Created
May 20, 2013 20:25
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| #lang racket | |
| ;; Report each unique line from stdin | |
| (let ([saw (make-hash)]) | |
| (for ([line (in-lines)]) | |
| (unless (hash-ref saw line #f) | |
| (displayln line)) | |
| (hash-set! saw line #t))) | |
| ;; do it purely. | |
| (for/fold ([seen (set)]) | |
| ([line (in-lines)]) | |
| (unless (set-contains? seen line) | |
| (displayln line)) | |
| (set-add seen line)) |
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