#464 Support for self-defined peridodic functions

[oliver]

Would be nice to have a way, to plot self-defined functions, that are periodic.
e.g.
f(x) = (x-a) ^ 3, defined for -2 <= x < 2, and being periodically repeated if x < -2 or x > 2, and that ad infinitum (modulo x-range of that function).

That way a lot of real world functions could be ploted.

[Ethan Merritt]

mod(x) = (x-2)-floor((x-2)/4.)*4.
plot f(mod(x))

[Shigeharu TAKENO]

Another solution:
mod(x) = (x<-2) ? mod(x+4) : (x>=2) ? mod(x-4) : x
plot f(mod(x))