small updates, move contributing info out of readme

CONTRIBUTING.md

@@ -0,0 +1,38 @@
+# Contributing
+
+Clock accepts contributions of code and documentation from the community. 
+These contributions can be made in the form of Issues or [Pull Requests](http://help.github.com/send-pull-requests/) on the [Clock repository](https://github.com/ericsizemore/clock).
+
+Clock is licensed under the MIT license. When submitting new features or patches to Clock, you are giving permission to license those features or patches under the MIT license.
+
+Clock tries to adhere to PHPStan level 9 with strict rules and bleeding edge. Please ensure any contributions do as well.
+
+
+## Guidelines
+
+Before we look into how, here are the guidelines. If your Pull Requests fail to pass these guidelines it will be declined, and you will need to re-submit when you’ve made the changes. This might sound a bit tough, but it is required for me to maintain quality of the code-base.
+
+
+## PHP Style
+
+Please ensure all new contributions match the [PSR-12](https://www.php-fig.org/psr/psr-12/) coding style guide. The project is not fully PSR-12 compatible, yet; however, to ensure the easiest transition to the coding guidelines, I would like to go ahead and request that any contributions follow them.
+
+
+## Documentation
+
+If you change anything that requires a change to documentation then you will need to add it. New methods, parameters, changing default values, adding constants, etc. are all things that will require a change to documentation. The change-log must also be updated for every change. Also, PHPDoc blocks must be maintained.
+
+
+### Documenting functions/variables (PHPDoc)
+
+Please ensure all new contributions adhere to:
+
+* [PSR-5 PHPDoc](https://github.com/php-fig/fig-standards/blob/master/proposed/phpdoc.md)
+* [PSR-19 PHPDoc Tags](https://github.com/php-fig/fig-standards/blob/master/proposed/phpdoc-tags.md)
+
+when documenting new functions, or changing existing documentation.
+
+
+### Branching
+
+One thing at a time: A pull request should only contain one change. That does not mean only one commit, but one change - however many commits it took. The reason for this is that if you change X and Y but send a pull request for both at the same time, we might really want X but disagree with Y, meaning we cannot merge the request. Using the Git-Flow branching model you can create new branches for both of these features and send two requests.

README.md

@@ -52,42 +52,7 @@ Issues are the quickest way to report a bug. If you find a bug or documentation
 
 ### Contributing
 
-Clock accepts contributions of code and documentation from the community. 
-These contributions can be made in the form of Issues or [Pull Requests](http://help.github.com/send-pull-requests/) on the [Clock repository](https://github.com/ericsizemore/clock).
-
-Clock is licensed under the MIT license. When submitting new features or patches to Clock, you are giving permission to license those features or patches under the MIT license.
-
-Clock tries to adhere to PHPStan level 9 with strict rules and bleeding edge. Please ensure any contributions do as well.
-
-
-#### Guidelines
-
-Before we look into how, here are the guidelines. If your Pull Requests fail to pass these guidelines it will be declined, and you will need to re-submit when you’ve made the changes. This might sound a bit tough, but it is required for me to maintain quality of the code-base.
-
-
-#### PHP Style
-
-Please ensure all new contributions match the [PSR-12](https://www.php-fig.org/psr/psr-12/) coding style guide. The project is not fully PSR-12 compatible, yet; however, to ensure the easiest transition to the coding guidelines, I would like to go ahead and request that any contributions follow them.
-
-
-#### Documentation
-
-If you change anything that requires a change to documentation then you will need to add it. New methods, parameters, changing default values, adding constants, etc. are all things that will require a change to documentation. The change-log must also be updated for every change. Also, PHPDoc blocks must be maintained.
-
-
-##### Documenting functions/variables (PHPDoc)
-
-Please ensure all new contributions adhere to:
-
-* [PSR-5 PHPDoc](https://github.com/php-fig/fig-standards/blob/master/proposed/phpdoc.md)
-* [PSR-19 PHPDoc Tags](https://github.com/php-fig/fig-standards/blob/master/proposed/phpdoc-tags.md)
-
-when documenting new functions, or changing existing documentation.
-
-
-#### Branching
-
-One thing at a time: A pull request should only contain one change. That does not mean only one commit, but one change - however many commits it took. The reason for this is that if you change X and Y but send a pull request for both at the same time, we might really want X but disagree with Y, meaning we cannot merge the request. Using the Git-Flow branching model you can create new branches for both of these features and send two requests.
+* See [CONTRIBUTING.MD](CONTRIBUTING.MD)
 
 
 ### Backward Compatibility Promise

src/ClockInterface.php

@@ -29,6 +29,8 @@ public function now(): DateTimeImmutable;
 
     /**
      * Returns a new *Clock at current system time in UTC.
+     *
+     * @throws \DateInvalidTimeZoneException
      */
     public static function fromUtc(): ClockInterface;
 }

src/FrozenClock.php

@@ -48,7 +48,7 @@ public function now(): DateTimeImmutable
     }
 
     /**
-     * @inheritDoc
+     * Sets the FrozenClock to a specific time.
      */
     public function setTo(DateTimeImmutable $now): void
     {
@@ -58,9 +58,9 @@ public function setTo(DateTimeImmutable $now): void
     /**
      * @inheritDoc
      */
-    public static function fromUtc(): static
+    public static function fromUtc(): FrozenClock
     {
-        return new static(
+        return new FrozenClock(
             new DateTimeImmutable('now', new DateTimeZone('UTC'))
         );
     }

src/SystemClock.php

@@ -28,9 +28,9 @@
  *
  * @immutable
  */
-final class SystemClock implements ClockInterface
+final readonly class SystemClock implements ClockInterface
 {
-    private readonly DateTimeZone $timezone;
+    private DateTimeZone $timezone;
 
     /**
      * @throws DateInvalidTimeZoneException If $timezone is passed as string and is invalid.
@@ -42,7 +42,8 @@ public function __construct(DateTimeZone | string | null $timezone = null)
 
             try {
                 $this->timezone = new DateTimeZone($timezone === '' ? 'UTC' : $timezone);
-            } catch (Throwable $throwable) { // \Exception < PHP 8.3, \DateInvalidTimeZoneException >= PHP 8.3
+            // \Exception < PHP 8.3, \DateInvalidTimeZoneException >= PHP 8.3
+            } catch (Throwable $throwable) {
                 throw new DateInvalidTimeZoneException($throwable->getMessage(), \intval($throwable->getCode()), $throwable);
             }
 
@@ -83,17 +84,19 @@ public function now(): DateTimeImmutable
 
     /**
      * Returns a new SystemClock at current system time using the system's timezone.
+     *
+     * @throws DateInvalidTimeZoneException
      */
-    public static function fromSystemTimezone(): static
+    public static function fromSystemTimezone(): SystemClock
     {
-        return new static(new DateTimeZone(date_default_timezone_get()));
+        return new SystemClock(new DateTimeZone(date_default_timezone_get()));
     }
 
     /**
      * @inheritDoc
      */
-    public static function fromUtc(): static
+    public static function fromUtc(): SystemClock
     {
-        return new static(new DateTimeZone('UTC'));
+        return new SystemClock(new DateTimeZone('UTC'));
     }
 }