diff --git a/src/include/array/array_base.cc.h b/src/include/array/array_base.cc.h
index 31021d1..ca1f4f9 100644
--- a/src/include/array/array_base.cc.h
+++ b/src/include/array/array_base.cc.h
@@ -118,7 +118,7 @@ namespace CNORXZ
 	if(npack.size() == 0){
 	    return nullptr;
 	}
-	return mkXIndex(yindexPtr(npack));
+	return xindexPtr(yindexPtr(npack));
     }
 
     /******************
diff --git a/src/include/base/iter.cc.h b/src/include/base/iter.cc.h
index 73c97b7..2798132 100644
--- a/src/include/base/iter.cc.h
+++ b/src/include/base/iter.cc.h
@@ -23,6 +23,33 @@ namespace CNORXZ
     {
 	return iteri(g, f, Isqr<B,E>{});
     }
+
+    template <SizeT E, SizeT I, class G, class F, class C, typename... Args>
+    constexpr decltype(auto) iterIfi(const G& g, const F& f, const C& c, const Args&... args)
+    {
+	if constexpr(I >= E){
+	    if constexpr(std::is_same<F,NoF>::value){
+		return;
+	    }
+	    else {
+		return f(args...);
+	    }
+	}
+	else {
+	    if constexpr(c(std::integral_constant<SizeT,I>{})){
+		return iterIfi<E,I+1>(g, f, c, args..., g(std::integral_constant<SizeT,I>{}));
+	    }
+	    else {
+		return iterIfi<E,I+1>(g, f, c, args...);
+	    }
+	}
+    }
+
+    template <SizeT B, SizeT E, class G, class F, class C>
+    constexpr decltype(auto) iterIf(const G& g, const F& f, const C& c)
+    {
+	return iterIfi<E,B>(g, f, c);
+    }
 }
 
 #endif
diff --git a/src/include/base/iter.h b/src/include/base/iter.h
index abc088e..5ed55dd 100644
--- a/src/include/base/iter.h
+++ b/src/include/base/iter.h
@@ -12,6 +12,12 @@ namespace CNORXZ
 
     template <SizeT B, SizeT E, class G, class F>
     constexpr decltype(auto) iter(const G& g, const F& f);
+
+    template <SizeT E, SizeT I, class G, class F, class C, typename... Args>
+    constexpr decltype(auto) iterIfi(const G& g, const F& f, const C& c, const Args&... args);
+
+    template <SizeT B, SizeT E, class G, class F, class C>
+    constexpr decltype(auto) iterIf(const G& g, const F& f, const C& c);
 }
 
 #endif
diff --git a/src/include/ranges/dindex.h b/src/include/ranges/dindex.h
index 2681337..f2827e8 100644
--- a/src/include/ranges/dindex.h
+++ b/src/include/ranges/dindex.h
@@ -54,6 +54,9 @@ namespace CNORXZ
 	DType meta() const;
 	DIndex& at(const DType& meta);
 
+	Sptr<DIndex> format(const Sptr<DIndex>& ind) const;
+	Sptr<DIndex> slice(const Sptr<DIndex>& ind) const;
+	
 	DXpr<SizeT> ifor(const DXpr<SizeT>& xpr, std::function<SizeT(SizeT,SizeT)>&& f) const;
 
 	const XIndexPtr& xptr() const;
@@ -61,7 +64,10 @@ namespace CNORXZ
     private:
 	XIndexPtr mI;
     };
-    
+
+    template <>
+    struct has_sub<DIndex>
+    { static constexpr bool value = true; };
 }
 
