Maintaining surrounding parenthesis when assigning an invocation result to a variable, re: issue #9

Author: SteveWilkes

ReadableExpressions.UnitTests/WhenFormattingCode.cs

@@ -547,6 +547,23 @@ public void ShouldNotRemoveParenthesesFromMultiParameterLambdaArguments()
             Assert.AreEqual(EXPECTED, translated);
         }
 
+        // See https://github.com/agileobjects/ReadableExpressions/issues/9
+        [TestMethod]
+        public void ShouldNotRemoveParenthesesFromALambdaInvokeResultAssignment()
+        {
+            Expression<Func<int, int, int>> intsAdder = (a, b) => a + b;
+            var one = Expression.Constant(1);
+            var two = Expression.Constant(2);
+            var lambdaInvocation = Expression.Invoke(intsAdder, one, two);
+            var result = Expression.Variable(typeof(int), "result");
+            var assignInvokeResult = Expression.Assign(result, lambdaInvocation);
+
+            const string EXPECTED = "result = ((a, b) => a + b).Invoke(1, 2)";
+            var translated = assignInvokeResult.ToReadableString();
+
+            Assert.AreEqual(EXPECTED, translated);
+        }
+
         [TestMethod]
         public void ShouldUseMethodGroupsForStaticMethods()
         {

ReadableExpressions/StringExtensions.cs

@@ -118,6 +118,11 @@ private static bool KeepSurroundingParentheses(Expression expression)
                     }
 
                     return (expression.NodeType == ExpressionType.Convert);
+
+                case ExpressionType.Invoke:
+                    var invocation = (InvocationExpression)expression;
+
+                    return invocation.Expression.NodeType == ExpressionType.Lambda;
             }
 
             return false;