1"""Alias generators for converting between different capitalization conventions."""
2
3import re
4
5__all__ = ('to_pascal', 'to_camel', 'to_snake')
6
7# TODO: in V3, change the argument names to be more descriptive
8# Generally, don't only convert from snake_case, or name the functions
9# more specifically like snake_to_camel.
10
11
12def to_pascal(snake: str) -> str:
13 """Convert a snake_case string to PascalCase.
14
15 Args:
16 snake: The string to convert.
17
18 Returns:
19 The PascalCase string.
20 """
21 camel = snake.title()
22 return re.sub('([0-9A-Za-z])_(?=[0-9A-Z])', lambda m: m.group(1), camel)
23
24
25def to_camel(snake: str) -> str:
26 """Convert a snake_case string to camelCase.
27
28 Args:
29 snake: The string to convert.
30
31 Returns:
32 The converted camelCase string.
33 """
34 # If the string is already in camelCase and does not contain a digit followed
35 # by a lowercase letter, return it as it is
36 if re.match('^[a-z]+[A-Za-z0-9]*$', snake) and not re.search(r'\d[a-z]', snake):
37 return snake
38
39 camel = to_pascal(snake)
40 return re.sub('(^_*[A-Z])', lambda m: m.group(1).lower(), camel)
41
42
43def to_snake(camel: str) -> str:
44 """Convert a PascalCase, camelCase, or kebab-case string to snake_case.
45
46 Args:
47 camel: The string to convert.
48
49 Returns:
50 The converted string in snake_case.
51 """
52 # Handle the sequence of uppercase letters followed by a lowercase letter
53 snake = re.sub(r'([A-Z]+)([A-Z][a-z])', lambda m: f'{m.group(1)}_{m.group(2)}', camel)
54 # Insert an underscore between a lowercase letter and an uppercase letter
55 snake = re.sub(r'([a-z])([A-Z])', lambda m: f'{m.group(1)}_{m.group(2)}', snake)
56 # Insert an underscore between a digit and an uppercase letter
57 snake = re.sub(r'([0-9])([A-Z])', lambda m: f'{m.group(1)}_{m.group(2)}', snake)
58 # Insert an underscore between a lowercase letter and a digit
59 snake = re.sub(r'([a-z])([0-9])', lambda m: f'{m.group(1)}_{m.group(2)}', snake)
60 # Replace hyphens with underscores to handle kebab-case
61 snake = snake.replace('-', '_')
62 return snake.lower()