From 83128f00e9149f3c1bcd4450eb0ed3620a37149c Mon Sep 17 00:00:00 2001
From: Ludovic Courtès <ludo@gnu.org>
Date: Thu, 16 Mar 2023 22:18:52 +0100
Subject: read-print: 'read-with-comments' reads comments within gexps.

Fixes <https://issues.guix.gnu.org/62059>.
Reported by Maxim Cournoyer <maxim.cournoyer@gmail.com>.

* guix/read-print.scm (read-with-comments): Special-case #~, #$, and #+.
* tests/read-print.scm: Add two tests.
---
 guix/read-print.scm | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

(limited to 'guix/read-print.scm')

diff --git a/guix/read-print.scm b/guix/read-print.scm
index fdc85c2693..515eb7669c 100644
--- a/guix/read-print.scm
+++ b/guix/read-print.scm
@@ -219,6 +219,27 @@ BLANK-LINE? is true, assume PORT is at the beginning of a new line."
               (list 'quote (loop #f return)))
              ((eq? chr #\`)
               (list 'quasiquote (loop #f return)))
+             ((eq? chr #\#)
+              (match (read-char port)
+                (#\~ (list 'gexp (loop #f return)))
+                (#\$ (list (match (peek-char port)
+                             (#\@
+                              (read-char port)    ;consume
+                              'ungexp-splicing)
+                             (_
+                              'ungexp))
+                           (loop #f return)))
+                (#\+ (list (match (peek-char port)
+                             (#\@
+                              (read-char port)    ;consume
+                              'ungexp-native-splicing)
+                             (_
+                              'ungexp-native))
+                           (loop #f return)))
+                (chr
+                 (unread-char chr port)
+                 (unread-char #\# port)
+                 (read port))))
              ((eq? chr #\,)
               (list (match (peek-char port)
                       (#\@
-- 
cgit v1.2.3