[PD] phasor~: change freq on wraparound

[Orm Finnendahl]

Hi List,

 sorry if I'm missing the obvious: I'd like to implement a phasor~,
which only allows its frequency to be changed on wraparound. Using a
samphold~ for that purpose connected to the outlet and inlet of the
phasor~ doesn't work as this creates a dsp loop. 

I prefer a pd vanilla solution (I know how to implement it as an
external, but for portability I'd like to get it done without).

Any ideas?

Yours,
Orm