diff --git a/include/builtin.h b/include/builtin.h
index 64f3960..5e42a47 100644
--- a/include/builtin.h
+++ b/include/builtin.h
@@ -12,9 +12,9 @@ template<class T>
 ObjectBase* Get(const ObjectList* input)
 {
  if(input->Size()!=2) return 0;
- const ObjectBase* ob=input->At(0);
- const ObjectBase* name=input->At(1);
- if( (!IS_OTYPE(ob,T)) || (!IS_OTYPE(name,ObjectString)) ) return 0;
+ OBType<T> ob(input->At(0));
+ OBType<ObjectString> name(input->At(1));
+ if(!(ob && name)) return 0;
 
- return dynamic_cast<const T*>(ob)->Get(dynamic_cast<const ObjectString*>(name)->Value());
+ return ob->Get(name->Value());
 }
diff --git a/include/common.h b/include/common.h
index a931960..520096d 100644
--- a/include/common.h
+++ b/include/common.h
@@ -14,10 +14,6 @@
 enum debug_level {INTERNALREQUEST,MOREDEBUG,DEBUG,INFO,NORMAL,WARNING,ERROR};
 EXPORT std::ostream& COUT(debug_level dl);
 
-// Check if pointer is ObjectBase derivative class
-#define IS_OTYPE(quo,equ) (std::type_index(typeid(*quo))==std::type_index(typeid(equ)))
-#define IS_OTYPEI(quo,equ) (std::type_index(typeid(quo))==std::type_index(typeid(equ)))
-
 typedef std::set<std::string> UsedType;
 
 // Base class for all objects
@@ -46,6 +42,24 @@ public:
  virtual void UsedIdents(UsedType& ids) const {}
 };
 
+
+// Template for checking and using ObjectBase derivative classes
+// Checking if arg is pointer on Derived: if(OBType<Derived>(arg))
+// Using const ObjectBase* arg as const Derived*: OBType<Derived>(arg)->SomeCall()
+template<class O>
+class OBType
+{
+ const O* p;
+ public:
+ OBType() = delete;
+ OBType(OBType&&) = delete;
+ OBType(OBType&) = delete;
+ OBType(const ObjectBase* arg) {if(typeid(*arg)==typeid(O)) p=dynamic_cast<const O*>(arg); else p=0;}
+ const O* operator->() const {return p;}
+ operator bool() const {return 0!=p;}
+};
+
+
 // Template for objects without specific constructor/destructor
 template<class T>
 class EXPORT ObjectSimple: public ObjectBase
@@ -244,9 +258,10 @@ public:
   for(auto& i: *vals)
   {
    p=0;
-   if(IS_OTYPE(i,ObjectPair)) p=dynamic_cast<const ObjectPair*>(i)->Get(gname);
-   if(0!=p) return p;
-   if(IS_OTYPE(i,ObjectList)) p=dynamic_cast<const ObjectList*>(i)->Get(gname);
+   OBType<ObjectPair> pair(i);
+   OBType<ObjectList> list(i);
+   if(pair) p=pair->Get(gname);
+   else if(list) p=list->Get(gname);
    if(0!=p) return p;
   }
   return 0;
diff --git a/include/object.h b/include/object.h
index 44ad3d3..8ced9ec 100644
--- a/include/object.h
+++ b/include/object.h
@@ -51,12 +51,12 @@ class OFunc: public ObjectBase
 public:
  OFunc(const std::string* t, ObjectBase* p):name(*t)
  {
-  if(IS_OTYPE(p,ObjectList)) args=dynamic_cast<ObjectList*>(p);
+  if(OBType<ObjectList>(p)) args=dynamic_cast<ObjectList*>(p);
   else args=new ObjectList(p);
  }
  OFunc(const char* t, ObjectBase* p):name(t)
  {
-  if(IS_OTYPE(p,ObjectList)) args=dynamic_cast<ObjectList*>(p);
+  if(OBType<ObjectList>(p)) args=dynamic_cast<ObjectList*>(p);
   else args=new ObjectList(p);
  }
  ~OFunc() {if(args!=0) delete args;}
diff --git a/src/builtin.cpp b/src/builtin.cpp
index df9ec0e..adabd3d 100644
--- a/src/builtin.cpp
+++ b/src/builtin.cpp
@@ -1,28 +1,31 @@
 #include <math.h>
 #include "object.h"
 
+class Val
+{
+ double v;
+ public:
+ Val() = delete;
+ Val(Val&&) = delete;
+ Val(Val&) = delete;
+ Val(const OBType<ObjectInt>& i, const OBType<ObjectReal>& r) {v=r?r->Value():i->Value();}
+ Val(const OBType<ObjectReal>& r, const OBType<ObjectInt>& i) {v=r?r->Value():i->Value();}
+ operator double() const {return v;}
+};
+
 ObjectBase* Arifm_Add(const ObjectList* input)
 {
  if(input->Size()!=2) return 0;
  const ObjectBase *arg1=input->At(0),*arg2=input->At(1);
- std::type_index t1(typeid(*arg1)),t2(typeid(*arg2));
- std::type_index tr(typeid(ObjectReal)),ti(typeid(ObjectInt));
+ OBType<ObjectInt> i1(arg1), i2(arg2);
+ OBType<ObjectReal> r1(arg1), r2(arg2);
 
- if( (t1!=tr && t1!=ti) || (t2!=tr && t2!=ti) ) return 0;
+ if( !(i1 || r1) || !(i2 || r2) ) return 0;
 
  // Integer arifmetic
- if(t1==ti && t2==ti) return new ObjectInt(dynamic_cast<const ObjectInt*>(arg1)->Value() + dynamic_cast<const ObjectInt*>(arg2)->Value());
-
+ if(i1 && i2) return new ObjectInt(i1->Value()+i2->Value());
  // Real arifmetic
- double r1,r2;
-
- if(t1==tr) r1=dynamic_cast<const ObjectReal*>(arg1)->Value();
- else r1=dynamic_cast<const ObjectInt*>(arg1)->Value();
-
- if(t2==tr) r2=dynamic_cast<const ObjectReal*>(arg2)->Value();
- else r2=dynamic_cast<const ObjectInt*>(arg2)->Value();
-
- return new ObjectReal(r1+r2);
+ return new ObjectReal(Val(i1,r1)+Val(i2,r2));
 }
 
 
@@ -30,24 +33,15 @@ ObjectBase* Arifm_Sub(const ObjectList* input)
 {
  if(input->Size()!=2) return 0;
  const ObjectBase *arg1=input->At(0),*arg2=input->At(1);
- std::type_index t1(typeid(*arg1)),t2(typeid(*arg2));
- std::type_index tr(typeid(ObjectReal)),ti(typeid(ObjectInt));
+ OBType<ObjectInt> i1(arg1), i2(arg2);
+ OBType<ObjectReal> r1(arg1), r2(arg2);
 
- if( (t1!=tr && t1!=ti) || (t2!=tr && t2!=ti) ) return 0;
+ if( !(i1 || r1) || !(i2 || r2) ) return 0;
 
  // Integer arifmetic
- if(t1==ti && t2==ti) return new ObjectInt(dynamic_cast<const ObjectInt*>(arg1)->Value() - dynamic_cast<const ObjectInt*>(arg2)->Value());
-
+ if(i1 && i2) return new ObjectInt(i1->Value()-i2->Value());
  // Real arifmetic
- double r1,r2;
-
- if(t1==tr) r1=dynamic_cast<const ObjectReal*>(arg1)->Value();
- else r1=dynamic_cast<const ObjectInt*>(arg1)->Value();
-
- if(t2==tr) r2=dynamic_cast<const ObjectReal*>(arg2)->Value();
- else r2=dynamic_cast<const ObjectInt*>(arg2)->Value();
-
- return new ObjectReal(r1-r2);
+ return new ObjectReal(Val(i1,r1)-Val(i2,r2));
 }
 
