Bash-like string expansion in Python.

expand.py

"""Bash-like string expansion in Python.

Author: Dan Søndergaard <[email protected]>
License: MIT
"""

import re
from itertools import product

GROUP_RE = re.compile(r'\{.+?\}')

def _parse_group(s, match):
    group_str = s[match.start() + 1:match.end() - 1]
    return group_str.split(',')

def iterexpand(s):
    fmt = re.sub(GROUP_RE, r'{}', s)
    groups = (_parse_group(s, match) for match in re.finditer(GROUP_RE, s))
    return (fmt.format(*reps) for reps in product(*groups))

def expand(s):
    return list(iterexpand(s))
    

print(expand('a.{c,d}'))
# => ['a.c', 'a.d']
print(expand('{a,b}.{c,d}'))
# => ['a.c', 'a.d', 'b.c', 'b.d']
print(expand('{a,b,c}/{d,e}.{f,g}'))
# => ['a/d.f', 'a/d.g', 'a/e.f', 'a/e.g', 'b/d.f', 'b/d.g', 'b/e.f', 'b/e.g', 'c/d.f', 'c/d.g', 'c/e.f', 'c/e.g']