[PT Run] Calculator plugin: Various improvements

src/modules/launcher/Plugins/Microsoft.PowerToys.Run.Plugin.Calculator.UnitTest/ExtendedCalculatorParserTests.cs

@@ -36,7 +36,6 @@ public void Interpret_ThrowError_WhenCalledNullOrEmpty(string input)
         }
 
         [DataTestMethod]
-        [DataRow("42")]
         [DataRow("test")]
         [DataRow("pi(2)")] // Incorrect input, constant is being treated as a function.
         [DataRow("e(2)")]

src/modules/launcher/Plugins/Microsoft.PowerToys.Run.Plugin.Calculator/CalculateEngine.cs

@@ -47,6 +47,10 @@ public CalculateResult Interpret(string input, CultureInfo cultureInfo)
             }
 
             result = TransformResult(result);
+            if (result is string)
+            {
+                throw new ArithmeticException(result as string);
+            }
 
             if (string.IsNullOrEmpty(result?.ToString()))
             {
@@ -68,7 +72,7 @@ public static decimal Round(decimal value)
             return Math.Round(value, RoundingDigits, MidpointRounding.AwayFromZero);
         }
 
-        private static object TransformResult(object result)
+        private static dynamic TransformResult(object result)
         {
             if (result.ToString() == "NaN")
             {

src/modules/launcher/Plugins/Microsoft.PowerToys.Run.Plugin.Calculator/CalculateHelper.cs

@@ -29,7 +29,7 @@ public static bool InputValid(string input)
             }
 
             bool singleDigitFactorial = input.EndsWith("!", StringComparison.InvariantCulture);
-            if (input.Length <= 2 && !singleDigitFactorial)
+            if (input.Length <= 0 && !singleDigitFactorial)
             {
                 return false;
             }

src/modules/launcher/Plugins/Microsoft.PowerToys.Run.Plugin.Calculator/Main.cs

@@ -33,6 +33,11 @@ public List<Result> Query(Query query)
                 throw new ArgumentNullException(paramName: nameof(query));
             }
 
+            if (string.IsNullOrEmpty(query.Search))
+            {
+                return new List<Result>();
+            }
+
             NumberTranslator translator = NumberTranslator.Create(CultureInfo.CurrentCulture, new CultureInfo("en-US"));
             var input = translator.Translate(query.Search.Normalize(NormalizationForm.FormKC));
 
@@ -61,10 +66,23 @@ public List<Result> Query(Query query)
             catch (Exception e)
 #pragma warning restore CA1031 // Do not catch general exception types
             {
-                Log.Exception("Exception when query for <{query}>", e, GetType());
-            }
+                // error log
+                Log.Exception($"Exception when query for <{query}>", e, GetType());
 
-            return new List<Result>();
+                // error message result on keyword queries
+                if (string.IsNullOrEmpty(query.ActionKeyword))
+                {
+                    return new List<Result>();
+                }
+                else
+                {
+                    string err = (e is Mages.Core.ParseException) ? Properties.Resources.wox_plugin_calculator_expression_not_complete : e.Message;
+                    return new List<Result>
+                    {
+                        ResultHelper.CreateErrorResult(Properties.Resources.wox_plugin_calculator_calculation_failed, err, IconPath),
+                    };
+                }
+            }
         }
 
         public void Init(PluginInitContext context)

src/modules/launcher/Plugins/Microsoft.PowerToys.Run.Plugin.Calculator/Properties/Resources.resx

@@ -124,7 +124,7 @@
     <value>Does mathematical calculations (e.g. 5*3-2).</value>
   </data>
   <data name="wox_plugin_calculator_not_a_number" xml:space="preserve">
-    <value>Not a number (NaN)</value>
+    <value>Calculation result is not a valid number (NaN)</value>
   </data>
   <data name="wox_plugin_calculator_expression_not_complete" xml:space="preserve">
     <value>Expression wrong or incomplete (Did you forget some parentheses?)</value>
@@ -135,4 +135,7 @@
   <data name="wox_plugin_calculator_copy_failed" xml:space="preserve">
     <value>Copy failed, please try later</value>
   </data>
+  <data name="wox_plugin_calculator_calculation_failed" xml:space="preserve">
+    <value>Failed to calculate the input</value>
+  </data>
 </root>

src/modules/launcher/Plugins/Microsoft.PowerToys.Run.Plugin.Calculator/ResultHelper.cs

@@ -36,6 +36,17 @@ public static Result CreateResult(decimal? roundedResult, string iconPath)
             };
         }
 
+        public static Result CreateErrorResult(string errorMsg, string exceptMsg, string iconPath)
+        {
+            return new Result
+            {
+                Title = errorMsg,
+                SubTitle = exceptMsg,
+                IcoPath = iconPath,
+                Score = 300,
+            };
+        }
+
         public static bool Action(decimal? roundedResult)
         {
             var ret = false;