Path: cwi.nl!sun4nl!mcsun!uunet!cs.utexas.edu!convex!usenet

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

References: <17458@ector.cs.purdue.edu> <1992Jan16.165347.25583@cherokee.uswest.com> <=#Hues+4@cs.psu.edu>

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Reply-To: tchrist@convex.COM (Tom Christiansen)

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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