From a222503a89a0ed81cdea49c13fb4f582b8924447 Mon Sep 17 00:00:00 2001
From: Juliana Sims <juli@incana.org>
Date: Fri, 10 Nov 2023 23:25:56 -0500
Subject: [PATCH] =?UTF-8?q?Second=20argument=20of=20=E2=80=98unread-string?=
 =?UTF-8?q?=E2=80=99=20is=20optional.?=
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Fixes <https://bugs.gnu.org/67063>.

* doc/ref/api-io.texi (Venerable Port Interfaces): Bring unread-string
procedure documentation in line with other procedures in the section.
* libguile/ports.c (scm_unread_string): Make port argument optional.
* test-suite/tests/ports.test: Test unread-char and unread-string
without ports.
* NEWS: Update.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>
---
 NEWS                        | 2 ++
 doc/ref/api-io.texi         | 2 +-
 libguile/ports.c            | 2 +-
 test-suite/tests/ports.test | 6 +++---
 4 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/NEWS b/NEWS
index 8a61bf65d..3c4854ca9 100644
--- a/NEWS
+++ b/NEWS
@@ -59,6 +59,8 @@ files.  See "Random Access" in the manual for details.
    (<https://bugs.gnu.org/55356>)
 ** 'read-u8' in (scheme base) now defaults to (current-input-port)
    (<https://bugs.gnu.org/62690>)
+** Second argument of 'unread-string' is now optional, as previously documented
+   (<https://bugs.gnu.org/67063>)
 ** 'ftw' now correctly deals with directory permissions
    (<https://bugs.gnu.org/55344>)
 ** 'make-custom-port' now honors its #:conversion-strategy argument
diff --git a/doc/ref/api-io.texi b/doc/ref/api-io.texi
index d0076bf68..79bc9e9d6 100644
--- a/doc/ref/api-io.texi
+++ b/doc/ref/api-io.texi
@@ -2000,7 +2000,7 @@ The same as @code{unget-char}, except that @var{port} defaults to the
 current input port, and the arguments are swapped.  @xref{Textual I/O}.
 @end deffn
 
-@deffn {Scheme Procedure} unread-string str port
+@deffn {Scheme Procedure} unread-string str [port]
 @deffnx {C Function} scm_unread_string (str, port)
 The same as @code{unget-string}, except that @var{port} defaults to the
 current input port, and the arguments are swapped.  @xref{Textual I/O}.
diff --git a/libguile/ports.c b/libguile/ports.c
index d3f763400..d0e4e0c7f 100644
--- a/libguile/ports.c
+++ b/libguile/ports.c
@@ -2228,7 +2228,7 @@ SCM_DEFINE (scm_unread_char, "unread-char", 1, 1, 0,
 }
 #undef FUNC_NAME
 
-SCM_DEFINE (scm_unread_string, "unread-string", 2, 0, 0,
+SCM_DEFINE (scm_unread_string, "unread-string", 1, 1, 0,
             (SCM str, SCM port),
 	    "Place the string @var{str} in @var{port} so that its characters will be\n"
 	    "read in subsequent read operations.  If called multiple times, the\n"
diff --git a/test-suite/tests/ports.test b/test-suite/tests/ports.test
index 27acf13b4..7b5b535e7 100644
--- a/test-suite/tests/ports.test
+++ b/test-suite/tests/ports.test
@@ -636,13 +636,13 @@
 (with-input-from-string "walk on the moon\nmoon"
                         (lambda ()
                           (read-char)
-                          (unread-char #\a (current-input-port))
+                          (unread-char #\a)
                           (pass-if "unread-char"
                                    (char=? (read-char) #\a))
                           (read-line)
                           (let ((replacenoid "chicken enchilada"))
-                            (unread-char #\newline (current-input-port))
-                            (unread-string replacenoid (current-input-port))
+                            (unread-char #\newline)
+                            (unread-string replacenoid)
                             (pass-if "unread-string"
                                      (string=? (read-line) replacenoid)))
                           (pass-if "unread residue"