[FEATURE] Support emphasize-lines in code-block directive

packages/guides-restructured-text/src/RestructuredText/Directives/CodeBlockDirective.php

@@ -10,7 +10,9 @@
 use phpDocumentor\Guides\RestructuredText\Parser\BlockContext;
 use phpDocumentor\Guides\RestructuredText\Parser\Directive;
 use phpDocumentor\Guides\RestructuredText\Parser\DirectiveOption;
+use Psr\Log\LoggerInterface;
 
+use function preg_match;
 use function trim;
 
 /**
@@ -26,8 +28,13 @@
  */
 class CodeBlockDirective extends BaseDirective
 {
-    public function __construct(private readonly CodeNodeOptionMapper $codeNodeOptionMapper)
-    {
+    /** @see https://regex101.com/r/I3KttH/1 */
+    public const LINE_NUMBER_RANGES_REGEX = '/^\d+(-\d+)?(?:,\s*\d+(-\d+)?)*$/';
+
+    public function __construct(
+        private readonly LoggerInterface $logger,
+        private readonly CodeNodeOptionMapper $codeNodeOptionMapper,
+    ) {
     }
 
     public function getName(): string
@@ -58,6 +65,7 @@ public function process(
 
         $this->setStartingLineNumberBasedOnOptions($directive->getOptions(), $node);
         $this->setCaptionBasedOnOptions($directive->getOptions(), $node);
+        $this->setEmphasizeLinesBasedOnOptions($blockContext, $directive->getOptions(), $node);
         $this->codeNodeOptionMapper->apply($node, $directive->getOptions());
 
         if ($directive->getVariable() !== '') {
@@ -101,4 +109,19 @@ private function setCaptionBasedOnOptions(array $options, CodeNode $node): void
 
         $node->setCaption($caption);
     }
+
+    /** @param DirectiveOption[] $options */
+    private function setEmphasizeLinesBasedOnOptions(BlockContext $blockContext, array $options, CodeNode $node): void
+    {
+        $emphasizeLines = null;
+        if (isset($options['emphasize-lines'])) {
+            $emphasizeLines = (string) $options['emphasize-lines']->getValue();
+            if (!preg_match(self::LINE_NUMBER_RANGES_REGEX, $emphasizeLines)) {
+                // Input does not fit the pattern, log a warning
+                $this->logger->warning('Invalid value for option emphasize-lines in code-block directive. Expected format: \'1-5, 7, 33\'', $blockContext->getLoggerInformation());
+            }
+        }
+
+        $node->setEmphasizeLines($emphasizeLines);
+    }
 }

packages/guides-restructured-text/tests/unit/Parser/Productions/DirectiveRuleTest.php

@@ -103,7 +103,7 @@ public function testCodeBlockValue(string $input, string $expectedValue): void
             $this->givenInlineMarkupRule(),
             new Logger('test'),
             new GeneralDirective(new DirectiveContentRule(new RuleContainer())),
-            [$this->directiveHandler, new CodeBlockDirective(new CodeNodeOptionMapper())],
+            [$this->directiveHandler, new CodeBlockDirective(new Logger('test'), new CodeNodeOptionMapper())],
         );
         $context = $this->createContext($input);
         $node = $this->rule->apply($context);

packages/guides/resources/template/html/body/code.html.twig

@@ -7,5 +7,7 @@
             <span class="caption-text">{{ node.caption }}</span>
         </div>
     {%- endif -%}
-    <pre{% if node.classes %} class="{{ node.classesString }}"{% endif %}><code class="language-{{ node.language }}{{ node.startingLineNumber ? ' line-numbers' }}" {%- if node.startingLineNumber %} data-start="{{ node.startingLineNumber }}"{% endif %}>{{ node.value }}</code></pre>
+    <pre{% if node.classes %} class="{{ node.classesString }}"{% endif %}><code class="language-{{ node.language }}{{ node.startingLineNumber ? ' line-numbers' }}"
+                {%- if node.startingLineNumber %} data-start="{{ node.startingLineNumber }}"{% endif -%}
+                {%- if node.emphasizeLines %} data-emphasize-lines="{{ node.emphasizeLines }}"{% endif -%}>{{ node.value }}</code></pre>
 {%- endif -%}

packages/guides/src/Nodes/CodeNode.php

@@ -22,6 +22,8 @@ class CodeNode extends TextNode
 
     private string|null $caption = null;
 
+    private string|null $emphasizeLines = null;
+
     /** @param string[] $lines */
     public function __construct(array $lines, protected string|null $language = null)
     {
@@ -57,4 +59,14 @@ public function setCaption(string|null $caption): void
     {
         $this->caption = $caption;
     }
+
+    public function getEmphasizeLines(): string|null
+    {
+        return $this->emphasizeLines;
+    }
+
+    public function setEmphasizeLines(string|null $emphasizeLines): void
+    {
+        $this->emphasizeLines = $emphasizeLines;
+    }
 }

tests/Integration/tests/code/code-block-emphasize/expected/index.html

@@ -0,0 +1,19 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <title>Title</title>
+
+</head>
+<body>
+    <div class="section" id="title">
+    <h1>Title</h1>
+
+            <pre><code class="language-python" data-emphasize-lines="3,5">def some_function():
+    interesting = False
+    print(&#039;This line is highlighted.&#039;)
+    print(&#039;This one is not...&#039;)
+    print(&#039;...but this one is.&#039;)</code></pre>
+    </div>
+
+</body>
+</html>

tests/Integration/tests/code/code-block-emphasize/input/index.rst

@@ -0,0 +1,11 @@
+Title
+=====
+
+..  code-block:: python
+    :emphasize-lines: 3,5
+
+    def some_function():
+        interesting = False
+        print('This line is highlighted.')
+        print('This one is not...')
+        print('...but this one is.')