Concerning this exercise, would it be simply possible to take the most of lazy evaluation and build a graph?<br><br>A node would be:<br><span style="font-family: courier new,monospace;">Node a = </span><span style="font-family: courier new,monospace;"><font face="courier new,monospace">Node { data    :: a,<br>


                parents :: [Node a],<br>
                children :: [Node a] }<br><br><span style="font-family: arial,helvetica,sans-serif;">Then, whichever node you are on, you can still directly find its predecessors, i.e. your way back in the labyrinth.</span><br style="font-family: arial,helvetica,sans-serif;">



<span style="font-family: arial,helvetica,sans-serif;">I find it more simple than a zipper (of course, now you cannot serialize it, due to the cross-references).</span><br></font></span><br><br><div class="gmail_quote">2011/3/16 Andrew Coppin <span dir="ltr">&lt;<a href="mailto:andrewcoppin@btinternet.com" target="_blank">andrewcoppin@btinternet.com</a>&gt;</span><br>



<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div>On 15/03/2011 11:35 PM, Brent Yorgey wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
I am pleased to announce that the special Poetry and Fiction Edition<br>
of The Monad.Reader is now available [1]. Enjoy!<br>
</blockquote>
<br></div>
I love exercise 8, &quot;write a complete computer game using this idea&quot; (!)<div><div></div><div><br>
<br>
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