Implement labeling function library

src/labeling_function_lib/labeling_function_lib.py

@@ -0,0 +1,68 @@
+from typing import Callable, List, Any
+
+class LabelingFunctionLib:
+    def __init__(self) -> None:
+        """Initialize an empty labeling function library."""
+        self.label_functions = {}
+
+    def register(self, name: str, func: Callable[[Any], Any]) -> None:
+        """
+        Register a labeling function with a given name.
+
+        Args:
+            name (str): The name of the labeling function.
+            func (Callable[[Any], Any]): The labeling function to be registered.
+
+        Raises:
+            TypeError: If the provided argument is not a function.
+            ValueError: If a label function with the same name has already been registered.
+        """
+        if not callable(func):
+            raise TypeError("The provided argument is not a function.")
+        elif name in self.label_functions:
+            raise ValueError(f"A label function named '{name}' has already been registered.")
+        else:
+            self.label_functions[name] = func
+
+    def get(self, name: str) -> Callable[[Any], Any]:
+        """
+        Retrieve a label function by name.
+
+        Args:
+            name (str): The name of the label function to retrieve.
+
+        Returns:
+            Callable[[Any], Any]: The label function.
+
+        Raises:
+            LookupError: If the label function with the given name does not exist.
+        """
+        try:
+            return self.label_functions[name]
+        except KeyError as e:
+            raise LookupError(f"No such label function: {e}") from e
+
+    def get_all(self) -> List[Callable[[Any], Any]]:
+        """
+        Returns a list of all labeling functions.
+
+        Returns:
+            List[Callable[[Any], Any]]: A list of all labeling functions.
+        """
+        return list(self.label_functions.values())
+
+    def unregister(self, name: str) -> None:
+        """
+        Unregisters a labeling function by removing it from the label_functions dictionary.
+
+        Args:
+            name (str): The name of the labeling function to unregister.
+
+        Returns:
+            None
+        """
+        del self.label_functions[name]
+
+    def clear(self) -> None:
+        """Remove all label functions from the library."""
+        self.label_functions = {}

tests/labeling_function_lib/test_labeling_function_lib.py

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+import pytest
+from labeling_function_lib.labeling_function_lib import LabelingFunctionLib
+
+def dummy_label_func(item):
+    return "dummy_label"
+
+def test_register_and_get():
+    lib = LabelingFunctionLib()
+    lib.register("dummy", dummy_label_func)
+    assert lib.get("dummy") == dummy_label_func, "Failed to register or get the label function"
+
+def test_register_existing_name():
+    lib = LabelingFunctionLib()
+    lib.register("dummy", dummy_label_func)
+    with pytest.raises(ValueError):
+        lib.register("dummy", dummy_label_func)
+
+def test_register_not_callable():
+    lib = LabelingFunctionLib()
+    with pytest.raises(TypeError):
+        lib.register("not_callable", "this is not a function")
+
+def test_get_non_existent():
+    lib = LabelingFunctionLib()
+    with pytest.raises(LookupError):
+        lib.get("non_existent")
+
+def test_get_all():
+    lib = LabelingFunctionLib()
+    lib.register("dummy1", dummy_label_func)
+    lib.register("dummy2", dummy_label_func)
+    assert len(lib.get_all()) == 2, "Failed to retrieve all label functions"
+
+def test_unregister():
+    lib = LabelingFunctionLib()
+    lib.register("dummy", dummy_label_func)
+    lib.unregister("dummy")
+    with pytest.raises(LookupError):
+        lib.get("dummy")
+
+def test_clear():
+    lib = LabelingFunctionLib()
+    lib.register("dummy1", dummy_label_func)
+    lib.register("dummy2", dummy_label_func)
+    lib.clear()
+    assert len(lib.get_all()) == 0, "Failed to clear all label functions"