[robotpy] Mirror robotpy's commands-v2 (#8369)

Project import generated by Copybara.

GitOrigin-RevId: 715c8e8372d936f447f2937aab6b1a22dc619126

commandsv2/src/main/python/commands2/functionalcommand.py

@@ -0,0 +1,59 @@
+# validated: 2024-01-19 DS 6e58db398d63 FunctionalCommand.java
+from __future__ import annotations
+
+from typing import Any, Callable
+
+from .command import Command
+from .subsystem import Subsystem
+
+
+class FunctionalCommand(Command):
+    """
+    A command that allows the user to pass in functions for each of the basic command methods through
+    the constructor. Useful for inline definitions of complex commands - note, however, that if a
+    command is beyond a certain complexity it is usually better practice to write a proper class for
+    it than to inline it.
+    """
+
+    def __init__(
+        self,
+        onInit: Callable[[], Any],
+        onExecute: Callable[[], Any],
+        onEnd: Callable[[bool], Any],
+        isFinished: Callable[[], bool],
+        *requirements: Subsystem,
+    ):
+        """
+        Creates a new FunctionalCommand.
+
+        :param onInit: the function to run on command initialization
+        :param onExecute: the function to run on command execution
+        :param onEnd: the function to run on command end
+        :param isFinished: the function that determines whether the command has finished
+        :param requirements: the subsystems required by this command
+        """
+        super().__init__()
+
+        assert callable(onInit)
+        assert callable(onExecute)
+        assert callable(onEnd)
+        assert callable(isFinished)
+
+        self._onInit = onInit
+        self._onExecute = onExecute
+        self._onEnd = onEnd
+        self._isFinished = isFinished
+
+        self.addRequirements(*requirements)
+
+    def initialize(self):
+        self._onInit()
+
+    def execute(self):
+        self._onExecute()
+
+    def end(self, interrupted: bool):
+        self._onEnd(interrupted)
+
+    def isFinished(self) -> bool:
+        return self._isFinished()