrect.lua
@@ -0,0 +1,33 @@
+return function(draw)
+
+function draw:rrect(m, x, y, w, h, r)
+  local rtl, rtr, rbl, rbr = r[1] or 8, r[2], r[3], r[4]
+  rtr = rtr or rtl
+  rbl = rbl or rtl
+  rbr = rbr or rbl
+
+  local ml, mr, Ml, Mr, Mt, Mb =
+    math.min(rtl, rbl), math.min(rtr, rbr),
+    math.max(rtl, rbl), math.max(rtr, rbr),
+    math.max(rtl, rtr), math.max(rbl, rbr)
+  if m == FILL then self
+    :rect(m, x + Ml, y + Mt, w - Ml - Mr, h - Mt - Mb)
+    :rect(m, x + rtl, y, w - rtl - rtr, Mt)          -- top
+    :rect(m, x + rbl, y + h - Mb, w - rbl - rbr, Mb) -- bottom
+    :rect(m, x, y + rtl, Ml, h - rtl - rbl)          -- left
+    :rect(m, x + w - Mr, y + rtr, Mr, h - rtr - rbr) -- right
+  end
+  self
+  :line(x + rtl, y, x + w - rtr, y)
+  :line(x, y + rtl, x, y + h - rbl)
+  :line(x + rbl, y + h, x + w - rbr, y + h)
+  :line(x + w, y + rtr, x + w, y + h - rbr)
+
+  :arc(m, x + rtl,     y + rtl,     rtl, math.pi, math.pi * 1.5)
+  :arc(m, x + w - rtr, y + rtr,     rtr, math.pi * 1.5, math.pi * 2)
+  :arc(m, x + w - rbr, y + h - rbr, rbr, 0, math.pi / 2)
+  :arc(m, x + rbl,     y + h - rbl, rbl, math.pi / 2, math.pi)
+  return self
+end
+
+end
diff --git a/src/draw/system.lua b/src/draw/system.lua
new file mode 100644
index 0000000..231e1ed
--- /dev/null
+++ b/src/draw/system.lua
@@ -0,0 +1,36 @@
+return function(draw)
+
+function draw:free(f)
+  if self.fr then return end
+  self.fr = true
+  --if self._cr then self._cr:release() end
+  if f then draw:freeFont() end
+  collectgarbage 'collect'
+end
+function draw:freeFont()
+  if self.f then self.f:release() end
+end
+
+function draw:give()
+  if self.fr then return end
+  self.pc = love.graphics.getCanvas()
+  if self.pc ~= self.cr then
+    love.graphics.push()
+    love.graphics.origin()
+    love.graphics.setCanvas(self._cr)
+  end
+  return self
+end
+
+function draw:back()
+  love.graphics.setCanvas(self.pc)
+  love.graphics.pop()
+  return self
+end
+
+function draw:full(full)
+  love.window.setFullscreen(full or false)
+  return self
+end
+
+end
\ No newline at end of file
diff --git a/src/draw/transform.lua b/src/draw/transform.lua
new file mode 100644
index 0000000..72be04c
--- /dev/null
+++ b/src/draw/transform.lua
@@ -0,0 +1,18 @@
+return function(draw)
+
+function draw:orig()
+  love.graphics.origin()
+  return self
+end
+
+function draw:move(x, y)
+  love.graphics.translate(x, y)
+  return self
+end
+
+function draw:scale(sx, sy)
+  love.graphics.scale(sx, sy)
+  return self
+end
+
+end
\ No newline at end of file
diff --git a/src/fs.lua b/src/fs.lua
new file mode 100644
index 0000000..5ad852a
--- /dev/null
+++ b/src/fs.lua
@@ -0,0 +1,31 @@
+return function()
+
+local lfs = love.filesystem
+
+function fsLs(path)
+  return lfs.getDirectoryItems(path)
+end
+
+function fsHas(file)
+  if lfs.getInfo
+  then return not not lfs.getInfo(file) end
+  return lfs.exists(file)
+end
+
+function fsInfo(file)
+  if lfs.getInfo
+  then return lfs.getInfo(file)
+  end
+  if not fsHas(file)
+  then return end
+  local info = {}
+  if     lfs.isFile(file)      then info.type = 'file'
