Calculator: empty-input handling, cleaner results, new operations

gradio_calculator.py

@@ -1,41 +1,80 @@
+import math
+
 import gradio as gr
 
+OPERATIONS = {
+    "+": lambda a, b: a + b,
+    "-": lambda a, b: a - b,
+    "*": lambda a, b: a * b,
+    "/": lambda a, b: a / b,
+    "^": lambda a, b: a**b,
+    "mod": lambda a, b: a % b,
+    "√": lambda a, b: math.sqrt(a),
+    "% of": lambda a, b: a / 100 * b,
+}
+
+# Operations that only use the first number.
+UNARY_OPS = {"√"}
+
+
+def format_result(value):
+    """Show 5 instead of 5.0 and strip floating-point noise like 0.30000000000000004."""
+    value = round(value, 10) + 0.0  # + 0.0 turns -0.0 into 0.0
+    if value.is_integer() and abs(value) < 1e15:
+        return str(int(value))
+    return str(value)
+
 
 def calculate(num1, num2, operation):
+    if operation not in OPERATIONS:
+        return "Invalid operation"
+    if num1 is None:
+        return "Please enter the first number"
+    if num2 is None and operation not in UNARY_OPS:
+        return "Please enter both numbers"
+
     try:
         num1 = float(num1)
-        num2 = float(num2)
-
-        if operation == "+":
-            result = num1 + num2
-        elif operation == "-":
-            result = num1 - num2
-        elif operation == "*":
-            result = num1 * num2
-        elif operation == "/":
-            if num2 == 0:
-                return "Cannot divide by zero"
-            result = num1 / num2
-        else:
-            return "Invalid operation"
-
-        return result
-    except ValueError:
+        num2 = float(num2) if num2 is not None else 0.0
+
+        if operation == "/" and num2 == 0:
+            return "Cannot divide by zero"
+        if operation == "mod" and num2 == 0:
+            return "Cannot take modulo by zero"
+        if operation == "√" and num1 < 0:
+            return "Cannot take square root of a negative number"
+
+        result = OPERATIONS[operation](num1, num2)
+    except OverflowError:
+        return "Result is too large"
+    except (ValueError, TypeError):
         return "Please enter valid numbers"
 
+    if isinstance(result, complex):
+        return "Result is not a real number"
+    if not math.isfinite(result):
+        return "Result is too large"
+    return format_result(result)
+
 
 with gr.Blocks() as demo:
     gr.Markdown("# Simple Calculator")
 
     with gr.Row():
         num1 = gr.Number(label="First number")
-        operation = gr.Dropdown(["+", "-", "*", "/"], label="Operation", value="+")
+        operation = gr.Dropdown(list(OPERATIONS), label="Operation", value="+")
         num2 = gr.Number(label="Second number")
 
     calc_button = gr.Button("Calculate")
     output = gr.Textbox(label="Result")
 
+    operation.change(
+        fn=lambda op: gr.update(visible=op not in UNARY_OPS),
+        inputs=operation,
+        outputs=num2,
+    )
     calc_button.click(fn=calculate, inputs=[num1, num2, operation], outputs=output)
 
 
-demo.launch()
+if __name__ == "__main__":
+    demo.launch()

test_calculator.py

@@ -0,0 +1,43 @@
+import pytest
+
+from gradio_calculator import calculate
+
+
+@pytest.mark.parametrize(
+    "num1, num2, op, expected",
+    [
+        (2, 3, "+", "5"),
+        (0.1, 0.2, "+", "0.3"),
+        (5, 8, "-", "-3"),
+        (4, 2.5, "*", "10"),
+        (7, 2, "/", "3.5"),
+        (1, 3, "/", "0.3333333333"),
+        (2, 10, "^", "1024"),
+        (10, 3, "mod", "1"),
+        (16, None, "√", "4"),
+        (2, None, "√", "1.4142135624"),
+        (15, 240, "% of", "36"),
+        (0, -5, "*", "0"),
+    ],
+)
+def test_operations(num1, num2, op, expected):
+    assert calculate(num1, num2, op) == expected
+
+
+@pytest.mark.parametrize(
+    "num1, num2, op, expected",
+    [
+        (None, 3, "+", "Please enter the first number"),
+        (2, None, "+", "Please enter both numbers"),
+        (None, None, "√", "Please enter the first number"),
+        (1, 0, "/", "Cannot divide by zero"),
+        (1, 0, "mod", "Cannot take modulo by zero"),
+        (-4, None, "√", "Cannot take square root of a negative number"),
+        (10, 1000, "^", "Result is too large"),
+        (1e308, 10, "*", "Result is too large"),
+        (-8, 0.5, "^", "Result is not a real number"),
+        (1, 2, "?", "Invalid operation"),
+    ],
+)
+def test_errors(num1, num2, op, expected):
+    assert calculate(num1, num2, op) == expected