read-print: 'pretty-print-with-comments' keeps newlines on long strings.

* guix/read-print.scm (printed-string)[preserve-newlines?]: New
procedure.
Use it to preserve newlines on long strings.
* tests/read-print.scm: Add test.

1 files changed, 5 insertions, 0 deletions

diff --git a/tests/read-print.scm b/tests/read-print.scm
index f4627e076a4..c2b236b1721 100644
--- a/tests/read-print.scm
+++ b/tests/read-print.scm
@@ -195,6 +195,11 @@ expressions."
 (string-append \"a\\tb\" \"\\n\")")
 
 (test-pretty-print "\
+(display \"This is a very long string.
+It contains line breaks, which are preserved,
+because it's a long string.\")")
+
+(test-pretty-print "\
 (description \"abcdefghijkl
 mnopqrstuvwxyz.\")"
                    #:max-width 30)