discrete-time (slew) rate limiting algorithm
Like the old German saying goes:

If you give a man a filter, everything looks like a signal that needs to be low-pass filtered

or so. 

Slew rate and signal bandwidth are closely related. Simply low-pass filter your signal; usually, you'd do that with a linear filter, not an non-linear filter, and especially not a non-linear recursive one, because those are pretty hard to get stable.

By the way, if you look at FIR and IIR filters, you'll notice that we model these in z-Domain as polynomials, but by doing so, we can apply them to the signal in a linear way.