Set Heading

function setHeading(heading,newHeading)
     if(heading ~= 'N' and heading ~= 'n' and heading ~= 'E' and heading ~= 'e' and heading ~= 'S' and heading ~= 's' and heading ~= 'W' and heading ~= 'w') then
        if(turtle.getFuelLevel() < 2) then
            error("Insufficient fuel")
        end
                local start = vector.new(gps.locate())
                while(turtle.detect()) do
                        turtle.dig()
                end
                turtle.forward()
                local current = vector.new(gps.locate())
                turtle.back()
                if(start.z - current.z > 0) then
                        heading = 'N'
                elseif (start.z - current.z < 0) then
                        heading = 'S'
                end
                if(start.x - current.x > 0) then
                        heading = 'W'
                elseif (start.x - current.x < 0) then
                        heading = 'E'
                end
        end

    if(heading ~= newHeading) then
        if(newHeading == 'N' or newHeading == 'n') then
            if(heading == 'S' or heading == 's') then
                turtle.turnLeft()
                turtle.turnLeft()
            end
            if(heading == 'E' or heading == 'e') then
                turtle.turnLeft()
            end
            if(heading == 'W' or heading == 'w') then
                turtle.turnRight()
            end
        end
        if(newHeading == 'E' or newHeading == 'e') then
            if(heading == 'S' or heading == 's') then
                turtle.turnLeft()
            end
            if(heading == 'N' or heading == 'n') then
                turtle.turnRight()
            end
            if(heading == 'W' or heading == 'w') then
                turtle.turnRight()
                turtle.turnRight()
            end
        end
        if(newHeading == 'S' or newHeading == 's') then
            if(heading == 'N' or heading == 'n') then
                turtle.turnLeft()
                turtle.turnLeft()
            end
            if(heading == 'E' or heading == 'e') then
                turtle.turnRight()
            end
            if(heading == 'W' or heading == 'w') then
                turtle.turnLeft()
            end
        end
        if(newHeading == 'W' or newHeading == 'w') then
            if(heading == 'S' or heading == 's') then
                turtle.turnRight()
            end
            if(heading == 'E' or heading == 'e') then
                turtle.turnLeft()
                turtle.turnLeft()
            end
            if(heading == 'N' or heading == 'n') then
                turtle.turnLeft()
            end
        end
    end
end


print("Please enter heading")
heading = read()
newheading = read()
setHeading(heading,newheading)