gps

turtlemove = {}

local ALLCMDS=fbudlrxsg
function turtlemove.doString(str, checkFuel, refuel, fuelRetLocation)
  local function fuelCheck()
    --TODO
  end
  local pos=0
  local str = string.lower(str)
  while pos <= string.len(str) do
    pos = pos+1
    fuelCheck()
    local c = string.sub(str,pos,pos)
    if string.find(ALLCMDS,c,1,true) then
      if string.find("fbudlr",c,1,true) then
        if c=="f" then
          while not turtle.forward() do os.sleep(0.01) end
        elseif c=="b" then
          while not turtle.back() do os.sleep(0.01) end
        elseif c=="u" then
          while not turtle.up() do os.sleep(0.01) end
        elseif c=="d" then
          while not turtle.down() do os.sleep(0.01) end
        elseif c=="l" then
          while not turtle.turnLeft() do os.sleep(0.01) end
        elseif c=="r" then
          while not turtle.turnRight() do os.sleep(0.01) end
        end
      elseif c=="x" then
        local numstr = ""
        while pos <= string.len(str) do
          pos = pos + 1
          c2 = string.sub(str,pos,pos)
          -- break check
          if c2 == "[" then break end
          -- errorcheck
          if not string.find("0123456789",c2,1,true) then error("Unexpected character "..c2.." at position "..pos.." in repetition count") end
          numstr = numstr .. c2
        end
        local pos_b = pos
        local reps = tonumber(numstr)
        if reps == nil then error("Repeated section at postition "..pos.." has no repetition count") end
        while true do
          pos=pos+1
          c3=string.sub(str,pos,pos)
          if c3=="]" then break end
          if pos > string.len(str) then error("Repeated section not closed by position "..pos) end
        end
        local cmdstr = string.sub(str,pos_b,pos)
        for i=1, reps do
          turtlemove.doString(cmdstr)
        end
      else
        error("Unimplemented character "..string.sub(str,pos,pos).." at position "..pos)
      end
    else
      error("Unexpected character "..string.sub(str,pos,pos).." at position "..pos)
    end
  end
end