diff --git a/src/include/ranges/xfor/pos_type.cc.h b/src/include/ranges/xfor/pos_type.cc.h
index 710e2d7..ff36b24 100644
--- a/src/include/ranges/xfor/pos_type.cc.h
+++ b/src/include/ranges/xfor/pos_type.cc.h
@@ -3,6 +3,7 @@
 #define __cxz_pos_type_cc_h__
 
 #include "pos_type.h"
+#include "vpos_type.h"
 
 namespace CNORXZ
 {
@@ -339,7 +340,12 @@ namespace CNORXZ
 
     inline const VPosBase* DPos::get() const
     {
-	return mC->get();
+	return mC->vget();
+    }
+
+    inline const VPosBase* DPos::vpos() const
+    {
+	return mC.get();
     }
 
     inline bool DPos::F() const
@@ -365,21 +371,35 @@ namespace CNORXZ
     template <class PosT>
     inline DPos DPos::operator+(const PosT& a) const
     {
-	return DPos(mC->vplus( VPosRef<PosT>(&a) ));
+	if constexpr(std::is_same<PosT,DPos>::value or std::is_same<PosT,DPosRef>::value){
+	    return DPos(mC->vplus( a.vpos() ));
+	}
+	else {
+	    return DPos(mC->vplus( VPosRef<PosT>(&a) ));
+	}
     }
 
     template <class PosT>
     inline DPos DPos::operator*(const PosT& a) const
     {
-	
-	return DPos(mC->vtimes( VPosRef<PosT>(&a) ));
+	if constexpr(std::is_same<PosT,DPos>::value or std::is_same<PosT,DPosRef>::value){
+	    return DPos(mC->vtimes( a.vpos() ));
+	}
+	else {
+	    return DPos(mC->vtimes( VPosRef<PosT>(&a) ));
+	}
     }
 
     // same as operator*, except for FPos/SFPos, where map is executed
     template <class PosT>
     inline DPos DPos::operator()(const PosT& a) const
     {
-	return DPos(mC->vexec( VPosRef<PosT>(&a) ));
+	if constexpr(std::is_same<PosT,DPos>::value or std::is_same<PosT,DPosRef>::value){
+	    return DPos(mC->vexec( a.vpos() ));
+	}
+	else {
+	    return DPos(mC->vexec( VPosRef<PosT>(&a) ));
+	}
     }
 	
     template <class PosT>
@@ -396,7 +416,12 @@ namespace CNORXZ
 
     inline const VPosBase* DPosRef::get() const
     {
-	return mP->get();
+	return mP->vget();
+    }
+
+    inline const VPosBase* DPosRef::vpos() const
+    {
+	return mP;
     }
 
     inline bool DPosRef::F() const
@@ -422,20 +447,35 @@ namespace CNORXZ
     template <class PosT>
     inline DPos DPosRef::operator+(const PosT& a) const
     {
-	return DPos(mP->vplus( VPosRef<PosT>(&a) ));
+	if constexpr(std::is_same<PosT,DPos>::value or std::is_same<PosT,DPosRef>::value){
+	    return DPos(mP->vplus( a.vpos() ));
+	}
+	else {
+	    return DPos(mP->vplus( VPosRef<PosT>(&a) ));
+	}
     }
 
     template <class PosT>
     inline DPos DPosRef::operator*(const PosT& a) const
     {
-	return DPos(mP->vtimes( VPosRef<PosT>(&a) ));
+	if constexpr(std::is_same<PosT,DPos>::value or std::is_same<PosT,DPosRef>::value){
+	    return DPos(mP->vtimes( a.vpos() ));
+	}
+	else {
+	    return DPos(mP->vtimes( VPosRef<PosT>(&a) ));
+	}
     }
 
     // same as operator*, except for FPos/SFPos, where map is executed
     template <class PosT>
     inline DPos DPosRef::operator()(const PosT& a) const
     {
-	return DPos(mP->vexec( VPosRef<PosT>(&a) ));
+	if constexpr(std::is_same<PosT,DPos>::value or std::is_same<PosT,DPosRef>::value){
+	    return DPos(mP->vexec( a.vpos() ));
+	}
+	else {
+	    return DPos(mP->vexec( VPosRef<PosT>(&a) ));
+	}
     }
 	
     template <class PosT>
diff --git a/src/include/ranges/xfor/pos_type.h b/src/include/ranges/xfor/pos_type.h
index 485b9e0..041eff9 100644
--- a/src/include/ranges/xfor/pos_type.h
+++ b/src/include/ranges/xfor/pos_type.h
@@ -12,7 +12,10 @@ namespace CNORXZ
 
