Source code for target_extraction.data_types_util

'''
Module that contains helpful classes and methods for 
`target_extraction.data_types`

classes:

1. Span
2. OverLappingTargetsError
3. AnonymisedError
4. OverwriteError
'''
from typing import NamedTuple

class Span(NamedTuple):
    '''
    Span is a named tuple. It has two fields:

    1. start -- An integer that specifies the start of a target word within a 
       text.
    2. end -- An integer that specifies the end of a target word within a text.
    '''
    start: int = 0
    end: int = 0

class OverLappingTargetsError(Exception):
    '''
    If two targets within the same sentence overlap with each other when they 
    shouldn't.
    '''
    pass

class AnonymisedError(Exception):
   '''
   If the something cannot be performed because the 
   :py:class:`target_extraction.data_types.TargetText` 
   or :py:class:`target_extraction.data_types.TargetTextCollection` 
   object has been anonymised.
   '''
   def __init__(self, error_string: str) -> None:
        '''
        :param error_string: The error string to attach to this exception.
        '''
        super().__init__(error_string)

class OverwriteError(Exception):
   '''
   If some key exists in a dictionary like object and the intended action 
   is to write data to that key when it should not then this error is raised 
   to indicate this action was going to be performed.
   '''
   def __init__(self, error_string: str) -> None:
        '''
        :param error_string: The error string to attach to this exception.
        '''
        super().__init__(error_string)