+  elseif lfs.isDirectory(file) then info.type = 'directory'
+  elseif lfs.isSymlink(file)   then info.type = 'symlink'
+  else info.type = 'other' end
+  info.size    = lfs.getSize(file)
+  info.modtime = lfs.getLastModified(file)
+  return info
+end
+
+end
diff --git a/src/gui.lua b/src/gui.lua
new file mode 100644
index 0000000..a2ad4e1
--- /dev/null
+++ b/src/gui.lua
@@ -0,0 +1,28 @@
+local nlv = {}
+for k, v in pairs(love) do
+  nlv[k] = v
+end
+
+local gui = {}
+
+function gui.init()
+  love.draw   = gui.draw
+  love.update = gui.update
+
+  love.keypressed = nil
+  love.keyreleased = nil
+  love.textedited = nil
+  love.textinput = nil
+end
+
+function gui.update(dt)
+  updM()
+end
+
+function gui.stop()
+  for k, v in pairs(nlv) do
+    love[k] = v
+  end
+end
+
+return gui
diff --git a/src/hack.ttf b/src/hack.ttf
new file mode 100644
index 0000000..92a90cb
Binary files /dev/null and b/src/hack.ttf differ
diff --git a/src/mouse.lua b/src/mouse.lua
new file mode 100644
index 0000000..601df3b
--- /dev/null
+++ b/src/mouse.lua
@@ -0,0 +1,53 @@
+return function(con)
+
+local mob = love.system.getOS() == 'Android'
+
+m = {
+  x = 0, y = 0,
+  mx = 0, my = 0,
+  b = 0, pb = 0,
+  t = os.time(),
+}
+function updM()
+  local x, y = love.mouse.getPosition()
+  m.mx, m.my = x - m.x, y - m.y
+  m.x, m.y = x, y
+
+  m.pb = m.b
+  if     love.mouse.isDown(1) then m.b = 1
+  elseif love.mouse.isDown(2) then m.b = 2
+  elseif love.mouse.isDown(3) then m.b = 3
+  else m.b = 0 end
+
+  if m.b ~= 0 and m.pb == 0
+  then m.t = os.time() end
+
+  if m.pb == 0 and m.b ~= 0
+  then m.mx, m.my = 0, 0
+  end
+end
+
+function love.update(dt)
+  updM()
+
+  if m.b == 0 and m.pb ~= 0 then
+    if os.time() - m.t < 1 then
+      if mob
+      then love.keyboard.setTextInput(
+        not love.keyboard.hasTextInput(),
+        0, con.th + con.oy,
+        con.w * con.cw, con.ch)
+      end
+      con.down()
+    end
+  end
+
+  if m.b == 1
+  then con.move(m.my) end
+end
+
+function love.wheelmoved(x, y)
+  con.move(y * con.ch)
+end
+
+end
diff --git a/src/os.lua b/src/os.lua
new file mode 100644
index 0000000..528425e
--- /dev/null
+++ b/src/os.lua
@@ -0,0 +1,55 @@
+VER = '0.1'
+
+return function(con)
+
+love.keyboard.setKeyRepeat(true)
+
+require 'src.mouse' (con)
+require 'src.fs' ()
+require 'src.async'
+draw = require 'src.draw'
+
+local w, h
+function love.resize(x, y)
+  w, h = math.max(32, x), math.max(32, y)
+  draw:newFont('src/hack.ttf', math.min(w, h) / 32)
+  local cw, ch = draw:getFText 'A'
+  collectgarbage 'collect'
+  con:emit('res', w, h, cw, ch)
+end
+love.resize(love.graphics.getDimensions())
+love.window.setMode(w, h, {
+  resizable = true,
+  minwidth  = 32,
+  minheight = 32
+})
+
+love.textinput  = con.type
+love.keypressed = con.keydown
+
+function love.draw()
+  draw:color(100, 255, 0)
+  con.forText(function(l, x, y)
+    local cw, ch = draw:getFText(l)
+    if not (
+         l == '\n'
+      or l == '\r'
+      or l == '\v'
+      or l == '\t'
+    )
+    then draw:text(l, x * con.cw + (con.cw - cw) / 2, y * con.ch + con.oy)
+    end
+  end)
+end
+
+function loadapp(name, ...)
