1 files changed, 126 insertions, 0 deletions
diff --git a/sphinx/domains/index.py b/sphinx/domains/index.py
new file mode 100644
index 0000000..c084516
--- /dev/null
+++ b/sphinx/domains/index.py
@@ -0,0 +1,126 @@
+"""The index domain."""
+
+from __future__ import annotations
+
+from typing import TYPE_CHECKING, Any
+
+from docutils import nodes
+from docutils.parsers.rst import directives
+
+from sphinx import addnodes
+from sphinx.domains import Domain
+from sphinx.util import logging
+from sphinx.util.docutils import ReferenceRole, SphinxDirective
+from sphinx.util.index_entries import split_index_msg
+from sphinx.util.nodes import process_index_entry
+
+if TYPE_CHECKING:
+    from collections.abc import Iterable
+
+    from docutils.nodes import Node, system_message
+
+    from sphinx.application import Sphinx
+    from sphinx.environment import BuildEnvironment
+    from sphinx.util.typing import OptionSpec
+
+
+logger = logging.getLogger(__name__)
+
+
+class IndexDomain(Domain):
+    """Mathematics domain."""
+    name = 'index'
+    label = 'index'
+
+    @property
+    def entries(self) -> dict[str, list[tuple[str, str, str, str, str | None]]]:
+        return self.data.setdefault('entries', {})
+
+    def clear_doc(self, docname: str) -> None:
+        self.entries.pop(docname, None)
+
+    def merge_domaindata(self, docnames: Iterable[str], otherdata: dict[str, Any]) -> None:
+        for docname in docnames:
+            self.entries[docname] = otherdata['entries'][docname]
+
+    def process_doc(self, env: BuildEnvironment, docname: str, document: Node) -> None:
+        """Process a document after it is read by the environment."""
+        entries = self.entries.setdefault(env.docname, [])
+        for node in list(document.findall(addnodes.index)):
+            try:
+                for (entry_type, value, _target_id, _main, _category_key) in node['entries']:
+                    split_index_msg(entry_type, value)
+            except ValueError as exc:
+                logger.warning(str(exc), location=node)
+                node.parent.remove(node)
+            else:
+                for entry in node['entries']:
+                    entries.append(entry)
+
+
+class IndexDirective(SphinxDirective):
+    """
+    Directive to add entries to the index.
+    """
+    has_content = False
+    required_arguments = 1
+    optional_arguments = 0
+    final_argument_whitespace = True
+    option_spec: OptionSpec = {
+        'name': directives.unchanged,
+    }
+
+    def run(self) -> list[Node]:
+        arguments = self.arguments[0].split('\n')
+
+        if 'name' in self.options:
+            targetname = self.options['name']
+            targetnode = nodes.target('', '', names=[targetname])
+        else:
+            targetid = 'index-%s' % self.env.new_serialno('index')
+            targetnode = nodes.target('', '', ids=[targetid])
+
+        self.state.document.note_explicit_target(targetnode)
+        indexnode = addnodes.index()
+        indexnode['entries'] = []
+        indexnode['inline'] = False
+        self.set_source_info(indexnode)
+        for entry in arguments:
+            indexnode['entries'].extend(process_index_entry(entry, targetnode['ids'][0]))
+        return [indexnode, targetnode]
+
+
+class IndexRole(ReferenceRole):
+    def run(self) -> tuple[list[Node], list[system_message]]:
+        target_id = 'index-%s' % self.env.new_serialno('index')
+        if self.has_explicit_title:
+            # if an explicit target is given, process it as a full entry
+            title = self.title
+            entries = process_index_entry(self.target, target_id)
+        else:
+            # otherwise we just create a single entry
+            if self.target.startswith('!'):
+                title = self.title[1:]
+                entries = [('single', self.target[1:], target_id, 'main', None)]
+            else:
+                title = self.title
+                entries = [('single', self.target, target_id, '', None)]
+
+        index = addnodes.index(entries=entries)
+        target = nodes.target('', '', ids=[target_id])
+        text = nodes.Text(title)
+        self.set_source_info(index)
+        return [index, target, text], []
+
+
+def setup(app: Sphinx) -> dict[str, Any]:
+    app.add_domain(IndexDomain)
+    app.add_directive('index', IndexDirective)
+    app.add_role('index', IndexRole())
+
+    return {
+        'version': 'builtin',
+        'env_version': 1,
+        'parallel_read_safe': True,
+        'parallel_write_safe': True,
+    }