added calculator to gradio

Gradio_UI.py

@@ -292,5 +292,48 @@ class GradioUI:
 
         demo.launch(debug=True, share=True, **kwargs)
 
+# ADDED: Calculator function to evaluate arithmetic expressions safely.
+def calculator(expression: str) -> str:
+    """
+    Safely evaluate a basic arithmetic expression and return the result as a string.
+    
+    This function uses Python's AST module to parse and evaluate the expression,
+    allowing only basic arithmetic operators.
+    """
+    try:
+        import ast
+        import operator as op
+
+        # Define supported operators
+        operators = {
+            ast.Add: op.add,
+            ast.Sub: op.sub,
+            ast.Mult: op.mul,
+            ast.Div: op.truediv,
+            ast.Mod: op.mod,
+            ast.Pow: op.pow,
+            ast.USub: op.neg,
+            ast.UAdd: op.pos,
+        }
+
+        def eval_node(node):
+            if isinstance(node, ast.Num):  # For Python < 3.8
+                return node.n
+            elif isinstance(node, ast.Constant):  # For Python >= 3.8
+                return node.value
+            elif isinstance(node, ast.BinOp):
+                return operators[type(node.op)](eval_node(node.left), eval_node(node.right))
+            elif isinstance(node, ast.UnaryOp):
+                return operators[type(node.op)](eval_node(node.operand))
+            else:
+                raise TypeError(f"Unsupported expression: {node}")
+
+        # Parse the expression and evaluate
+        node = ast.parse(expression, mode='eval').body
+        result = eval_node(node)
+        return str(result)
+    except Exception as e:
+        return f"Error: {e}"
+
 
-__all__ = ["stream_to_gradio", "GradioUI"]
+__all__ = ["stream_to_gradio", "GradioUI", "calculator"]