Without a microcontroller it'll be pretty tricky - is there any reason you don't want to use one? You'll need a quadrature encoder if you want it to work in both directions - a quadrature encoder has two outputs, and the order in which they trigger gives the direction of motion. If you really don't want to use a microcontroller, this is what I'd do:
Start with the quadrature encoder and a stepper motor driver that takes a direction input, and a step input (a pololu would be fine).
Connect the two quadrature encoder pins to the input of a 2-input AND gate (or NAND). Connect the output to the step pin of the driver.
Connect the two encoder pins to the S and R inputs of an SR latch. Connect the output to the direction pin of the driver.
This /should/ work, assuming I haven't made a silly mistake.
Start with the quadrature encoder and a stepper motor driver that takes a direction input, and a step input (a pololu would be fine).
Connect the two quadrature encoder pins to the input of a 2-input AND gate (or NAND). Connect the output to the step pin of the driver.
Connect the two encoder pins to the S and R inputs of an SR latch. Connect the output to the direction pin of the driver.
This /should/ work, assuming I haven't made a silly mistake.