enumFrom documentation seems inaccurate

[jchia]

The documentation for enumFrom disagrees with my REPL experiment.
https://hackage.haskell.org/package/streaming-0.2.3.0/docs/Streaming-Prelude.html#v:enumFrom

I replaced the S.enumFrom 1 with S.each [1..] and got the same result, contrary to the documentation which says "With each [1..] the following bit of connect-and-resume would be impossible". Is the documentation out of date or am I misreading the documentation?

[danidiaz]

You are correct that with S.each [1..] it works. What fails is using S.each ['a'..], like this:

rest <- S.print $ S.zip (S.each ['a'..]) $ S.splitAt 3 $ S.enumFrom 1

The reason is that S.splitAt puts "the rest of the stream" in the resulting Stream's return value. Since the stream created by S.each ['a'...] has return type () instead of being polymorphic, there's now a type mismatch in S.zip.

So perhaps the example should be changed to mention S.each ['a'..] instead.

Or better yet: modify the example in this way:

rest <- S.print $ S.zip (S.enumFrom 1) $ S.splitAt 3 $ S.each ['a'..'z']

Here each is used with a finite list, as intended, and the S.enumFrom 1 is not changeable with S.each [1..].