"""Expand bash-style brace patterns in glob expressions."""
import re
from typing import List
def expand_braces(pattern: str) -> List[str]:
"""
Expand brace expressions in a glob pattern.
Converts patterns like "**/*.{py,js,ts}" into multiple patterns:
["**/*.py", "**/*.js", "**/*.ts"]
Args:
pattern: Glob pattern potentially containing brace expressions
Returns:
List of expanded patterns (single item if no braces)
Examples:
expand_braces("**/*.{py,js}") → ["**/*.py", "**/*.js"]
expand_braces("src/**/*.{ts,tsx}") → ["src/**/*.ts", "src/**/*.tsx"]
expand_braces("**/*.py") → ["**/*.py"]
"""
# Find brace expressions: {option1,option2,option3}
brace_pattern = r'\{([^}]+)\}'
match = re.search(brace_pattern, pattern)
if not match:
# No braces, return as-is
return [pattern]
# Extract the options inside braces
options_str = match.group(1)
options = [opt.strip() for opt in options_str.split(',')]
# Get the parts before and after the braces
before = pattern[:match.start()]
after = pattern[match.end():]
# Generate patterns for each option
expanded = []
for option in options:
new_pattern = f"{before}{option}{after}"
# Recursively expand in case there are more braces
expanded.extend(expand_braces(new_pattern))
return expanded
