[Haskell-cafe] Re: Query on list comprehension

[Richard O'Keefe]

The problem we were asked about was specifically
     a
     aa
     aaa
The code (iterate ('a':) "\n") does not give the right answer.
It's not just that it produces an infinite list instead of three
strings, it doesn't even start with the right string.  It starts
with "\n" when we need "a\n".

To produce the specified output using that pattern, you need
     (take 3 . tail . iterate ('a':)) "\n"
or any of several other alternatives.

The original poster also didn't ask "what is the best way to do
this", but specifically asked about doing it with list
comprehension.  Presumably this was an attempt to understand list
comprehension better.