On 17/09/12 19:23, Danny Yoo wrote:
Hi Paolo,
When I look at the program more closely, I think the structure of the
iteration might be improved with a "for" loop and the match library.
I'm trying to avoid let loops these days just because they remind me
too much of GOTO-sytle programming. :)
Embarrassingly when I started using Scheme we didn't have for loops so I
actually have never used them but I will take a look at their syntax.
Here's my take on your snippet:
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(for ([line (in-lines in)])
(match (string-split line ",")
[(list path modtime-str md5-str)
(define modtime (string->number (string-trim modtime-str)))
(define md5 (string->bytes/utf-8 (string-trim md5-str)))
why not let for these?
I have always heard these kind of define's would be poor style. What's
your take on this?
(cond
[(or (not path) (not modtime) (not md5))
(printf "[2] read-cache fails, unexpected line in cache file:
~a, ignoring.~n" line)]
[else
(hash-set! (*cache*) path (cons modtime md5))])]
[else
(printf "[1] read-cache fails, unexpected line in cache file: ~a,
ignoring.~n" line)]))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
Looks much better. Thanks.
Good luck!
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