> 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)))
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