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

On May 20, 2007, at 7:34 PM, SpinyNorman wrote:

> 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?

Yes, it's for him. And he might be you. Promised. Try it out.

;; ---

You want to close ports because some OSes don't support too many
open ports at once. It's just something to get used to.

-- Matthias






>
>
>
> 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
>>
>>> _________________________________________________
>>>  For list-related administrative tasks:
>>>  http://list.cs.brown.edu/mailman/listinfo/plt-scheme
>>
>> _________________________________________________
>>   For list-related administrative tasks:
>>  http://list.cs.brown.edu/mailman/listinfo/plt-scheme
>
> _________________________________________________
>   For list-related administrative tasks:
>   http://list.cs.brown.edu/mailman/listinfo/plt-scheme