Add support for multiple pipes in placeholder modifiers

docs/PlaceholderFormatter.md

@@ -59,6 +59,35 @@ echo $formatter->format('Phone: {{phone|pattern:(###) ###-####}}');
 
 See the [FormatterModifier](modifiers/FormatterModifier.md) documentation for all available formatters and options.
 
+#### Multiple Pipes
+
+You can chain multiple modifiers together using the pipe (`|`) character. Modifiers are applied sequentially from left to right.
+
+```php
+$formatter = new PlaceholderFormatter([
+    'phone' => '1234567890',
+    'value' => '12345',
+]);
+
+// Apply pattern formatting, then mask sensitive data
+echo $formatter->format('Phone: {{phone|pattern:(###) ###-####|mask:6-12}}');
+// Output: Phone: (123) ******90
+
+// Apply number formatting, then mask
+echo $formatter->format('Value: {{value|number:0|mask:1-3}}');
+// Output: Value: ***45
+```
+
+**Escaped Pipes:** If you need to use the pipe character (`|`) as part of a modifier argument (not as a separator), escape it with a backslash (`\|`):
+
+```php
+$formatter = new PlaceholderFormatter(['value' => '123456']);
+
+// Escaped pipe in pattern, then apply mask
+echo $formatter->format('{{value|pattern:###\|###|mask:1-3}}');
+// Output: ***|456
+```
+
 You can also use other modifiers like `list` and `trans`:
 
 ```php
@@ -91,15 +120,17 @@ Formats with additional parameters merged with constructor parameters. Construct
 
 ## Template Syntax
 
-Placeholders follow the format `{{name}}` where `name` is a valid parameter key. Modifiers can be added after a pipe: `{{name|modifier}}`.
+Placeholders follow the format `{{name}}` where `name` is a valid parameter key. Modifiers can be added after a pipe: `{{name|modifier}}`. Multiple modifiers can be chained: `{{name|modifier1|modifier2}}`.
 
 **Rules:**
 
 - Names must match `\w+` (letters, digits, underscore)
 - Names are case-sensitive
 - No whitespace inside braces or around the pipe
+- Multiple pipes are separated by `|` and applied sequentially
+- Escaped pipes (`\|`) within modifiers are treated as literal characters, not separators
 
-**Valid:** `{{name}}`, `{{user_id}}`, `{{name|raw}}`
+**Valid:** `{{name}}`, `{{user_id}}`, `{{name|raw}}`, `{{value|date:Y-m-d|mask:1-5}}`
 
 **Invalid:** `{name}`, `{{ name }}`, `{{first-name}}`, `{{}}`
 

docs/modifiers/Modifiers.md

@@ -15,6 +15,27 @@ Modifiers form a chain where each modifier can:
 1. **Handle the value** and return a transformed string
 2. **Pass the value** to the next modifier in the chain
 
+### Chaining Multiple Modifiers
+
+You can chain multiple modifiers together by separating them with the pipe (`|`) character. Modifiers are applied sequentially from left to right, with each modifier receiving the output of the previous one.
+
+```php
+$formatter = new PlaceholderFormatter([
+    'phone' => '1234567890',
+    'value' => '123456',
+]);
+
+// Apply pattern formatting, then mask sensitive data
+echo $formatter->format('Phone: {{phone|pattern:(###) ###-####|mask:6-12}}');
+// Output: Phone: (123) ******90
+
+// Escaped pipe in pattern argument, then apply mask
+echo $formatter->format('{{value|pattern:###\|###|mask:1-3}}');
+// Output: ***|456
+```
+
+**Important:** When using the pipe character (`|`) as part of a modifier argument (not as a separator), escape it with a backslash (`\|`).
+
 ## Basic Usage
 
 ```php

src/PlaceholderFormatter.php

@@ -18,6 +18,7 @@
 
 use function array_key_exists;
 use function preg_replace_callback;
+use function preg_split;
 
 final readonly class PlaceholderFormatter implements Formatter
 {
@@ -67,6 +68,17 @@ private function processPlaceholder(array $matches, array $parameters): string
             return $placeholder;
         }
 
