read-line

Conformance: SketchyLISP Extension

Purpose: Read a newline-terminated sequence of characters. Return a string containing the characters read.

Implementation:

(define (read-line)
  (letrec
    ((collect-chars
       (lambda (c s)
         (cond ((or (eof-object? c) (char=? c #\newline))
             (apply string (reverse s)))
           (else (collect-chars (read-char) (cons c s))))))
     (first-char
       (read-char)))
    (cond ((eof-object? first-char) first-char)
      (else (collect-chars first-char '())))))

Example:

(read-line) hello world 
=> " hello world "