pathnames in Common Lisp, filenames with wildcards in them

Question

The characters * and ? are used as wildcards in pathnames. How does one refer to a filename that has ? as one of its actual characters? For example: [18]> (wild-pathname-p #p"foo") NIL [19]> (wild-pathname-p #p"foo?") T So referring to the filename "foo?" cannot be done this way. I tried to escape the ? with a backslash, but that didn't work. I tried going unicode by using \u3f or \u003f, but that didn't work.

How do I refer to a file that contains a wildcard as part of its name: How to probe it, open it, etc.?

score 3 · Accepted Answer · answered May 05 '15 at 20:37

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It depends on the implementation, but for some, a backslash does in fact work. But because namestrings are strings, to get a string with a backslash in it, you have to escape the backslash with another backslash. So, for example, "foo?" is escaped as "foo\\?", not "foo\?".

Last time I checked, in CLISP, there is no way to refer to files with wildcards in the names. My solution to that is to avoid CLISP.

answered May 05 '15 at 20:37

Xach

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SBCL exhibits similar behaviour as CLISP, so apparently the common lisp standard doesn't include a mechanism for escaping the wildcard, which is weird. What is no less weird is that cltl2, page 628 gives a BNF for pathname namestrings, and this does not include the `?` character. Only `*` ad `**` – Mayer Goldberg May 05 '15 at 20:49
SBCL supports escaping with backslashes. – Xach May 05 '15 at 20:50
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Unix-style globbing with `*` and `?` within pathname components is a non-standard but frequent extension to pathnames and namestring syntax. – Xach May 05 '15 at 20:51
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Do you mean something like: `* (wild-pathname-p #p"foo?") T * (wild-pathname-p #p"foo\?") T * (wild-pathname-p #p"foo\\?") NIL` – Mayer Goldberg May 05 '15 at 20:52
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You can refer to a file with a Unix pathname of "foo?" with #p"foo\\?" in SBCL. – Xach May 05 '15 at 20:56

score 1 · Answer 2 · answered May 06 '15 at 16:33

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On my Mac running Mac OS X 10.10.3: Clozure CL, SBCL and LispWorks write a pathname with * like this:

#P"/private/tmp/test.\\*"

They might differ in some other details, though.

answered May 06 '15 at 16:33

Rainer Joswig

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(wild-pathname-p #p"test.\\*") returns T in sbcl but NIL in clisp. This seems to be the issue: There is no way of removing the special status of the wildcards in clisp. – Mayer Goldberg May 07 '15 at 17:47

score 0 · Answer 3 · answered Nov 17 '21 at 09:41

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SBCL supports (make-pathname :directory "" :name file) to escape a string to a proper pathname.

answered Nov 17 '21 at 09:41

HappyFace

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pathnames in Common Lisp, filenames with wildcards in them

3 Answers3