Add copy function, fix pre-release regexes

Author: z4kn4fein

README.md

@@ -10,13 +10,26 @@ Semantic version utility library with parser and comparator written in PHP. It p
 ## Requirements
 [PHP](https://www.php.net/) >= 5.5
 
-## Installation with [Composer](https://getcomposer.org/)
+## Install with [Composer](https://getcomposer.org/)
 ```shell
 composer require z4kn4fein/php-semver
 ```
 
 ## Usage
-#### Parsing and available properties
+The following options are supported to construct a `Version`:
+1. Building part by part with `Version.create()`.
+
+   ```php
+   Version::create(3, 5, 2, "alpha", "build")
+   ```
+
+2. Parsing from a string with `Version.parse()`.
+
+   ```php
+   Version::parse("3.5.2-alpha+build")
+   ```
+
+The following information is accessible on a constructed `Version` object:
 ```php
 <?php
 
@@ -27,11 +40,12 @@ $version = Version::parse('2.5.6-alpha.12+build.34');
 echo $version->getMajor();                  // 2
 echo $version->getMinor();                  // 5
 echo $version->getPatch();                  // 6
-echo (string)$version->getPreRelease();     // alpha.12
+echo $version->getPreRelease();             // alpha.12
 echo $version->getBuildMeta();              // build.34
 echo (string)$version;                      // 2.5.6-alpha.12+build.34
 ```
-#### Comparing two versions
+### Comparing two versions
+It is possible to compare two `Version` objects with the following comparison methods.
 ```php
 <?php
 
@@ -53,7 +67,9 @@ echo $version->isGreaterThan('2.5.6');               // false
 echo $version->isLessThanOrEqual('2.5.6-alpha.12');  // true
 echo $version->isEqual('2.5.6-alpha.12+build.56');   // true
 ```
-#### Producing incremented versions
+### Increment
+`Version` objects can produce incremented versions of themselves with the `getNext{Major|Minor|Patch|PreRelease}Version` methods.
+These methods can be used to determine the next version in order incremented by the according part.
 ```php
 <?php
 
@@ -65,6 +81,29 @@ echo (string)$version->getNextMajorVersion();        // 3.0.0
 echo (string)$version->getNextMinorVersion();        // 2.4.0
 echo (string)$version->getNextPatchVersion();        // 2.3.5
 echo (string)$version->getNextPreReleaseVersion();   // 2.3.5-alpha.5
+
+$version = Version::create(1, 0, 0);
+
+echo (string)$version->getNextMajorVersion();        // 2.0.0
+echo (string)$version->getNextMinorVersion();        // 1.1.0
+echo (string)$version->getNextPatchVersion();        // 1.0.1
+echo (string)$version->getNextPreReleaseVersion();   // 1.0.1-0
 ```
+
+### Copy
+It's possible to make a copy of a particular version with the `copy()` method.
+It allows altering the copied version's properties with optional parameters.
+```php
+$version = Version::parse("1.0.0-alpha.2+build.1");
+
+echo (string)$version->copy(3)                                       // 3.0.0
+echo (string)$version->copy(null, 4)                                 // 1.4.0
+echo (string)$version->copy(null, null, 5)                           // 1.0.5
+echo (string)$version->copy(null, null, null, "alpha.4")             // 1.0.0-alpha.4
+echo (string)$version->copy(null, null, null, null, "build.3")       // 1.0.0-alpha.2+build.3
+echo (string)$version->copy(3, 4, 5)                                 // 3.4.5-alpha.2+build.1
+```
+> Without setting any optional parameter, the `copy()` method will produce an exact copy of the original version.
+
 ## Invalid version handling
 When the version parsing fails due to an invalid format, the library throws a specific `VersionFormatException`.

src/PreRelease.php

@@ -9,15 +9,15 @@ class PreRelease
 
     /**
      * PreRelease constructor.
-     * @param array $preReleaseParts The prerelease parts.
+     * @param array $preReleaseParts The pre-release parts.
      */
     private function __construct($preReleaseParts)
     {
         $this->preReleaseParts = $preReleaseParts;
     }
 
     /**
-     * @return PreRelease The incremented prerelease
+     * @return PreRelease The incremented pre-release.
      */
     public function increment()
     {
@@ -39,13 +39,16 @@ public function increment()
     }
 
     /**
-     * @return string The string representation of the prerelease.
+     * @return string The string representation of the pre-release.
      */
     public function __toString()
     {
         return implode('.', $this->preReleaseParts);
     }
 
+    /**
+     * @return PreRelease The copied pre-release.
+     */
     private function copy()
     {
         return new PreRelease($this->preReleaseParts);
@@ -57,20 +60,16 @@ private function copy()
     private function validate()
     {
         foreach ($this->preReleaseParts as $part) {
-            if ($this->hasOnlyNumbers($part)) {
-                if (strlen($part) > 1 && $part[0] == "0") {
-                    throw new VersionFormatException(sprintf(
-                        "The prerelease part '%s' is numeric but contains a leading zero.",
-                        $part
-                    ));
-                } else {
-                    continue;
-                }
+            if ($this->hasOnlyNumbers($part) && strlen($part) > 1 && $part[0] == "0") {
+                throw new VersionFormatException(sprintf(
+                    "The pre-release part '%s' is numeric but contains a leading zero.",
+                    $part
+                ));
             }
 
             if (!$this->hasOnlyAlphanumericsAndHyphen($part)) {
                 throw new VersionFormatException(sprintf(
-                    "The prerelease part '%s' contains invalid character.",
+                    "The pre-release part '%s' contains invalid character.",
                     $part
                 ));
             }
@@ -79,36 +78,36 @@ private function validate()
 
     /**
      * @param string $part part to check.
-     * @return bool True when the part is containing only numbers.
+     * @return bool True when the part has only numbers.
      */
     private function hasOnlyNumbers($part)
     {
-        return !preg_match("/[^0-9]/", $part);
+        return preg_match("/^[0-9]+$/", $part);
     }
 
     /**
      * @param string $part The part to check.
-     * @return bool True when the part is only containing alphanumerics.
+     * @return bool True when the part has only alphanumerics.
      */
     private function hasOnlyAlphanumericsAndHyphen($part)
     {
-        return !preg_match("/[^0-9A-Za-z-]/", $part);
+        return preg_match("/^[0-9A-Za-z-]+$/", $part);
     }
 
     /**
-     * Creates a new prerelease tag with initial default value (-0).
+     * Creates a new pre-release tag with initial default value (-0).
      *
-     * @return PreRelease The default prerelease tag.
+     * @return PreRelease The default pre-release tag.
      */
     public static function createDefault()
     {
         return new PreRelease([0]);
     }
 
     /**
-     * @param string $preReleaseString The prerelease string.
-     * @return PreRelease The parsed prerelease part.
-     * @throws VersionFormatException When the given prerelease string is invalid.
+     * @param string $preReleaseString The pre-release string.
+     * @return PreRelease The parsed pre-release part.
+     * @throws VersionFormatException When the given pre-release string is invalid.
      */
     public static function parse($preReleaseString)
     {
@@ -127,7 +126,7 @@ public static function parse($preReleaseString)
      * @param string|PreRelease $p1 The left side of the comparison.
      * @param string|PreRelease $p2 The right side of the comparison.
      * @return int -1 when $p1 < $p2, 0 when $p1 == $p2, 1 when $p1 > $p2.
-     * @throws VersionFormatException When the given prerelease values are invalid.
+     * @throws VersionFormatException When the given pre-release values are invalid.
      */
     public static function compare($p1, $p2)
     {