* fixes equals and not equals comparison to ignore decimal scale (#421)

* fixes documentation layout for date / time
* adds note of minimum Java version to README and documentation

README.md

@@ -30,6 +30,7 @@ EvalEx is a handy expression evaluator for Java, that allows to parse and evalua
 - Supports implicit multiplication, e.g. 2x or (a+b)(a-b) or 2(x-y) which equals to (a+b)\*(a-b) or 2\*(
   x-y)
 - Lazy evaluation of function parameters (see the IF function) and support of sub-expressions.
+- Requires minimum Java version 11.
 
 ## Documentation
 

docs/concepts/date_time_duration.md

@@ -31,6 +31,7 @@ The infix plus and minus operators can be used to do calculations with _DATE_TIM
 The outcome of the operation depends on the operator types:
 
 #### Addition
+
 | Left Operand | Right Operand | Result                                                                 |
 |--------------|---------------|------------------------------------------------------------------------|
 | _DATE_TIME_  | _DURATION_    | A new _DATE_TIME_ where the duration is added to the date.             |
@@ -54,6 +55,7 @@ System.out.println(result); // will print "EvaluationValue(value=2023-12-04T02:1
 ```
 
 #### Subtraction
+
 | Left Operand | Right Operand | Result                                                                      |
 |--------------|---------------|-----------------------------------------------------------------------------|
 | _DATE_TIME_  | _DATE_TIME_   | A duration which reflects the difference between the two date-times.        |

docs/index.md

@@ -24,6 +24,7 @@ EvalEx is a handy expression evaluator for Java, that allows to parse and evalua
 - Supports implicit multiplication, e.g. 2x or (a+b)(a-b) or 2(x-y) which equals to (a+b)\*(a-b) or 2\*(
   x-y)
 - Lazy evaluation of function parameters (see the IF function) and support of sub-expressions.
+- Requires minimum Java version 11.
 
 ## Documentation
 

src/main/java/com/ezylang/evalex/operators/booleans/InfixEqualsOperator.java

@@ -30,6 +30,12 @@ public class InfixEqualsOperator extends AbstractOperator {
   @Override
   public EvaluationValue evaluate(
       Expression expression, Token operatorToken, EvaluationValue... operands) {
-    return expression.convertValue(operands[0].equals(operands[1]));
+    if (operands[0].isNullValue() && operands[1].isNullValue()) {
+      return EvaluationValue.booleanValue(true);
+    }
+    if (operands[0].isNullValue() || operands[1].isNullValue()) {
+      return EvaluationValue.booleanValue(false);
+    }
+    return expression.convertValue(operands[0].compareTo(operands[1]) == 0);
   }
 }

src/main/java/com/ezylang/evalex/operators/booleans/InfixNotEqualsOperator.java

@@ -30,6 +30,12 @@ public class InfixNotEqualsOperator extends AbstractOperator {
   @Override
   public EvaluationValue evaluate(
       Expression expression, Token operatorToken, EvaluationValue... operands) {
-    return expression.convertValue(!operands[0].equals(operands[1]));
+    if (operands[0].isNullValue() && operands[1].isNullValue()) {
+      return EvaluationValue.booleanValue(false);
+    }
+    if (operands[0].isNullValue() || operands[1].isNullValue()) {
+      return EvaluationValue.booleanValue(true);
+    }
+    return expression.convertValue(operands[0].compareTo(operands[1]) != 0);
   }
 }

src/test/java/com/ezylang/evalex/ExpressionEvaluatorDecimalPlacesTest.java

@@ -18,6 +18,7 @@
 import static org.assertj.core.api.Assertions.assertThat;
 
 import com.ezylang.evalex.config.ExpressionConfiguration;
+import com.ezylang.evalex.data.EvaluationValue;
 import com.ezylang.evalex.parser.ParseException;
 import java.math.BigDecimal;
 import java.util.HashMap;
@@ -190,4 +191,20 @@ void testDecimalPlacesResultAndAuto() throws EvaluationException, ParseException
 
     assertThat(expression.evaluate().getStringValue()).isEqualTo("5.01");
   }
+
+  @Test
+  void testEqualsIgnoresScale() throws EvaluationException, ParseException {
+    Expression expression = new Expression("a == b");
+    EvaluationValue result = expression.with("a", 70).and("b", 70.0).evaluate();
+
+    assertThat(result.getBooleanValue()).isTrue();
+  }
+
+  @Test
+  void testNotEqualsIgnoresScale() throws EvaluationException, ParseException {
+    Expression expression = new Expression("a != b");
+    EvaluationValue result = expression.with("a", 70).and("b", 70.0).evaluate();
+
+    assertThat(result.getBooleanValue()).isFalse();
+  }
 }

src/test/java/com/ezylang/evalex/ExpressionEvaluatorNullTest.java

@@ -26,17 +26,27 @@
 class ExpressionEvaluatorNullTest extends BaseExpressionEvaluatorTest {
 
   @Test
-  void testNullEquals() throws ParseException, EvaluationException {
+  void testSecondNullEquals() throws ParseException, EvaluationException {
     Expression expression = createExpression("a == null");
     assertExpressionHasExpectedResult(expression.with("a", null), "true");
-    assertExpressionHasExpectedResult(expression.with("a", 99), "false");
   }
 
   @Test
-  void testNullNotEquals() throws ParseException, EvaluationException {
+  void testSecondNullNotEquals() throws ParseException, EvaluationException {
     Expression expression = new Expression("a != null");
     assertExpressionHasExpectedResult(expression.with("a", null), "false");
-    assertExpressionHasExpectedResult(expression.with("a", 99), "true");
+  }
+
+  @Test
+  void testFirstNullEquals() throws ParseException, EvaluationException {
+    Expression expression = createExpression("null == a");
+    assertExpressionHasExpectedResult(expression.with("a", null), "true");
+  }
+
+  @Test
+  void testFirstNullNotEquals() throws ParseException, EvaluationException {
+    Expression expression = new Expression("null != a");
+    assertExpressionHasExpectedResult(expression.with("a", null), "false");
   }
 
   @Test