Get includes working relatively.

docs/read-page/nodes/Heading.js

@@ -1,6 +1,6 @@
 import slugify from '@sindresorhus/slugify'
 
-export default async function (doc, rootLevel, pageData) {
+export default async function (doc, rootLevel, context) {
   const { next, line, match, tail, level, head } = doc
 
   const headingLevel = +tail().split(' ')[0]
@@ -22,7 +22,7 @@ export default async function (doc, rootLevel, pageData) {
     if (match('href')) node.href = tail()
   }
 
-  pageData.headings.push(node)
+  context.page.headings.push(node)
 
   return node
 }

docs/read-page/nodes/Include.js

@@ -2,10 +2,12 @@ import { useDocument } from '@terrace-lang/js/document'
 import { createFileReader } from '@terrace-lang/js/readers/node-readline'
 import fs from 'fs/promises'
 import path from 'path'
+import process from 'node:process'
 import knownNodes from './index.js'
 
-export default async function (originalDoc, rootLevel, ...args) {
-  const includedDoc = useDocument(createFileReader(originalDoc.tail()))
+export default async function (originalDoc, rootLevel, context) {
+  const includePath = originalDoc.tail()
+  const includedDoc = useDocument(createFileReader(includePath))
   const { next, head, tail, level } = includedDoc
 
   const node = {
@@ -14,13 +16,21 @@ export default async function (originalDoc, rootLevel, ...args) {
     children: []
   }
 
+
+  const root = path.dirname(context.filePath)
+  const originalFilepath = context.filePath
+  context.filePath = includePath
+
+  process.chdir(path.dirname(originalFilepath))
   while (await next()) {
     if (!head()) continue
     const block = head()
 
     if (!knownNodes[block]) continue
-    node.children.push(await knownNodes[block](includedDoc, level(), ...args))
+    node.children.push(await knownNodes[block](includedDoc, level(), context))
   }
 
+  process.chdir(path.dirname(originalFilepath))
+
   return node
 }