Re: Handling files with problem characters in their names?

I will - that looks very useful.
Thanks.


On Fri, 20 Dec 2024 21:20:37 +0000
Hraban via Sbcl-help <[email protected]> wrote:

> Confirmed the राम.txt works here too (mac, emacs, slime).
> 
> Wanted to echo Richard's point about converting to pathnames as early as 
> possible: strings are rather ambiguous representations of pathnames in 
> CL, as you're experiencing.
> 
> If you want a "Do-What-I-Mean" kind of function to convert strings to 
> pathnames which is reasonably cross platform and cross lisp, have a look 
> at uiop:ensure-pathname: 
> https://asdf.common-lisp.dev/uiop.html#index-ensure_002dpathname
> 
> 
> 
> On 12/20/24 3:11 PM, Richard M Kreuter via Sbcl-help wrote:
> > What error do you get for the second example (the one with the Devangari
> > characters)? This works for me on MacOS:
> > 
> > * (setq *default-pathname-defaults* #P"/tmp/")
> > #P"/tmp/"
> > * (with-open-file (f "राम.txt" :direction :output :if-does-not-exist :create)
> >      (write-line "foo" f))
> > "foo"
> > * (probe-file "राम.txt")
> > #P"/private/tmp/राम.txt"
> > 
> > Anyhow, there are three ways file naming can go haywire in most CLs:
> > 
> > 1. conversion from an not-validly-encoded C string into a Lisp string
> >     (on OSes where that's possible),
> > 
> > 2. parsing a Lisp string into a pathname (which all the standard CL
> >     functions are required to do implicitly),
> > 
> > 3. unparsing a pathname into a filename (which happens implicitly in
> >     OPEN and the like, but which you might need to do anyplace you're
> >     using an FFI or communicating with another program).
> > 
> > Your "file with [brackets].txt" is an example of the second. SBCL offers
> > an extension to cope with the difference between Lisp syntax and native
> > syntax: SB-EXT:PARSE-NATIVE-NAMESTRING.
> > 
> > If you're listing files with CL:DIRECTORY, you'll get back something
> > like #P"/path/to/file with \\[brackets].txt" for that file; and
> > FILE-NAMESTRING will return "file with \\[brackets].txt" for it, so if
> > you'd written that pathname somewhere using the Lisp printer, you'd have
> > the escape character. Given that you have the string,
> > "file with [brackets].txt", I'd expect this string comes from another
> > origin, e.g., a database lookup, an FFI call, a pipe or file from
> > another program, etc. If that's the case, I'd suggest putting
> > PARSE-NATIVE-NAMESTRING calls as close as possible to the origin,
> > because the nature of the source more or less determines what syntax to
> > use for parsing the string.
> > 
> > Regards,
> > Richard
> > 
> > Jeff Cunningham <[email protected]> wrote:
> >   
> >> What is the best way to handle files whose names contain characters
> >> that break functions like FILE-LENGTH, NAMESTRING, and OPEN?
> >>
> >> I keep running into this problem where I have large numbers of files
> >> from external sources - I have no control over how they are named and
> >> shouldn't change their names. Here's an example:
> >>
> >> "file with [brackets].txt"
> >>
> >> The pathname functions think it's a wildcard specification. I can
> >> escape the left-bracket it to work with most of those, but that
> >> doesn't work. Here's another example:
> >>
> >> "राम.txt"
> >>
> >> I keep coming up with adhoc solutions but I'm wondering how better
> >> programmers handle this?
> >>
> >> Thanks.
> >>
> >> -- Jeff
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >> _______________________________________________
> >> Sbcl-help mailing list
> >> [email protected]
> >> https://lists.sourceforge.net/lists/listinfo/sbcl-help  
> > 
> > 
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> 
> 
> 
> 
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