ExpressionEqualsNode: Rewrite to be less strict

VAR.ExpressionEvaluator.Tests/ParserTests.cs

@@ -547,6 +547,11 @@ namespace VAR.ExpressionEvaluator.Tests
             Assert.False((bool?)Parser.EvaluateString("true and false"));
             Assert.True((bool?)Parser.EvaluateString("true and true"));
 
+            Assert.False((bool?)Parser.EvaluateString("False And False"));
+            Assert.False((bool?)Parser.EvaluateString("False And True"));
+            Assert.False((bool?)Parser.EvaluateString("True And False"));
+            Assert.True((bool?)Parser.EvaluateString("True And True"));
+
             Assert.False((bool?)Parser.EvaluateString("false && false"));
             Assert.False((bool?)Parser.EvaluateString("false && true"));
             Assert.False((bool?)Parser.EvaluateString("true && false"));
@@ -561,6 +566,11 @@ namespace VAR.ExpressionEvaluator.Tests
             Assert.True((bool?)Parser.EvaluateString("true or false"));
             Assert.True((bool?)Parser.EvaluateString("true or true"));
 
+            Assert.False((bool?)Parser.EvaluateString("False Or False"));
+            Assert.True((bool?)Parser.EvaluateString("False Or True"));
+            Assert.True((bool?)Parser.EvaluateString("True Or False"));
+            Assert.True((bool?)Parser.EvaluateString("True Or True"));
+
             Assert.False((bool?)Parser.EvaluateString("false || false"));
             Assert.True((bool?)Parser.EvaluateString("false || true"));
             Assert.True((bool?)Parser.EvaluateString("true || false"));
@@ -577,7 +587,6 @@ namespace VAR.ExpressionEvaluator.Tests
             Assert.False((bool?)Parser.EvaluateString("not true"));
         }
 
-
         #endregion BooleanOps
 
         #region Null value
@@ -621,6 +630,40 @@ namespace VAR.ExpressionEvaluator.Tests
 
         #endregion
 
+        #region String coercions
+
+        [Fact()]
+        public void StringCoercions__Var1NullEqualsStringEmpty_EqualsTrue()
+        {
+            EvaluationContext evaluationContex = new EvaluationContext();
+            evaluationContex.SetVariable("v1", null);
+            string expression = "v1 = \"\"";
+            object result = Parser.EvaluateString(expression, evaluationContex);
+            Assert.True((bool?)result);
+        }
+
+        [Fact()]
+        public void StringCoercions__Var1TrueStringEqualsTrue_EqualsTrue()
+        {
+            EvaluationContext evaluationContex = new EvaluationContext();
+            evaluationContex.SetVariable("v1", "True");
+            string expression = "v1 = true";
+            object result = Parser.EvaluateString(expression, evaluationContex);
+            Assert.True((bool?)result);
+        }
+
+        [Fact()]
+        public void StringCoercions__Var1FalseStringEqualsFalse_EqualsTrue()
+        {
+            EvaluationContext evaluationContex = new EvaluationContext();
+            evaluationContex.SetVariable("v1", "False");
+            string expression = "v1 = false";
+            object result = Parser.EvaluateString(expression, evaluationContex);
+            Assert.True((bool?)result);
+        }
+
+        #endregion String coercions
+
         #region Excepctions
 
         [Fact]

VAR.ExpressionEvaluator/ExpressionNodes/ExpressionEqualsNode.cs

@@ -1,6 +1,4 @@
-using System;
+namespace VAR.ExpressionEvaluator
-
-namespace VAR.ExpressionEvaluator
 {
     public class ExpressionEqualsNode : ExpressionBinaryNode
     {
@@ -9,49 +7,17 @@ namespace VAR.ExpressionEvaluator
         {
         }
 
-        private static object EqualsOp(object leftValue, object rightValue)
+        public static object EqualsOp(object leftValue, object rightValue)
         {
-            if (leftValue is string && rightValue is string)
+            // Null
-            {
+            if (leftValue is string && string.IsNullOrEmpty(leftValue as string))
-                return string.Compare((string)leftValue, (string)rightValue) == 0;
-            }
-
-            if ((leftValue is string && rightValue == null) || (leftValue == null && rightValue is string))
-            {
-                return false;
-            }
-
-            if (leftValue is string)
-            {
-                if (string.IsNullOrEmpty((string)leftValue))
             {
                 leftValue = null;
             }
-                else
+            if (rightValue is string && string.IsNullOrEmpty(rightValue as string))
             {
-                    if (decimal.TryParse((string)leftValue, out decimal dec) == false)
+                rightValue = null;
-                    {
-                        throw new Exception(string.Format("Can't convert to decimal string value \"{0}\"", (string)leftValue));
             }
-                    leftValue = dec;
-                }
-            }
-            if (rightValue is string)
-            {
-                if (string.IsNullOrEmpty((string)rightValue))
-                {
-                    leftValue = null;
-                }
-                else
-                {
-                    if (decimal.TryParse((string)rightValue, out decimal dec) == false)
-                    {
-                        throw new Exception(string.Format("Can't convert to decimal string value \"{0}\"", (string)rightValue));
-                    }
-                    rightValue = dec;
-                }
-            }
-
             if (leftValue == null && rightValue == null)
             {
                 return true;
@@ -61,11 +27,85 @@ namespace VAR.ExpressionEvaluator
                 return false;
             }
 
