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#lang racket
(provide get-lines
enumerate
repeat
split-list-by)
(define (repeat n e)
(let loop ((i 0) (ret '()))
(if (>= i n)
ret
(loop (+ 1 i) (cons e ret)))))
(define (get-lines fp)
(let loop ((lines '()))
(define l (read-line fp))
(if (eof-object? l)
(reverse lines)
(loop (cons l lines)))))
(define (enumerate lst)
(let loop ((i 1) (ret '()) (remain lst))
(if (null? remain)
(reverse ret)
(loop (+ 1 i) (cons (list (car remain) i) ret) (cdr remain)))))
(define (split-list-by e lst . eq)
(define cmp (if (null? eq) equal? eq))
(let loop ((ret '())
(cur '())
(lst lst))
(if (null? lst)
(reverse (cons (reverse cur) ret))
(if (cmp e (car lst))
(loop (cons (reverse cur) ret) '() (cdr lst))
(loop ret (cons (car lst) cur) (cdr lst))))))
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