Allow passing a custom template registry

2 files changed, 32 insertions, 5 deletions

diff --git a/wikimini/__init__.py b/wikimini/__init__.py
index 876c7a7..00179cc 100644
--- a/wikimini/__init__.py
+++ b/wikimini/__init__.py
@@ -25,13 +25,26 @@ class Wikimini:
     """The main object for Wikipedia/Gemini access and conversion.
 
     Attributes:
-        api_url (str): The base URL of the API.
-        table_format (str): The name of the table style, see
-            :const:`TABLE_FORMAT`.
+        api_url: The base URL of the API.
+        table_format: The name of the table style, see :const:`TABLE_FORMAT`.
+        template_registry: The template registry to use. If :any:`None`, the
+            global registry will be used.
     """
-    def __init__(self, api_url=API_URL, table_format=TABLE_FORMAT):
+    api_url: str
+    table_format: str
+    template_registry: "templates.Registry"
+
+    def __init__(
+            self,
+            api_url=API_URL,
+            table_format=TABLE_FORMAT,
+            template_registry=None,
+    ):
         self.api_url = api_url
         self.table_format = table_format
+        if template_registry is None:
+            template_registry = templates.registry
+        self.template_registry = template_registry
 
     def page_url(self, title: str) -> str:
         """Returns the link for page with the given title.
@@ -180,7 +193,7 @@ class Wikimini:
             # however, some of them are useful and provide some output that we
             # should mimic (for example, the convert template).
             name = str(obj.name)
-            template = templates.registry.get(name)
+            template = self.template_registry.get(name)
             if template is None:
                 return default(obj)
             else:
diff --git a/wikimini/templates/__init__.py b/wikimini/templates/__init__.py
index 360b3fa..ebe3bbc 100644
--- a/wikimini/templates/__init__.py
+++ b/wikimini/templates/__init__.py
@@ -6,6 +6,7 @@ A template is a function that takes the :class:`~wikimini.Wikimini` instance
 and the :class:`~mwparserfromhell.nodes.template.Template` node to convert, and
 returns a string with the template output (see :const:`Template`).
 """
+import copy
 from typing import Callable, Optional
 
 import mwparserfromhell as mwp
@@ -49,6 +50,19 @@ class Registry:
         """
         self.templates[name] = template
 
+    def copy(self) -> "Registry":
+        """Returns a copy of the registry.
+
+        This is useful if you want to use the global registry as a starting
+        point to add your own templates, without modifying the global instance.
+
+        Returns:
+            A copy of the registry.
+        """
+        copied = Registry()
+        copied.templates = copy.copy(self.templates)
+        return copied
+
 
 #: The global template registry.
 registry = Registry()