[plt-dev] Racket web page

Very nice --- thanks!

At Tue, 25 May 2010 13:29:15 -0400, Danny Yoo wrote:
> > We'd like to have more 7-line programs for the middle slideshow, so
> > please contribute.
> 
> Three programs:
> 
> 
> 
> ;; gets the unique lines, although not guaranteeing order:
> (let ([a-ht  (for/fold ([a-ht #hash()])
>                                 ([line (in-lines (current-input-port))])
>          (hash-set a-ht line #t))])
>   (for ([line (in-hash-keys a-ht)])
>     (printf "~a~n" line)))
> 
> 
> 
> ;; nl: show line numbers along the side
> (for ([line (in-lines (current-input-port))]
>       [no (in-naturals 1)])
>   (printf "~a: ~a~n" no line))
> 
> 
> 
> #lang racket
> ;; Compute md5 checksum of the file given at the command line
> (require scheme/cmdline
>          file/md5)
> (printf "~a~n" (md5 (command-line #:args (filename) filename)))