1 racket comment ;; language declaration commented out until someone extends the
2 racket comment ;; parser to support it:
4 racket comment ;; #lang racket
6 racket comment ;; Report each unique line from stdin
7 racket code (let ([saw (make-hash)])
8 racket code (for ([line (in-lines)])
9 racket code (unless (hash-ref saw line #f)
10 racket code (displayln line))
11 racket code (hash-set! saw line #t)))