Tabakal@UB.CC.UMICH.EDU (09/01/90)
Do standard ProDOS subdirectories have a pointer to their parent
directory? Or do they have to scan from root to find it? It seems
that noone implements the equivalent of a .. parameter when they
implement a change directory command (with the exception of APW).
I've never understood why. It's very useful when you're hopping
from children to parent to sibling directories.
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Todd A. Bakal All snappy sayings aside,
U of M Apple User's Group !Index will be updated
Ann Arbor, Michigan ASAP or my name's not...
Internet: Tabakal@ub.cc.umich.edu FTP: ummts.cc.umich.edu
Tab@terminator.cc.umich.edu 35.1.1.43 (PC5:)
UUCP: ...!uunet!ub.cc.umich.edu!tabakal BITnet: Tabakal@UMICHUBtoddpw@tybalt.caltech.edu (Todd P. Whitesel) (09/05/90)
Tabakal@UB.CC.UMICH.EDU writes: >Do standard ProDOS subdirectories have a pointer to their parent >directory? Or do they have to scan from root to find it? It seems >that noone implements the equivalent of a .. parameter when they >implement a change directory command (with the exception of APW). >I've never understood why. It's very useful when you're hopping >from children to parent to sibling directories. They're supposed to, according to the prodos specs. Has anybody written a decent CD for basic.system yet? I'm sick of PREFIX. Maybe I should get off my duff and write one after Turbo Binscii is finished. Todd Whitesel toddpw @ tybalt.caltech.edu
vw3@cunixf.cc.columbia.edu (Vernon Williams) (09/05/90)
In article <5928366@ub.cc.umich.edu> Tabakal@UB.CC.UMICH.EDU writes: >Do standard ProDOS subdirectories have a pointer to their parent >directory? Or do they have to scan from root to find it? It seems >that noone implements the equivalent of a .. parameter when they >implement a change directory command (with the exception of APW). Not entirely true. Don Elton's ECP8 has such a command. It's the \ (backslash) command. Invoking this command sends you up one directory level as does ".." >I've never understood why. It's very useful when you're hopping >from children to parent to sibling directories. I can't imagine why either. It seems that it woulkd be a most helpful command to have especially in "command line" environments... [Tod's sig deleted] +-------------------------------------------------------+--------------------+ |Vernon Williams | vw3@cunixf | |Evening Supervisor/Library Assistant +--------------------+ |Thomas J. Watson Library of Business and Economics | 130 Uris Hall |
gwyn@smoke.BRL.MIL (Doug Gwyn) (09/05/90)
In article <1990Sep5.031342.27820@cunixf.cc.columbia.edu> vw3@cunixf.cc.columbia.edu (Vernon Williams) writes: >In article <5928366@ub.cc.umich.edu> Tabakal@UB.CC.UMICH.EDU writes: >>Do standard ProDOS subdirectories have a pointer to their parent >>directory? Or do they have to scan from root to find it? It seems >>that noone implements the equivalent of a .. parameter when they >>implement a change directory command (with the exception of APW). I've created for my own purposes an implementation of a canonicalizer for GS/OS pathnames, which I plan to post to the sources group some day. chdir("..") is implementable simply by trimming off the trailing piece of the current prefix #0, which is the GS/OS equivalent of UNIX CWD. By interposing such a canonicalizer in the path taken by an argument to any filename-driven function, you automatically get UNIX-like path interpretation for the function. By the way, I hereby stake out a claim to the external name subspace matching the regular expression "_Q8Q_*" for my own use in internal support for UNIX-like C library extensions. (Unfortunately, there is no central registry for allocating portions of global name space.)
mattd@Apple.COM (Matt Deatherage) (09/07/90)
In article <5928366@ub.cc.umich.edu> Tabakal@UB.CC.UMICH.EDU writes: >Do standard ProDOS subdirectories have a pointer to their parent >directory? Or do they have to scan from root to find it? It seems >that noone implements the equivalent of a .. parameter when they >implement a change directory command (with the exception of APW). >I've never understood why. It's very useful when you're hopping >from children to parent to sibling directories. > It's not there for application use, generally -- it's there for the file system's use. If you OPEN and READ a directory, you won't ever see the parent pointers - only if you do block access will you see them, and that makes you incompatible with AppleShare. Davex implements a .. directory walking command (which as Doug Gwyn points out can be done by simply stripping off the last part of any prefix), but it doesn't work multiply. (for example, "cd .." works but "cd ../.." doesn't.) -- ============================================================================ Matt Deatherage, Apple Computer, Inc. | "The opinions represented here are Developer Technical Support, Apple II | not necessarily those of Apple Group. Personal mail only, please. | Computer, Inc. Remember that." ============================================================================
scottr@gnh-applesauce.cts.com (Scott Rothstein) (09/10/90)
Find GS+ magazine -- they wrote a CD called Prefixer. GS+ -- 615-870-4960 scottr@applesauce.bb.ny