chickadee » fmt » line-numbers

line-numbers #!optional <start>procedure

A convenience utility, just formats an infinite stream of numbers (in the current radix) beginning with <start>, which defaults to 1.

The Unix nl(1) utility could be implemented as:

  (fmt #t (columnar 6 'right 'infinite (line-numbers)
                    " " (fmt-file "read-line.scm")))
    2 (define (read-line . o)
    3   (let ((port (if (pair? o) (car o) (current-input-port))))
    4     (let lp ((res '()))
    5       (let ((c (read-char port)))
    6         (if (or (eof-object? c) (eqv? c #\newline))
    7             (list->string (reverse res))
    8             (lp (cons c res)))))))