+  local succ, msg = pcall(require, 'sysapps.'.. name)
+  if not succ then
+    con.println('ERROR: '.. msg)
+    print(msg)
+  else
+    msg({...}, con)
+  end
+end
+
+end
diff --git a/src/term/events.lua b/src/term/events.lua
new file mode 100644
index 0000000..28de8d0
--- /dev/null
+++ b/src/term/events.lua
@@ -0,0 +1,51 @@
+--[[ Events library
+  -- (c) Er2 2021 <er2@dismail.de>
+  -- Zlib License
+--]]
+
+local events = {}
+events.__index = events
+
+function events:_add(t, n, f)
+  table.insert(self._ev_, {
+    type = t,
+    name = n,
+      fn = f,
+  })
+end
+
+function events:on(n,f)   self:_add('on', n,f)   end
+function events:once(n,f) self:_add('once', n,f) end
+
+function events:off(f)
+  for k, v in pairs(self._ev_) do
+    if v.fn == f then
+      table.remove(self._ev_, k)
+    end
+  end
+end
+
+function events:_ev(t, i, name, ...)
+  local v = t[i]
+  if v.name == name then
+    v.fn(...)
+    if v.type == 'once' then table.remove(t, i) end
+  end
+end
+
+function events:emit(name, ...)
+  local t = self._ev_
+  for i = 1, #t do
+    local v = t[i] or {}
+    if  type(v)      == 'table'
+    and type(v.name) == 'string'
+    and type(v.type) == 'string'
+    and type(v.fn)   == 'function'
+    then self:_ev(t, i, name, ...) end
+  end
+end
+
+return function(t)
+  t._ev_ = {}
+  return setmetatable(t, events)
+end
diff --git a/src/term/get.lua b/src/term/get.lua
new file mode 100644
index 0000000..6eccd27
--- /dev/null
+++ b/src/term/get.lua
@@ -0,0 +1,43 @@
+return function(con)
+
+function con.getch(tout)
+  local t, ch = os.time(), nil
+  con.usebs = false
+  con:once('type', function(text)
+    ch = text:sub(1, 1)
+  end)
+  await(function() return
+    ch ~= nil
+    or (tout and os.time() - t >= tout)
+  end)
+  con.usebs = true
+  return ch
+end
+
+function con.getln()
+  local ln, du = '', true
+  local function _ln(text)
+    ln = ln .. text
+  end
+  local function _dwn(k)
+    if k == 'backspace' then
+      if #ln == 0 then con.usebs = false
+      else
+        con.usebs = true
+        ln = con.bs(ln)
+      end
+    end
+  end
+  con:on('type', _ln)
+  con:on('down', _dwn)
+  con:once('return', function()
+    con:off(_ln)
+    con:off(_dwn)
+    con.usebs = true
+    du = false
+  end)
+  await(function() return not du end)
+  return ln
+end
+
+end
diff --git a/src/term/init.lua b/src/term/init.lua
new file mode 100644
index 0000000..8882903
--- /dev/null
+++ b/src/term/init.lua
@@ -0,0 +1,24 @@
+utf8 = require 'utf8'
+
+-- Model
+local con = {
+  text = {''},
+  w = 0, h = 0,
+  cw = 0, ch = 0,
+  oy = 0, th = 0,
+  usebs = true,
+}
+
+local m = {
+  'events', -- REQUIRED!
