[Haskell-cafe] Need help - my haskell code is over 50 times slower than equivalent perl implementation

C K Kashyap ckkashyap at gmail.com
Wed Jun 25 01:56:43 UTC 2014


Thank you Tom, Niklas, Nicolas and Stuart,
Calculating the length was just an illustration - what I really need to do
is parse the file. Anyway, it is clear that String for IO is a bad idea - I
wonder if examples of String based readFile etc for beginners is a good
idea or not.
Regards,
Kashyap


On Tue, Jun 24, 2014 at 10:44 PM, Tom Ellis <
tom-lists-haskell-cafe-2013 at jaguarpaw.co.uk> wrote:

> On Tue, Jun 24, 2014 at 10:37:35PM +0530, C K Kashyap wrote:
> > Thanks Nicholas :) ... and if I understand right doing `seq` would be
> > equivalent to Strict IO that Darren mentioned. right?
>
> It's probably best to think of them as distinct.
>
> Strict IO roughly means the whole file will be read at once so the file
> handle can be released.  On the other hand `seq`ing the `length` forces the
> calculation of the length so the file is read completely and the file
> handle
> can be released.  They have similar outcomes but the means of achieving
> them
> is different.
>
> Tom
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