     template <class T>
     struct is_scalar_pos_type { CXZ_CVAL_FALSE; };
-    
+
+    template <class T>
+    struct is_static_pos_type { CXZ_CVAL_FALSE; };
+
     template <SizeT N>
     class SPos
     {
@@ -170,6 +173,7 @@ namespace CNORXZ
 	inline explicit DPos(PosT&& a);
 
 	inline const VPosBase* get() const;
+	inline const VPosBase* vpos() const;
 	inline bool F() const;
 	inline SizeT size() const;
 	inline SizeT val() const;
@@ -200,6 +204,7 @@ namespace CNORXZ
 	explicit DPosRef(const VPosBase* p);
 
 	inline const VPosBase* get() const;
+	inline const VPosBase* vpos() const;
 	inline bool F() const;
 	inline SizeT size() const;
 	inline SizeT val() const;
@@ -221,12 +226,14 @@ namespace CNORXZ
     
     template <SizeT N> struct is_pos_type<SPos<N>> { CXZ_CVAL_TRUE; };
     template <SizeT N> struct is_scalar_pos_type<SPos<N>> { CXZ_CVAL_TRUE; };
+    template <SizeT N> struct is_static_pos_type<SPos<N>> { CXZ_CVAL_TRUE; };
     template <> struct is_pos_type<UPos> { CXZ_CVAL_TRUE; };
     template <> struct is_scalar_pos_type<UPos> { CXZ_CVAL_TRUE; };
     template <> struct is_pos_type<FPos> { CXZ_CVAL_TRUE; };
     template <> struct is_scalar_pos_type<FPos> { CXZ_CVAL_TRUE; };
     template <SizeT N, SizeT... Ms> struct is_pos_type<SFPos<N,Ms...>> { CXZ_CVAL_TRUE; };
     template <SizeT N, SizeT... Ms> struct is_scalar_pos_type<SFPos<N,Ms...>> { CXZ_CVAL_TRUE; };
+    template <SizeT N, SizeT... Ms> struct is_static_pos_type<SFPos<N,Ms...>> { CXZ_CVAL_TRUE; };
     template <class BPosT, class NPosT> struct is_pos_type<MPos<BPosT,NPosT>> { CXZ_CVAL_TRUE; };
     template <> struct is_pos_type<DPos> { CXZ_CVAL_TRUE; };
     template <> struct is_pos_type<DPosRef> { CXZ_CVAL_TRUE; };
diff --git a/src/include/ranges/xfor/vpos_type.cc.h b/src/include/ranges/xfor/vpos_type.cc.h
index 3ac2147..5332973 100644
--- a/src/include/ranges/xfor/vpos_type.cc.h
+++ b/src/include/ranges/xfor/vpos_type.cc.h
@@ -3,6 +3,7 @@
 #define __cxz_vpos_type_cc_h__
 
 #include "vpos_type.h"
+#include "pos_type.h"
 
 namespace CNORXZ
 {
@@ -28,14 +29,14 @@ namespace CNORXZ
 	return this->vextend(static_cast<const PosT1&>(a))->vextend(a.next());
     }
 
-    inline Uptr<VPosBase> vextend(const DPos& a) const
+    inline Uptr<VPosBase> VPosBase::vextend(const DPos& a) const
     {
-	Uptr out = nullptr;
+	Uptr<VPosBase> out = nullptr;
 	if(a.F()){
-	    out = this->vextend(dynamic_cast<const FPos*>(a.get()));
+	    out = this->vextend(*dynamic_cast<const FPos*>(a.get()));
 	}
 	else {
-	    out = this->vextend(dynamic_cast<const UPos*>(a.get()));
+	    out = this->vextend(*dynamic_cast<const UPos*>(a.get()));
 	}
 	if(a.size() > 1){
 	    return out->vextend(a.next());
@@ -45,14 +46,14 @@ namespace CNORXZ
 	}
     }
     
-    inline Uptr<VPosBase> vextend(const DPosRef& a) const
+    inline Uptr<VPosBase> VPosBase::vextend(const DPosRef& a) const
     {
-	Uptr out = nullptr;
+	Uptr<VPosBase> out = nullptr;
 	if(a.F()){
-	    out = this->vextend(dynamic_cast<const FPos*>(a.get()));
+	    out = this->vextend(*dynamic_cast<const FPos*>(a.get()));
 	}
 	else {
-	    out = this->vextend(dynamic_cast<const UPos*>(a.get()));
+	    out = this->vextend(*dynamic_cast<const UPos*>(a.get()));
 	}
 	if(a.size() > 1){
 	    return out->vextend(a.next());
@@ -77,10 +78,16 @@ namespace CNORXZ
 	return std::make_unique<VPos<PosT>>(*this);
     }
 
