cpython/Tools/scripts/dutree.doc

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From: tchrist@convex.COM (Tom Christiansen)
Newsgroups: comp.lang.perl
Subject: Re: The problems of Perl (Re: Question (silly?))
Message-ID: <1992Jan17.053115.4220@convex.com>
Date: 17 Jan 92 05:31:15 GMT
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From the keyboard of flee@cs.psu.edu (Felix Lee):
:And Perl is definitely awkward with data types.  I haven't yet found a
:pleasant way of shoving non-trivial data types into Perl's grammar.

Yes, it's pretty aweful at that, alright.  Sometimes I write perl programs
that need them, and sometimes it just takes a little creativity.  But
sometimes it's not worth it.  I actually wrote a C program the other day
(gasp) because I didn't want to deal with a game matrix with six links per node.

:Here's a very simple problem that's tricky to express in Perl: process
:the output of "du" to produce output that's indented to reflect the
:tree structure, and with each subtree sorted by size.  Something like:
:    434 /etc
:      |     344 .
:      |      50 install
:      |      35 uucp
:      |       3 nserve
:      |       |       2 .
:      |       |       1 auth.info
:      |       1 sm
:      |       1 sm.bak

At first I thought I could just keep one local list around
at once, but this seems inherently recursive.  Which means 
I need an real recursive data structure.  Maybe you could
do it with one of the %assoc arrays Larry uses in the begat
programs, but I broke down and got dirty.  I think the hardest
part was matching Felix's desired output exactly.  It's not 
blazingly fast: I should probably inline the &childof routine,
but it *was* faster to write than I could have written the 
equivalent C program.


--tom

--
"GUIs normally make it simple to accomplish simple actions and impossible
to accomplish complex actions."   --Doug Gwyn  (22/Jun/91 in comp.unix.wizards)

     Tom Christiansen           tchrist@convex.com      convex!tchrist