small update

Author: MartinPdeS

PyOptik/material/sellmeier_class.py

@@ -51,7 +51,7 @@ def __repr__(self) -> str:
         return self.__str__()
 
     def __str__(self) -> str:
-        return self.filename
+        return self.filename + '[Sellmeier]'
 
     def _load_coefficients(self) -> None:
         """

PyOptik/material/tabulated_class.py

@@ -53,7 +53,7 @@ def __repr__(self) -> str:
         return self.__str__()
 
     def __str__(self) -> str:
-        return self.filename
+        return self.filename + '[Tabulated]'
 
     def _load_tabulated_data(self) -> None:
         """

PyOptik/material_bank.py

@@ -186,6 +186,11 @@ def all(self) -> List[str]:
         """
         return self.sellmeier + self.tabulated
 
+    def __iter__(self):
+        """Iterator over all available material names."""
+        for material in self.all:
+            yield material
+
     def print_available(self) -> None:
         """Display all available materials in a table.
 
@@ -521,3 +526,4 @@ def create_tabulated_file(
 
 
 MaterialBank = _MaterialBank()
+