Handling null-terminating characters in string and character constants, fixes #43 (#45)

Author: SteveWilkes

ReadableExpressions.UnitTests/WhenTranslatingConstants.cs

@@ -27,6 +27,17 @@ public void ShouldTranslateAString()
             translated.ShouldBe("\"hello!\"");
         }
 
+        // See https://github.com/agileobjects/ReadableExpressions/issues/43
+        [Fact]
+        public void ShouldTranslateAStringWithANullTerminatingCharacter()
+        {
+            var stringConstant = Constant("hel\0lo!", typeof(string));
+
+            var translated = ToReadableString(stringConstant);
+
+            translated.ShouldBe(@"""hel\0lo!""");
+        }
+
         [Fact]
         public void ShouldTranslateABoolean()
         {

ReadableExpressions.UnitTests/WhenTranslatingStringConcatenation.cs

@@ -101,5 +101,16 @@ public void ShouldMaintainNumericOperandParentheses()
 
             translated.ShouldBe("((i - j) / k) + \" Maths!\"");
         }
+
+        // See https://github.com/agileobjects/ReadableExpressions/issues/43
+        [Fact]
+        public void ShouldChandleANullTerminatingCharacter()
+        {
+            var concat = CreateLambda((string str1, string str2) => str1 + '\0' + str2);
+
+            var translated = ToReadableString(concat.Body);
+
+            translated.ShouldBe("str1 + '\\0' + str2");
+        }
     }
 }

ReadableExpressions/Translations/ConstantTranslation.cs

@@ -74,8 +74,9 @@ private static bool TryTranslateFromTypeCode(
                     return true;
 
                 case NetStandardTypeCode.Char:
-                    translation = new TranslationWrapper(FixedValueTranslation(constant)).WrappedWith("'", "'");
-
+                    var character = (char)constant.Value;
+                    var value = character == '\0' ? Expression.Constant(@"\0") : constant;
+                    translation = new TranslationWrapper(FixedValueTranslation(value)).WrappedWith("'", "'");
                     return true;
 
                 case NetStandardTypeCode.DateTime:
@@ -123,7 +124,7 @@ private static bool TryTranslateFromTypeCode(
                     return true;
 
                 case NetStandardTypeCode.String:
-                    var stringValue = (string)constant.Value;
+                    var stringValue = ((string)constant.Value).Replace("\0", @"\0");
 
                     if (stringValue.IsComment())
                     {