def Alt(*args):
"""exp1, exp2, ... -> match exp1 or (if that fails) match exp2 or ..."""
# Do some type checking
for arg in args:
assert isinstance(arg, Expression.Expression), \
"expecting an Expression, not a %s" % type(arg)
return Expression.Alt(args)
# Convert an 'assert_not' tuple into a Assert object, as a negative assertion
def convert_assert_not(group_names, name, (direction, terms)):
assert direction == 1, "does not support lookbehind"
return Expression.Assert(convert_list(group_names, terms), 1)
# Convert a 'branch' tuple into an Alt object
def convert_branch(group_names, name, (ignore, branches)):
assert ignore is None, "what is %s?" % repr(ignore)
results = []
for branch in branches:
results.append(convert_list(group_names, branch))
if len(results) == 1:
return results[0]
return Expression.Alt(tuple(results))
# I know, it's only good for ASCII...
def invert(s):
"""s -> a string containing all the characters not present in s"""
letters = []
if not (isinstance(s, type(""))):
s = str(s)
for c in map(chr, range(256)):
if c not in s:
letters.append(c)
return string.join(letters, "")
# Map from the msre_parse category names into actual characters.
def Str(*args):
"""(s1, s2, ...) -> match s1 or s2 or ..."""
if len(args) == 1:
return Str1(args[0])
return Expression.Alt(tuple(map(Str, args)))
