add calculator

calculator/pkg/render.py

@@ -0,0 +1,14 @@
+import json
+
+
+def format_json_output(expression: str, result: float, indent: int = 2) -> str:
+    if isinstance(result, float) and result.is_integer():
+        result_to_dump = int(result)
+    else:
+        result_to_dump = result
+
+    output_data = {
+        "expression": expression,
+        "result": result_to_dump,
+    }
+    return json.dumps(output_data, indent=indent)