Re: The Logical Pathname (Song)

Martin Simmons <[email protected]>
Newsgroups gmane.lisp.lispworks.general
Message-ID <[email protected]> 
OK, so LW and SBCL agree on the correct answer :-)

The reason I think this is correct is because logical pathname syntax uses a
semicolon prefix to denote a relative pathname (this is the opposite of Unix
and Windows filenames that use a slash prefix to denote absolute).

As a result, "ASD.F" is parsed as an absolute logical pathname.  If you want a
relative logical pathname then you need to use ";ASD.F" instead.

-- 
Martin Simmons
LispWorks Ltd
http://www.lispworks.com/



>>>>> On Fri, 13 Mar 2026 21:04:26 +0100, Marco Antoniotti (as marco dot antoniotti at unimib dot it) said:
> 
> This is CCL
> 
> CL-USER> (describe (merge-pathnames "ASD.F" "LP:FOO;QWE;"))
> #P"LP:FOO;QWE;ASD.F.newest"
> Type: LOGICAL-PATHNAME
> Class: #<BUILT-IN-CLASS LOGICAL-PATHNAME>
> TYPE: (LOGICAL-PATHNAME . #<CCL::CLASS-WRAPPER LOGICAL-PATHNAME
> #x30004003C6ED>)
> 1: (:ABSOLUTE "FOO" "QWE")
> 2: "ASD"
> 3: "F"
> %LOGICAL-PATHNAME-HOST: "LP"
> %LOGICAL-PATHNAME-VERSION: :NEWEST
> ; No value
> 
> CL-USER> (describe (merge-pathnames "" "LP:FOO;QWE;"))
> #P"LP:FOO;QWE;..newest"
> Type: LOGICAL-PATHNAME
> Class: #<BUILT-IN-CLASS LOGICAL-PATHNAME>
> TYPE: (LOGICAL-PATHNAME . #<CCL::CLASS-WRAPPER LOGICAL-PATHNAME
> #x30004003C6ED>)
> 1: (:ABSOLUTE "FOO" "QWE")
> 2: NIL
> 3: NIL
> %LOGICAL-PATHNAME-HOST: "LP"
> %LOGICAL-PATHNAME-VERSION: :NEWEST
> ; No value
> CL-USER>
> 
> 
> This is ECL (not very useful)
> 
> CL-USER> (describe (merge-pathnames "ASD.F" "LP:FOO;QWE;"))
> 
> #P"LP:FOO;QWE;ASD.F.NEWEST" - LOGICAL-PATHNAME
> ; No value
> CL-USER> (describe (merge-pathnames "" "LP:FOO;QWE;"))
> 
> #P"LP:FOO;QWE;.NEWEST" - LOGICAL-PATHNAME
> ; No value
> CL-USER>
> 
> 
> This is SBCL
> 
> CL-USER> (describe (merge-pathnames "ASD.F" "LP:FOO;QWE;"))
> #P"LP:ASD.F.NEWEST"
>   [logical-pathname]
> 
>   HOST       = #<SB-KERNEL:LOGICAL-HOST "LP">
>   DEVICE     = :UNSPECIFIC
>   DIRECTORY  = (:ABSOLUTE)
>   NAME       = "ASD"
>   TYPE       = "F"
>   VERSION    = :NEWEST
> ; No value
> 
> CL-USER> (describe (merge-pathnames "" "LP:FOO;QWE;"))
> #<LOGICAL-PATHNAME (with no namestring)..
>   [logical-pathname]
> 
>   HOST       = #<SB-KERNEL:LOGICAL-HOST "LP">
>   DEVICE     = :UNSPECIFIC
>   DIRECTORY  = (:ABSOLUTE)
>   VERSION    = :NEWEST
> ; No value
> 
> 
> ... and finally, LWM
> 
> CL-USER 65 > (describe (merge-pathnames "ASD.F" "LP:FOO;QWE;"))
> 
> #P"LP:ASD.F.NEWEST" is a LOGICAL-PATHNAME
> HOST           "LP"
> DEVICE         :UNSPECIFIC
> DIRECTORY      (:ABSOLUTE)
> NAME           "ASD"
> TYPE           "F"
> VERSION        :NEWEST
> 
> CL-USER 68 > (describe (merge-pathnames "" "LP:FOO;QWE;"))
> 
> #P"LP:" is a LOGICAL-PATHNAME
> HOST           "LP"
> DEVICE         :UNSPECIFIC
> DIRECTORY      (:ABSOLUTE)
> NAME           NIL
> TYPE           NIL
> VERSION        :NEWEST
> 
> CLs are not logical, Spok.
> 
> MA
> 
> 
> 
> 
> 
> 
> On Fri, Mar 13, 2026 at 8:50 PM Robert Goldman <[email protected]> wrote:
> 
> > Maybe call DESCRIBE on each of these so we can see what's in each one in
> > full detail?
> >
> > On 13 Mar 2026, at 14:40, Marco Antoniotti (as marco dot antoniotti at
> > unimib dot it) wrote:
> >
> > This is CCL
> >
> >
> > CL-USER>
> > (setf (logical-pathname-translations "LP")                '(("**;*.*.*"
