6 files changed, 8 insertions, 8 deletions
diff --git a/src/main/CompositeElement.h b/src/main/CompositeElement.h
index 2c0c6d4..638e74a 100644
--- a/src/main/CompositeElement.h
+++ b/src/main/CompositeElement.h
@@ -54,7 +54,7 @@ public:
 		return e;
 	}
 
-	virtual void accept(ElementVisitor& v) {
+	virtual void accept(const ElementVisitor& v) const {
 		for (int i(0); i < elements.size(); ++i) {
 			elements[i]->accept(v);
 		}
diff --git a/src/main/Dipole.h b/src/main/Dipole.h
index 6edfb91..a455b36 100644
--- a/src/main/Dipole.h
+++ b/src/main/Dipole.h
@@ -65,7 +65,7 @@ public:
 		return s.str();
 	}
 
-	virtual void accept(ElementVisitor& v) {v.visit(this);}
+	virtual void accept(const ElementVisitor& v) const {v.visit(this);}
 
 	virtual Dipole* clone() const {
 		return new Dipole(getEntryPosition(), getExitPosition(), getSectionRadius(), getCurvature(), _magneticField);
diff --git a/src/main/Element.h b/src/main/Element.h
index 4ce1d00..32ba2db 100644
--- a/src/main/Element.h
+++ b/src/main/Element.h
@@ -134,7 +134,7 @@ public:
 		return s.str();
 	}
 
-	virtual void accept(ElementVisitor& v) = 0;
+	virtual void accept(const ElementVisitor& v) const = 0;
 };
 
 }
diff --git a/src/main/ElementVisitor.h b/src/main/ElementVisitor.h
index cf14aca..89de7d7 100644
--- a/src/main/ElementVisitor.h
+++ b/src/main/ElementVisitor.h
@@ -30,11 +30,11 @@ public:
 	ElementVisitor();
 	virtual ~ElementVisitor();
 
-	virtual void visit(StraightElement* straight) = 0;
+	virtual void visit(const StraightElement* straight) const = 0;
 
-	virtual void visit(Quadrupole* quadrupole) = 0;
+	virtual void visit(const Quadrupole* quadrupole) const = 0;
 
-	virtual void visit(Dipole* dipole) = 0;
+	virtual void visit(const Dipole* dipole) const = 0;
 };
 
 }
diff --git a/src/main/Quadrupole.h b/src/main/Quadrupole.h
index 1f4903b..32eac23 100644
--- a/src/main/Quadrupole.h
+++ b/src/main/Quadrupole.h
@@ -46,7 +46,7 @@ public:
 
 	virtual std::string getType() const {return "Quadrupole";}
 
-	virtual void accept(ElementVisitor& v) {v.visit(this);}
+	virtual void accept(const ElementVisitor& v) const {v.visit(this);}
 
 	virtual Quadrupole* clone() const {return new Quadrupole(getEntryPosition(), getExitPosition(), getSectionRadius(), focusingCoefficient);}
 };
diff --git a/src/main/StraightElement.h b/src/main/StraightElement.h
index 3a7fcf4..dc7603b 100644
--- a/src/main/StraightElement.h
+++ b/src/main/StraightElement.h
@@ -46,7 +46,7 @@ public:
 		return s.str();
 	}
 
-	virtual void accept(ElementVisitor& v) {v.visit(this);}
+	virtual void accept(const ElementVisitor& v) const {v.visit(this);}
 
 	virtual StraightElement* clone() const {return new StraightElement(getEntryPosition(), getExitPosition(), getSectionRadius());}