From 1bbe496d7d194ce6da2e710d0cc9a125e51a77b9 Mon Sep 17 00:00:00 2001
From: David Kastrup <dak@gnu.org>
Date: Sat, 4 Feb 2017 22:08:25 +0100
Subject: [PATCH] Issue 5057/1: Add Protected_scm::is_bound () function

Since SCM_UNBNDP has problems with arguments of type Protected_scm, an
alternative member function seems like a viable alternative.
---
 lily/include/protected-scm.hh | 1 +
 lily/protected-scm.cc         | 8 ++++++++
 2 files changed, 9 insertions(+)

diff --git a/lily/include/protected-scm.hh b/lily/include/protected-scm.hh
index 0115cb9f9f..db8a151ff5 100644
--- a/lily/include/protected-scm.hh
+++ b/lily/include/protected-scm.hh
@@ -54,6 +54,7 @@ public:
   Protected_scm &operator = (Protected_scm const &);
   operator const SCM & () const;
   operator SCM & ();
+  bool is_bound () const;  // SCM_UNBNDP balks at Protected_scm
 };
 
 #endif /* PROTECTED_SCM_HH */
diff --git a/lily/protected-scm.cc b/lily/protected-scm.cc
index a9fabdc4f2..3a16254187 100644
--- a/lily/protected-scm.cc
+++ b/lily/protected-scm.cc
@@ -86,3 +86,11 @@ Protected_scm::operator SCM & ()
 
   return *SCM_CARLOC (object_);
 }
+
+bool
+Protected_scm::is_bound () const
+{
+  if (SCM_CONSP (object_))
+    return !SCM_UNBNDP (SCM_CAR (object_));
+  return !SCM_UNBNDP (object_);
+}
-- 
2.39.2