feat: TagFormatter - Allow users to customize component template tags (#572)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

src/django_components/expression.py

@@ -4,6 +4,14 @@ from django.template import Context
 from django.template.base import FilterExpression, Parser
 
 
+class AggregateFilterExpression:
+    def __init__(self, dict: Dict[str, FilterExpression]) -> None:
+        self.dict = dict
+
+
+Expression = Union[FilterExpression, AggregateFilterExpression]
+
+
 def resolve_expression_as_identifier(
     context: Context,
     fexp: FilterExpression,
@@ -20,19 +28,22 @@ def resolve_expression_as_identifier(
     return resolved
 
 
-def safe_resolve_list(args: List[FilterExpression], context: Context) -> List:
+def safe_resolve_list(args: List[Expression], context: Context) -> List:
     return [safe_resolve(arg, context) for arg in args]
 
 
 def safe_resolve_dict(
-    kwargs: Union[Mapping[str, FilterExpression], Dict[str, FilterExpression]],
+    kwargs: Union[Mapping[str, Expression], Dict[str, Expression]],
     context: Context,
 ) -> Dict:
     return {key: safe_resolve(kwarg, context) for key, kwarg in kwargs.items()}
 
 
-def safe_resolve(context_item: FilterExpression, context: Context) -> Any:
+def safe_resolve(context_item: Expression, context: Context) -> Any:
     """Resolve FilterExpressions and Variables in context if possible. Return other items unchanged."""
+    if isinstance(context_item, AggregateFilterExpression):
+        return safe_resolve_dict(context_item.dict, context)
+
     return context_item.resolve(context) if hasattr(context_item, "resolve") else context_item
 
 
@@ -42,5 +53,11 @@ def resolve_string(
     context: Optional[Mapping[str, Any]] = None,
 ) -> str:
     parser = parser or Parser([])
-    context = context or {}
+    context = Context(context or {})
     return parser.compile_filter(s).resolve(context)
+
+
+def is_aggregate_key(key: str) -> bool:
+    # NOTE: If we get a key that starts with `:`, like `:class`, we do not split it.
+    # This syntax is used by Vue and AlpineJS.
+    return ":" in key and not key.startswith(":")