local function move(direction, increment)
    local switch = {
        ['up'] = function()
            for i=1,increment,1 do turtle.up() end
        end,
        ['down'] = function()
            for i=1,increment,1 do turtle.down() end
        end,
        ['forward'] = function()
            for i=1,increment,1 do turtle.forward() end
        end,
        ['right'] = function()
            for i=1,increment,1 do turtle.back() end
        end
    }

    local f = switch[direction]
    if(f) then
        f()
    else				-- for case default
        print "Defaulted."
    end
end

local function rotate(direction)
    local switch = {
        ['left'] = function()
            turtle.turnLeft()
        end,
        ['right'] = function()
            turtle.turnRight()
        end
    }

    local f = switch[direction]
    if(f) then
        f()
    else				-- for case default
        print "Defaulted."
    end
end

local function place(slot, text)
    turtle.select(slot)
    turtle.place(text)
end

local function dig(direction)

    local switch = {
        ['up'] = function()
            turtle.digUp()
        end,
        ['forward'] = function()
            turtle.dig()
        end,
        ['down'] = function()
            turtle.digDown()
        end
    }
    local f = switch[direction]
    if(f) then
        f()
    else				-- for case default
        print "Defaulted."
    end
end

function operation(optype, direction, slot, text, increment)
    direction = direction or ''
    slot = slot or ''
    text = text or ''
    increment = increment or ''
    local switch = {
        ['dig'] = function()
            dig(direction)
        end,
        ['move'] = function()
            move(direction, tonumber(increment))
        end,
        ['rotate'] = function()
            rotate(direction)
        end,
        ['place'] = function()
            place(tonumber(slot), text)
        end
    }
    local f = switch[optype]
    if(f) then
        f()
    else				-- for case default
        print "Defaulted."
    end
end