+  'loop',
+  'resize', 'type', 'get',
+}
+
+for _, v in pairs(m) do
+  require('src.term.'.. v)(con)
+end
+
+con:emit('init')
+
+return con
diff --git a/src/term/loop.lua b/src/term/loop.lua
new file mode 100644
index 0000000..097e9cb
--- /dev/null
+++ b/src/term/loop.lua
@@ -0,0 +1,27 @@
+return function(con)
+
+function con.forLine(l, fn, oy)
+  local x, y = 0, 0
+  for j, l in utf8.codes(con.text[l]) do
+    l = utf8.char(l)
+    if fn then fn(l, x, y + oy) end
+    if l == '\t' then x = x + 8 - (x % 8)
+    elseif l == '\v' then y = y + 1
+    elseif l == '\r' then x = 0
+    else x = x + 1
+    end
+    if x + 1 > con.w
+    then x, y = 0, y + 1 end
+  end
+  return y
+end
+
+function con.forText(fn)
+  local y = 0
+  for i = 1, #con.text do
+    y = y + 1 + con.forLine(i, fn, y)
+  end
+  return y
+end
+
+end
diff --git a/src/term/resize.lua b/src/term/resize.lua
new file mode 100644
index 0000000..0aafafd
--- /dev/null
+++ b/src/term/resize.lua
@@ -0,0 +1,31 @@
+return function(con)
+
+con:on('res', function(w, h, cw, ch)
+  con.cw, con.ch = cw or con.cw, ch or con.ch
+  con.w, con.h =
+    math.floor(w / cw),
+    math.floor(h / ch)
+  con:emit('resT')
+end)
+
+con:on('resT', function()
+  local y = con.forText()
+  con.th = y * con.ch
+end)
+
+function con.down()
+  con.oy = 0
+  con.move(-math.huge)
+end
+
+function con.move(oy)
+  con.oy = con.oy + oy
+  con.oy = math.max(
+    -(con.th - con.ch * con.h / 1.2),
+    math.min(con.oy, 0)
+  )
+  if con.th < (con.ch - 1) * con.h
+  then con.oy = 0 end
+end
+
+end
diff --git a/src/term/type.lua b/src/term/type.lua
new file mode 100644
index 0000000..bd6b48a
--- /dev/null
+++ b/src/term/type.lua
@@ -0,0 +1,67 @@
+return function(con)
+
+function con.curln(of)
+  return con.text[#con.text - (of or 0)]
+end
+
+function con.setln(v, of)
+  con.text[#con.text - (of or 0)] = tostring(v)
+  return v
+end
+
+function con.bs(oth)
+  if not con.usebs then return end
+  local s = oth or con.curln()
+  local off = utf8.offset(s, -1)
+  if off then
+    s = s:sub(1, off - 1)
+  end
+  if not oth then con.setln(s) end
+  return s
+end
+
+function con.cls()
+  con.text = {''}
+  con.oy = 0
+end
+
+function con.print(text)
+  for i, v in utf8.codes(tostring(text)) do
+    v = utf8.char(v)
+    if     v == '\n' then con.ret()
+    elseif v == '\b' then con.bs()
+    -- \r\t\v is in loop
+    else con.puts(v)
+    end
+  end
+end
+
+function con.puts(text)
+  con.setln(con.curln().. text)
+  con:emit('resT')
+end
+
+function con.println(text)
+  con.print(tostring(text).. '\n')
+end
+
+function con.ret()
+  table.insert(con.text, '')
+end
+
+function con.type(text)
+  con.puts(text)
+  con:emit('type', text)
+end
+
+function con.keydown(k)
+  con:emit('down', k)
+  if k == 'backspace'  then con.bs()
+  elseif k == 'return' then
+    con.ret()
+    con.down()
+    con:emit('return')
+  end
+end
+
+end
diff --git a/src/win.lua b/src/win.lua
new file mode 100644
index 0000000..c7eb88a
--- /dev/null
+++ b/src/win.lua
