Direct Turtle command template

--[[
    Template program for using 4 commands:
    f 5 dig translates to move forward 5 blocks, dig anything in the way
    u 3     translates to move up 3 blocks, do not break any blocks.
    d 6 dig translates to move down 6 blocks, digDown anything in the way
    b 4     translates to move back 4 blocks, do not break any blocks
    name your 4 programs f.lua, u.lua, d.lua, b.lua
    Change the direction in line 100 to suit
]]
args = {...}

function checkArgs()
    local numBlocksRequested = 1
    local doDig = false
    if args[1] ~= nil then
        numBlocksRequested = args[1]
    end
    if args[2] ~= nil then
        doDig = true
    end
    return numBlocksRequested, doDig
end

function doMoves(numBlocksRequested, doDig, direction)
    local errorMsg = nil
    local numBlocksMoved = 0
    local Move, Dig, Detect

    -- re-assign turtle functions to new variables
    if direction == "f" or direction == "b" then
        Move = turtle.forward
        Dig = turtle.dig
        Detect = turtle.detect
    elseif direction == "u" then
        Move = turtle.up
        Dig = turtle.digUp
        Detect = turtle.detectUp
    else
        Move = turtle.down
        Dig = turtle.digDown
        Detect = turtle.detectDown
    end

    if direction == "b" then
        turtle.turnRight()
        turtle.turnRight()
    end

    for i = 1, numBlocksRequested, 1 do
        local moveOK, moveError = Move() -- try to move forward/up/down
        if doDig then
            if moveOK then
                numBlocksMoved = numBlocksMoved + 1
            else
                -- while moveOK == false do -- same effect if you prefer.
                while not moveOK do -- did not move if obstruction
                    local digOK, digError = Dig()
                    if digOK then
                        sleep(0.5) -- allow sand / gravel to drop if digging forward / up
                    else -- unable to dig, or nothing to dig
                        if digError == "Unbreakable block detected" then
                            errorMsg = digError
                            break
                        end
                    end
                    moveOK, moveError = Move() -- try to move forward/up/down again
                    if moveOK then
                        numBlocksMoved = numBlocksMoved + 1
                    end
                end
            end
        else
            if moveOK then
                numBlocksMoved = numBlocksMoved + 1
            else
                errorMsg = moveError
            end
        end
    end

    if direction == "b" then
        turtle.turnRight()
        turtle.turnRight()
    end

    return numBlocksMoved, errorMsg
end


function printLog(numBlocksRequested, numBlocksMoved, errorMsg)
    print("Moved forwards "..numBlocksMoved.. " / ".. numBlocksRequested)
    if errorMsg ~= nil then
        print (errorMsg)
    end
end

function main()
    --***********************************************************************************************
    --Change this to "f" or "d" or "u" or "b" to suit application (forward, up, down, back) f.lua, d.lua, u.lua, b.lua
    local direction = "f" -- this is for f.lua
    --***********************************************************************************************
    local numBlocksRequested, doDig = checkArgs()
    if turtle.getFuelLevel() == 0 then
        print("No fuel")
    else
        print("Fuel level: "..turtle.getFuelLevel())
        local numBlocksMoved, errorMsg = doMoves(numBlocksRequested, doDig, direction)
        printLog(numBlocksRequested, numBlocksMoved, errorMsg)
    end
end

main()