Replace the custom template tag with a decorator

The decorator now adds a method to the dataclass that handles the rendering logic. This
is only done when no rendering method exists yet.

This allows for completely custom rendering logic to be added.

I find, this also reduces the logic and the complexity of the "templex" pattern, because
we can work with fewer moving pieces.

lpld/settings.py

@@ -134,7 +134,6 @@
             "libraries": {
                 "lpldutils": "lpld.templatetags.lpldutils",
                 "navigation": "lpld.templatetags.navigation",
-                "templex": "lpld.templatetags.templex",
             },
         },
     },

lpld/templates/molecules/teaser/teaser.py

@@ -1,14 +1,51 @@
 import dataclasses
-from typing import Optional
+import functools
+from typing import Optional, Type
 
+from django import template as django_template
 from wagtail.images import models as images_models
 from wagtailmedia import models as media_models
 
 
-@dataclasses.dataclass
-class Teaser:
-    template = "molecules/teaser/teaser.html"
+def templex(template: str):
+    """
+    Turn class into a templex object.
+
+    The class is turned into a data class and a `render` method is added (if it
+    doesn't already exist). Pass the template to render the templex with as a parameter
+    to the decorator.
+
+    """
+
+    def wrapper(klass):
+        """
+        The actual decorator.
+
+        The template that this decorator adds to the class is injected from the
+        surrounding scope.
+
+        """
+        def render_templex(self):
+            templex_template = django_template.loader.get_template(self.template)
+            data_dict = dataclasses.asdict(self)
+            return templex_template.render(data_dict)
 
+        @functools.wraps(klass)
+        def wrap(klass: Type):
+            klass = dataclasses.dataclass(klass)
+            if not hasattr(klass, "template"):
+                klass.template = template
+            if not hasattr(klass, "render"):
+                klass.render = render_templex
+            return klass
+
+        return wrap(klass)
+
+    return wrapper
+
+
+@templex(template="molecules/teaser/teaser.html")
+class Teaser:
     heading: str
     introduction: str
     href: str

lpld/templates/pages/home/home.html

@@ -1,6 +1,5 @@
 {% extends "base-page.html" %}
-{% load templex %}
-{% load slippers static templex wagtailcore_tags wagtailimages_tags %}
+{% load slippers static wagtailcore_tags wagtailimages_tags %}
 
 {% block content %}
     <section class="mt-44">
@@ -47,7 +46,7 @@
         <ul class="mt-16 grid grid-cols-1 md:grid-cols-2 md:gap-x-12 gap-y-12 sm:gap-y-16 ">
             {% for teaser in page.project_teasers  %}
                 <li>
-                    {% include_templex teaser %}
+                    {{ teaser.render }}
                 </li>
             {% endfor %}
         </ul>