 #endif
diff --git a/src/include/ranges/mrange.cc.h b/src/include/ranges/mrange.cc.h
index 6538b31..3534477 100644
--- a/src/include/ranges/mrange.cc.h
+++ b/src/include/ranges/mrange.cc.h
@@ -414,29 +414,24 @@ namespace CNORXZ
 	static_assert(has_sub<Index>::value, "try to format single index");
 	if constexpr(has_static_sub<Index>::value){
 	    static_assert(index_dim<Index>::value == NI, "got index with conflicting static dimension");
-	    typedef std::remove_reference<decltype(ind->blockSizes())>::type BT;
 	    return iter<0,NI>
 		( [&](auto i) {
-		    std::get<i>(mIPack)->format(std::get<i>(ind->pack()));
+		    return std::get<i>(mIPack)->format(std::get<i>(ind->pack()));
 		},
-		    [](const auto&... e) {
-			return std::make_shared<GMIndex<BT,Indices...>>
-			    (mBlockSizes, e... );
+		    [&](const auto&... e) {
+			return gmindexPtr(mBlockSizes, e... );
 		    } );
 	}
 	else {
-	    typedef Arr<UPos,NI> BT;
 	    auto pack = ind->pack();
 	    CXZ_ASSERT(pack.size() == NI, "attempt to format index of dimension " << NI
-		       << " using index of dimension " << bs.size());
-	    auto bs = ind->blockSizes();
+		       << " using index of dimension " << pack.size());
 	    return iter<0,NI>
 		( [&](auto i) {
 		    return std::get<i>(mIPack)->format(pack[i]);
 		},
-		    [](const auto&... e) {
-			return std::make_shared<GMIndex<BlockType,Indices...>>
-			    (mBlockSizes, e... );
+		    [&](const auto&... e) {
+			return gmindexPtr(mBlockSizes, e... );
 		    } );
 	}
     }
@@ -446,6 +441,46 @@ namespace CNORXZ
     decltype(auto) GMIndex<BlockType,Indices...>::slice(const Sptr<Index>& ind) const
     {
 	static_assert(is_index<Index>::value, "got non-index type");
+	static_assert(has_sub<Index>::value, "try to slice single index");
+	if constexpr(has_static_sub<Index>::value and
+		     ((has_static_sub<Indices>::value and ...) or
+		      (not has_sub<Indices>::value and ...)) ){
+	    static_assert(index_dim<Index>::value == NI, "got index with conflicting static dimension");
+	    const auto bs = iterIf<0,NI>
+		( [&](auto i) { return std::get<i>(mBlockSizes); },
+		  [](const auto&... e) { std::make_tuple(e...); },
+		  [](auto i) {
+		      return std::is_same<typename TupleElem<i>::type,NIndex>::value;
+		  });
+	    return iterIf<0,NI>
+		( [&](auto i) { return std::get<i>(mIPack)->slice(std::get<i>(ind->pack())); },
+		    [&](const auto&... e) { return gmindex(bs, e... ); },
+		    [](auto i) {
+			return std::is_same<typename TupleElem<i>::type,NIndex>::value;
+		    } );
+	}
+	else {
+	    Vector<SizeT> bs;
+	    Vector<XIndexPtr> ivec;
+	    bs.reserve(NI);
+	    ivec.reserve(NI);
+	    auto pack = ind->pack();
+	    CXZ_ASSERT(pack.size() == NI, "attempt to slice index of dimension " << NI
+		       << " using index of dimension " << pack.size());
+	    iter<0,NI>
+		( [&](auto i) {
+		    if(std::get<i>(mIPack)->dim() == 0){
+			bs.push_back(std::get<i>(mBlockSizes).val());
+			if constexpr(has_static_sub<Index>::value){
+			    ivec.push_back( xindexPtr( std::get<i>(ind->pack()) ) );
+			}
+			else {
+			    ivec.push_back( xindexPtr( ind->pack()[i] ) );
+			}
+		    }
+		}, NoF {});
+	    return yindexPtr(bs, ivec);
+	}
     }
     
     template <class BlockType, class... Indices>	
@@ -523,6 +558,11 @@ namespace CNORXZ
 	return MIndex<Indices...>(is...);
     }    
 
+    template <class BlockType, class... Indices>
+    constexpr decltype(auto) gmindexPtr(const BlockType& bs, const Sptr<Indices>&... is)
+    {
+	return std::make_shared<GMIndex<BlockType,Indices...>>(bs, is...);
+    }    
     
     /*********************
      *   MRangeFactory   *
diff --git a/src/include/ranges/mrange.h b/src/include/ranges/mrange.h
index 835aac4..a54cd9b 100644
--- a/src/include/ranges/mrange.h
+++ b/src/include/ranges/mrange.h
@@ -72,7 +72,7 @@ namespace CNORXZ
 	template <class Index>
 	decltype(auto) slice(const Sptr<Index>& ind) const;
 	// -> IndexInterface;
-	// drop index instance or drop blockSize if that if ind is Null
+	// drop index instance or drop blockSize of ind if that of *this is not Null
 	// return result as new instance
 
 	template <class Xpr, class F>
@@ -152,6 +152,8 @@ namespace CNORXZ
     template <class... Indices>
     constexpr decltype(auto) mindex(const Sptr<Indices>&... is);
 