 
@@ -55,24 +49,15 @@ ObjectBase* Arifm_Mul(const ObjectList* input)
 {
  if(input->Size()!=2) return 0;
  const ObjectBase *arg1=input->At(0),*arg2=input->At(1);
- std::type_index t1(typeid(*arg1)),t2(typeid(*arg2));
- std::type_index tr(typeid(ObjectReal)),ti(typeid(ObjectInt));
+ OBType<ObjectInt> i1(arg1), i2(arg2);
+ OBType<ObjectReal> r1(arg1), r2(arg2);
 
- if( (t1!=tr && t1!=ti) || (t2!=tr && t2!=ti) ) return 0;
+ if( !(i1 || r1) || !(i2 || r2) ) return 0;
 
  // Integer arifmetic
- if(t1==ti && t2==ti) return new ObjectInt(dynamic_cast<const ObjectInt*>(arg1)->Value() * dynamic_cast<const ObjectInt*>(arg2)->Value());
-
+ if(i1 && i2) return new ObjectInt(i1->Value()*i2->Value());
  // Real arifmetic
- double r1,r2;
-
- if(t1==tr) r1=dynamic_cast<const ObjectReal*>(arg1)->Value();
- else r1=dynamic_cast<const ObjectInt*>(arg1)->Value();
-
- if(t2==tr) r2=dynamic_cast<const ObjectReal*>(arg2)->Value();
- else r2=dynamic_cast<const ObjectInt*>(arg2)->Value();
-
- return new ObjectReal(r1*r2);
+ return new ObjectReal(Val(i1,r1)*Val(i2,r2));
 }
 
 
@@ -80,24 +65,15 @@ ObjectBase* Arifm_Div(const ObjectList* input)
 {
  if(input->Size()!=2) return 0;
  const ObjectBase *arg1=input->At(0),*arg2=input->At(1);
- std::type_index t1(typeid(*arg1)),t2(typeid(*arg2));
- std::type_index tr(typeid(ObjectReal)),ti(typeid(ObjectInt));
+ OBType<ObjectInt> i1(arg1), i2(arg2);
+ OBType<ObjectReal> r1(arg1), r2(arg2);
 
- if( (t1!=tr && t1!=ti) || (t2!=tr && t2!=ti) ) return 0;
+ if( !(i1 || r1) || !(i2 || r2) ) return 0;
 
  // Integer arifmetic
- if(t1==ti && t2==ti) return new ObjectInt(dynamic_cast<const ObjectInt*>(arg1)->Value() / dynamic_cast<const ObjectInt*>(arg2)->Value());
-
+ if(i1 && i2) return new ObjectInt(i1->Value()/i2->Value());
  // Real arifmetic
- double r1,r2;
-
- if(t1==tr) r1=dynamic_cast<const ObjectReal*>(arg1)->Value();
- else r1=dynamic_cast<const ObjectInt*>(arg1)->Value();
-
- if(t2==tr) r2=dynamic_cast<const ObjectReal*>(arg2)->Value();
- else r2=dynamic_cast<const ObjectInt*>(arg2)->Value();
-
- return new ObjectReal(r1/r2);
+ return new ObjectReal(Val(i1,r1)/Val(i2,r2));
 }
 
 
@@ -105,21 +81,13 @@ ObjectBase* Arifm_Pow(const ObjectList* input)
 {
  if(input->Size()!=2) return 0;
  const ObjectBase *arg1=input->At(0),*arg2=input->At(1);
- std::type_index t1(typeid(*arg1)),t2(typeid(*arg2));
- std::type_index tr(typeid(ObjectReal)),ti(typeid(ObjectInt));
+ OBType<ObjectInt> i1(arg1), i2(arg2);
+ OBType<ObjectReal> r1(arg1), r2(arg2);
 