-        return $this->modifier->modify($parameters[$name], $pipe);
+        $value = $parameters[$name];
+        if ($pipe === null) {
+            return $this->modifier->modify($value, null);
+        }
+
+        $pipes = preg_split('/(?<!\\\\)\|/', $pipe) ?: [];
+        foreach ($pipes as $pipe) {
+            $value = $this->modifier->modify($value, $pipe);
+        }
+
+        /** @phpstan-ignore return.type */
+        return $value;
     }
 }

tests/Unit/PlaceholderFormatterTest.php

@@ -671,4 +671,122 @@ public static function providerForEscapedPipes(): array
             ],
         ];
     }
+
+    /** @param array<string, mixed> $parameters */
+    #[Test]
+    #[DataProvider('providerForMultiplePipes')]
+    public function itShouldHandleMultiplePipesInSequence(
+        array $parameters,
+        string $template,
+        string $expected,
+    ): void {
+        $formatter = new PlaceholderFormatter($parameters);
+        $actual = $formatter->format($template);
+
+        self::assertSame($expected, $actual);
+    }
+
+    /** @return array<string, array{0: array<string, mixed>, 1: string, 2: string}> */
+    public static function providerForMultiplePipes(): array
+    {
+        return [
+            'date then mask' => [
+                ['value' => '2024-01-15'],
+                '{{value|date:Y/m/d|mask:5-8}}',
+                '2024****15',
+            ],
+            'pattern then mask' => [
+                ['phone' => '1234567890'],
+                '{{phone|pattern:(###) ###-####|mask:7-12}}',
+                '(123) ******90',
+            ],
+            'number then mask' => [
+                ['value' => '12345'],
+                '{{value|number:0|mask:1-2}}',
+                '**,345',
+            ],
+            'pattern then number' => [
+                ['value' => '12345'],
+                '{{value|pattern:###.##|number:2}}',
+                '123.45',
+            ],
+            'three pipes: pattern, date, mask' => [
+                ['value' => '20240115'],
+                '{{value|pattern:####-##-##|date:Y/m/d|mask:5-7}}',
+                '2024***/15',
+            ],
+        ];
+    }
+
+    /** @param array<string, mixed> $parameters */
+    #[Test]
+    #[DataProvider('providerForMultiplePipesWithEscaping')]
+    public function itShouldHandleMultiplePipesWithEscapedCharacters(
+        array $parameters,
+        string $template,
+        string $expected,
+    ): void {
+        $formatter = new PlaceholderFormatter($parameters);
+        $actual = $formatter->format($template);
+
+        self::assertSame($expected, $actual);
+    }
+
+    /** @return array<string, array{0: array<string, mixed>, 1: string, 2: string}> */
+    public static function providerForMultiplePipesWithEscaping(): array
+    {
+        return [
+            'pattern with escaped pipe then mask' => [
+                ['value' => '123456'],
+                '{{value|pattern:###\|###|mask:1-3}}',
+                '***|456',
+            ],
+            'pattern with escaped colon then pattern with escaped pipe' => [
+                ['value' => '12345678'],
+                '{{value|pattern:####\:####|pattern:0000\|0000}}',
+                '1234|5678',
+            ],
+        ];
+    }
+
+    /** @param array<string, mixed> $parameters */
+    #[Test]
+    #[DataProvider('providerForEmptyPipe')]
+    public function itShouldHandleEmptyPipe(
+        array $parameters,
+        string $template,
+        string $expected,
+    ): void {
+        $formatter = new PlaceholderFormatter($parameters);
+        $actual = $formatter->format($template);
+
+        self::assertSame($expected, $actual);
+    }
+
+    /** @return array<string, array{0: array<string, mixed>, 1: string, 2: string}> */
+    public static function providerForEmptyPipe(): array
+    {
+        return [
+            'empty pipe at end' => [
+                ['name' => 'John'],
+                'Hello {{name|}}!',
+                'Hello John!',
+            ],
+            'empty pipes' => [
+                ['name' => 'John'],
+                'Hello {{name||}}!',
+                'Hello John!',
+            ],
+            'empty pipe in middle' => [
+                ['first' => 'A', 'second' => 'B'],
+                '{{first|}}-{{second}}',
+                'A-B',
+            ],
+            'empty pipe with missing parameter' => [
+                [],
+                'Hello {{name|}}!',
+                'Hello {{name|}}!',
+            ],
+        ];
+    }
 }