+            // String
+            if (leftValue is string && rightValue is string)
+            {
+                return string.Compare((string)leftValue, (string)rightValue) == 0;
+            }
+
+            // Bool
+            if (leftValue is bool || rightValue is bool)
+            {
+                bool? leftBool = ConvertToNullableBool(leftValue);
+                bool? rightBool = ConvertToNullableBool(rightValue);
+                return leftBool == rightBool;
+            }
+
+            // Decimal
+            if (leftValue is string)
+            {
+                if (decimal.TryParse((string)leftValue, out decimal dec) == false)
+                {
+                    leftValue = null;
+                }
+                else
+                {
+                    leftValue = dec;
+                }
+            }
+            if (rightValue is string)
+            {
+                if (decimal.TryParse((string)rightValue, out decimal dec) == false)
+                {
+                    rightValue = null;
+                }
+                else
+                {
+                    rightValue = dec;
+                }
+            }
             if ((leftValue is decimal) == false || (rightValue is decimal) == false)
             {
-                throw new Exception("Can't compare non decimal values");
+                return false;
             }
             return (decimal)leftValue == (decimal)rightValue;
         }
+
+        private static bool? ConvertToNullableBool(object value)
+        {
+            if (value is bool)
+            {
+                return (bool)value;
+            }
+            if (value is string)
+            {
+                string text = value as string;
+                if (string.IsNullOrEmpty(text))
+                {
+                    return null;
+                }
+                decimal decValue;
+                if (decimal.TryParse(text, out decValue))
+                {
+                    return decValue != 0;
+                }
+                string textLower = text.ToLower();
+                if (textLower == "false" || textLower == "no" || textLower == "ez" || textLower == "non" || textLower == "nein")
+                {
+                    return false;
+                }
+                if (textLower == "true" || textLower == "si" || textLower == "sí" || textLower == "yes" || textLower == "bai" || textLower == "oui" || textLower == "ja")
+                {
+                    return true;
+                }
+
+                return null;
+            }
+            if (value is decimal)
+            {
+                return ((decimal)value) != 0;
+            }
+            return false;
+        }
     }
 }

VAR.ExpressionEvaluator/ExpressionNodes/ExpressionNotEqualsNode.cs

@@ -1,6 +1,4 @@
-using System;
+namespace VAR.ExpressionEvaluator
-
-namespace VAR.ExpressionEvaluator
 {
     public class ExpressionNotEqualsNode : ExpressionBinaryNode
     {
@@ -11,56 +9,8 @@ namespace VAR.ExpressionEvaluator
 
         private static object NotEqualsOp(object leftValue, object rightValue)
         {
-            if (leftValue is string && rightValue is string)
+            bool result = (bool)ExpressionEqualsNode.EqualsOp(leftValue, rightValue);
-            {
+            return !result;
-                return string.Compare((string)leftValue, (string)rightValue) != 0;
-            }
-
-            if (leftValue is string)
-            {
-                if (string.IsNullOrEmpty((string)leftValue))
-                {
-                    leftValue = null;
-                }
-                else
-                {
-                    if (decimal.TryParse((string)leftValue, out decimal dec) == false)
-                    {
-                        throw new Exception(string.Format("Can't convert to decimal string value \"{0}\"", (string)leftValue));
-                    }
-                    leftValue = dec;
-                }
-            }
-            if (rightValue is string)
-            {
-                if (string.IsNullOrEmpty((string)rightValue))
-                {
-                    leftValue = null;
-                }
-                else
-                {
-                    if (decimal.TryParse((string)rightValue, out decimal dec) == false)
-                    {
-                        throw new Exception(string.Format("Can't convert to decimal string value \"{0}\"", (string)rightValue));
-                    }
-                    rightValue = dec;
-                }
-            }
-
-            if (leftValue == null && rightValue == null)
-            {
-                return false;
-            }
-            if (leftValue == null || rightValue == null)
-            {
-                return true;
-            }
-
-            if ((leftValue is decimal) == false || (rightValue is decimal) == false)
-            {
-                throw new Exception("Can't compare non decimal values");
-            }
-            return (decimal)leftValue != (decimal)rightValue;
         }
     }
 }

VAR.ExpressionEvaluator/Parser.cs

@@ -84,6 +84,13 @@ namespace VAR.ExpressionEvaluator
                     IExpressionNode rightNode = ParsePlusAndMinus();
                     leftNode = new ExpressionEqualsNode(leftNode, rightNode);
                 }
+                if (_tokenizer.Token == Token.ExclusiveEquals)
+                {
+                    // TODO: Implement ExpressionExclusiveEqualsNode
+                    _tokenizer.NextToken();
+                    IExpressionNode rightNode = ParsePlusAndMinus();
+                    leftNode = new ExpressionEqualsNode(leftNode, rightNode);
+                }
                 else if (_tokenizer.Token == Token.NotEquals)
                 {
                     _tokenizer.NextToken();