- if( (t1!=tr && t1!=ti) || (t2!=tr && t2!=ti) ) return 0;
+ if( !(i1 || r1) || !(i2 || r2) ) return 0;
 
  // Only real arifmetic
- double r1,r2;
-
- if(t1==tr) r1=dynamic_cast<const ObjectReal*>(arg1)->Value();
- else r1=dynamic_cast<const ObjectInt*>(arg1)->Value();
-
- if(t2==tr) r2=dynamic_cast<const ObjectReal*>(arg2)->Value();
- else r2=dynamic_cast<const ObjectInt*>(arg2)->Value();
-
- return new ObjectReal(pow(r1,r2));
+ return new ObjectReal(pow(Val(i1,r1),Val(i2,r2)));
 }
 
 
@@ -127,13 +95,13 @@ ObjectBase* Arifm_Neg(const ObjectList* input)
 {
  if(input->Size()!=1) return 0;
  const ObjectBase *arg=input->At(0);
- std::type_index t(typeid(*arg));
- std::type_index tr(typeid(ObjectReal)),ti(typeid(ObjectInt));
+ OBType<ObjectInt> i(arg);
+ OBType<ObjectReal> r(arg);
 
  // Integer arifmetic
- if(t==ti) return new ObjectInt(-dynamic_cast<const ObjectInt*>(arg)->Value());
+ if(i) return new ObjectInt(-i->Value());
  // Real arifmetic
- if(t==tr) return new ObjectReal(-dynamic_cast<const ObjectReal*>(arg)->Value());
+ if(r) return new ObjectReal(-r->Value());
 
  return 0;
 }
@@ -143,13 +111,13 @@ ObjectBase* Arifm_Pos(const ObjectList* input)
 {
  if(input->Size()!=1) return 0;
  const ObjectBase *arg=input->At(0);
- std::type_index t(typeid(*arg));
- std::type_index tr(typeid(ObjectReal)),ti(typeid(ObjectInt));
+ OBType<ObjectInt> i(arg);
+ OBType<ObjectReal> r(arg);
 
  // Integer arifmetic
- if(t==ti) return new ObjectInt(dynamic_cast<const ObjectInt*>(arg)->Value());
+ if(i) return new ObjectInt(i->Value());
  // Real arifmetic
- if(t==tr) return new ObjectReal(dynamic_cast<const ObjectReal*>(arg)->Value());
+ if(r) return new ObjectReal(r->Value());
 
  return 0;
 }
diff --git a/src/globals.cpp b/src/globals.cpp
index a13a03a..1cd0002 100644
--- a/src/globals.cpp
+++ b/src/globals.cpp
@@ -116,12 +116,9 @@ bool Save(const ObjectList* input)
  }
 
  // Check arguments types
- const ObjectBase* arg1;
- const ObjectString* arg2;
  for(i=0;i<sz/2;i++)
  {
-  arg1=input->At(i*2+1);
-  if(!IS_OTYPE(arg1,ObjectString))
+  if(!OBType<ObjectString>(input->At(i*2+1)))
   {
    COUT(ERROR)<<"Save format is save(object_1,file_1,...,object_n,file_n) where file_i is string"<<std::endl;
    return false;
@@ -129,10 +126,11 @@ bool Save(const ObjectList* input)
  }
 
  // Save
+ const ObjectBase* arg1;
  for(i=0;i<sz/2;i++)
  {
   arg1=input->At(i*2);
-  arg2=dynamic_cast<const ObjectString*>(input->At(i*2+1));
+  OBType<ObjectString> arg2(input->At(i*2+1));
   if(!arg1->Save(arg2->Value().c_str()))
   {
    COUT(ERROR)<<"Can't save object "<<arg1->Dump()<<" to file "<<arg2->Value()<<std::endl;