worked out some bugs in extension loading

doc/configuration.toml

@@ -65,8 +65,8 @@ sitetitle = ""
 
 [extensions]
 # Full classnames of the extensions to be loaded.
-load = ["dragonglass.extensions.breadcrumbs.BreadcrumbExtension"]
+load = ["dragonglass.extensions.breadcrumbs.Breadcrumbs"]
 
-[extensions.BreadcrumbExtension]
-# Configuration data for BreadcrumbExtension.
+[extensions.Breadcrumbs]
+# Configuration data for Breadcrumbs.
 var = "value"

src/dragonglass/config.py

@@ -49,8 +49,6 @@ CALLOUT_ICONS = {
     'todo': 'circle-check',
     'warning': 'triangle-alert'
 }
-"""Cache of extension module names."""
-EXTENSION_PKGS = {}
 
 
 def load_extension_class(name: str, sect: dict[str, Any]) -> Extension:
@@ -65,15 +63,14 @@ def load_extension_class(name: str, sect: dict[str, Any]) -> Extension:
         Extension: Instance of the extension class.
     """
     components = name.split('.')
-    classname = components.pop()
-    modname = ".".join(components)
-    if modname not in EXTENSION_PKGS:
-        EXTENSION_PKGS[modname] = __import__(modname)
-    extclass = getattr(EXTENSION_PKGS[modname], classname)
-    cfg_sect = sect.get(classname, {})
-    rc = extclass(cfg_sect)
+    modname = ".".join(components[:-1])
+    b = __import__(modname)
+    for c in components[1:]:
+        b = getattr(b, c)
+    cfg_sect = sect.get(components[-1], {})
+    rc = b(cfg_sect)
     if not isinstance(rc, Extension):
-        raise RuntimeError(f"class {name} is not a valid Dragonglass extension")
+        raise RuntimeError(f"class {name} is not a valid dragonglass extension")
     return rc
 
 

src/dragonglass/extensions/breadcrumbs.py

@@ -9,11 +9,17 @@ from ..tree import SourceNode, SourceIndex
 """The extension for generating breadcrumb informatioon."""
 
 
-class BreadcrumbExtension(Extension):
+class Breadcrumbs(Extension):
     LINK = re.compile(r'^\[\[(.+)(?:\|.+)?\]\]')
 
     def __init__(self, config: dict[str, Any]):
-        super(BreadcrumbExtension, self).__init__(config)
+        """
+        Initialize the Breadcrumbs extension.
+
+        Args:
+            config (dict[str, Any]): Configuration variables for this extension.
+        """
+        super(Breadcrumbs, self).__init__(config)
         self._root_nodes: list[SourceNode] = []
         self._raw_targets: list[tuple[SourceNode, str]] = []
         self._parents: dict[SourceNode, SourceNode] = {}