[Haskell-cafe] strange stack overflow with Data.Map

Bulat Ziganshin bulatz at HotPOP.com
Thu Dec 29 03:22:11 EST 2005

Hello David,

Thursday, December 29, 2005, 3:42:05 AM, you wrote:

>> stats elems = foldl add_elem Map.empty elems

DR> This program has a space leak and runs out of stack space.  I'm guessing
DR> that I'm being bit here by an unnatural amount of laziness in
DR> Map.insertWith

stack overflows AFAIK is never occur because of laziness, but only
because your recursion is not tail-optimized. as Udo says, problem may
be fixed by using proper fold. if foldl' will not work - try to write
your own, explicit looping scheme

Best regards,
 Bulat                            mailto:bulatz at HotPOP.com

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