> > "~/Projects/Foo/Bar/**/")))
> > (("**;*.*.*" "~/Projects/Foo/Bar/**/"))
> > CL-USER> (merge-pathnames "ASD.F" "LP:FOO;QWE;")
> > #P"LP:FOO;QWE;ASD.F.newest"
> > CL-USER> (merge-pathnames "" "LP:FOO;QWE;")
> > #P"LP:FOO;QWE;..newest"
> > CL-USER>
> >
> >
> > This is ECL
> >
> > CL-USER>
> > (setf (logical-pathname-translations "LP")                '(("**;*.*.*"
> > "~/Projects/Foo/Bar/**/")))*
> > ((#P"LP:**;*.*.*" #P"/Users/marcoxa/Projects/Foo/Bar/**/"))
> > CL-USER>  (merge-pathnames "ASD.F" "LP:FOO;QWE;")
> > #P"LP:FOO;QWE;ASD.F.NEWEST"
> > CL-USER>  (merge-pathnames "" "LP:FOO;QWE;")
> > #P"LP:FOO;QWE;.NEWEST"
> > CL-USER>
> >
> > This is SBCL
> >
> > CL-USER>
> > (setf (logical-pathname-translations "LP")                '(("**;*.*.*"
> > "~/Projects/Foo/Bar/**/")))
> > (("**;*.*.*" "~/Projects/Foo/Bar/**/"))
> > CL-USER> (merge-pathnames "ASD.F" "LP:FOO;QWE;")
> > #P"LP:ASD.F.NEWEST"
> > CL-USER> (merge-pathnames "" "LP:FOO;QWE;")
> > #<LOGICAL-PATHNAME (with no namestring)
> >                    :HOST #<SB-KERNEL:LOGICAL-HOST "LP">
> >                    :DEVICE :UNSPECIFIC
> >                    :DIRECTORY (:ABSOLUTE)
> >                    :NAME NIL
> >                    :TYPE NIL
> >                    :VERSION :NEWEST>
> > CL-USER>
> >
> > This is LWM (same setup)
> >
> > CL-USER 61 > (merge-pathnames "ASD.F" "LP:FOO;QWE;")
> > #P"LP:ASD.F.NEWEST"
> >
> > CL-USER 62 > (merge-pathnames "" "LP:FOO;QWE;")
> > #P"LP:"
> >
> > CL-USER 63 >
> >
> > As you see there isn't much... logic in the results. 🙄
> >
> > Cheers
> >
> > MA
> >
> >
> >
> > On Fri, Mar 13, 2026 at 7:36 PM Martin Simmons <[email protected]>
> > wrote:
> >
> >> It looks correct to me.  What are other CL's doing differently?
> >>
> >> --
> >> Martin Simmons
> >> LispWorks Ltd
> >> http://www.lispworks.com/
> >>
> >>
> >>
> >> >>>>> On Wed, 11 Mar 2026 19:54:07 +0100, Marco Antoniotti (as marco dot
> >> antoniotti at unimib dot it) said:
> >> >
> >> > Hi
> >> >
> >> > I have the following
> >> >
> >> > CL-USER 225 >
> >> > (setf (logical-pathname-translations "LP")
> >> > '(("**;*.*.*" "~/Projects/Foo/Bar/**/")))
> >> > (("**;*.*.*" "~/Projects/Foo/Bar/**/"))
> >> >
> >> > Then
> >> >
> >> > CL-USER 256 > (merge-pathnames "ASD.F" "LP:FOO;QWE;")
> >> > #P"LP:ASD.F.NEWEST"
> >> >
> >> > Which is ... different from what other CL's do.
> >> >
> >> > Any hermeneutics about this in LW?
> >> >
> >> > Cheers
> >> > MA
> >> >
> >> >
> >> > --
> >> > Marco Antoniotti, Professor, Director         tel. +39 - 02 64 48 79 01
> >> > DISCo, University of Milan-Bicocca U14 2043
> >> http://dcb.disco.unimib.it
> >> > Viale Sarca 336
> >> > I-20126 Milan (MI) ITALY
> >> >
> >> > REGAINS: https://regains.disco.unimib.it/
> >> >
> >>
> >
> >
> > --
> > Marco Antoniotti, Professor, Director         tel. +39 - 02 64 48 79 01
> > DISCo, University of Milan-Bicocca U14 2043   http://dcb.disco.unimib.it
> > Viale Sarca 336
> > I-20126 Milan (MI) ITALY
> >
> > REGAINS: https://regains.disco.unimib.it/
> >
> >
> 
> -- 
> Marco Antoniotti, Professor, Director         tel. +39 - 02 64 48 79 01
> DISCo, University of Milan-Bicocca U14 2043   http://dcb.disco.unimib.it
> Viale Sarca 336
> I-20126 Milan (MI) ITALY
> 
> REGAINS: https://regains.disco.unimib.it/
> 

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