+    template <class BlockType, class... Indices>
+    constexpr decltype(auto) gmindexPtr(const BlockType& bs, const Sptr<Indices>&... is);
     
     template <class... Ranges>
     class MRangeFactory : public RangeFactoryBase
diff --git a/src/include/ranges/urange.cc.h b/src/include/ranges/urange.cc.h
index c0923b1..4964586 100644
--- a/src/include/ranges/urange.cc.h
+++ b/src/include/ranges/urange.cc.h
@@ -136,6 +136,25 @@ namespace CNORXZ
     {
 	return UPos(id == this->id() ? 1 : 0);
     }
+
+    template <typename MetaType>
+    template <class Index>
+    decltype(auto) UIndex<MetaType>::format(const Sptr<Index>& ind) const
+    {
+	return ind;
+    }
+
+    template <typename MetaType>
+    template <class Index>
+    decltype(auto) UIndex<MetaType>::slice(const Sptr<Index>& ind) const
+    {
+	if(ind != nullptr){
+	    if(ind->dim() != 0) {
+		return Sptr<CIndex>();
+	    }
+	}
+	return std::make_shared<CIndex>(*this);
+    }
     
     template <typename MetaType>
     template <class Xpr, class F>
diff --git a/src/include/ranges/urange.h b/src/include/ranges/urange.h
index 5ee64fc..b6493e1 100644
--- a/src/include/ranges/urange.h
+++ b/src/include/ranges/urange.h
@@ -47,6 +47,12 @@ namespace CNORXZ
 	const MetaT& meta() const;
 	UIndex& at(const MetaT& metaPos);
 
+	template <class Index>
+	decltype(auto) format(const Sptr<Index>& ind) const;
+
+	template <class Index>
+	decltype(auto) slice(const Sptr<Index>& ind) const;
+
 	template <class Xpr, class F>
 	decltype(auto) ifor(const Xpr& xpr, F&& f) const;
 
diff --git a/src/include/ranges/xindex.cc.h b/src/include/ranges/xindex.cc.h
index a3b6c24..bc277a2 100644
--- a/src/include/ranges/xindex.cc.h
+++ b/src/include/ranges/xindex.cc.h
@@ -133,7 +133,7 @@ namespace CNORXZ
 	if constexpr(has_static_sub<Index>::value){
 	    constexpr SizeT D = index_dim<Index>::value;
 	    return iter<0,D>
-		( [&](auto i) { return mkXIndex(std::get<i>(mI->THIS().pack())); },
+		( [&](auto i) { return xindexPtr(std::get<i>(mI->THIS().pack())); },
 		  [](const auto&... e) { return Vector<XIndexPtr>({ e ... }); } );
 	}
 	else if constexpr(has_sub<Index>::value){
@@ -177,7 +177,7 @@ namespace CNORXZ
 		return nullptr;
 	    }
 	    else {
-		return mkXIndex(replaceBlockSizes(arr, std::static_pointer_cast<Index>(mI)));
+		return xindexPtr(replaceBlockSizes(arr, std::static_pointer_cast<Index>(mI)));
 	    }
 	}
 	else if constexpr(has_sub<Index>::value) {
@@ -209,6 +209,22 @@ namespace CNORXZ
 	return *this;
     }
 
+    template <class Index, typename Meta>
+    Sptr<DIndex> XIndex<Index,Meta>::format(const Sptr<DIndex>& ind) const
+    {
+	CXZ_ERROR("IMPLEMENT!!!");
+	return nullptr;
+	//return std::make_shared<DIndex>(xindexPtr(mI->format(ind)));
+    }
+    
+    template <class Index, typename Meta>
+    Sptr<DIndex> XIndex<Index,Meta>::slice(const Sptr<DIndex>& ind) const
+    {
+	CXZ_ERROR("IMPLEMENT!!!");
+	return nullptr;
+	//return std::make_shared<DIndex>(xindexPtr(mI->slice(ind)));
+    }
+
     template <class Index, typename Meta>
     DXpr<SizeT> XIndex<Index,Meta>::ifor(const DXpr<SizeT>& xpr,
 					 std::function<SizeT(SizeT,SizeT)>&& f) const
@@ -217,12 +233,18 @@ namespace CNORXZ
     }
 
     template <class Index>
-    XIndexPtr mkXIndex(const Sptr<Index>& i)
+    inline XIndexPtr xindexPtr(const Sptr<Index>& i)
     {
 	typedef typename Index::MetaType Meta;
 	return std::make_shared<XIndex<Index,Meta>>
 	    (std::dynamic_pointer_cast<IndexInterface<Index,Meta>>(i));
     }
+
+    template <>
+    inline XIndexPtr xindexPtr<XIndexBase>(const Sptr<XIndexBase>& i)
+    {
+	return i;
+    }
 }
 
 #endif
diff --git a/src/include/ranges/xindex.h b/src/include/ranges/xindex.h
index 4da6a42..df4c604 100644
--- a/src/include/ranges/xindex.h
+++ b/src/include/ranges/xindex.h
@@ -9,10 +9,12 @@
 
 namespace CNORXZ
 {
-    // Future IndexWrapper
     class XIndexBase
     {
     public:
+
+	//typedef DType MetaType;
+	
 	DEFAULT_MEMBERS(XIndexBase);
 	virtual ~XIndexBase() = default;
 	virtual XIndexPtr copy() const = 0;
@@ -44,6 +46,9 @@ namespace CNORXZ
 	virtual DType meta() const = 0;
 	virtual XIndexBase& at(const DType& meta) = 0;
 
