[LUA] BrainFuck

local sub, char, byte, match = string.sub, string.char, string.byte, string.match

local cpu = {}

local params = _ARGS
if not params then return end
local ret = ''

local text, chars = match(AnsiToUtf8(params), '(%S+)%s*(.*)')

local l, j, brc, i = 0, 0, 0, 0

local function getChar()
  l = l + 1
  return byte(chars, l)
end

while #text > i do
  i = i + 1
  local ch = sub(text, i, i)
  if ch == '>' then j = j + 1
  elseif ch == '<' then j = j - 1
  elseif ch == '+' then cpu[j] = ( cpu[j] or 0 ) + 1
  elseif ch == '-' then cpu[j] = ( cpu[j] or 0 ) - 1
  elseif ch == '.' then ret = ret .. char(cpu[j])
  elseif ch == ',' then cpu[j] = getChar()
  elseif ch == '[' then
    if not cpu[j] or cpu[j] == 0 then
      brc = brc + 1
      while brc ~= 0 do
        i = i + 1
        local chh = sub(text, i, i)
        if chh == '[' then brc = brc + 1
        elseif chh == ']' then brc = brc - 1 end
      end
    end
  elseif ch == ']' then
    if cpu[j] and cpu[j] > 0 then
      brc = brc + 1
      while brc ~= 0 do
        i = i - 1
        local chh = sub(text, i, i)
        if chh == '[' then brc = brc - 1
        elseif chh == ']' then brc = brc + 1 end
      end
      i = i - 1
    end
  end
end

return ret