Implemented support for output type casting in flexible_listlike_input

polymerist/genutils/decorators/functional.py

@@ -2,15 +2,16 @@
 
 from typing import Callable, Iterable, Optional, Type, Union
 
-import inspect
-from functools import wraps
+from inspect import signature, Parameter
+from functools import wraps, partial
 
 from copy import deepcopy
 from pathlib import Path
 
 from .meta import extend_to_methods
 from . import signatures
 from ..typetools.parametric import T, Args, KWArgs
+from ..typetools.categorical import ListLike
 from ..fileutils.pathutils import aspath, asstrpath
 
 
@@ -19,7 +20,7 @@ def optional_in_place(funct : Callable[[object, Args, KWArgs], None]) -> Callabl
     '''Decorator function for allowing in-place (writeable) functions which modify object attributes
     to be not performed in-place (i.e. read-only), specified by a boolean flag'''
     # TODO : add assertion that the wrapped function has at least one arg AND that the first arg is of the desired (limited) type
-    old_sig = inspect.signature(funct)
+    old_sig = signature(funct)
 
     @wraps(funct) # for preserving docstring and type annotations / signatures
     def in_place_wrapper(obj : object, *args : Args, in_place : bool=False, **kwargs : KWArgs) -> Optional[object]: # read-only by default
@@ -34,11 +35,11 @@ def in_place_wrapper(obj : object, *args : Args, in_place : bool=False, **kwargs
     # ADD IN-PLACE PARAMETER TO FUNCTION SIGNATURE
     new_sig = signatures.insert_parameter_at_index(
         old_sig,
-        new_param=inspect.Parameter(
+        new_param=Parameter(
             name='in_place',
             default=False,
             annotation=bool,
-            kind=inspect.Parameter.KEYWORD_ONLY
+            kind=Parameter.KEYWORD_ONLY
         ),
         index=signatures.get_index_after_positionals(old_sig)
     )
@@ -49,29 +50,36 @@ def in_place_wrapper(obj : object, *args : Args, in_place : bool=False, **kwargs
 
     return in_place_wrapper
 
-@extend_to_methods
-def flexible_tuple_input(func : Callable[[tuple], T], valid_types : Union[Type, tuple[Type]]=object) -> Callable[[Iterable], T]:
-    '''Wrapper which allows a function which expects a single tuple to accept Iterable or even star-unpacked arguments'''
-    @wraps(func)
+# TODO : implement support for extend_to_methods (current mechanism is broken by additional deocrator parameters)
+def flexible_listlike_input(funct : Callable[[ListLike], T]=None, CastType : Type[ListLike]=list, valid_member_types : Union[Type, tuple[Type]]=object) -> Callable[[Iterable], T]:
+    '''Wrapper which allows a function which expects a single list-initializable, Container-like object to accept any Iterable (or even star-unpacked arguments)'''
+    if not issubclass(CastType, ListLike):
+        raise TypeError(f'Cannot wrap listlike input with non-listlike type "{CastType.__name__}"')
+
+    @wraps(funct)
     def wrapper(*args) -> T: # wrapper which accepts an arbitrary number of non-keyword argument
         if (len(args) == 1) and isinstance(args[0], Iterable):
             args = args[0]
 
         inputs = []
-        for value in args:
-            if isinstance(value, valid_types): # works because isinstance() accepts either a single type or a tuple of types
-                inputs.append(value)
+        for member in args:
+            if isinstance(member, valid_member_types): # works because isinstance() accepts either a single type or a tuple of types
+                inputs.append(member)
             else:
-                raise TypeError
-        return func(inputs) # TODO: modify input type signature of wrapper function
+                raise TypeError(f'Item {member!r} of type {type(member).__name__} is not an instance of any of the following valid wrapped types: {valid_member_types}')
+        inputs = CastType(inputs) # convert to the expected cast type (this is where the requirement of listlike cast types comes into play)
+
+        return funct(inputs) # TODO: modify input type signature of wrapper function
 
+    if funct is None:
+        return partial(flexible_listlike_input, CastType=CastType, valid_member_types=valid_member_types)
     return wrapper
 
 @extend_to_methods
 def allow_string_paths(funct : Callable[[Path, Args, KWArgs], T]) -> Callable[[Union[Path, str], Args, KWArgs], T]:
     '''Modifies a function which expects a Path as its first argument to also accept string-paths'''
     # TODO : add assertion that the wrapped function has at least one arg AND that the first arg is of the desired (limited) type
-    old_sig = inspect.signature(funct) # lookup old type signature
+    old_sig = signature(funct) # lookup old type signature
 
     @wraps(funct) # for preserving docstring and type annotations / signatures
     def str_path_wrapper(flex_path : Union[str, Path], *args : Args, **kwargs : KWArgs) -> T:
@@ -91,7 +99,7 @@ def str_path_wrapper(flex_path : Union[str, Path], *args : Args, **kwargs : KWAr
 def allow_pathlib_paths(funct : Callable[[str, Args, KWArgs], T]) -> Callable[[Union[Path, str], Args, KWArgs], T]:
     '''Modifies a function which expects a string path as its first argument to also accept canonical pathlib Paths'''
     # TODO : add assertion that the wrapped function has at least one arg AND that the first arg is of the desired (limited) type
-    old_sig = inspect.signature(funct) # lookup old type signature
+    old_sig = signature(funct) # lookup old type signature
 
     @wraps(funct) # for preserving docstring and type annotations / signatures
     def str_path_wrapper(flex_path : Union[str, Path], *args : Args, **kwargs : KWArgs) -> T: