In Maple 2018 help written:
The interpolation methods available in the Interpolation package all work as follows. First, the user calls one of the commands in the package, submitting the input points and the values at these points. This returns an object encapsulating all the data and options submitted. This object can then be used like a normal mathematical function, e.g. for plotting, integration, or just to evaluate at a given point.
The Interpolation[Interpolate] command was introduced in Maple 2018
My test example:
points := [seq(x, x = 0 .. 10, 1)]; data := [seq(sqrt(1.+x^2), x = 0 .. 10, 1)];
f := Interpolate(points, data);
f(1); # OK works :).
int(f(x), x = 0 .. 1); # Not working ?
int(f(x), x = 0 .. 1,numeric); # Not working ?
eval(diff(f(x), x), x = 2);# Not working ?
plot(f(x), x = 0 .. 10);# OK works :)
plot([f(x), diff(f(x), x)], x = 0 .. 10);# Not working ?
plot([f, diff(f, x)], 0 .. 10);# Only a half working ?