Accumulate iterator adapter for rust itertools (like itertools.accumulate in Python itertools)

[evan0greenup]

I don't find iterator adapter like itertools.accumulate(iterable[, func, *, initial=None]) in Rust itertools.

It would be nice to add it in.

[phimuemue]

Isn't this scan?

[Philippe-Cholet]

Yes it very similar to scan but it's not very obvious at first look. With initial=0 and the default func the addition.

(1..8).scan(0, |x, y| { *x += y; Some(*x) })

while people from coming Python would expect something more like

(1..8).some_name(0, |x, y| x + y)

Like in #147

EDIT: Playground example of accumulate[_add] functions.