<html> <head> <style></style> </head> <body class='hmmessage'> <div><br></div>I always assumed that using lists as trees/sets/maps was fairly idiomatic Scheme when prototyping / dealing with small datasets.<div><br></div><div><br></div><div>> Subject: Re: [plt-scheme] append-map examples<br>> From: matthias@ccs.neu.edu<br>> Date: Fri, 9 Apr 2010 22:49:29 -0400<br>> CC: skeptic2000@hotmail.com; plt-scheme@list.cs.brown.edu<br>> To: ryanc@ccs.neu.edu<br>> <br>> <br>> Dan Friedman once shared a rule with me: when you use append-map, you are using the wrong data representation. <br>> <br>> Examples: <br>> <br>> <br>> On Apr 9, 2010, at 10:40 PM, Ryan Culpepper wrote:<br>> <br>> > Skeptic . wrote:<br>> >> Hi,<br>> >> Does someone knows canonical/pedagogical exemples of append-map except other than flatten ?<br>> > <br>> > Collect a list of all the X in a Y.<br>> > <br>> > eg, the list of free variables in a lambda term<br>> <br>> Free variables come in sets, not lists. <br>> <br>> <br>> > eg, the list of links in a web page (as xexpr or sxml)<br>> <br>> Ditto. <br>> <br>> <br></div> <br /><hr />Messenger sur votre téléphone = MI sur la route <a href='http://go.microsoft.com/?linkid=9724469' target='_new'>Essayez-le maintenant.</a></body> </html>