Hi Adam!
I was confused with the name "file" here since it acts more like a port rather than a filename. If it's expected to be a opened port passed from the caller, it's better rename to "port".
In your context, I think you want to check if it's the end of file, so you may use eof-object?
To make your patch more useful, IMHO, you may support filename string and file port both. And close the port properly when it's end.
From 3c7e1af1f4812d0e4c5d10e841cf9546e5ba2887 Mon Sep 17 00:00:00 2001
From: AwesomeAdam54321 <adam.faiz@disroot.org>
Date: Sun, 15 Dec 2024 23:48:30 +0800
Subject: [PATCH v1] rdelim: Add new procedure `for-line-in-file`.
* module/ice-9/rdelim.scm (for-line-in-file): Add it.
This procedure makes it convenient to do per-line processing of a text
file.
---
module/ice-9/rdelim.scm | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/module/ice-9/rdelim.scm b/module/ice-9/rdelim.scm
index d2cd081d7..833639219 100644
--- a/module/ice-9/rdelim.scm
+++ b/module/ice-9/rdelim.scm
@@ -23,7 +23,8 @@
;;; similar to (scsh rdelim) but somewhat incompatible.
(define-module (ice-9 rdelim)
- #:export (read-line
+ #:export (for-line-in-file
+ read-line
read-line!
read-delimited
read-delimited!
@@ -206,3 +207,12 @@ characters to read. By default, there is no limit."
line)
(else
(error "unexpected handle-delim value: " handle-delim)))))
+
+(define (for-line-in-file file proc)
+ "Call PROC for every line in FILE until the eof-object is reached.
+The line provided to PROC is guaranteed to be a string."
+ (while #t
+ (let ((line (read-line file)))
+ (if (string? line)
+ (proc line)
+ (break)))))
--
2.41.0