Re: Handling files with problem characters in their names?

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
> 
> 
> 
> 
> 
> 
> 
> 
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