@@ -0,0 +1,54 @@
+local gui = require 'src.gui'
+
+local wins = {
+  {x = 64, y = 64, w = 64, h = 64},
+}
+
+local bw, th = 8, 16
+
+function gui.draw()
+  draw:color(0, 100, 150)
+  :rect(FILL, 0, 0, gui.w, gui.h)
+  :color(255, 255, 255)
+  :text('This is a demo of GUI in ErDOS', gui.w / 4, gui.h / 2)
+  for i = #wins, 1, -1 do
+    local v = wins[i]
+    draw
+    :color(100, 100, 100)
+    :rrect(FILL,
+      v.x - bw, v.y - bw - th,
+      v.w + bw * 2, v.h + bw * 2 + th,
+      {bw}
+    )
+    :color(255, 255, 255)
+    :rect(FILL, v.x, v.y, v.w, v.h)
+  end
+end
+
+function AABB(x1, y1, w1, h1, x2, y2, w2, h2)
+  return
+      x1 + w1 > x2
+  and x2 + w2 > x1
+  and y1 + h1 > y2
+  and y2 + h2 > y1
+end
+
+function gui.update(dt)
+  updM()
+  for i = 1, #wins do
+    local v = wins[i]
+    if AABB(m.x, m.y, 0, 0,
+      v.x - bw, v.y - bw - th,
+      v.w + bw * 2, v.h + bw * 2 + th
+    ) then
+      gui.stop()
+    end
+  end
+end
+
+return function(w, h)
+  gui.init()
+  gui.w, gui.h =
+    w or gui.w or 0,
+    h or gui.h or 0
+end
diff --git a/sysapps/choise.lua b/sysapps/choise.lua
new file mode 100644
index 0000000..e266c62
--- /dev/null
+++ b/sysapps/choise.lua
@@ -0,0 +1,35 @@
+return function(argv, con)
+  -- /Ckeys /S text
+  local ch = {'Y', 'N'}
+  local cs = false
+  local i = 2
+  while argv[i] do
+    local v = argv[i]:upper()
+    if v:sub(1,1) == '/'
+    then table.remove(argv, i)
+    else i = i + 1
+    end
+    if v:sub(1, 2) == '/C'
+    and #v > 2 then
+      ch = {}
+      for l in v:sub(3):gmatch '.' do table.insert(ch, l) end
+    elseif v == '/S' then cs = true
+    end
+  end
+  con.print(table.concat(argv, ' ', 2))
+  con.print(' ['.. table.concat(ch, ',') ..'] ')
+  con.print('('.. ch[1] ..') ')
+  local chr = con.getch(10)
+  if not chr then chr = ch[1] end
+
+  local ret = 0
+  for k, v in pairs(ch) do
+    if v == chr
+    or (not cs and v:upper() == chr:upper())
+    then ret = k end
+  end
+
+  con.print '\n'
+
+  return ret
+end
diff --git a/sysapps/cls.lua b/sysapps/cls.lua
new file mode 100644
index 0000000..b4c8d6a
--- /dev/null
+++ b/sysapps/cls.lua
@@ -0,0 +1,3 @@
+return function(argv, con)
+  con.cls()
+end
diff --git a/sysapps/dir.lua b/sysapps/dir.lua
new file mode 100644
index 0000000..759a5a3
--- /dev/null
+++ b/sysapps/dir.lua
@@ -0,0 +1,31 @@
+return function(argv, con)
+  local dir = argv[2] or ''
+  con.print(' Listing of '..dir ..'\n\n')
+  local d = fsLs(dir)
+  local dirs, files, tb = 0, 0, 0
+  for _, v in pairs(d) do
+    local i = fsInfo(dir..'/'..v)
+    con.print(os.date('%m/%d/%Y %I:%M %p  ', i.modtime))
+    if i.type == 'directory'   then con.print '<DIR>'
+    elseif i.type == 'symlink' then con.print '<SYM>'
+    elseif i.type == 'other'   then con.print '<OTH>'
+    else con.print '     ' end
+    if i.type == 'directory' then
+      dirs = dirs + 1
+      con.print '         '
+    else
+      files = files + 1
+      tb = tb + i.size
+      con.print ' '
