I&#39;m a beginner too but, if I am not wrong, then you will not be able to write a function that can receive input of type [[a]] as well as input of type [[[a]]].<div><br></div><div>Is that the behaviour that you have in mind?<br>

<br><div class="gmail_quote">On Thu, Apr 8, 2010 at 09:08, Ben Derrett <span dir="ltr">&lt;<a href="mailto:ben.derrett@googlemail.com">ben.derrett@googlemail.com</a>&gt;</span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">

Hi,<div>I&#39;m trying to write a generalization of the map function that operates on nested lists, e.g. [[a]] or [[[a]]]. (It should map all elements of type a (not list) with f)</div><div><br></div><div>I was thinking of something along these lines:</div>



<div>mapN f *list of type [a] (where a is not a list type)* = map f l</div><div>mapN f l = (mapN f (head l)):(mapN f (tail l))<br><div><br></div><div>Any suggestions about how to go about this?</div><div><br></div><div>Many thanks,</div>



<div><br></div><div>Ben</div><div><br></div><div><br>-- <br>Ben Derrett<br>Department of Mathematics<br>MIT Class of 2012<br><a href="mailto:bderrett@mit.edu" target="_blank">bderrett@mit.edu</a><br>
</div></div>
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<br></blockquote></div><br><br clear="all"><br>-- <br>mac<br>
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