feat: more safety in BaseBindable, AsyncBindable, Bindable

src/snakia/core/rx/async_bindable.py

@@ -1,4 +1,12 @@
-from typing import Any, Awaitable, Callable, Generic, Literal, TypeVar, overload
+from typing import (
+    Any,
+    Awaitable,
+    Callable,
+    Generic,
+    Literal,
+    TypeVar,
+    overload,
+)
 
 from .base_bindable import BaseBindable, BindableSubscriber, ValueChanged
 
@@ -23,6 +31,9 @@ class AsyncBindable(BaseBindable[T], Generic[T]):
 
     async def set(self, value: T) -> None:
         """Set the value."""
+        if not (self.has_default_value or self.has_value):
+            self.set_silent(value)
+            return
         e = ValueChanged(self.value, value)
         self.set_silent(value)
         for subscriber in self.__subscribers:
@@ -55,19 +66,25 @@ class AsyncBindable(BaseBindable[T], Generic[T]):
         if run_now:
 
             async def _run() -> None:
-                await subscriber(ValueChanged(self.__default_value, self.value))
+                await subscriber(
+                    ValueChanged(self.__default_value, self.value)
+                )
 
             return _run()
         return None
 
-    def unsubscribe(self, subscriber: BindableSubscriber[T, Awaitable[Any]]) -> None:
+    def unsubscribe(
+        self, subscriber: BindableSubscriber[T, Awaitable[Any]]
+    ) -> None:
         """Unsubscribe from an value."""
         self.__subscribers.remove(subscriber)
 
     @overload
     def on(
         self, run_now: Literal[True]
-    ) -> Callable[[BindableSubscriber[T, Awaitable[Any]]], Awaitable[None]]: ...
+    ) -> Callable[
+        [BindableSubscriber[T, Awaitable[Any]]], Awaitable[None]
+    ]: ...
 
     @overload
     def on(
@@ -87,7 +104,9 @@ class AsyncBindable(BaseBindable[T], Generic[T]):
             if run_now:
 
                 async def _run() -> None:
-                    await subscriber(ValueChanged(self.__default_value, self.value))
+                    await subscriber(
+                        ValueChanged(self.__default_value, self.value)
+                    )
 
                 return _run()
             return None

src/snakia/core/rx/base_bindable.py

@@ -27,7 +27,26 @@ class BaseBindable(Generic[T]):
 
     @property
     def value(self) -> T:
-        return self.__value
+        if self.has_value:
+            return self.__value
+        else:
+            return self.default_value
+
+    @property
+    def has_value(self) -> bool:
+        try:
+            _ = self.__value
+            return True
+        except AttributeError:
+            return False
+
+    @property
+    def has_default_value(self) -> bool:
+        try:
+            _ = self.__default_value
+            return True
+        except AttributeError:
+            return False
 
     def set_silent(self, value: T) -> None:
         self.__value = value

src/snakia/core/rx/bindable.py

@@ -21,6 +21,9 @@ class Bindable(BaseBindable[T], Generic[T]):
 
     def set(self, value: T) -> None:
         """Set the value."""
+        if not (self.has_default_value or self.has_value):
+            self.set_silent(value)
+            return
         e = ValueChanged(self.value, value)
         self.set_silent(value)
         for subscriber in self.__subscribers: