[ clisp-Bugs-3110367 ] :case :common for logical pathnames.

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Bugs item #3110367, was opened at 2010-11-17 00:33
Message generated for change (Comment added) made by informatimago
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Category: clisp
Group: ANSI compliance issue
Status: Closed
Resolution: Rejected
Priority: 5
Private: No
Submitted By: Pascal J. Bourguignon (informatimago)
Assigned to: Bruno Haible (haible)
Summary: :case :common for logical pathnames.

Initial Comment:
When creating a logical pathname with make-pathname, :case :common, the pathname components are downcased.  

I would argue that the customary case for logical pathnames is upper case, since:

    19.3.1.1.7 Lowercase Letters in a Logical Pathname Namestring

    When parsing words and wildcard-words, lowercase letters are translated to uppercase. 

I'd expect (string= (pathname-name (make-pathname :host "TEST" :name "FILE" :type "DATA" :case :common))
                               (pathname-name #P"TEST:FILE.DATA"))
and of course (string= "FILE" (pathname-name #P"TEST:FILE.DATA"))
and similarly for the other pathname components.

[pjb@kuiper :0.0 ~]$ clisp -norc -ansi
  i i i i i i i       ooooo    o        ooooooo   ooooo   ooooo
  I I I I I I I      8     8   8           8     8     o  8    8
  I  \ `+' /  I      8         8           8     8        8    8
   \  `-+-'  /       8         8           8      ooooo   8oooo
    `-__|__-'        8         8           8           8  8
        |            8     o   8           8     o     8  8
  ------+------       ooooo    8oooooo  ooo8ooo   ooooo   8

Welcome to GNU CLISP 2.49 (2010-07-07) <http://clisp.cons.org/>

Copyright (c) Bruno Haible, Michael Stoll 1992, 1993
Copyright (c) Bruno Haible, Marcus Daniels 1994-1997
Copyright (c) Bruno Haible, Pierpaolo Bernardi, Sam Steingold 1998
Copyright (c) Bruno Haible, Sam Steingold 1999-2000
Copyright (c) Sam Steingold, Bruno Haible 2001-2010

Type :h and hit Enter for context help.

[1]> (setf (logical-pathname-translations "TEST") nil)
NIL
[2]> (setf (logical-pathname-translations "TEST") (quote ((#P"TEST:**;*.*" "/tmp/**/*.*")
                                                     (#P"TEST:**;*" "/tmp/**/*"))))
((#P"TEST:**;*.*" "/tmp/**/*.*") (#P"TEST:**;*" "/tmp/**/*"))
[3]> (pathname-name (make-pathname :host "TEST" :name "FILE" :type "DATA" :case :common))
"file"
[4]> (pathname-name #P"TEST:FILE.DATA")
"FILE"
[5]> 

----------------------------------------------------------------------

Comment By: Pascal J. Bourguignon (informatimago)
Date: 2010-11-17 09:04

Message:
I forgot the definition of print-pathname:

(defun print-pathname (pathname)
  (format t "~%~A ~S~%" (type-of pathname) pathname)
  (format t "--------------------  :case :local (default)~%")
  (format t "~&~{~{~@(~9A~) : ~S~&~}~}"
          (mapcar (lambda (name field) (list name (funcall field
pathname)))
                  '(host device directory name type version)
                  '(pathname-host pathname-device pathname-directory
                    pathname-name pathname-type pathname-version)))
  (format t "--------------------  :case :common~%")
  (format t "~&~{~{~@(~9A~) : ~S~&~}~}"
          (mapcar (lambda (name field arguments) (list name (apply field
pathname arguments)))
                  '(host device directory name type version)
                  '(pathname-host pathname-device pathname-directory
                    pathname-name pathname-type pathname-version)
                  '((:case :common) (:case :common) (:case :common)
                    (:case :common) (:case :common) ())))
  (format t "--------------------  ~%")
  pathname)

----------------------------------------------------------------------

Comment By: Pascal J. Bourguignon (informatimago)
Date: 2010-11-17 09:04

Message:
- I agree, I was wrong, 19.3.1.1.7 doesn't apply.

- make-pathname creates a logical pathname when the :host parameter is
  a logical host, in clisp, as in any conforming implementation.

- I was also wrong with:
  (pathname-name (make-pathname :host "TEST" :name  "FILE" :type "DATA"
:case :common))
  it should indeed return "file"; this is correctly implemented in clisp.

