MathML Reader : Support for Semantics

src/Math/Element/Semantics.php

@@ -0,0 +1,33 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpOffice\Math\Element;
+
+class Semantics extends AbstractGroupElement
+{
+    /**
+     * @var array<string, string>
+     */
+    protected $annotations = [];
+
+    public function addAnnotation(string $encoding, string $annotation): self
+    {
+        $this->annotations[$encoding] = $annotation;
+
+        return $this;
+    }
+
+    public function getAnnotation(string $encoding): ?string
+    {
+        return $this->annotations[$encoding] ?? null;
+    }
+
+    /**
+     * @return array<string, string>
+     */
+    public function getAnnotations(): array
+    {
+        return $this->annotations;
+    }
+}

src/Math/Reader/MathML.php

@@ -49,6 +49,17 @@ protected function parseNode(?DOMNode $nodeRowElement, $parent): void
     {
         $this->xpath = new DOMXpath($this->dom);
         foreach ($this->xpath->query('*', $nodeRowElement) ?: [] as $nodeElement) {
+            if ($parent instanceof Element\Semantics
+                && $nodeElement instanceof DOMElement
+                && $nodeElement->nodeName == 'annotation') {
+                $parent->addAnnotation(
+                    $nodeElement->getAttribute('encoding'),
+                    trim($nodeElement->nodeValue)
+                );
+
+                continue;
+            }
+
             $element = $this->getElement($nodeElement);
             $parent->add($element);
 
@@ -103,6 +114,8 @@ protected function getElement(DOMNode $nodeElement): Element\AbstractElement
                 }
 
                 return $element;
+            case 'semantics':
+                return new Element\Semantics();
             default:
                 throw new Exception(sprintf(
                     '%s : The tag `%s` is not implemented',

tests/Math/Reader/MathMLTest.php

@@ -151,4 +151,49 @@ public function testReadFraction(): void
         $this->assertInstanceOf(Element\Identifier::class, $denominator);
         $this->assertEquals('d', $denominator->getValue());
     }
+
+    /**
+     * @covers \MathML::read
+     */
+    public function testReadSemantics(): void
+    {
+        $content = '<?xml version="1.0" encoding="UTF-8"?>
+        <math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
+            <semantics>
+                <mrow>
+                    <mfrac>
+                        <mi>π</mi>
+                        <mn>2</mn>
+                    </mfrac>
+                    <mo stretchy="false">+</mo>
+                    <mrow>
+                        <mi>a</mi>
+                        <mo stretchy="false">∗</mo>
+                        <mn>2</mn>
+                    </mrow>
+                </mrow>
+                <annotation encoding="StarMath 5.0">{π} over {2}  + { a } * 2 </annotation>
+            </semantics>
+        </math>';
+
+        $reader = new MathML();
+        $math = $reader->read($content);
+        $this->assertInstanceOf(Math::class, $math);
+
+        $elements = $math->getElements();
+        $this->assertCount(1, $elements);
+        $this->assertInstanceOf(Element\Semantics::class, $elements[0]);
+
+        /** @var Element\Semantics $element */
+        $element = $elements[0];
+
+        // Check MathML
+        $subElements = $element->getElements();
+        $this->assertCount(1, $subElements);
+        $this->assertInstanceOf(Element\Row::class, $subElements[0]);
+
+        // Check Annotation
+        $this->assertCount(1, $element->getAnnotations());
+        $this->assertEquals('{π} over {2}  + { a } * 2', $element->getAnnotation('StarMath 5.0'));
+    }
 }