Thanks Wren,

Thanks Dave ... a quick question though could you point me to an example where I could build up my own in place modifiable data structure in Haskell without using any standard library stuff?

For example, if I wanted an image representation such as this [[(Int,Int.Int)]] - basically a list of lists of 3 tuples (rgb) and wanted to do in place replacement to set the pixel values, how could I go about it.


On Fri, Jul 16, 2010 at 9:47 AM, wren ng thornton <wren@freegeek.org> wrote:
C K Kashyap wrote:
Thanks Daniel,

Better refactorability.
If you're using monadic style, changing from, say,
State Thing
to
StateT Thing OtherMonad

or from
StateT Thing FirstMonad
to
StateT Thing SecondMonad

typically requires only few changes. Explicit state-passing usually
requires more changes.

So, performance gain (runtime/memory) is not a side effect of Monadic style
right?

Generally speaking, right: monadic style won't improve performance.

However, using monadic notation may allow you to change the backing monad to a different representation of "the same" computation, thereby giving asymptotic improvements[1]. However, the improvements themselves are coming from the different representation; the use of monadic notation just allows you to switch the representation without altering the code.


[1] http://www.iai.uni-bonn.de/~jv/mpc08.pdf

--
Live well,
~wren


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Regards,
Kashyap