| | """Bash-style brace expansion""" |
| | import re |
| | import string |
| | import sys |
| | from itertools import chain, product |
| |
|
| | __version__ = '0.1.7' |
| |
|
| | __all__ = ['braceexpand', 'alphabet', 'UnbalancedBracesError'] |
| |
|
| | class UnbalancedBracesError(ValueError): pass |
| |
|
| | PY3 = sys.version_info[0] >= 3 |
| |
|
| | if PY3: |
| | xrange = range |
| |
|
| | alphabet = string.ascii_uppercase + string.ascii_lowercase |
| |
|
| | int_range_re = re.compile(r'^(-?\d+)\.\.(-?\d+)(?:\.\.-?(\d+))?$') |
| | char_range_re = re.compile(r'^([A-Za-z])\.\.([A-Za-z])(?:\.\.-?(\d+))?$') |
| |
|
| |
|
| | def braceexpand(pattern, escape=True): |
| | """braceexpand(pattern) -> iterator over generated strings |
| | |
| | Returns an iterator over the strings resulting from brace expansion |
| | of pattern. This function implements Brace Expansion as described in |
| | bash(1), with the following limitations: |
| | |
| | * A pattern containing unbalanced braces will raise an |
| | UnbalancedBracesError exception. In bash, unbalanced braces will either |
| | be partly expanded or ignored. |
| | |
| | * A mixed-case character range like '{Z..a}' or '{a..Z}' will not |
| | include the characters '[]^_`' between 'Z' and 'a'. |
| | |
| | When escape is True (the default), characters in pattern can be |
| | prefixed with a backslash to cause them not to be interpreted as |
| | special characters for brace expansion (such as '{', '}', ','). |
| | To pass through a a literal backslash, double it ('\\\\'). |
| | |
| | When escape is False, backslashes in pattern have no special |
| | meaning and will be preserved in the output. |
| | |
| | Examples: |
| | |
| | >>> from braceexpand import braceexpand |
| | |
| | # Integer range |
| | >>> list(braceexpand('item{1..3}')) |
| | ['item1', 'item2', 'item3'] |
| | |
| | # Character range |
| | >>> list(braceexpand('{a..c}')) |
| | ['a', 'b', 'c'] |
| | |
| | # Sequence |
| | >>> list(braceexpand('index.html{,.backup}')) |
| | ['index.html', 'index.html.backup'] |
| | |
| | # Nested patterns |
| | >>> list(braceexpand('python{2.{5..7},3.{2,3}}')) |
| | ['python2.5', 'python2.6', 'python2.7', 'python3.2', 'python3.3'] |
| | |
| | # Prefixing an integer with zero causes all numbers to be padded to |
| | # the same width. |
| | >>> list(braceexpand('{07..10}')) |
| | ['07', '08', '09', '10'] |
| | |
| | # An optional increment can be specified for ranges. |
| | >>> list(braceexpand('{a..g..2}')) |
| | ['a', 'c', 'e', 'g'] |
| | |
| | # Ranges can go in both directions. |
| | >>> list(braceexpand('{4..1}')) |
| | ['4', '3', '2', '1'] |
| | |
| | # Numbers can be negative |
| | >>> list(braceexpand('{2..-1}')) |
| | ['2', '1', '0', '-1'] |
| | |
| | # Unbalanced braces raise an exception. |
| | >>> list(braceexpand('{1{2,3}')) |
| | Traceback (most recent call last): |
| | ... |
| | UnbalancedBracesError: Unbalanced braces: '{1{2,3}' |
| | |
| | # By default, the backslash is the escape character. |
| | >>> list(braceexpand(r'{1\\{2,3}')) |
| | ['1{2', '3'] |
| | |
| | # Setting 'escape' to False disables backslash escaping. |
| | >>> list(braceexpand(r'\\{1,2}', escape=False)) |
| | ['\\\\1', '\\\\2'] |
| | |
| | """ |
| | return (_flatten(t, escape) for t in parse_pattern(pattern, escape)) |
