make var system expandable (#4175)

* make var system expandable

* use old syntax

* remove newer features

* that's a weird error

* remove unnecessary error message

* remove hacky getattr as it's no longer necessary

* improve color handling

* get it right pyright

* dang it darglint

* fix prototype to string

* don't try twice

* adjust test case

* add test for var alpha

* change place of type ignore

* fix json

* add name to custom var operation

* don't delete that you silly

* change logic

* remove extra word

reflex/event.py

@@ -12,7 +12,6 @@
 from typing import (
     Any,
     Callable,
-    ClassVar,
     Dict,
     Generic,
     List,
@@ -33,9 +32,7 @@
 from reflex.utils.types import ArgsSpec, GenericType
 from reflex.vars import VarData
 from reflex.vars.base import (
-    LiteralNoneVar,
     LiteralVar,
-    ToOperation,
     Var,
 )
 from reflex.vars.function import (
@@ -1254,7 +1251,7 @@ def get_fn_signature(fn: Callable) -> inspect.Signature:
     return signature.replace(parameters=(new_param, *signature.parameters.values()))
 
 
-class EventVar(ObjectVar):
+class EventVar(ObjectVar, python_types=EventSpec):
     """Base class for event vars."""
 
 
@@ -1315,7 +1312,7 @@ def create(
         )
 
 
-class EventChainVar(FunctionVar):
+class EventChainVar(FunctionVar, python_types=EventChain):
     """Base class for event chain vars."""
 
 
@@ -1384,32 +1381,6 @@ def create(
         )
 
 
-@dataclasses.dataclass(
-    eq=False,
-    frozen=True,
-    **{"slots": True} if sys.version_info >= (3, 10) else {},
-)
-class ToEventVarOperation(ToOperation, EventVar):
-    """Result of a cast to an event var."""
-
-    _original: Var = dataclasses.field(default_factory=lambda: LiteralNoneVar.create())
-
-    _default_var_type: ClassVar[Type] = EventSpec
-
-
-@dataclasses.dataclass(
-    eq=False,
-    frozen=True,
-    **{"slots": True} if sys.version_info >= (3, 10) else {},
-)
-class ToEventChainVarOperation(ToOperation, EventChainVar):
-    """Result of a cast to an event chain var."""
-
-    _original: Var = dataclasses.field(default_factory=lambda: LiteralNoneVar.create())
-
-    _default_var_type: ClassVar[Type] = EventChain
-
-
 G = ParamSpec("G")
 
 IndividualEventType = Union[EventSpec, EventHandler, Callable[G, Any], Var[Any]]
@@ -1537,8 +1508,6 @@ class EventNamespace(types.SimpleNamespace):
     LiteralEventVar = LiteralEventVar
     EventChainVar = EventChainVar
     LiteralEventChainVar = LiteralEventChainVar
-    ToEventVarOperation = ToEventVarOperation
-    ToEventChainVarOperation = ToEventChainVarOperation
     EventType = EventType
 
     __call__ = staticmethod(event_handler)