[plt-scheme] Re: Using PLT Scheme libs elsewhere?

Is the (UNLESS ...) vs. (IF (NOT...)) issue purely stylistic, or for
enhancing clarity for the poor schmo who has to read my code a month
from now, or would you expect a speed difference?



On May 18, 7:37 am, Matthias Felleisen <matth... at ccs.neu.edu> wrote:
> Thanks. I'd use UNLESS instead of (if (not blah) one-armed-if).
>
> On May 18, 2007, at 4:18 AM, Jens Axel Søgaard wrote:
>
>
>
> > Hi,
>
> > SpinyNorman wrote:
>
> >> Share?  I'm flattered.  Here it is, and my only claim at this
> >> point is
> >> that hey, it works.  Algorithmic insights are more than welcome.
>
> >> (require (lib "md5.ss"))
>
> > This md5.ss implements MD5 in Scheme. The Java MD5 is probably
> > implemented in C.
> > So if you switch to a C-based MD5 implementation, you'll get a
> > speedup. Here is
> > what to do:
>
> > (require (planet "digest.ss" ("soegaard" "digest.plt" 1 2)))
> > (require mzscheme)
>
> > (define test-string (make-string 10000))
>
> > (define (md-file-chunks port chunk-size)
> >  (let loop ()
> >    (begin
> >      (display (md5 (read-bytes chunk-size port)))
> >      (newline))
> >    (if (not (eof-object? (peek-byte port)))
> >    (loop))))
>
> > (md-file-chunks (open-input-string test-string) 1024)
>
> > See
> > <http://planet.plt-scheme.org/display.ss?
> > package=digest.plt&owner=soegaard>
> > for documentation.
>
> > This was tested on Windows, but ought to work elsewhere too.
> > You'll need a relatively new version of PLT Scheme, for
> > example 369.100.
>
> > It wasn't obvious whether you put the md-file-chunks in a module or
> > whether you are using the top-level. If you are using the top-level,
> > the line
>
> >    (require mzscheme)
>
> > makes sure primitive operations are inlined.
>
> > I'd love to hear your new timings.
>
> > PS: Remember to close file ports after use.
>
> > --
> > Jens Axel Søgaard
>
> > _________________________________________________
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>
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