+    template <class PosT>
+    const VPosBase* VPos<PosT>::vget() const
+    {
+	return this;
+    }
+    
     template <class PosT>
     bool VPos<PosT>::F() const
     {
-	if constexpr(typename std::is_same<PosT,FPos>::value){
+	if constexpr(std::is_same<PosT,FPos>::value){
 	    return true;
 	}
 	else {
@@ -149,6 +156,7 @@ namespace CNORXZ
     template <class PosT1, class PosT2>
     VPos<MPos<PosT1,PosT2>>::VPos(const MPos<PosT1,PosT2>& a) :
 	MPos<PosT1,PosT2>(a),
+	mTRef(this),
 	mNRef(&this->next())
     {}
 	
@@ -158,10 +166,16 @@ namespace CNORXZ
 	return std::make_unique<VPos<MPos<PosT1,PosT2>>>(*this);
     }
     
+    template <class PosT1, class PosT2>
+    const VPosBase* VPos<MPos<PosT1,PosT2>>::vget() const
+    {
+	return &mTRef;
+    }
+
     template <class PosT1, class PosT2>
     bool VPos<MPos<PosT1,PosT2>>::F() const
     {
-	if constexpr(typename std::is_same<PosT1,FPos>::value){
+	if constexpr(std::is_same<PosT1,FPos>::value){
 	    return true;
 	}
 	else {
@@ -237,10 +251,16 @@ namespace CNORXZ
 	return std::make_unique<VPos<PosT>>(*mC);
     }
     
+    template <class PosT>
+    const VPosBase* VPosRef<PosT>::vget() const
+    {
+	return this;
+    }
+    
     template <class PosT>
     bool VPosRef<PosT>::F() const
     {
-	if constexpr(typename std::is_same<PosT,FPos>::value){
+	if constexpr(std::is_same<PosT,FPos>::value){
 	    return true;
 	}
 	else {
@@ -307,7 +327,7 @@ namespace CNORXZ
 
     template <class PosT1, class PosT2>
     VPosRef<MPos<PosT1,PosT2>>::VPosRef(const MPos<PosT1,PosT2>* c) :
-	mC(c), mNRef(c->vnext())
+	mC(c), mTRef(this), mNRef(c->vnext())
     {}
 
     template <class PosT1, class PosT2>
@@ -316,10 +336,16 @@ namespace CNORXZ
 	return std::make_unique<VPos<MPos<PosT1,PosT2>>>(*mC);
     }
 
+    template <class PosT1, class PosT2>
+    const VPosBase* VPosRef<MPos<PosT1,PosT2>>::vget() const
+    {
+	return &mTRef;
+    }
+
     template <class PosT1, class PosT2>
     bool VPosRef<MPos<PosT1,PosT2>>::F() const
     {
-	if constexpr(typename std::is_same<PosT1,FPos>::value){
+	if constexpr(std::is_same<PosT1,FPos>::value){
 	    return true;
 	}
 	else {
diff --git a/src/include/ranges/xfor/vpos_type.h b/src/include/ranges/xfor/vpos_type.h
index 33bec21..1cf36cf 100644
--- a/src/include/ranges/xfor/vpos_type.h
+++ b/src/include/ranges/xfor/vpos_type.h
@@ -45,6 +45,7 @@ namespace CNORXZ
 	VPos(const PosT& a);
 	
 	virtual Uptr<VPosBase> copy() const override final;
+	virtual const VPosBase* vget() const override final;
 	virtual bool F() const override final;
 	virtual SizeT vsize() const override final;
 	virtual SizeT vval() const override final;
@@ -60,6 +61,7 @@ namespace CNORXZ
     class VPos<MPos<PosT1,PosT2>> : public VPosBase, public MPos<PosT1,PosT2>
     {
     private:
+	VPosRef<PosT1> mTRef;
 	VPosRef<PosT2> mNRef;
 
     public:
@@ -67,6 +69,7 @@ namespace CNORXZ
 	VPos(const MPos<PosT1,PosT2>& a);
 	
 	virtual Uptr<VPosBase> copy() const override final;
+	virtual const VPosBase* vget() const override final;
 	virtual bool F() const override final;
 	virtual SizeT vsize() const override final;
 	virtual SizeT vval() const override final;
@@ -89,6 +92,7 @@ namespace CNORXZ
 	VPosRef(const PosT* c);
 