+      local s = tostring(i.size)
+      con.print((' '):rep(7 - #s))
+      con.print(s)
+      con.print ' '
+    end
+
+    con.println(v)
+  end
+  con.println(('%d File(s)\n%d Dir(s)\n%d Bytes total')
+    :format(files, dirs, tb))
+  con.print '\n'
+end
diff --git a/sysapps/echo.lua b/sysapps/echo.lua
new file mode 100644
index 0000000..619b5c7
--- /dev/null
+++ b/sysapps/echo.lua
@@ -0,0 +1,3 @@
+return function(argv, con)
+  con.println(table.concat(argv, ' ', 2))
+end
diff --git a/sysapps/ersh.lua b/sysapps/ersh.lua
new file mode 100644
index 0000000..56d8f83
--- /dev/null
+++ b/sysapps/ersh.lua
@@ -0,0 +1,65 @@
+return function(argv, con)
+
+if argv[2] == '-v'
+then
+  con.println 'Er2Shell 0.5'
+  return
+end
+
+local sh = require 'src.baseshell' (con)
+
+function sh:prompt()
+  return ('%d > '):format(self.env.code)
+end
+
+function sh:run(ln)
+  local argv = self:parseArgs(ln)
+
+  if not argv[1] then -- nothing
+
+  elseif argv[1] == 'exit' then
+    self.runs = false
+
+  elseif argv[1] == 'which' then
+    local fnd, snd = self:which(argv[2])
+    if not fnd then self.env.code = 1
+    else self.env.code = 0
+      return fnd..snd
+    end
+
+  elseif argv[1] == 'env' then
+    local ls = ''
+    for k, v in pairs(self.env) do
+      k, v = tostring(k), tostring(v)
+      ls=ls.. ('$%s=%s\n')
+      :format(k, v:match '%s' and '"'..v..'"' or v)
+    end
+    self.env.code = 0
+    return ls:sub(1, -2)
+
+  else
+    local fnd, snd = self:which(argv[1])
+    if not fnd then
+      self.env.code = 127
+      return argv[1].. ': command not found'
+    else self.env.code = 0
+      local succ, msg = pcall(select(2, pcall(loadfile, fnd..snd)))
+      if not succ then
+        print(msg)
+        self.env.code = 126
+        return argv[1].. ': file error'
+      else
+        local succ, msg = pcall(msg, argv, con, self.env)
+        if not succ then
+          self.env.code = self.env.code ~= 0 and self.env.code or 1
+          return argv[1].. ': '.. tostring(msg)
+        else self.env.code = tonumber(msg) or 0
+        end
+      end
+    end
+  end
+end
+
+sh:loop()
+
+end
diff --git a/sysapps/run.lua b/sysapps/run.lua
new file mode 100644
index 0000000..393fa93
--- /dev/null
+++ b/sysapps/run.lua
@@ -0,0 +1,7 @@
+return function(argv, con)
+  local pr = print
+  print = con.println
+  local suc, ret = pcall(load(table.concat(argv, ' ', 2)))
+  print(ret)
+  print = pr
+end
diff --git a/sysapps/ver.lua b/sysapps/ver.lua
new file mode 100644
index 0000000..1467c18
--- /dev/null
+++ b/sysapps/ver.lua
@@ -0,0 +1,5 @@
+return function(argv, con)
+  con.println('ErDOS version '.. VER)
+  con.println('Runs on\vLove2D '.. table.concat({love.getVersion()}, '.', 1, 3))
+  con.println('(c) Er2 2022\tZlib License\n')
+end
diff --git a/sysapps/win.lua b/sysapps/win.lua
new file mode 100644
index 0000000..2a71dc6
--- /dev/null
+++ b/sysapps/win.lua
@@ -0,0 +1,3 @@
+return function(argv, con)
+  require 'src.win' (con.w * con.cw, con.h * con.ch)
+end