Improving detection of statement existing surrounding parentheses

Author: SteveWilkes

ReadableExpressions.UnitTests/WhenTranslatingConditionals.cs

@@ -456,6 +456,27 @@ public void ShouldBreakLongMultipleConditionsOntoMultipleLines()
 
             Assert.Equal(EXPECTED.TrimStart(), translated);
         }
+
+        [Fact]
+        public void ShouldTranslateAssignmentOutcomeTests()
+        {
+            var intVariable = Expression.Variable(typeof(int), "i");
+            var intValue = Expression.Constant(123);
+            var intAssignment = Expression.Assign(intVariable, intValue);
+            var intDefault = Expression.Default(typeof(int));
+            var assignmentResultNotDefault = Expression.NotEqual(intAssignment, intDefault);
+            var doNothing = Expression.Default(typeof(void));
+            var ifNotdefaultDoNothing = Expression.IfThen(assignmentResultNotDefault, doNothing);
+
+            var translated = ifNotdefaultDoNothing.ToReadableString();
+
+            const string EXPECTED = @"
+if ((i = 123) != default(int))
+{
+}";
+
+            Assert.Equal(EXPECTED.TrimStart(), translated);
+        }
     }
 
     #region Helpers

ReadableExpressions/StringExtensions.cs

@@ -120,14 +120,36 @@ public static string WithoutUnindents(this string code)
             return code;
         }
 
-        public static string WithSurroundingParentheses(this string value, bool checkExisting = false)
+        public static string WithSurroundingParentheses(this string value)
         {
-            if (checkExisting && value.HasSurroundingParentheses())
+            if (!value.HasSurroundingParentheses())
             {
-                return value;
+                return "(" + value + ")";
+            }
+
+            var openParenthesesCount = 0;
+
+            for (var i = 1; i < value.Length - 1; ++i)
+            {
+                switch (value[i])
+                {
+                    case '(':
+                        ++openParenthesesCount;
+                        continue;
+
+                    case ')':
+                        --openParenthesesCount;
+
+                        if (openParenthesesCount < 0)
+                        {
+                            return "(" + value + ")";
+                        }
+
+                        continue;
+                }
             }
 
-            return $"({value})";
+            return value;
         }
 
         public static string WithoutSurroundingParentheses(this string value, Expression expression)

ReadableExpressions/Translators/BinaryExpressionTranslator.cs

@@ -92,7 +92,7 @@ private static string TranslateOperand(Expression expression, TranslationContext
             var translation = context.Translate(expression);
 
             return expression.IsAssignment()
-                ? translation.WithSurroundingParentheses(checkExisting: true)
+                ? translation.WithSurroundingParentheses()
                 : translation;
         }
 

ReadableExpressions/Translators/Formatting/FormattedCondition.cs

@@ -28,13 +28,11 @@ public FormattedCondition(
                 test = test.TrimStart();
             }
 
-            _singleLineTest = test.WithSurroundingParentheses(CheckExistingParentheses());
+            _singleLineTest = FinaliseCondition(test.WithSurroundingParentheses());
 
             MultipleLineTranslationFactory = GetMultipleLineTranslation;
         }
 
-        private bool CheckExistingParentheses() => IsNotRelevantBinary(_condition, out var _);
-
         protected override Func<string> SingleLineTranslationFactory => () => _singleLineTest;
 
         protected override Func<string> MultipleLineTranslationFactory { get; }
@@ -54,7 +52,7 @@ private string GetMultipleLineTranslation()
 {conditionLeft} {conditionOperator}
 {conditionRight.ToString().Indented()}".TrimStart().WithSurroundingParentheses();
 
-            return condition;
+            return FinaliseCondition(condition);
         }
 
         private static bool IsNotRelevantBinary(Expression condition, out BinaryExpression binary)
@@ -72,5 +70,10 @@ private static bool IsNotRelevantBinary(Expression condition, out BinaryExpressi
             binary = null;
             return true;
         }
+
+        private static string FinaliseCondition(string condition)
+        {
+            return condition;
+        }
     }
 }

ReadableExpressions/Translators/Formatting/FormattedTernary.cs

@@ -35,7 +35,7 @@ private static string GetTest(Expression condition, TranslationContext context)
                 return test.WithoutSurroundingParentheses(condition);
             }
 
-            return test.WithSurroundingParentheses(checkExisting: true);
+            return test.WithSurroundingParentheses();
         }
 
         private static string GetBranch(CodeBlock codeBlock)

ReadableExpressions/Translators/NegationExpressionTranslator.cs

@@ -36,7 +36,7 @@ private static string Translate(ExpressionType negationType, Expression expressi
 
             if (WrapNegatedValue(valueToNegate, expression))
             {
-                valueToNegate = valueToNegate.WithSurroundingParentheses(checkExisting: true);
+                valueToNegate = valueToNegate.WithSurroundingParentheses();
             }
 
             return _negationsByNodeType[negationType] + valueToNegate;