Stairs

--To build stairs, need width of stairwell, height of stairwell, depth of stairwell
local tArgs = {...}

-- Deal with arguments and variables
local args = tArgs
local curr_height,curr_width,curr_depth = 1
local direction = nil
local dig = nil

-- error handling
local syntax_error="Invalid syntax.  Try using:\n stairs X Y Z\n X = Height of stairwell\n Y = Width of stairwell\n Z = Depth of stairwell\n\nX, Y, and Z must be integers"

-- right # & type of arguments?
function initialize()
    if #args ~= 3 or tonumber(value)==nil then
            return print(syntax_error)

    else
            -- set measurements
            local height = tonumber(args[1])
            local width = tonumber(args[2])
            local depth = tonumber(args[3])

            -- get direction
            print("<U>p or <D>own?")
            local input=string.lower(read())
            responses = {"up"=true,"down"=true,"u"=true,"d"=true}

            -- return lowercase first character to determine stairwell direction
            if responses.input then
                    direction = string.sub(input,1,1)
                    return direction
            end
    end


-- dig one column to specified height
function column(direction, height)
        if direction == "u" then
                while curr_height < height do
                        turtle.digUp()
                        turtle.moveUp()
                        curr_height = curr_height + 1
                end
                while curr_height ~=1 do
                        turtle.moveDown()
                        curr_height = curr_height - 1
                end
        else
                while curr_height < height - 1 do
                        turtle.digDown()
                        turtle.digUp()
                        turtle.moveUp()
                        curr_height = curr_height + 1
                end
        end
        return
end

-- digs riser to width and height
function digriser(width)
        for col=1, width, 1 do
                column()
                turtle.turnRight()
                turtle.moveForward()
                turtle.turnLeft()
        end
        turtle.turnLeft()
        turtle.turnLeft()
        turtle.moveForward(width - 1)
        turtle.turnRight()
        turtle.dig()
        turtle.moveForward()
        return
end

-- digs out the stairs
function digstairs(depth)
        while curr_depth ~= depth do
                digriser(width)
                curr_dept = curr_depth + 1
        end
end