v0.3.1 with Saxon fully working

src/validation/xsltValidation.ts

@@ -0,0 +1,63 @@
+import type { TransformEngineId } from '../transform/transformTypes';
+import { parseXmlDocument } from './xmlValidation';
+import type { DiagnosticMessage } from './validationTypes';
+
+const XSLT_NAMESPACE = 'http://www.w3.org/1999/XSL/Transform';
+
+export function validateXslt(
+  text: string,
+  engine: TransformEngineId = 'native-xsltprocessor'
+): DiagnosticMessage[] {
+  const { document: stylesheet, diagnostics } = parseXmlDocument(
+    text,
+    'XSLT stylesheet'
+  );
+
+  if (diagnostics.some((diagnostic) => diagnostic.severity === 'error')) {
+    return diagnostics;
+  }
+
+  const root = stylesheet.documentElement;
+  if (!root) {
+    return [
+      ...diagnostics,
+      {
+        severity: 'error',
+        source: 'XSLT stylesheet',
+        message: 'The stylesheet has no document element.',
+      },
+    ];
+  }
+
+  if (
+    root.namespaceURI !== XSLT_NAMESPACE ||
+    !['stylesheet', 'transform'].includes(root.localName)
+  ) {
+    diagnostics.push({
+      severity: 'error',
+      source: 'XSLT stylesheet',
+      message:
+        'The root element should be xsl:stylesheet or xsl:transform in the XSLT namespace.',
+    });
+  }
+
+  const version = root.getAttribute('version');
+  if (!version) {
+    diagnostics.push({
+      severity: 'warning',
+      source: 'XSLT stylesheet',
+      message: 'The stylesheet root should declare a version attribute.',
+    });
+  }
+
+  if (engine === 'native-xsltprocessor' && version && version !== '1.0') {
+    diagnostics.push({
+      severity: 'warning',
+      source: 'XSLT stylesheet',
+      message:
+        'The native browser engine usually supports XSLT 1.0 only. XSLT 2.0/3.0 features may fail.',
+    });
+  }
+
+  return diagnostics;
+}