Show Collection is Immutable & Operations Pure

src/Collection.php

@@ -133,6 +133,8 @@
 use const PHP_INT_MIN;
 
 /**
+ * @immutable
+ *
  * @template TKey
  * @template T
  *
@@ -153,6 +155,8 @@ final class Collection implements CollectionInterface
     private $source;
 
     /**
+     * @psalm-external-mutation-free
+     *
      * @param callable(mixed ...$parameters): iterable<TKey, T> $callable
      * @param mixed ...$parameters
      */
@@ -400,6 +404,7 @@ public function frequency(): CollectionInterface
     }
 
     /**
+     * @pure
      * @template NewTKey
      * @template NewT
      *
@@ -414,6 +419,8 @@ public static function fromCallable(callable $callable, ...$parameters): self
     }
 
     /**
+     * @pure
+     *
      * @return self<int, string>
      */
     public static function fromFile(string $filepath): self
@@ -425,6 +432,8 @@ public static function fromFile(string $filepath): self
     }
 
     /**
+     * @pure
+     *
      * @template NewTKey
      * @template NewT
      *
@@ -441,6 +450,8 @@ public static function fromIterable(iterable $iterable): self
     }
 
     /**
+     * @pure
+     *
      * @param resource $resource
      *
      * @return self<int, string>
@@ -457,6 +468,8 @@ public static function fromResource($resource): self
     }
 
     /**
+     * @pure
+     *
      * @return self<int, string>
      */
     public static function fromString(string $string, string $delimiter = ''): self

src/Contract/Collection.php

@@ -124,6 +124,8 @@
 use loophp\collection\Contract\Operation\Zipable;
 
 /**
+ * @immutable
+ *
  * @template TKey
  * @template T
  *

src/Contract/Operation.php

@@ -11,9 +11,16 @@
 
 use Closure;
 
+/** @immutable */
 interface Operation
 {
+    /**
+     * @pure
+     */
     public function __invoke(): Closure;
 
+    /**
+     * @pure
+     */
     public static function of(): Closure;
 }

src/Operation/AbstractOperation.php

@@ -12,12 +12,21 @@
 use Closure;
 use loophp\collection\Contract\Operation;
 
+/**
+ * @immutable
+ */
 abstract class AbstractOperation implements Operation
 {
+    /**
+     * @pure
+     */
     final public function __construct()
     {
     }
 
+    /**
+     * @pure
+     */
     public static function of(): Closure
     {
         return (new static())->__invoke();

src/Operation/Append.php

@@ -14,12 +14,16 @@
 use loophp\collection\Iterator\MultipleIterableIterator;
 
 /**
+ * @immutable
+ *
  * @template TKey
  * @template T
  */
 final class Append extends AbstractOperation
 {
     /**
+     * @pure
+     *
      * @return Closure(T...): Closure(Iterator<TKey, T>): Iterator<int|TKey, T>
      */
     public function __invoke(): Closure

src/Operation/Apply.php

@@ -14,6 +14,8 @@
 use Iterator;
 
 /**
+ * @immutable
+ *
  * @template TKey
  * @template T
  *
@@ -22,6 +24,8 @@
 final class Apply extends AbstractOperation
 {
     /**
+     * @pure
+     *
      * @return Closure(callable(T, TKey, Iterator<TKey, T>):bool ...): Closure(Iterator<TKey, T>): Generator<TKey, T>
      */
     public function __invoke(): Closure

src/Operation/Associate.php

@@ -15,6 +15,8 @@
 use Iterator;
 
 /**
+ * @immutable
+ *
  * @template TKey
  * @template T
  *
@@ -23,6 +25,8 @@
 final class Associate extends AbstractOperation
 {
     /**
+     * @pure
+     *
      * @return Closure(callable(TKey, TKey, T, Iterator<TKey, T>): (T|TKey) ...): Closure((callable(T, TKey, T, Iterator<TKey, T>): (T|TKey))...): Closure(Iterator<TKey, T>): Generator<TKey|T, T|TKey>
      */
     public function __invoke(): Closure

src/Operation/AsyncMap.php

@@ -27,7 +27,7 @@
 }
 // phpcs:enable
 /**
- * Class AsyncMap.
+ * @immutable
  *
  * @template TKey
  * @template T
@@ -37,6 +37,8 @@
 final class AsyncMap extends AbstractOperation
 {
     /**
+     * @pure
+     *
      * @return Closure(callable(T, TKey): T ...): Closure(Iterator<TKey, T>): Generator<TKey, T>
      */
     public function __invoke(): Closure

src/Operation/Cache.php

@@ -15,6 +15,8 @@
 use Psr\Cache\CacheItemPoolInterface;
 
