refactor(pyargus): define a runtime checkable Signal protocol

pyargus/argus/_argus.pyi

@@ -1,4 +1,4 @@
-from typing import ClassVar, Generic, Protocol, TypeVar, final
+from typing import ClassVar, Protocol, final
 
 from typing_extensions import Self
 
@@ -134,9 +134,7 @@ class dtype:  # noqa: N801
     def __eq__(self, other: object) -> bool: ...
     def __int__(self) -> int: ...
 
-_SignalKind = TypeVar("_SignalKind", bool, int, float, covariant=True)
-
-class Signal(Generic[_SignalKind], Protocol):
+class Signal:
     def is_empty(self) -> bool: ...
     @property
     def start_time(self) -> float | None: ...
@@ -146,16 +144,16 @@ class Signal(Generic[_SignalKind], Protocol):
     def kind(self) -> dtype: ...
 
 @final
-class BoolSignal(Signal[bool]):
+class BoolSignal(Signal):
     @classmethod
     def constant(cls, value: bool) -> Self: ...
     @classmethod
     def from_samples(cls, samples: list[tuple[float, bool]]) -> Self: ...
     def push(self, time: float, value: bool) -> None: ...
-    def at(self, time: float) -> _SignalKind | None: ...
+    def at(self, time: float) -> bool | None: ...
 
 @final
-class IntSignal(Signal[int]):
+class IntSignal(Signal):
     @classmethod
     def constant(cls, value: int) -> Self: ...
     @classmethod
@@ -164,7 +162,7 @@ class IntSignal(Signal[int]):
     def at(self, time: float) -> int | None: ...
 
 @final
-class UnsignedIntSignal(Signal[int]):
+class UnsignedIntSignal(Signal):
     @classmethod
     def constant(cls, value: int) -> Self: ...
     @classmethod
@@ -173,7 +171,7 @@ class UnsignedIntSignal(Signal[int]):
     def at(self, time: float) -> int | None: ...
 
 @final
-class FloatSignal(Signal[float]):
+class FloatSignal(Signal):
     @classmethod
     def constant(cls, value: float) -> Self: ...
     @classmethod

pyargus/argus/signals.py

@@ -1,4 +1,43 @@
-from argus._argus import BoolSignal, FloatSignal, IntSignal, Signal, UnsignedIntSignal
+from typing import List, Optional, Protocol, Tuple, TypeVar, runtime_checkable
+
+from typing_extensions import Self
+
+from argus._argus import BoolSignal, FloatSignal, IntSignal, UnsignedIntSignal, dtype
+
+T = TypeVar("T", bool, int, float)
+
+
+@runtime_checkable
+class Signal(Protocol[T]):
+    def is_empty(self) -> bool:
+        ...
+
+    @property
+    def start_time(self) -> Optional[float]:
+        ...
+
+    @property
+    def end_time(self) -> Optional[float]:
+        ...
+
+    @property
+    def kind(self) -> dtype:
+        ...
+
+    @classmethod
+    def constant(cls, value: T) -> Self:
+        ...
+
+    @classmethod
+    def from_samples(cls, samples: List[Tuple[float, T]]) -> Self:
+        ...
+
+    def push(self, time: float, value: T) -> None:
+        ...
+
+    def at(self, time: float) -> Optional[T]:
+        ...
+
 
 __all__ = [
     "Signal",