slider Control - new to coding

Hi all, I’m new to coding and new to corona. I’m messing around trying to learn my way around. 

I’m getting a little stuck on my code. I am trying to move an object on the screen a specific amount for every time a finger drags along the screen a specific amount, kind of like tetris.

For example every time my finger moves 100 pixels on along the x-axis I want to move the object 50 pixels on the axis in the direction I am moving my finger (east - west).

Here is my code I tried… it only moves once then stops

Thanks 

[lua]

local scrollSpeed = 100

function controlBar:touch( event )

    startPosition = event.xStart

    currentPosition = event.x

    newPosition = event.x

    slide = startPosition -currentPosition

    if event.phase == “moved” then

        if slide == scrollSpeed then

            baseBlock001.x = baseBlock001.x - baseBlock001.contentWidth

            currentPosition = 0        

        elseif     slide == -scrollSpeed then

            baseBlock001.x = baseBlock001.x + baseBlock001.contentWidth – determine speed

            currentPosition = 0

        end    

        slide = newPosition - currentPosition    

    end

    

end

[/lua]