 /**
+ * @immutable
+ *
  * @template TKey
  * @template T
  *
@@ -23,6 +25,8 @@
 final class Cache extends AbstractOperation
 {
     /**
+     * @pure
+     *
      * @return Closure(CacheItemPoolInterface): Closure(Iterator<TKey, T>): Iterator<TKey, T>
      */
     public function __invoke(): Closure

src/Operation/Chunk.php

@@ -18,12 +18,16 @@
 use function count;
 
 /**
+ * @immutable
+ *
  * @template TKey
  * @template T
  */
 final class Chunk extends AbstractOperation
 {
     /**
+     * @pure
+     *
      * @return Closure(int...): Closure(Iterator<TKey, T>): Generator<int, list<T>>
      */
     public function __invoke(): Closure

src/Operation/Coalesce.php

@@ -14,12 +14,16 @@
 use Iterator;
 
 /**
+ * @immutable
+ *
  * @template TKey
  * @template T
  */
 final class Coalesce extends AbstractOperation
 {
     /**
+     * @pure
+     *
      * @return Closure(Iterator<TKey, T>): Generator<TKey, T>
      */
     public function __invoke(): Closure

src/Operation/Collapse.php

@@ -14,12 +14,16 @@
 use Iterator;
 
 /**
+ * @immutable
+ *
  * @template TKey
  * @template T
  */
 final class Collapse extends AbstractOperation
 {
     /**
+     * @pure
+     *
      * @return Closure(Iterator<TKey, (T|iterable<TKey, T>)>): Generator<TKey, T>
      */
     public function __invoke(): Closure

src/Operation/Column.php

@@ -14,12 +14,16 @@
 use Iterator;
 
 /**
+ * @immutable
+ *
  * @template TKey
  * @template T
  */
 final class Column extends AbstractOperation
 {
     /**
+     * @pure
+     *
      * @return Closure(T): Closure(Iterator<TKey, T>): Generator<int, iterable<TKey, T>>
      */
     public function __invoke(): Closure

src/Operation/Combinate.php

@@ -17,11 +17,16 @@
 use function count;
 
 /**
+ * @immutable
+ *
  * @template TKey
  * @template T
  */
 final class Combinate extends AbstractOperation
 {
+    /**
+     * @pure
+     */
     public function __invoke(): Closure
     {
         return static function (?int $length = null): Closure {

src/Operation/Combine.php

@@ -17,12 +17,16 @@
 use const E_USER_WARNING;
 
 /**
+ * @immutable
+ *
  * @template TKey
  * @template T
  */
 final class Combine extends AbstractOperation
 {
     /**
+     * @pure
+     *
      * @return Closure(T...): Closure(Iterator<TKey, T>): Generator<T, T>
      */
     public function __invoke(): Closure

src/Operation/Compact.php

@@ -16,6 +16,8 @@
 use function in_array;
 
 /**
+ * @immutable
+ *
  * @template TKey
  * @template T
  *
@@ -24,6 +26,8 @@
 final class Compact extends AbstractOperation
 {
     /**
+     * @pure
+     *
      * @return Closure(T...): Closure(Iterator<TKey, T>): Generator<TKey, T>
      */
     public function __invoke(): Closure

src/Operation/Contains.php

@@ -14,12 +14,16 @@
 use Iterator;
 
 /**
+ * @immutable
+ *
  * @template TKey
  * @template T
  */
 final class Contains extends AbstractOperation
 {
     /**
+     * @pure
+     *
      * @return Closure(T ...$values): Closure(Iterator<TKey, T>): Generator<TKey, bool>
      */
     public function __invoke(): Closure

src/Operation/Current.php

@@ -14,12 +14,16 @@
 use Iterator;
 
 /**
+ * @immutable
+ *
  * @template TKey
  * @template T
  */
 final class Current extends AbstractOperation
 {
     /**
+     * @pure
+     *
      * @return Closure(int $index): Closure(Iterator<TKey, T>): Generator<TKey, T>
      */
     public function __invoke(): Closure

src/Operation/Cycle.php

@@ -14,12 +14,16 @@
 use Iterator;
 
 /**
+ * @immutable
+ *
  * @template TKey
  * @template T
  */
 final class Cycle extends AbstractOperation
 {
     /**
+     * @pure
+     *
      * @return Closure(Iterator<TKey, T>): Iterator<TKey, T>
      */
     public function __invoke(): Closure

src/Operation/Diff.php

@@ -16,12 +16,16 @@
 use function in_array;
 
 /**
+ * @immutable
+ *
  * @template TKey
  * @template T
  */
 final class Diff extends AbstractOperation
 {
     /**
+     * @pure
+     *
      * @return Closure(T...): Closure(Iterator<TKey, T>): Generator<TKey, T>
      */
     public function __invoke(): Closure