Kent M. Pitman wrote:

> ... What i want to do is start at the beginning of the
> file( which I can do) and search for the word "entity".
> Once I find this, I want to assign the next word to a
> variable. ...
>
> Use WITH-OPEN-FILE to open the stream. It will let you specify
> a variable to which the stream is bound. The I/O routines all
> take a stream as argument. e.g.,
>
> (defun find-word-association-in-file (word file)
> (with-open-file (stream file :direction :input)
> (loop
> (let ((line (read-line stream nil nil)))
> (declare (type string line))
> (unless line (return nil))
> (let ((pos1 (position #\Space line :test #'char-equal)))
> (when (and pos1 (string-equal word line :end2 pos1))
> (let ((pos2 (position #\Space line
> :test (complement #'char-equal)
> :start pos1)))
> (when pos2
> (return (subseq line pos2
> (position #\Space line
> :test #'char-equal
> :start pos2)))))))))))
>
> Given a data file "delete-me.text" containing:
>
> FOO OOF
> BAR RAB XYZZY
> BAZ ZAB PLOVER PLUGH
> NUL NIL
>
> I find that:
>
> (find-word-association-in-file "FOO" "delete-me.text") => "OOF"
> (find-word-association-in-file "BAZ" "delete-me.text") => "ZAB"
> (find-word-association-in-file "NUL" "delete-me.text") => "NIL"
> (find-word-association-in-file "GEE" "delete-me.text") => NIL

Gauche Scheme

(use file.util) ;; file->string-list
(use srfi-13) ;; string-tokenize
(use srfi-14) ;; character-sets

;; Assumes that the "next word" has to be on the same line.
(define (find-word-association-in-file word file)
(any
(lambda (line)
(let* ((words (string-tokenize line char-set:letter))
(tail (member word words string=?)))
(and tail (pair? (cdr tail)) (cadr tail))))
(file->string-list file)))

(find-word-association-in-file "FOO" "delete-me.txt")
===>
"OOF"

(find-word-association-in-file "PLOVER" "delete-me.txt")
===>
"PLUGH"

(find-word-association-in-file "PLUGH" "delete-me.txt")
===>
#f

On 2024-07-02, B. Pym <No_spamming@noWhere_7073.org> wrote:
> Gauche Scheme
>
> (use file.util) ;; file->string-list
> (use srfi-13) ;; string-tokenize
> (use srfi-14) ;; character-sets

This is garbage. If it comes with the language, the language should
understand it without any import statement nonsense.

(At least a high-level, dynamic language. Medium-level, non-interactive
languages like Ada and Modula-2 have decent reasons for it.)

> ;; Assumes that the "next word" has to be on the same line.
> (define (find-word-association-in-file word file)
> (any
> (lambda (line)
> (let* ((words (string-tokenize line char-set:letter))
> (tail (member word words string=?)))
> (and tail (pair? (cdr tail)) (cadr tail))))
> (file->string-list file)))

TXR Lisp:

(defun find-following-word-in-file (path word)
(if-match @(some @(scan (@word @other . @nil)))
(mapcar (op tok #/\w+/) (file-get-lines path))
other))

--
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