Why can't the Iterator work correctly?

[hmf]

@MikuChaser

I think Martin Odersky may not want to create a lazy map method. Is it a bug?

No it is not a bug. For an explanation of why, look at:

Why is my implementation of Iterable not lazy

I am implementing a wrapper that manages iterators within it. Essentially I keep iterators in the wrapper that represent columns of data. While testing I found that my wrapper is not lazy. So I made this very simple test: val counter1 = Stream.from(1).toIterable // No need to call toIterable val r1 = counter1.map( _ * 2).take(25).toList // terminates println(r1) The infinite stream above can be processed lazily. So now I implement my own Iterable and expect it to behave lazily …

Its seems this will change in 2.13 and map should retain its laziness.