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<DIV dir=ltr align=left><SPAN class=553374505-01052010><FONT color=#0000ff
face=Arial>When generating all rearra</FONT></SPAN><SPAN
class=553374505-01052010><FONT color=#0000ff face=Arial>ngements of a list (with
or without duplicates)</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=553374505-01052010><FONT color=#0000ff
face=Arial>This can be done with only one natural number for the internal
state, but call/cc seems more efficient to me.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=553374505-01052010><FONT color=#0000ff
face=Arial>Jos</FONT></SPAN></DIV><BR>
<DIV dir=ltr lang=en-us class=OutlookMessageHeader align=left>
<HR tabIndex=-1>
<FONT face=Tahoma><B>From:</B> plt-scheme-bounces@list.cs.brown.edu
[mailto:plt-scheme-bounces@list.cs.brown.edu] <B>On Behalf Of </B>Skeptic
.<BR><B>Sent:</B> 01 May 2010 03:11<BR><B>To:</B>
plt-scheme@list.cs.brown.edu<BR><B>Subject:</B> [plt-scheme] call/cc and
generators<BR></FONT><BR></DIV>
<DIV></DIV>
<DIV><BR></DIV>
<DIV>Hi,</DIV>
<DIV><BR></DIV>
<DIV>Generators are often given as good usage of call/cc, but in many cases it
seems to me that explicitly saving the state is simple enougth that capturing
the continutation is not needed.</DIV>
<DIV><BR></DIV>
<DIV>For example, if one wants to do something like (make-unfold-generator ...)
it is easy to manage the unfold index inside a closure.</DIV>
<DIV><BR></DIV>
<DIV>The only good counter-example I have seen and used before is a recursive
tree traversal, in this case call/cc appears to be the only way to
go. </DIV>
<DIV><BR></DIV>
<DIV>I'm curious if someone have other examples of generators where call/cc is a
good solution (or any interesting not-too-complex usage of call/cc).</DIV>
<DIV><BR></DIV>
<DIV>Thanks.</DIV>
<DIV><BR></DIV>
<DIV><BR></DIV><BR>
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