/Tools/scripts/dutree.doc

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  1. Path: cwi.nl!sun4nl!mcsun!uunet!cs.utexas.edu!convex!usenet
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  2. From: tchrist@convex.COM (Tom Christiansen)
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  3. Newsgroups: comp.lang.perl
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  4. Subject: Re: The problems of Perl (Re: Question (silly?))
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  5. Message-ID: <1992Jan17.053115.4220@convex.com>
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  6. Date: 17 Jan 92 05:31:15 GMT
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  7. References: <17458@ector.cs.purdue.edu> <1992Jan16.165347.25583@cherokee.uswest.com> <=#Hues+4@cs.psu.edu>
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  8. Sender: usenet@convex.com (news access account)
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  9. Reply-To: tchrist@convex.COM (Tom Christiansen)
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  10. Organization: CONVEX Realtime Development, Colorado Springs, CO
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  11. Lines: 83
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  12. Nntp-Posting-Host: pixel.convex.com
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  14. From the keyboard of flee@cs.psu.edu (Felix Lee):
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  15. :And Perl is definitely awkward with data types.  I haven't yet found a
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  16. :pleasant way of shoving non-trivial data types into Perl's grammar.
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    18. 

  18. Yes, it's pretty aweful at that, alright.  Sometimes I write perl programs
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  19. that need them, and sometimes it just takes a little creativity.  But
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  20. sometimes it's not worth it.  I actually wrote a C program the other day
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  21. (gasp) because I didn't want to deal with a game matrix with six links per node.
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    23. 

  23. :Here's a very simple problem that's tricky to express in Perl: process
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  24. :the output of "du" to produce output that's indented to reflect the
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  25. :tree structure, and with each subtree sorted by size.  Something like:
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  26. :    434 /etc
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  27. :      |     344 .
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  28. :      |      50 install
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  29. :      |      35 uucp
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  30. :      |       3 nserve
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  31. :      |       |       2 .
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  32. :      |       |       1 auth.info
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  33. :      |       1 sm
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  34. :      |       1 sm.bak
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  35. 

  36. At first I thought I could just keep one local list around
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  37. at once, but this seems inherently recursive.  Which means 
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  38. I need an real recursive data structure.  Maybe you could
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  39. do it with one of the %assoc arrays Larry uses in the begat
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  40. programs, but I broke down and got dirty.  I think the hardest
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  41. part was matching Felix's desired output exactly.  It's not 
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  42. blazingly fast: I should probably inline the &childof routine,
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  43. but it *was* faster to write than I could have written the 
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  44. equivalent C program.
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  46. 

  47. --tom
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  48. 

  49. --
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  50. "GUIs normally make it simple to accomplish simple actions and impossible
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  51. to accomplish complex actions."   --Doug Gwyn  (22/Jun/91 in comp.unix.wizards)
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    53. 

  53.      Tom Christiansen           tchrist@convex.com      convex!tchrist
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