- updated phpunit xml

- updated readme

README.md

@@ -71,7 +71,7 @@ try {
 
 ### Optional String Validation
 ```php
-$pattern = ":string :regexp('^[ab]+$')";
+$pattern = ":string :regexp('#^[ab]+$#')";
 $builder = \PASVL\Validation\ValidatorBuilder::forString($pattern);
 $validator = $builder->build();
 $validator->validate("abab"); // the string is valid
@@ -121,7 +121,7 @@ It looks like this:
   ```
 - as rule with subrules
   ```php
-  $pattern = ["name" => ":string :regexp('\d*')"]; // the value must be a string which contains only digits
+  $pattern = ["name" => ":string :regexp('#\d*#')"]; // the value must be a string which contains only digits
   ```
 - as rule with quantifiers
   ```php
@@ -153,7 +153,7 @@ To add new custom rules, follow these steps:
 ## Built-in Rules
 This package comes with a few built-in rules and their corresponding sub-rules (see in folder `src/Validation/Rules/Library`): 
 - `:string` - the value must be string
-  - `:regexp(<string>)` - provide a regular expression without trailing delimiters
+  - `:regexp(<string>)` - provide a regular expression(the same as for `preg_match()`)
   - `:url`
   - `:email`
   - `:uuid`
@@ -200,7 +200,8 @@ This package comes with a few built-in rules and their corresponding sub-rules (
 ## 🏆 Contributors
 - **[Greg Corrigan](https://github.com/corrigang)**. Greg spotted a problem with nullable values reported as invalid.
 - **Henry Combrinck**. Henry tested the library extensively on real data and found tricky bugs and edge cases. Awesome contribution to make the package valuable to the community.
-- **[@Averor](https://github.com/Averor)**. Found a bug in parenthesis parsing.   
+- **[@Averor](https://github.com/Averor)**. Found a bug in parentheses parsing.
+- **[Julien Gidel](https://github.com/JuGid)**. Improved `regexp` sub-rule.
 
 ## License
 This project is licensed under the terms of the MIT license.

phpunit.xml

@@ -1,23 +1,26 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<phpunit backupGlobals="false"
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         backupGlobals="false"
          backupStaticAttributes="false"
          bootstrap="vendor/autoload.php"
          colors="true"
          convertErrorsToExceptions="true"
          convertNoticesToExceptions="true"
          convertWarningsToExceptions="true"
          processIsolation="false"
-         stopOnFailure="true">
+         stopOnFailure="true"
+         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.3/phpunit.xsd"
+>
+    <coverage processUncoveredFiles="true">
+        <include>
+            <directory suffix=".php">./src</directory>
+        </include>
+    </coverage>
     <testsuites>
         <testsuite name="All tests">
             <directory suffix="Test.php">./tests</directory>
         </testsuite>
     </testsuites>
-    <filter>
-        <whitelist processUncoveredFilesFromWhitelist="true">
-            <directory suffix=".php">./src</directory>
-        </whitelist>
-    </filter>
     <php>
     </php>
 </phpunit>

src/Validation/Rules/Library/RuleString.php

@@ -98,18 +98,22 @@ public function min(int $len): void
 
     public function regexp(string $expr): void
     {
-      if(@preg_match($expr, '') === FALSE) {
-        throw new RuleFailed(sprintf("regexp is not a valid regular expression %s", $expr));
-      }
+        error_clear_last();
+        if (@preg_match($expr, '') === false) {
+            $lastError = error_get_last() ? error_get_last()['message'] : '';
+            throw new RuleFailed(sprintf("regexp is not a valid regular expression %s: %s", $expr, $lastError));
+        }
 
-      if(!preg_match($expr, $this->value)) {
-        throw new RuleFailed(sprintf("string does not match regular expression %s", $expr));
-      }
+        if (!preg_match($expr, $this->value)) {
+            throw new RuleFailed(sprintf("string does not match regular expression %s", $expr));
+        }
     }
 
     public function url(): void
     {
-        if (filter_var($this->value, FILTER_VALIDATE_URL) === false) throw new RuleFailed("string must be url");
+        if (filter_var($this->value, FILTER_VALIDATE_URL) === false) {
+            throw new RuleFailed("string must be url");
+        }
     }
 
     public function between(int $min, int $max): void