From bede62e2f7b65b0dd047eeabbbb548dca820fc70 Mon Sep 17 00:00:00 2001
From: Leonardo de Moura <leonardo@microsoft.com>
Date: Wed, 7 Aug 2013 21:04:41 -0700
Subject: [PATCH] Fix bug in sexpr operator <<.

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
---
 src/tests/util/sexpr/sexpr.cpp | 8 ++++++++
 src/util/sexpr/sexpr.cpp       | 3 ++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/tests/util/sexpr/sexpr.cpp b/src/tests/util/sexpr/sexpr.cpp
index dbcaad9d13..ee5a2f521a 100644
--- a/src/tests/util/sexpr/sexpr.cpp
+++ b/src/tests/util/sexpr/sexpr.cpp
@@ -4,6 +4,7 @@ Released under Apache 2.0 license as described in the file LICENSE.
 
 Author: Leonardo de Moura
 */
+#include <sstream>
 #include "sexpr.h"
 #include "sexpr_funcs.h"
 #include "mpq.h"
@@ -154,6 +155,12 @@ static void tst5() {
                 == 987654321);
 }
 
+static void tst6() {
+    std::ostringstream s;
+    sexpr foo("str with \"quote\"");
+    s << foo;
+    lean_assert(s.str() == "\"str with \\\"quote\\\"\"");
+}
 
 int main() {
     continue_on_violation(true);
@@ -162,5 +169,6 @@ int main() {
     tst3();
     tst4();
     tst5();
+    tst6();
     return has_violations() ? 1 : 0;
 }
diff --git a/src/util/sexpr/sexpr.cpp b/src/util/sexpr/sexpr.cpp
index 06a0e82adf..75f1128ebb 100644
--- a/src/util/sexpr/sexpr.cpp
+++ b/src/util/sexpr/sexpr.cpp
@@ -11,6 +11,7 @@ Author: Leonardo de Moura
 #include "name.h"
 #include "mpz.h"
 #include "mpq.h"
+#include "escaped.h"
 
 namespace lean {
 /** \brief Base class used to represent S-expression cells. */
@@ -213,7 +214,7 @@ int cmp(sexpr const & a, sexpr const & b) {
 std::ostream & operator<<(std::ostream & out, sexpr const & s) {
     switch (s.kind()) {
     case sexpr_kind::NIL:         out << "nil"; break;
-    case sexpr_kind::STRING:      out << "\"" << to_string(s) << "\""; break;
+    case sexpr_kind::STRING:      out << "\"" << escaped(to_string(s).c_str()) << "\""; break;
     case sexpr_kind::INT:         out << to_int(s); break;
     case sexpr_kind::DOUBLE:      out << to_double(s); break;
     case sexpr_kind::NAME:        out << to_name(s); break;