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Re: [Chicken-users] photo album in chicken


From: Kon Lovett
Subject: Re: [Chicken-users] photo album in chicken
Date: Sun, 30 Apr 2006 10:34:09 -0700

Hi Ashish,

Two points:

1) If anyone really cares the imlib egg can be easily modified to handle garbage images, will keeping an explicit destroy for backward compatibility.

2) In "fileutils.scm" suggest something like the following (sorry for the renaming, me spell U.S. "English"):

(use srfi-1 srfi-13 srfi-26 posix utils)

(define (pathname-normalize path)
  (let (
      [collapse-current-directories
        (lambda (splits)
          (reverse! (remove (cut string=? "." <>) splits)))])
(let loop ([parts (collapse-current-directories (string-split path "/"))] [norm-parts '()])
      (if (null? parts)
        (string-join norm-parts "/")
        (let ([cur (car parts)] [nxt (cdr parts)])
          (if (and (not (null? nxt)) (string=? ".." cur))
              (if (string=? ".." (car nxt))
                (loop nxt norm-parts)
                (loop (cdr nxt) norm-parts))
              (loop nxt (cons cur norm-parts))))))))

(define (make-directory! dir)
  (let loop ([dir (pathname-normalize dir)])
    (unless (or (not dir) (string-empty? dir))
      (unless (directory? dir)
        (loop (pathname-directory dir))
        (create-directory dir)))))

- SRFI-26 ('cut' above) is really useful.

- The bang '!' on the end of make-directory! is to emphasize the side- effecting nature.

- You may want to use the utf8 egg to handle UNICODE string pathnames.

- Needs chicken-2.223+ so decompose-pathname "correctly" strips trailing directory-separator '/' from the directory portion. (pathname-directory built on

- Something like the above probably should go into the library, used all over the place.

Best Wishes,
Kon





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