@Preben Alsholm, thank you for modification.
I thought that arrow operator is a special form of procedure, so it wouldn't be a big mistake to call this function a procedure. (At least Maplesoft says so: https://www.maplesoft.com/support/help/Maple/view.aspx?path=operators/functional)
I want to add method to this construction, because it's very slow that way.
# epsilon=1e-3 -- 1.388s
# epsilon=1e-4 -- 1.570s
# epsilon=1e-5 -- 2.193s
# epsilon=1e-6 -- wouldn't converge
Integrand should be oscillating so I wanted to add method=_d01akc from NAG Library. But I got an error:
Error, (in evalf/int) cannot handle unevaluated name `t` in evalhf