Henning Thielemann wrote:
On Wed, 4 Nov 2009, Sjoerd Visscher wrote:
On Nov 4, 2009, at 3:21 PM, Twan van Laarhoven wrote:
I looked on hackage but I was surprised that I couldn't find
this simple
monad. The package level-monad does look very similar, only it
uses a
different list type for the representation.
indeed, level-monad works as well:
import Control.Monad.Levels
import Data.FMList (fromList)
diagN = bfs . mapM fromList
Can someone explain the difference between control-monad-omega and
level-monad?
So from what I understand this is the difference:
Omega is biased towards the lower dimensions while Levels
treats all dimensions equally, or at least more equally. You can
formalize the latter by saying: the sums of the indices should be
non-decreasing.
From Omega's documentation I understand this is on purpose:
"(...) Likewise, a breadth-first search of a data structure can fall
short if it has an infinitely branching node. Omega addresses this
problem by using a "diagonal" traversal that gracefully dissolves such
data."
However, I can't verify this:
runOmega . mapM each $ map (:[]) [1..]
*** Exception: stack overflow
Or maybe I misunderstood Omega's documentation.
Martijn.
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