Quacky2200 · October 29, 2024 20:00 · robins80 · Feb 13, 2024 · Quacky2200 · Feb 13, 2024
diff --git a/repermute.py b/repermute.py
 # -*- coding: utf-8 -*-
 #
 # Used like this:
 #
 # from repermute import ipermute
 #
 # for s in ipermute('[A-Z]\d'):
 #    print s
 #
 # Almost all regular expression constructs are supported except for '*'
 # (which in the Python sre_parse implementation matches 0 to 65535
 # times), '+' and '^'. Non-ASCII characters doesn't work, but I think
 # that is a limitation in the sre_parse module. It works by first
 # parsing the regexp to string sequences so that [A-Z] becomes ['A',
 # 'B', ... 'Z'], \d becomes ['1', ... , '9']. Then a Cartesian join is
 # applied on all string sequences to get all possible permutations of
 # them all.

 import itertools
 from sre_constants import *
 import sre_parse
 import string

 category_chars = {
    CATEGORY_DIGIT : string.digits,
    CATEGORY_SPACE : string.whitespace,
    CATEGORY_WORD  : string.digits + string.ascii_letters + '_'
    }

 def unique_extend(res_list, list):
    for item in list:
        if item not in res_list:
            res_list.append(item)

 def handle_any(val):
    """
    This is different from normal regexp matching. It only matches
    printable ASCII characters.
    """
    return string.printable

 def handle_branch(_tuple):
    (tok, val) = _tuple
    all_opts = []
    for toks in val:
        opts = permute_toks(toks)
        unique_extend(all_opts, opts)
    return all_opts

 def handle_category(val):
    return list(category_chars[val])

 def handle_in(val):
    out = []
    for tok, val in val:
        out += handle_tok(tok, val)
    return out

 def handle_literal(val):
    return [chr(val)]

 def handle_max_repeat(repeat):
    (min, max, val) = repeat
    """
    Handle a repeat token such as {x,y} or ?.
    """
    subtok, subval = val[0]

    if max > 5000:
        # max is the number of cartesian join operations needed to be
        # carried out. More than 5000 consumes way to much memory.
        raise ValueError("To many repetitions requested (%d)" % max)

    optlist = handle_tok(subtok, subval)

    results = []
    for rep in range(min, max + 1):
        results += [''.join(it) for it in join([optlist] * rep)]

    return results

 def handle_range(val):
    lo, hi = val
    return (chr(x) for x in range(lo, hi + 1))

 def handle_subpattern(val):
    return list(permute_toks(val[3]))

 def handle_tok(tok, val):
    """
    Returns a list of strings of possible permutations for this regexp
    token.
    """
    handlers = {
        ANY        : handle_any,
        BRANCH     : handle_branch,
        CATEGORY   : handle_category,
        LITERAL    : handle_literal,
        IN         : handle_in,
        MAX_REPEAT : handle_max_repeat,
        RANGE      : handle_range,
        SUBPATTERN : handle_subpattern}
    try:
        return handlers[tok](val)
    except KeyError as e:
        fmt = "Unsupported regular expression construct: %s"
        raise ValueError(fmt % tok)

 def permute_toks(toks):
    """
    Returns a generator of strings of possible permutations for this
    regexp token list.
    """
    lists = [handle_tok(tok, val) for tok, val in toks]
    return (''.join(it) for it in join(lists))

 def join(iterlist):
    """
    Cartesian join as an iterator of the supplied sequences. Borrowed
    from:
    http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/302478
    """
    def rloop(seqin, comb):
        if seqin:
            for item in seqin[0]:
                newcomb = comb + [item]
                for item in rloop(seqin[1:], newcomb):
                    yield item
        else:
            yield comb
    return rloop(iterlist, [])

 ########## PUBLIC API ####################

 def ipermute(p):
    toks = [tok_n_val for tok_n_val in sre_parse.parse(p)]
    return permute_toks(toks)

 def permute(p):
    return list(ipermute(p))
	# -- coding: utf-8 --
	#
	# Used like this:
	#
	# from repermute import ipermute
	#
	# for s in ipermute('[A-Z]\d'):
	# print s
	#
	# Almost all regular expression constructs are supported except for '*'
	# (which in the Python sre_parse implementation matches 0 to 65535
	# times), '+' and '^'. Non-ASCII characters doesn't work, but I think
	# that is a limitation in the sre_parse module. It works by first
	# parsing the regexp to string sequences so that [A-Z] becomes ['A',
	# 'B', ... 'Z'], \d becomes ['1', ... , '9']. Then a Cartesian join is
	# applied on all string sequences to get all possible permutations of
	# them all.

	import itertools
	from sre_constants import *
	import sre_parse
	import string

	category_chars = {
	CATEGORY_DIGIT : string.digits,
	CATEGORY_SPACE : string.whitespace,
	CATEGORY_WORD : string.digits + string.ascii_letters + '_'
	}

	def unique_extend(res_list, list):
	for item in list:
	if item not in res_list:
	res_list.append(item)

	def handle_any(val):
	"""
	This is different from normal regexp matching. It only matches
	printable ASCII characters.
	"""
	return string.printable

	def handle_branch(_tuple):
	(tok, val) = _tuple
	all_opts = []
	for toks in val:
	opts = permute_toks(toks)
	unique_extend(all_opts, opts)
	return all_opts

	def handle_category(val):
	return list(category_chars[val])

	def handle_in(val):
	out = []
	for tok, val in val:
	out += handle_tok(tok, val)
	return out

	def handle_literal(val):
	return [chr(val)]

	def handle_max_repeat(repeat):
	(min, max, val) = repeat
	"""
	Handle a repeat token such as {x,y} or ?.
	"""
	subtok, subval = val[0]

	if max > 5000:
	# max is the number of cartesian join operations needed to be
	# carried out. More than 5000 consumes way to much memory.
	raise ValueError("To many repetitions requested (%d)" % max)

	optlist = handle_tok(subtok, subval)

	results = []
	for rep in range(min, max + 1):
	results += [''.join(it) for it in join([optlist] * rep)]

	return results

	def handle_range(val):
	lo, hi = val
	return (chr(x) for x in range(lo, hi + 1))

	def handle_subpattern(val):
	return list(permute_toks(val[3]))

	def handle_tok(tok, val):
	"""
	Returns a list of strings of possible permutations for this regexp
	token.
	"""
	handlers = {
	ANY : handle_any,
	BRANCH : handle_branch,
	CATEGORY : handle_category,
	LITERAL : handle_literal,
	IN : handle_in,
	MAX_REPEAT : handle_max_repeat,
	RANGE : handle_range,
	SUBPATTERN : handle_subpattern}
	try:
	return handlers[tok](val)
	except KeyError as e:
	fmt = "Unsupported regular expression construct: %s"
	raise ValueError(fmt % tok)

	def permute_toks(toks):
	"""
	Returns a generator of strings of possible permutations for this
	regexp token list.
	"""
	lists = [handle_tok(tok, val) for tok, val in toks]
	return (''.join(it) for it in join(lists))

	def join(iterlist):
	"""
	Cartesian join as an iterator of the supplied sequences. Borrowed
	from:
	http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/302478
	"""
	def rloop(seqin, comb):
	if seqin:
	for item in seqin[0]:
	newcomb = comb + [item]
	for item in rloop(seqin[1:], newcomb):
	yield item
	else:
	yield comb
	return rloop(iterlist, [])

	########## PUBLIC API ####################

	def ipermute(p):
	toks = [tok_n_val for tok_n_val in sre_parse.parse(p)]
	return permute_toks(toks)

	def permute(p):
	return list(ipermute(p))