On Sat, Sep 25, 2010 at 03:45:15AM +0200, Daniel Fischer wrote:
On Saturday 25 September 2010 02:55:24, Ian Lynagh wrote:
On Fri, Sep 24, 2010 at 09:21:19PM +0200, Daniel Fischer wrote:
Proposal: A stricter implementation of lines.
Reason: The current implementation causes a space leak (cf. http://homepages.inf.ed.ac.uk/wadler/papers/leak/leak.ps), at least in GHC.
The proposed implementation fixes the leak at the small cost of being stricter if the first _|_ in the String is the first character of a line.
I think this changes the definition from one that currently has a space leak with GHC, to one which necessarily must have a space leak (as all of l must be held in memory while we look for a newline).
No, with the proposed implementation, e.g. counting line lengths runs in constant space:
Ah, yes, you are right, sorry. I don't have a strong opinion, then. We ought to put the old definition into the H98 and H2010 packages, though. Hmm, but currently Prelude always comes from base. Thanks Ian