OC-PsychOS2/module/vt100.lua

function vt100emu(gpu) -- takes GPU component proxy *gpu* and returns a function to write to it in a manner like an ANSI terminal
 local colours = {0x0,0xFF0000,0x00FF00,0xFFFF00,0x0000FF,0xFF00FF,0x00B6FF,0xFFFFFF}
 local mx, my = gpu.maxResolution()
 local cx, cy = 1, 1
 local pc = " "
 local lc = ""
 local mode = "n"
 local lw = true
 local sx, sy = 1,1
 local cs = ""
 local bg, fg = 0, 0xFFFFFF

 -- setup
 gpu.setResolution(mx,my)
 gpu.fill(1,1,mx,my," ")

 function termwrite(s)
  local rs = ""
  s=s:gsub("\8","\27[D")
  pc = gpu.get(cx,cy)
  gpu.setForeground(fg)
  gpu.setBackground(bg)
  gpu.set(cx,cy,pc)
  for i = 1, s:len() do
   local cc = s:sub(i,i)

   if mode == "n" then
    if cc == "\n" then -- line feed
     cx, cy = 1, cy+1
    elseif cc == "\r" then -- cursor home
     cx = 1
    elseif cc == "\27" then -- escape
     mode = "e"
    elseif cc == "\t" then
     cx = 8*((cx+9)//8)
    elseif string.byte(cc) > 31 and string.byte(cc) < 127 then -- printable, I guess
     gpu.set(cx, cy, cc)
     cx = cx + 1
    end

   elseif mode == "e" then
    if cc == "[" then
     mode = "v"
     cs = ""
    elseif cc == "D" then -- scroll down
     gpu.copy(1,2,mx,my-1,0,-1)
     gpu.fill(1,my,mx,1," ")
     cy=cy+1
     mode = "n"
    elseif cc == "M" then -- scroll up
     gpu.copy(1,1,mx,my-1,0,1)
     gpu.fill(1,1,mx,1," ")
     mode = "n"
    else
     mode = "n"
    end

   elseif mode == "v" then
    mode = "n"
    if cc == "s" then -- save cursor
     sx, sy = cx, cy
    elseif cc == "u" then -- restore cursor
     cx, cy = sx, sy
    elseif cc == "H" then -- cursor home or to
     local tx, ty = cs:match("(%d+);(%d+)")
     tx, ty = tx or "1", ty or "1"
     cx, cy = tonumber(tx), tonumber(ty)
    elseif cc == "A" then -- cursor up
     cy = cy - (tonumber(cs) or 1)
    elseif cc == "B" then -- cursor down
     cy = cy + (tonumber(cs) or 1)
    elseif cc == "C" then -- cursor right
     cx = cx + (tonumber(cs) or 1)
    elseif cc == "D" then -- cursor left
     cx = cx - (tonumber(cs) or 1)
    elseif cc == "h" and lc == "7" then -- enable line wrap
     lw = true
    elseif cc == "l" and lc == "7" then -- disable line wrap
     lw = false
    elseif cc == "c" then
     rs = string.format("%s\27[%d;%d0c",rs,mx,my)
    elseif cc == "n" and lc == "6" then
     rs = string.format("%s\27[%d;%dR",rs,cx,cy)
    elseif cc == "m" then
     for num in cs:gmatch("%d+") do
      num=tonumber(num)
      if num == 0 then
       fg,bg = 0xFFFFFF,0
      elseif num == 7 then
       local nfg,nbg = bg, fg
       fg, bg = nfg, nbg
      elseif num > 29 and num < 38 then
       fg = colours[num-29]
      elseif num > 39 and num < 48 then
       bg = colours[num-39]
      end
     end
     gpu.setForeground(fg)
     gpu.setBackground(bg)
    else
     cs = cs .. cc
     if cc:match("[%d;]") then
      mode = "v"
     end
    end
   end

   if cx > mx and lw then
    cx, cy = 1, cy+1
   end
   if cy > my then
    gpu.copy(1,2,mx,my-1,0,-1)
    gpu.fill(1,my,mx,1," ")
    cy=my
   end
   if cy < 1 then cy = 1 end
   if cx < 1 then cx = 1 end

   lc = cc
  end
  pc = gpu.get(cx,cy)
  gpu.setForeground(bg)
  gpu.setBackground(fg)
  gpu.set(cx,cy,pc)
  gpu.setForeground(fg)
  gpu.setBackground(bg)
  return rs
 end

 return termwrite
end