How do I iterate through a directory in Common Lisp?

user_94239 0
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I'm using OpenMCL on Darwin, and I'd like to do something like:

(loop for f in (directory "somedir")
  collect (some-per-file-processing f))

But I can't get directory to return anything other than NIL, and I can't seem to find any good explanation online (other than "its different for each system").

Any pointers?

common-lisp lisp filesystems directory
4 Answers

I'll add an example that works for me, for the sake of a code snippet. I use osicat (similar to cl-fad) and str.

edit: also with uiop:directory-files. str:contains? could be done with search.

;; searching for "ref".
(setf *data-directory* "~/books/lisp")
(remove-if-not (lambda (it)
                   (str:contains? "ref" (namestring it)))
                (osicat:list-directory *data-directory*))

returns 

(#P"~/books/lisp/common-lisp-quick-reference-clqr-a4-booklet-all.pdf"
 #P"~/books/lisp/common-lisp-quick-reference-clqr-a4-consec.pdf"
 #P"~/books/lisp/commonLisp-interactive-approach-reference-buffalo.pdf")

It can certainly be improved my a proper use of wildcards. However that's a snippet you can use right now : )

References:

user_15063380
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