>From 302159fe61d9df526911ead8ea6ad823ad8b0443 Mon Sep 17 00:00:00 2001
From: AwesomeAdam54321 <adam.f...@disroot.org>
Date: Sun, 15 Dec 2024 23:48:30 +0800
Subject: [PATCH 1/2] rdelim: Add new procedure `for-rdelim-in-port`.
* module/ice-9/rdelim.scm (for-rdelim-in-port): Add it.
(for-delimited-in-port): Define as a specialised `for-rdelim-in-port`.
(for-line-in-file): Define as a specialised `for-delimited-in-port`.
These procedures provide a backbone for parsing, with domain-specific
logic implemented as a separate procedure to be passed as an argument.
---
module/ice-9/rdelim.scm | 35 ++++++++++++++++++++++++++++++++++-
1 file changed, 34 insertions(+), 1 deletion(-)
diff --git a/module/ice-9/rdelim.scm b/module/ice-9/rdelim.scm
index d2cd081d7..0bbaaf904 100644
--- a/module/ice-9/rdelim.scm
+++ b/module/ice-9/rdelim.scm
@@ -23,7 +23,10 @@
;;; similar to (scsh rdelim) but somewhat incompatible.
(define-module (ice-9 rdelim)
- #:export (read-line
+ #:export (for-delimited-in-port
+ for-line-in-file
+ for-rdelim-in-port
+ read-line
read-line!
read-delimited
read-delimited!
@@ -206,3 +209,33 @@ characters to read. By default, there is no limit."
line)
(else
(error "unexpected handle-delim value: " handle-delim)))))
+
+(define* (for-rdelim-in-port port proc rdelim-proc
+ #:key (stop-pred eof-object?))
+ "Call PROC for every (RDELIM-PROC PORT) in PORT until STOP-PRED returns #t.
+RDELIM-PROC has to advance through PORT with every call."
+ (let loop ((rdelim (rdelim-proc port)))
+ (cond ((stop-pred rdelim)
+ (close-port port))
+ (else
+ (proc rdelim)
+ (loop (rdelim-proc port))))))
+
+(define* (for-delimited-in-port port proc
+ #:key (delims "\n") (handle-delim 'trim))
+ "Call PROC for every delimited line in PORT until the eof-object is reached."
+ (for-rdelim-in-port port proc
+ (lambda (port)
+ (read-delimited delims port handle-delim))))
+
+(define* (for-line-in-file file proc
+ #:key (encoding #f) (guess-encoding #f))
+ "Call PROC for every line in FILE until the eof-object is reached.
+FILE must be a filename string.
+
+The line provided to PROC is guaranteed to be a string."
+ (call-with-input-file
+ file
+ (lambda (port)
+ (for-delimited-in-port port proc))
+ #:encoding encoding #:guess-encoding guess-encoding))
--
2.41.0
