Coverage for muutils / kappa.py: 100%

1"""anonymous getitem class 

2 

3util for constructing a class which has a getitem method which just calls a function 

4 

5a `lambda` is an anonymous function: kappa is the letter before lambda in the greek alphabet, 

6hence the name of this class""" 

7 

8from __future__ import annotations 

9 

10from typing import Callable, Final, Mapping, TypeVar 

11 

12_kappa_K = TypeVar("_kappa_K") 

13_kappa_V = TypeVar("_kappa_V") 

14 

15# get the docstring of this file 

16_BASE_DOC: Final[str] = ( 

17 # TYPING: type checkers complain here, they have no idea that this module does in fact have a __doc__ 

18 __doc__ 

19 or "anonymous getitem class" 

20 + """ 

21 

22source function docstring: 

23==============================\n 

24""" 

25) 

26 

27 

28class Kappa(Mapping[_kappa_K, _kappa_V]): 

29 def __init__(self, func_getitem: Callable[[_kappa_K], _kappa_V]) -> None: 

30 self.func_getitem = func_getitem 

31 self.doc = _BASE_DOC + str( 

32 getattr( 

33 func_getitem, "__doc__", "<no docstring provided for source function>" 

34 ) 

35 ) 

36 

37 def __getitem__(self, x: _kappa_K) -> _kappa_V: 

38 return self.func_getitem(x) 

39 

40 def __iter__(self) -> None: # type: ignore[override] 

41 raise NotImplementedError( 

42 "This method is not implemented for Kappa, we don't know the valid inputs" 

43 ) 

44 

45 def __len__(self) -> int: 

46 raise NotImplementedError( 

47 "This method is not implemented for Kappa, no idea how many valid inputs there are" 

48 )