rdelim: Add new procedure `for-line-in-file`.

From 18485a2b94595ae2239f5dcdeb06d3a80bb04bf1 Mon Sep 17 00:00:00 2001
From: AwesomeAdam54321 <[email protected]>
Date: Sun, 15 Dec 2024 23:48:30 +0800
Subject: [PATCH] rdelim: Add new procedure `for-line-in-file`.

* module/ice-9/rdelim.scm (for-line-in-file): Add it.
---
 module/ice-9/rdelim.scm | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/module/ice-9/rdelim.scm b/module/ice-9/rdelim.scm
index d2cd081d7..ffa38efad 100644
--- a/module/ice-9/rdelim.scm
+++ b/module/ice-9/rdelim.scm
@@ -206,3 +206,15 @@ characters to read.  By default, there is no limit."
 	      line)
       (else
        (error "unexpected handle-delim value: " handle-delim)))))
+
+;;; for-line-in-file [PORT BODY] calls BODY (a procedure with the
+;;; line from PORT as it's argument) for every line until the
+;;; eof-object is reached. The line provided to BODY is guaranteed
+;;; to be a string.
+
+(define (for-line-in-file file body)
+  (while #t
+    (let ((line (read-line file)))
+      (if (string? line)
+          (body line)
+          (break)))))
-- 
2.41.0