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From: "B. Pym" <Nobody447095@here-nor-there.org>
Newsgroups: comp.lang.lisp,comp.lang.scheme
Subject: Re: Unable to read a list with 'with-open-file'
Date: Fri, 6 Sep 2024 22:42:23 -0000 (UTC)
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Tim Bradshaw wrote:

> If you want to write a function that returns the lines in the file do
> this:
> 
> (defun read-lines-from-file (file)
>   ;; Return a list of all the lines in FILE.  FILE is either a string
> or
>   ;; a pathname
>   (with-open-file (in file :direction ':input)
>     ;; no real line can be NIL, so we don't need to worry about
>     ;; inventing a unique return value here
>     (loop for line = (read-line in nil nil)
>           while line collect line)))
....
> Note for CLL people: I think this is a great use of LOOP.  It's *so*
> easy to see what is happening here:
> 
>    loop for line = <get next line from file, NIL on EOF>
>         while line collect line
> 
> Of course it's not pure functional Lisp.  But *so what*?

Gauche Scheme

(use gauche.generator)

(with-input-from-file "output.dat" (lambda()
  (generator->list read-line)))
 

Another way:

(use file.util)

(file->list read-line "output.dat")


Another way:

(define (collect-file-lines file)
  (with-input-from-file file (lambda()
    (let go ()
      (if (eof-object? (peek-char))
        '()
        (cons (read-line) (go)))))))