Re: [Chicken-users] Re: photo album in chicken

[Kon Lovett]

On Apr 30, 2006, at 9:44 AM, Reed Sheridan wrote:

From: "Ashish Shrestha" <address@hidden >
Subject: [Chicken-users] photo album in chicken
To: address@hidden
Message-ID:
        < address@hidden>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

<snip>

Also, here is a more schemely and more compact normalise-path function:

(define (rps-normalise-path path)
  (let loop ((reverse-parts (reverse (string-split path "/")))
         (skip 0)
         (acc '()))
    (match reverse-parts
      (() (string-join acc "/"))
      (("." . more) (loop more skip acc))
      ((".." . more) (loop more (add1 skip) acc))
      ((path-part . more)
         (if (zero? skip)
             (loop more 0 (cons path-part acc))
             (loop more (sub1 skip) acc))))))

This version handles paths with "../../", but drops the leading "/" from absolute paths (so did yours).

Prefer your over my offering. (Would just stripping the current-directory elements be useful separately? Thought it might be so broke it out for later top-level define, but ...)

(define (pathname-normalize path)

  (let loop ([parts (reverse! (string-split path "/"))] [skip 0] [acc '()])

    (match parts

      (() (string-join (or (and (absolute-pathname? path) (cons "" acc)) acc) "/"))

      (("." . more) (loop more skip acc))

      ((".." . more) (loop more (add1 skip) acc))

      ((path-part . more)

         (if (zero? skip)

(loop more 0 (cons path-part acc))

(loop more (sub1 skip) acc))))))

Best Wishes,

Kon