refactor: Add Option.ofOptional, Option.ofNullable

Author: MarcellPerger1

src/main/java/net/marcellperger/mathexpr/util/rs/Option.java

@@ -3,9 +3,11 @@
 import net.marcellperger.mathexpr.util.Util;
 import org.jetbrains.annotations.Contract;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.util.Collections;
 import java.util.Iterator;
+import java.util.Optional;
 import java.util.function.Consumer;
 import java.util.function.Function;
 import java.util.function.Predicate;
@@ -46,6 +48,14 @@ record None<T>() implements Option<T> {
         return new None<>();
     }
 
+    static <T> Option<@NotNull T> ofNullable(@Nullable T value) {
+        return ofOptional(Optional.ofNullable(value));
+    }
+    @SuppressWarnings("OptionalUsedAsFieldOrParameterType")
+    static <T> Option<T> ofOptional(Optional<T> value) {
+        return value.map(Option::newSome).orElse(newNone());
+    }
+
     default boolean isSome() {
         return this instanceof Some<T>;
     }

src/main/java/net/marcellperger/mathexpr/util/rs/Result.java

@@ -91,8 +91,6 @@ default boolean isErrAnd(Predicate<? super E> f)  {
         };
     }
 
-    // TODO: once Option is done, do proper ok() / err() -> Option<T / E>
-
     default <U> Result<U, E> map(Function<? super T, ? extends U> op) {
         return switch (this) {
             case Ok(T value) -> new Ok<>(op.apply(value));

src/test/java/net/marcellperger/mathexpr/util/rs/OptionTest.java

@@ -6,6 +6,7 @@
 import java.util.ArrayList;
 import java.util.Iterator;
 import java.util.List;
+import java.util.Optional;
 
 import static org.junit.jupiter.api.Assertions.*;
 
@@ -343,4 +344,16 @@ void test_toString() {
         assertEquals("Some(314)", getSome().toString());
         assertEquals("None", getNone().toString());
     }
+
+    @Test
+    void ofOptional() {
+        assertEquals(Option.newSome(314), Option.ofOptional(Optional.of(314)));
+        assertEquals(Option.newNone(), Option.ofOptional(Optional.empty()));
+    }
+
+    @Test
+    void ofNullable() {
+        assertEquals(Option.newSome(314), Option.ofNullable(314));
+        assertEquals(Option.newNone(), Option.ofNullable(null));
+    }
 }