+	virtual Sptr<DIndex> format(const Sptr<DIndex>& ind) const = 0;
+	virtual Sptr<DIndex> slice(const Sptr<DIndex>& ind) const = 0;
+
 	virtual DXpr<SizeT> ifor(const DXpr<SizeT>& xpr,
 				 std::function<SizeT(SizeT,SizeT)>&& f) const = 0;
 
@@ -96,6 +101,9 @@ namespace CNORXZ
 	virtual DType meta() const override final;
 	virtual XIndexBase& at(const DType& meta) override final;
 
+	virtual Sptr<DIndex> format(const Sptr<DIndex>& ind) const override final;
+	virtual Sptr<DIndex> slice(const Sptr<DIndex>& ind) const override final;
+
 	virtual DXpr<SizeT> ifor(const DXpr<SizeT>& xpr,
 				 std::function<SizeT(SizeT,SizeT)>&& f) const override final;
 
@@ -109,8 +117,11 @@ namespace CNORXZ
     { static constexpr bool value = true; };
     
     template <class Index>
-    XIndexPtr mkXIndex(const Sptr<Index>& i);
-    
+    inline XIndexPtr xindexPtr(const Sptr<Index>& i);
+
+    template <>
+    inline XIndexPtr xindexPtr<XIndexBase>(const Sptr<XIndexBase>& i);
+
 }
 
 #endif
diff --git a/src/include/ranges/yrange.h b/src/include/ranges/yrange.h
index b88027a..49a2b1a 100644
--- a/src/include/ranges/yrange.h
+++ b/src/include/ranges/yrange.h
@@ -52,6 +52,9 @@ namespace CNORXZ
 	DType meta() const;
 	YIndex& at(const DType& meta);
 
+	Sptr<DIndex> format(const Sptr<DIndex>& ind) const;
+	Sptr<DIndex> slice(const Sptr<DIndex>& ind) const;
+	
 	DXpr<SizeT> ifor(const DXpr<SizeT>& xpr, std::function<SizeT(SizeT,SizeT)>&& f) const;
 
 	YIndex& operator()(const Sptr<YIndex>& i);
@@ -87,6 +90,7 @@ namespace CNORXZ
 
     YIndex yindex(const Vector<XIndexPtr>& is);
     Sptr<YIndex> yindexPtr(const Vector<XIndexPtr>& is);
+    Sptr<YIndex> yindexPtr(const Vector<SizeT>& bs, const Vector<XIndexPtr>& is);
 
     class YRangeFactory : public RangeFactoryBase
     {
diff --git a/src/lib/ranges/dindex.cc b/src/lib/ranges/dindex.cc
index dda7a95..7fd74f2 100644
--- a/src/lib/ranges/dindex.cc
+++ b/src/lib/ranges/dindex.cc
@@ -162,6 +162,16 @@ namespace CNORXZ
 	return *this;
     }
 
+    Sptr<DIndex> DIndex::format(const Sptr<DIndex>& ind) const
+    {
+	return mI->format(ind);
+    }
+    
+    Sptr<DIndex> DIndex::slice(const Sptr<DIndex>& ind) const
+    {
+	return mI->slice(ind);
+    }
+
     DXpr<SizeT> DIndex::ifor(const DXpr<SizeT>& xpr, std::function<SizeT(SizeT,SizeT)>&& f) const
     {
 	return DXpr<SizeT>(mI->ifor(xpr, std::forward<std::function<SizeT(SizeT,SizeT)>>(f)) );
diff --git a/src/lib/ranges/yrange.cc b/src/lib/ranges/yrange.cc
index cc6ecbf..f9027a3 100644
--- a/src/lib/ranges/yrange.cc
+++ b/src/lib/ranges/yrange.cc
@@ -339,6 +339,18 @@ namespace CNORXZ
 	return *this;
     }
 
+    Sptr<DIndex> YIndex::format(const Sptr<DIndex>& ind) const
+    {
+	CXZ_ERROR("IMPLEMENT!!!");
+	return nullptr;
+    }
+    
+    Sptr<DIndex> YIndex::slice(const Sptr<DIndex>& ind) const
+    {
+	CXZ_ERROR("IMPLEMENT!!!");
+	return nullptr;
+    }
+
     DXpr<SizeT> YIndex::ifor(const DXpr<SizeT>& xpr, std::function<SizeT(SizeT,SizeT)>&& f) const
     {
 	return mkIFor(0, xpr, std::forward<std::function<SizeT(SizeT,SizeT)>>(f));