| |
|
| |
|
| | def parse_pattern(pattern, escape): |
| | |
| | start = 0 |
| | pos = 0 |
| | bracketdepth = 0 |
| | items = [] |
| |
|
| | |
| | while pos < len(pattern): |
| | if escape and pattern[pos] == '\\': |
| | pos += 2 |
| | continue |
| | elif pattern[pos] == '{': |
| | if bracketdepth == 0 and pos > start: |
| | |
| | items.append([pattern[start:pos]]) |
| | start = pos |
| | bracketdepth += 1 |
| | elif pattern[pos] == '}': |
| | bracketdepth -= 1 |
| | if bracketdepth == 0: |
| | |
| | expr = pattern[start+1:pos] |
| | item = parse_expression(expr, escape) |
| | if item is None: |
| | items.extend([['{'], parse_pattern(expr, escape), ['}']]) |
| | else: |
| | items.append(item) |
| | start = pos + 1 |
| | pos += 1 |
| |
|
| | if bracketdepth != 0: |
| | raise UnbalancedBracesError("Unbalanced braces: '%s'" % pattern) |
| |
|
| | if start < pos: |
| | |
| | items.append([pattern[start:]]) |
| |
|
| | return product(*items) |
| |
|
| |
|
| | def parse_expression(expr, escape): |
| | int_range_match = int_range_re.match(expr) |
| | if int_range_match: |
| | return make_int_range(*int_range_match.groups()) |
| |
|
| | char_range_match = char_range_re.match(expr) |
| | if char_range_match: |
| | return make_char_range(*char_range_match.groups()) |
| |
|
| | return parse_sequence(expr, escape) |
| |
|
| |
|
| | def parse_sequence(seq, escape): |
| | |
| | start = 0 |
| | pos = 0 |
| | bracketdepth = 0 |
| | items = [] |
| |
|
| | |
| | while pos < len(seq): |
| | if escape and seq[pos] == '\\': |
| | pos += 2 |
| | continue |
| | elif seq[pos] == '{': |
| | bracketdepth += 1 |
| | elif seq[pos] == '}': |
| | bracketdepth -= 1 |
| | elif seq[pos] == ',' and bracketdepth == 0: |
| | items.append(parse_pattern(seq[start:pos], escape)) |
| | start = pos + 1 |
| | pos += 1 |
| |
|
| | if bracketdepth != 0 or not items: |
| | return None |
| |
|
| | |
| | items.append(parse_pattern(seq[start:], escape)) |
| | return chain(*items) |
| |
|
| |
|
| | def make_int_range(start, end, step=None): |
| | if any([s.startswith(('0', '-0')) |
| | for s in (start, end) if s not in ('0', '-0')]): |
| | padding = max(len(start), len(end)) |
| | else: |
| | padding = 0 |
| | step = (int(step) or 1) if step else 1 |
| | start = int(start) |
| | end = int(end) |
| | r = xrange(start, end+1, step) if start < end else \ |
| | xrange(start, end-1, -step) |
| | fmt = '%0{}d'.format(padding) |
| | return (fmt % i for i in r) |
| |
|
| |
|
| | def make_char_range(start, end, step=None): |
| | step = (int(step) or 1) if step else 1 |
| | start = alphabet.index(start) |
| | end = alphabet.index(end) |
| | if start < end: |
| | return alphabet[start:end+1:step] |
| | else: |
| | end = end or -len(alphabet) |
| | return alphabet[start:end-1:-step] |
| |
|
| |
|
| | escape_re = re.compile(r'\\(.)') |
| |
|
| | def _flatten(t, escape): |
| | l = [] |
| | for item in t: |
| | if isinstance(item, tuple): l.extend(_flatten(item, escape)) |
| | else: l.append(item) |
| | s = ''.join(l) |
| | |
| | return escape_re.sub(r'\1', s) if escape else s |
| |
|
| |
|
| | if __name__ == '__main__': |
| | import doctest |
| | import sys |
| | failed, _ = doctest.testmod(optionflags=doctest.IGNORE_EXCEPTION_DETAIL) |
| | if failed: |
| | sys.exit(1) |
| |
|