Adds BigInteger support to NumberConverter (#463)

docs/concepts/datatypes.md

@@ -34,6 +34,7 @@ automatically be converted from one of the following Java data types:
 - byte
 - double
 - float
+- java.math.BigInteger
 
 Be careful when passing double or float values, as these have to be converted from their
 floating-point arithmetic representation to a BigDecimal representation, which stores values a

src/main/java/com/ezylang/evalex/data/conversion/NumberConverter.java

@@ -18,6 +18,7 @@
 import com.ezylang.evalex.config.ExpressionConfiguration;
 import com.ezylang.evalex.data.EvaluationValue;
 import java.math.BigDecimal;
+import java.math.BigInteger;
 
 /** Converter to convert to the NUMBER data type. */
 public class NumberConverter implements ConverterIfc {
@@ -28,6 +29,8 @@ public EvaluationValue convert(Object object, ExpressionConfiguration configurat
 
     if (object instanceof BigDecimal) {
       bigDecimal = (BigDecimal) object;
+    } else if (object instanceof BigInteger) {
+      bigDecimal = new BigDecimal((BigInteger) object, configuration.getMathContext());
     } else if (object instanceof Double) {
       bigDecimal = new BigDecimal(Double.toString((double) object), configuration.getMathContext());
     } else if (object instanceof Float) {
@@ -50,6 +53,7 @@ public EvaluationValue convert(Object object, ExpressionConfiguration configurat
   @Override
   public boolean canConvert(Object object) {
     return (object instanceof BigDecimal
+        || object instanceof BigInteger
         || object instanceof Double
         || object instanceof Float
         || object instanceof Integer

src/test/java/com/ezylang/evalex/data/conversion/NumberConverterTest.java

@@ -21,6 +21,7 @@
 import com.ezylang.evalex.config.ExpressionConfiguration;
 import com.ezylang.evalex.data.EvaluationValue;
 import java.math.BigDecimal;
+import java.math.BigInteger;
 import org.junit.jupiter.api.Test;
 
 class NumberConverterTest {
@@ -40,6 +41,16 @@ void testBigDecimal() {
     assertThat(converted.getValue()).isEqualTo(value);
   }
 
+  @Test
+  void testBigInteger() {
+    BigInteger value = new BigInteger("23");
+
+    EvaluationValue converted = converter.convert(value, defaultConfiguration);
+
+    assertThat(converted.getDataType()).isEqualTo(EvaluationValue.DataType.NUMBER);
+    assertThat(converted.getNumberValue().toPlainString()).isEqualTo("23");
+  }
+
   @Test
   void testDouble() {
     double value = Double.parseDouble("2.5");
@@ -99,6 +110,7 @@ void testByte() {
   @Test
   void testCanConvert() {
     assertThat(converter.canConvert(new BigDecimal(8))).isTrue();
+    assertThat(converter.canConvert(new BigInteger("5"))).isTrue();
     assertThat(converter.canConvert(Double.parseDouble("3.0"))).isTrue();
     assertThat(converter.canConvert(Float.parseFloat("2.0"))).isTrue();
     assertThat(converter.canConvert(3)).isTrue();