From dadf30718d6084962be37dae8b94de41aaee90e2 Mon Sep 17 00:00:00 2001
From: Zoltan Somogyi <zoltan.somogyi@runbox.com>
Date: Sat, 6 Mar 2021 22:09:22 +1100
Subject: [PATCH] Add io.write_line_cc/4.

library/io.m:
    Add a version of io.write_line_cc that takes an explicit stream argument.

NEWS:
    Announce the addition.

browser/interactive_query.m:
    Use the new predicate.
---
 NEWS                        | 3 +++
 browser/interactive_query.m | 3 +--
 library/io.m                | 6 ++++++
 3 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/NEWS b/NEWS
index 65a1b37f0..4562329fb 100644
--- a/NEWS
+++ b/NEWS
@@ -124,6 +124,9 @@ Changes to the Mercury standard library
 
 ### Changes to the `io` module
 
+* The following predicate has been added to this module:
+    - pred `write_line_cc/4`
+
 * The following obsolete predicates have been removed:
 
     - pred `make_temp/3`            (replacement: `make_temp_file/3`)
diff --git a/browser/interactive_query.m b/browser/interactive_query.m
index e4e5f9419..a7c12fe82 100644
--- a/browser/interactive_query.m
+++ b/browser/interactive_query.m
@@ -940,8 +940,7 @@ write_binding(OutputStream, Bindings, Output, !IO) :-
 
 report_exception(OutputStream, Excp, !IO) :-
     io.write_string(OutputStream, "*** caught exception: ", !IO),
-    io.write_cc(OutputStream, Excp, !IO),
-    io.nl(OutputStream, !IO).
+    io.write_line_cc(OutputStream, Excp, !IO).
 
 %---------------------------------------------------------------------------%
 %
diff --git a/library/io.m b/library/io.m
index 772dfa1f0..219e9203d 100644
--- a/library/io.m
+++ b/library/io.m
@@ -1183,6 +1183,8 @@
 :- mode write_line(in, in, in, di, uo) is cc_multi.
 
 :- pred write_line_cc(T::in, io::di, io::uo) is cc_multi.
+:- pred write_line_cc(io.text_output_stream::in, T::in, io::di, io::uo)
+    is cc_multi.
 
     % Writes a binary representation of a term to the current binary output
     % stream or to the specified stream, in a format suitable for reading in
@@ -8848,6 +8850,10 @@ write_line_cc(X, !IO) :-
     io.write_cc(X, !IO),
     io.nl(!IO).
 
+write_line_cc(Stream, X, !IO) :-
+    io.write_cc(Stream, X, !IO),
+    io.nl(Stream, !IO).
+
 %---------------------%
 
 write_binary(Term, !IO) :-