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  ANSI Common Lisp   19 Filenames   19.4 Dictionary of Filenames

19.4.8 logical-pathname-translations Accessor

Syntax:
logical-pathname-translations host    translations

(setf (logical-pathname-translations host) new-translations)

Arguments and Values:
host--a logical host designator.

translations, new-translations - a list.

Description:
Returns the host's list of translations. Each translation is a list of at least two elements: from-wildcard and to-wildcard. Any additional elements are implementation-defined. From-wildcard is a logical pathname whose host is host. To-wildcard is a pathname.

(setf (logical-pathname-translations host) translations) sets a logical pathname host's list of translations. If host is a string that has not been previously used as a logical pathname host, a new logical pathname host is defined; otherwise an existing host's translations are replaced. logical pathname host names are compared with string-equal.

When setting the translations list, each from-wildcard can be a logical pathname whose host is host or a logical pathname namestring parseable by (parse-namestring string host), where host represents the appropriate object as defined by parse-namestring. Each to-wildcard can be anything coercible to a pathname by (pathname to-wildcard). If to-wildcard coerces to a logical pathname, translate-logical-pathname will perform repeated translation steps when it uses it.

host is either the host component of a logical pathname or a string that has been defined as a logical pathname host name by setf of logical-pathname-translations.

Examples:
 ;;;A very simple example of setting up a logical pathname host.  No
 ;;;translations are necessary to get around file system restrictions, so
 ;;;all that is necessary is to specify the root of the physical directory
 ;;;tree that contains the logical file system.
 ;;;The namestring syntax on the right-hand side is implementation-dependent.
 (setf (logical-pathname-translations "foo")
       '(("**;*.*.*"              "MY-LISPM:>library>foo>**>")))
 
 ;;;Sample use of that logical pathname.  The return value
 ;;;is implementation-dependent.          
 (translate-logical-pathname "foo:bar;baz;mum.quux.3")
 #P"MY-LISPM:>library>foo>bar>baz>mum.quux.3"
 
 ;;;A more complex example, dividing the files among two file servers
 ;;;and several different directories.  This Unix doesn't support
 ;;;:WILD-INFERIORS in the directory, so each directory level must
 ;;;be translated individually.  No file name or type translations
 ;;;are required except for .MAIL to .MBX.
 ;;;The namestring syntax on the right-hand side is implementation-dependent.
 (setf (logical-pathname-translations "prog")
       '(("RELEASED;*.*.*"        "MY-UNIX:/sys/bin/my-prog/")
         ("RELEASED;*;*.*.*"      "MY-UNIX:/sys/bin/my-prog/*/")
         ("EXPERIMENTAL;*.*.*"    "MY-UNIX:/usr/Joe/development/prog/")
         ("EXPERIMENTAL;DOCUMENTATION;*.*.*"
                                  "MY-VAX:SYSDISK:[JOE.DOC]")
         ("EXPERIMENTAL;*;*.*.*"  "MY-UNIX:/usr/Joe/development/prog/*/")
         ("MAIL;**;*.MAIL"        "MY-VAX:SYSDISK:[JOE.MAIL.PROG...]*.MBX")))

 ;;;Sample use of that logical pathname.  The return value
 ;;;is implementation-dependent.          
 (translate-logical-pathname "prog:mail;save;ideas.mail.3")
 #P"MY-VAX:SYS$DISK:[JOE.MAIL.PROG.SAVE]IDEAS.MBX.3"

 ;;;Example translations for a program that uses three files main.lisp,
 ;;;auxiliary.lisp, and documentation.lisp.  These translations might be
 ;;;supplied by a software supplier as examples.

 ;;;For Unix with long file names
 (setf (logical-pathname-translations "prog")
       '(("CODE;*.*.*"             "/lib/prog/")))

 ;;;Sample use of that logical pathname.  The return value
 ;;;is implementation-dependent.          
 (translate-logical-pathname "prog:code;documentation.lisp")
 #P"/lib/prog/documentation.lisp"

 ;;;For Unix with 14-character file names, using .lisp as the type
 (setf (logical-pathname-translations "prog")
       '(("CODE;DOCUMENTATION.*.*" "/lib/prog/docum.*")
         ("CODE;*.*.*"             "/lib/prog/")))

 ;;;Sample use of that logical pathname.  The return value
 ;;;is implementation-dependent.          
 (translate-logical-pathname "prog:code;documentation.lisp")
 #P"/lib/prog/docum.lisp"

 ;;;For Unix with 14-character file names, using .l as the type
 ;;;The second translation shortens the compiled file type to .b
 (setf (logical-pathname-translations "prog")
       `(("**;*.LISP.*"            ,(logical-pathname "PROG:**;*.L.*"))
         (,(compile-file-pathname (logical-pathname "PROG:**;*.LISP.*"))
                                   ,(logical-pathname "PROG:**;*.B.*"))
         ("CODE;DOCUMENTATION.*.*" "/lib/prog/documentatio.*")
         ("CODE;*.*.*"             "/lib/prog/")))

 ;;;Sample use of that logical pathname.  The return value
 ;;;is implementation-dependent.          
 (translate-logical-pathname "prog:code;documentation.lisp")
 #P"/lib/prog/documentatio.l"

 ;;;For a Cray with 6 character names and no directories, types, or versions.
 (setf (logical-pathname-translations "prog")
       (let ((l '(("MAIN" "PGMN")
                  ("AUXILIARY" "PGAUX")
                  ("DOCUMENTATION" "PGDOC")))
             (logpath (logical-pathname "prog:code;"))
             (phypath (pathname "XXX")))
         (append
           ;; Translations for source files
           (mapcar #'(lambda (x)
                       (let ((log (first x))
                             (phy (second x)))
                         (list (make-pathname :name log
                                              :type "LISP"
                                              :version :wild
                                              :defaults logpath)
                               (make-pathname :name phy
                                              :defaults phypath))))
                   l)
           ;; Translations for compiled files
           (mapcar #'(lambda (x)
                       (let* ((log (first x))
                              (phy (second x))
                              (com (compile-file-pathname
                                     (make-pathname :name log
                                                    :type "LISP"
                                                    :version :wild
                                                    :defaults logpath))))
                         (setq phy (concatenate 'string phy "B"))
                         (list com
                               (make-pathname :name phy
                                              :defaults phypath))))
                   l))))

 ;;;Sample use of that logical pathname.  The return value
 ;;;is implementation-dependent.          
 (translate-logical-pathname "prog:code;documentation.lisp")
 #P"PGDOC"

Exceptional Situations:
If host is incorrectly supplied, an error of type type-error is signaled.

See Also:
logical-pathname, Section 19.1.2 Pathnames as Filenames

Notes:
Implementations can define additional functions that operate on logical pathname hosts, for example to specify additional translation rules or options.

Allegro CL Implementation Details:
None.

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