- but the other form, (pathname-name #P"TEST:FILE.DATA") should return
  "file", not "FILE", because by default the :case parameter of
  pathname-name is :local, and "19.2.2.1.2.2 Common Case in Pathname
  Components" mentions that round trip should be information
  preserving (including case for local pathnames).

Actually there are other problems.  In an implementation where the
customary case is lower case, the pathname accessors cannot return the
same case with and without :case :common, but this is what clisp does:

CL-USER> (print-pathname (make-pathname :host "LOGICAL" :device
:unspecific :directory '(:absolute "DIR" "SUBDIR") :name  "NAME" :type
"DATA" :version nil :case :common))

LOGICAL-PATHNAME #P"LOGICAL:dir;subdir;name.data"
--------------------  :case :local (default)
Host      : "LOGICAL"
Device    : :UNSPECIFIC
Directory : (:ABSOLUTE "dir" "subdir")
Name      : "name"
Type      : "data"
Version   : NIL
--------------------  :case :common
Host      : "LOGICAL"
Device    : :UNSPECIFIC
Directory : (:ABSOLUTE "dir" "subdir")
Name      : "name"
Type      : "data"
Version   : NIL
--------------------  
#P"LOGICAL:dir;subdir;name.data"
CL-USER> (print-pathname #P"LOGICAL:dir;subdir;name.data")

LOGICAL-PATHNAME #P"LOGICAL:DIR;SUBDIR;NAME.DATA"
--------------------  :case :local (default)
Host      : "LOGICAL"
Device    : :UNSPECIFIC
Directory : (:ABSOLUTE "DIR" "SUBDIR")
Name      : "NAME"
Type      : "DATA"
Version   : NIL
--------------------  :case :common
Host      : "LOGICAL"
Device    : :UNSPECIFIC
Directory : (:ABSOLUTE "DIR" "SUBDIR")
Name      : "NAME"
Type      : "DATA"
Version   : NIL
--------------------  
#P"LOGICAL:DIR;SUBDIR;NAME.DATA"
CL-USER> (print-pathname #P"LOGICAL:DIR;SUBDIR;NAME.DATA")

LOGICAL-PATHNAME #P"LOGICAL:DIR;SUBDIR;NAME.DATA"
--------------------  :case :local (default)
Host      : "LOGICAL"
Device    : :UNSPECIFIC
Directory : (:ABSOLUTE "DIR" "SUBDIR")
Name      : "NAME"
Type      : "DATA"
Version   : NIL
--------------------  :case :common
Host      : "LOGICAL"
Device    : :UNSPECIFIC
Directory : (:ABSOLUTE "DIR" "SUBDIR")
Name      : "NAME"
Type      : "DATA"
Version   : NIL
--------------------  
#P"LOGICAL:DIR;SUBDIR;NAME.DATA"

There is also the problem that the result of:
 (make-pathname :host "LOGICAL" :device :unspecific :directory '(:absolute
"DIR" "SUBDIR") :name  "NAME" :type "DATA" :version nil :case :common)
is printed as #P"LOGICAL:dir;subdir;name.data".

It should be printed using the logical pathname syntax, that is, in
upper case, because:

1- it is a logical pathname,

2- its printed form should be readable as the 'same' logical pathname,
   that is, a pathname with the same components,

3- #P gives the string to parse-namestring, without addionnal
  argument, therefore :host is nil, and in this case, for the string
  to be parsed as a logical pathname, it needs to have the logical
  pathname syntax, which takes only upper case letters.

4- when reading back this lowercase form, we don't read the same
   pathname as originally returned by the make-pathname form.

----------------------------------------------------------------------

Comment By: Bruno Haible (haible)
Date: 2010-11-17 02:39

Message:
The behaviour of :case :common is specified in CLHS section 19.2.2.1.2.2
http://www.lispworks.com/documentation/HyperSpec/Body/19_bbabb.htm
For clisp, the "filesystem's customary case" is lowercase, both on Unix
and on Windows.

The section you cite, 19.3.1.1.7, doesn't apply for two reasons:
1) It applies only to logical pathnames. But
  (make-pathname :host "TEST" :name "FILE" :type "DATA" :case :common)
yields an ordinary pathname in clisp. If you want a logical pathname, use
the LOGICAL-PATHNAME function.
2) It applies to the parsing of namestrings for logical pathnames
that contain lowercase letters.
In your example (make-pathname :host "TEST" :name "FILE" :type "DATA"
:case :common)
all of these are upper case, therefore the contents of 19.3.1.1.7 doesn't
apply.

----------------------------------------------------------------------

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