Index: testsuite/Makefile.am
===================================================================
RCS file: /cvsroot/blitz/blitz/testsuite/Makefile.am,v
retrieving revision 1.12
diff -u -d -b -w -r1.12 Makefile.am
--- testsuite/Makefile.am	5 May 2004 21:29:00 -0000	1.12
+++ testsuite/Makefile.am	11 Sep 2004 05:45:53 -0000
@@ -18,7 +18,7 @@
 module newet Olaf-Ronneberger-1 peter-bienstman-1 peter-bienstman-2 \
 peter-bienstman-3 peter-bienstman-4 peter-bienstman-5 peter-nordlund-1 \
 peter-nordlund-2 peter-nordlund-3 promote qcd reduce reindex reverse \
-shapecheck shape storage stub theodore-papadopoulo-1 tinymat tinyvec \
+shapecheck shape storage stub ternary theodore-papadopoulo-1 tinymat tinyvec \
 transpose troyer-genilloud Ulisses-Mello-1 wei-ku-1 where
 
 Adnene_Ben_Abdallah_1_SOURCES = Adnene-Ben-Abdallah-1.cpp
@@ -68,6 +68,7 @@
 shape_SOURCES = shape.cpp
 storage_SOURCES = storage.cpp
 stub_SOURCES = stub.cpp
+ternary_SOURCES = ternary.cpp
 theodore_papadopoulo_1_SOURCES = theodore-papadopoulo-1.cpp
 tinymat_SOURCES = tinymat.cpp
 tinyvec_SOURCES = tinyvec.cpp
Index: blitz/array/asexpr.h
===================================================================
RCS file: /cvsroot/blitz/blitz/blitz/array/asexpr.h,v
retrieving revision 1.7
diff -u -d -b -w -r1.7 asexpr.h
--- blitz/array/asexpr.h	31 Dec 2003 01:50:04 -0000	1.7
+++ blitz/array/asexpr.h	11 Sep 2004 05:45:53 -0000
@@ -37,6 +37,7 @@
 
 template <typename T>
 struct asExpr {
+	enum { isBlitz = false };
     typedef _bz_ArrayExprConstant<T> T_expr;
     static T_expr getExpr(const T& x) { return T_expr(x); }
 };
@@ -45,6 +46,7 @@
 
 template <typename T>
 struct asExpr<_bz_ArrayExpr<T> > {
+	enum { isBlitz = true };
     typedef _bz_ArrayExpr<T> T_expr;
     static const T_expr& getExpr(const T_expr& x) { return x; }
 };
@@ -53,6 +55,7 @@
 
 template <typename T,int N>
 struct asExpr<Array<T,N> > {
+	enum { isBlitz = true };
     typedef FastArrayIterator<T,N> T_expr;
     static T_expr getExpr(const Array<T,N>& x) { return x.beginFast(); }
 };
@@ -61,6 +64,7 @@
 
 template <int N>
 struct asExpr<IndexPlaceholder<N> > {
+	enum { isBlitz = true };
     typedef IndexPlaceholder<N> T_expr;
     static T_expr getExpr(T_expr x) { return x; }
 };
Index: blitz/array/newet-macros.h
===================================================================
RCS file: /cvsroot/blitz/blitz/blitz/array/newet-macros.h,v
retrieving revision 1.14
diff -u -d -b -w -r1.14 newet-macros.h
--- blitz/array/newet-macros.h	9 Mar 2004 21:51:33 -0000	1.14
+++ blitz/array/newet-macros.h	11 Sep 2004 05:45:53 -0000
@@ -31,6 +31,41 @@
 #ifdef BZ_TEMPLATES_AS_TEMPLATE_ARGUMENTS
 
 /*
+ * Helpers
+ */
+// Inspired by Boost enable_if library <http://boost.org/libs/utility/enable_if.html>
+template <bool B, typename T = void>
+struct enable_if_c {
+	typedef T type;
+};
+
+template <typename T>
+struct enable_if_c<false, T> {};
+
+template <class Cond, typename T = void>
+struct enable_if : public enable_if_c<Cond::value, T> {};
+
+template<typename T1, typename T2>
+struct IsAtLeastOneOperandBlitz2 {
+	enum { value = asExpr<T1>::isBlitz || asExpr<T2>::isBlitz };
+};
+
+template<typename T1, typename T2, typename T3>
+struct IsAtLeastOneOperandBlitz3 {
+	enum { value = IsAtLeastOneOperandBlitz2<T1,T2>::value || asExpr<T3>::isBlitz };
+};
+
+template<typename T>
+const T& unwrap(const T& t) { return t; }
+
+template<typename T>
+const T& unwrap(const ETBase<T>& t) {
+	return t.unwrap();
+}
+
+// etc
+
+/*
  * Unary functions and operators
  */
 
@@ -98,12 +133,13 @@
 template <typename T1, typename T2, typename T3>                              \
 _bz_inline_et                                                                 \
 typename BzTernaryExprResult<applic, T1, T2, T3>::T_result                    \
-name(const ETBase<T1>& d1, const ETBase<T2>& d2, const ETBase<T3>& d3)        \
+name(const T1& d1, const T2& d2, const T3& d3,                            \
+	 typename enable_if< IsAtLeastOneOperandBlitz3<T1,T2,T3> >::type* dummy = 0)\
 {                                                                             \
     typedef typename BzTernaryExprResult<applic,T1,T2,T3>::T_result result;   \
-    return result(asExpr<T1>::getExpr(d1.unwrap()),                           \
-                  asExpr<T2>::getExpr(d2.unwrap()),                           \
-                  asExpr<T3>::getExpr(d3.unwrap()));                          \
+    return result(asExpr<T1>::getExpr(unwrap(d1)),                           \
+                  asExpr<T2>::getExpr(unwrap(d2)),                           \
+                  asExpr<T3>::getExpr(unwrap(d3)));                          \
 }
     
 #else
@@ -206,7 +242,8 @@
     applic<_bz_typename asExpr<T1>::T_expr::T_numtype,                    \
            _bz_typename asExpr<T2>::T_expr::T_numtype,                    \
            _bz_typename asExpr<T3>::T_expr::T_numtype> > >                \
-name(const ETBase<T1>& d1, const ETBase<T2>& d2, const ETBase<T3>& d3)    \
+name(const T1& d1, const T2& d2, const T3& d3,                            \
+	 typename enable_if< IsAtLeastOneOperandBlitz3<T1,T2,T3> >::type* dummy = 0)\
 {                                                                         \
     return _bz_ArrayExpr<_bz_ArrayExprTernaryOp<                          \
         _bz_typename asExpr<T1>::T_expr,                                  \
@@ -215,9 +252,9 @@
         applic<_bz_typename asExpr<T1>::T_expr::T_numtype,                \
                _bz_typename asExpr<T2>::T_expr::T_numtype,                \
                _bz_typename asExpr<T3>::T_expr::T_numtype> > >            \
-        (asExpr<T1>::getExpr(d1.unwrap()),                                \
-         asExpr<T2>::getExpr(d2.unwrap()),                                \
-         asExpr<T3>::getExpr(d3.unwrap()));                               \
+        (asExpr<T1>::getExpr(unwrap(d1)),                                \
+         asExpr<T2>::getExpr(unwrap(d2)),                                \
+         asExpr<T3>::getExpr(unwrap(d3)));                               \
 }
 
 #endif /* BZ_TEMPLATES_AS_TEMPLATE_ARGUMENTS */