 	virtual Uptr<VPosBase> copy() const override final;
+	virtual const VPosBase* vget() const override final;
 	virtual bool F() const override final;
 	virtual SizeT vsize() const override final;
 	virtual SizeT vval() const override final;
@@ -106,6 +110,7 @@ namespace CNORXZ
     {
     private:
 	const MPos<PosT1,PosT2>* mC = nullptr;
+	VPosRef<PosT1> mTRef;
 	VPosRef<PosT2> mNRef;
 
     public:
@@ -113,6 +118,7 @@ namespace CNORXZ
 	VPosRef(const MPos<PosT1,PosT2>* c);
 
 	virtual Uptr<VPosBase> copy() const override final;
+	virtual const VPosBase* vget() const override final;
 	virtual bool F() const override final;
 	virtual SizeT vsize() const override final;
 	virtual SizeT vval() const override final;
@@ -127,6 +133,26 @@ namespace CNORXZ
     };
 
     
+    // defined as empty since they should never instanciated
+    template <SizeT N>
+    class VPos<SPos<N>>
+    {};
+
+    // defined as empty since they should never instanciated
+    template <SizeT N>
+    class VPosRef<SPos<N>>
+    {};
+
+    // defined as empty since they should never instanciated
+    template <SizeT N, SizeT... Ms>
+    class VPos<SFPos<N,Ms...>>
+    {};
+
+    // defined as empty since they should never instanciated
+    template <SizeT N, SizeT... Ms>
+    class VPosRef<SFPos<N,Ms...>>
+    {};
+
     // defined as empty since they should never instanciated
     template <>
     class VPos<DPos>
diff --git a/src/tests/xfor_unit_test.cc b/src/tests/xfor_unit_test.cc
index 8a471fe..75de91b 100644
--- a/src/tests/xfor_unit_test.cc
+++ b/src/tests/xfor_unit_test.cc
@@ -102,20 +102,20 @@ namespace
     {
 	DPos dp01(static_cast<UPos>(mS2p));
 	DPos dp02(mUp1);
-	/*
-	DPos dp1(mkMPos(mS2p, mUp1));
-	DPos dp2(mkMPos(mUp2, mS4p));
+	
+	DPos dp1(mkMPos(static_cast<UPos>(mS2p), mUp1));
+	DPos dp2(mkMPos(mUp2, static_cast<UPos>(mS4p)));
 	auto dp3a = dp1 + dp2;
 	auto dp3b = dp2 + dp1;
 	auto dp4 = dp1 * dp01;
 	auto dp5 = dp2 * dp02;
-	*/
+	
 	EXPECT_EQ(dp01.size(), 1);
 	EXPECT_EQ(dp02.size(), 1);
 
 	EXPECT_EQ(dp01.val(), mS2p.val());
 	EXPECT_EQ(dp02.val(), mUp1.val());
-	/*
+	
 	EXPECT_EQ(dp1.size(), 2);
 	EXPECT_EQ(dp2.size(), 2);
 
@@ -124,19 +124,19 @@ namespace
 	EXPECT_EQ(dp4.size(), 2);
 	EXPECT_EQ(dp5.size(), 2);
 
-	EXPECT_EQ(dp1.first().val(), mS2p.val());
+	EXPECT_EQ(dp1.val(), mS2p.val());
 	EXPECT_EQ(dp1.next().val(), mUp1.val());
-	EXPECT_EQ(dp2.first().val(), mUp2.val());
+	EXPECT_EQ(dp2.val(), mUp2.val());
 	EXPECT_EQ(dp2.next().val(), mS4p.val());
-	EXPECT_EQ(dp3a.first().val(), mS2p.val() + mUp2.val());
+	EXPECT_EQ(dp3a.val(), mS2p.val() + mUp2.val());
 	EXPECT_EQ(dp3a.next().val(), mUp1.val() + mS4p.val());
-	EXPECT_EQ(dp3b.first().val(), mS2p.val() + mUp2.val());
+	EXPECT_EQ(dp3b.val(), mS2p.val() + mUp2.val());
 	EXPECT_EQ(dp3b.next().val(), mUp1.val() + mS4p.val());
-	EXPECT_EQ(dp4.first().val(), mS2p.val() * mS2p.val());
+	EXPECT_EQ(dp4.val(), mS2p.val() * mS2p.val());
 	EXPECT_EQ(dp4.next().val(), mUp1.val() * mS2p.val());
-	EXPECT_EQ(dp5.first().val(), mUp2.val() * mUp1.val());
+	EXPECT_EQ(dp5.val(), mUp2.val() * mUp1.val());
 	EXPECT_EQ(dp5.next().val(), mS4p.val() * mUp1.val());
-	*/
+	
     }
     
 }