feat(blog): complete XSLT/XPath reference — 229 function pages

Full coverage of XSLT 1.0, 2.0 and 3.0 elements and XPath functions:
- 59 XSLT elements (xsl:stylesheet → xsl:use-accumulators)
- 170 XPath functions (1.0 node/string/numeric/boolean, 2.0 sequence/
  date/QName/string, 3.0 HOF/map/array/JSON/streaming)
Each page: description, parameters table, return value, 2 runnable
Saxon examples with input XML + stylesheet + output, notes, cross-links.
xsltCompletions.js: all 229 entries now have blogSlug for hover links.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

site/content/xslt/functions/xsl-include.md

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+---
+title: "xsl:include"
+description: "Merges another stylesheet's top-level declarations into the current stylesheet at the same import precedence."
+date: 2026-04-18T00:00:00Z
+version: "1.0"
+versionLabel: "XSLT 1.0"
+category: "element"
+syntax: '<xsl:include href="uri"/>'
+tags: ["xslt", "reference", "xslt1"]
+---
+
+## Description
+
+`xsl:include` incorporates the top-level declarations of another stylesheet into the including stylesheet as if they had been written there directly. Unlike `xsl:import`, the included declarations have the **same import precedence** as the declarations in the including stylesheet. This means there is no override relationship — conflicts between included and including templates follow the same conflict-resolution rules as ordinary duplicates (a processor may signal an error or choose the last declaration).
+
+`xsl:include` is the right choice when you want to split a large stylesheet into modular files that all operate at the same level. Common patterns include separating formatting templates, utility named templates, and domain-specific rules into distinct files that are included by a master stylesheet.
+
+`xsl:include` must appear as a top-level child of `xsl:stylesheet`, and it must appear after all `xsl:import` elements but before any templates, variable declarations, or other top-level declarations.
+
+## Attributes
+
+| Attribute | Type | Required | Description |
+|-----------|------|----------|-------------|
+| `href` | URI reference | Yes | Location of the stylesheet to include. Resolved relative to the including stylesheet's base URI. |
+
+## Examples
+
+### Modular stylesheet organisation
+
+**utilities.xsl** (the included file):
+```xml
+<?xml version="1.0" encoding="UTF-8"?>
+<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
+
+  <xsl:template name="upper-first">
+    <xsl:param name="text"/>
+    <xsl:value-of select="concat(
+      translate(substring($text,1,1),
+        'abcdefghijklmnopqrstuvwxyz',
+        'ABCDEFGHIJKLMNOPQRSTUVWXYZ'),
+      substring($text,2))"/>
+  </xsl:template>
+
+</xsl:stylesheet>
+```
+
+**main.xsl** (the including stylesheet):
+```xml
+<?xml version="1.0" encoding="UTF-8"?>
+<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
+  <xsl:output method="xml" indent="yes"/>
+
+  <xsl:include href="utilities.xsl"/>
+
+  <xsl:template match="/words">
+    <result>
+      <xsl:for-each select="word">
+        <item>
+          <xsl:call-template name="upper-first">
+            <xsl:with-param name="text" select="."/>
+          </xsl:call-template>
+        </item>
+      </xsl:for-each>
+    </result>
+  </xsl:template>
+</xsl:stylesheet>
+```
+
+**Input XML:**
+```xml
+<?xml version="1.0" encoding="UTF-8"?>
+<words>
+  <word>hello</word>
+  <word>world</word>
+</words>
+```
+
+**Output:**
+```xml
+<result>
+  <item>Hello</item>
+  <item>World</item>
+</result>
+```
+
+### Including a shared output configuration
+
+**output-settings.xsl**:
+```xml
+<?xml version="1.0" encoding="UTF-8"?>
+<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
+  <xsl:output method="html" indent="yes" encoding="UTF-8"
+    doctype-public="-//W3C//DTD HTML 4.01//EN"/>
+</xsl:stylesheet>
+```
+
+**page.xsl**:
+```xml
+<?xml version="1.0" encoding="UTF-8"?>
+<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
+
+  <xsl:include href="output-settings.xsl"/>
+
+  <xsl:template match="/page">
+    <html><body><p><xsl:value-of select="."/></p></body></html>
+  </xsl:template>
+</xsl:stylesheet>
+```
+
+## Notes
+
+- Circular inclusion (A includes B which includes A) is an error. Processors must detect and reject cycles.
+- Because included declarations have the same precedence as the including stylesheet's own declarations, duplicate template rules may cause conflict. Use `xsl:import` if you want a clear override relationship.
+- `xsl:include` is resolved at stylesheet load time, not at transformation time; the referenced URI must be accessible when the processor compiles the stylesheet.
+- The included stylesheet's own `xsl:output` declarations merge with those of the including stylesheet. When there are conflicts, the `xsl:output` attribute from the stylesheet with higher import precedence wins.
+
+## See also
+
+- [xsl:import](../xsl-import)
+- [xsl:stylesheet](../xsl-stylesheet)