I don’t feel like Teletype scripts are the right tool for the job, given the available ops.
Linear ramps are pretty easy (CV.SET, CV.SLEW and CV). The first thing I would try would be multing a CV output through both inputs of a ring modulator to get exponential curves. Alternately, using an exponential VCA with a fixed CV offset to convert the linear ramp to a curved one – or some sort of triangle-to-sine waveshaper, maybe.
Otherwise, maybe a two-stage linear ramp is a close enough approximation – putting a second CV.SLEW command on a very short timer. I’m not sure whether Teletype’s timing is tight enough to accomplish that though.
Several weeks ago I brought up the possibility of a CV scaling function as a possible Teletype OP, for this purpose and for sine or sine-like LFOs.