209 lines
7.0 KiB
Python
209 lines
7.0 KiB
Python
"""A collection of string constants.
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Public module variables:
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whitespace -- a string containing all characters considered whitespace
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lowercase -- a string containing all characters considered lowercase letters
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uppercase -- a string containing all characters considered uppercase letters
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letters -- a string containing all characters considered letters
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digits -- a string containing all characters considered decimal digits
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hexdigits -- a string containing all characters considered hexadecimal digits
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octdigits -- a string containing all characters considered octal digits
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punctuation -- a string containing all characters considered punctuation
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printable -- a string containing all characters considered printable
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"""
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# Some strings for ctype-style character classification
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whitespace = ' \t\n\r\v\f'
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lowercase = 'abcdefghijklmnopqrstuvwxyz'
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uppercase = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
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letters = lowercase + uppercase
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ascii_lowercase = lowercase
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ascii_uppercase = uppercase
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ascii_letters = ascii_lowercase + ascii_uppercase
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digits = '0123456789'
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hexdigits = digits + 'abcdef' + 'ABCDEF'
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octdigits = '01234567'
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punctuation = """!"#$%&'()*+,-./:;<=>?@[\]^_`{|}~"""
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printable = digits + letters + punctuation + whitespace
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# Case conversion helpers
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# Use str to convert Unicode literal in case of -U
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l = map(chr, xrange(256))
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_idmap = str('').join(l)
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del l
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# Functions which aren't available as string methods.
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# Capitalize the words in a string, e.g. " aBc dEf " -> "Abc Def".
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def capwords(s, sep=None):
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"""capwords(s, [sep]) -> string
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Split the argument into words using split, capitalize each
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word using capitalize, and join the capitalized words using
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join. Note that this replaces runs of whitespace characters by
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a single space.
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"""
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return (sep or ' ').join([x.capitalize() for x in s.split(sep)])
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# Construct a translation string
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_idmapL = None
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def maketrans(fromstr, tostr):
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"""maketrans(frm, to) -> string
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Return a translation table (a string of 256 bytes long)
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suitable for use in string.translate. The strings frm and to
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must be of the same length.
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"""
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if len(fromstr) != len(tostr):
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raise ValueError, "maketrans arguments must have same length"
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global _idmapL
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if not _idmapL:
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_idmapL = map(None, _idmap)
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L = _idmapL[:]
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fromstr = map(ord, fromstr)
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for i in range(len(fromstr)):
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L[fromstr[i]] = tostr[i]
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return ''.join(L)
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####################################################################
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import re as _re
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class _multimap:
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"""Helper class for combining multiple mappings.
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Used by .{safe_,}substitute() to combine the mapping and keyword
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arguments.
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"""
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def __init__(self, primary, secondary):
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self._primary = primary
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self._secondary = secondary
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def __getitem__(self, key):
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try:
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return self._primary[key]
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except KeyError:
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return self._secondary[key]
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class _TemplateMetaclass(type):
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pattern = r"""
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%(delim)s(?:
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(?P<escaped>%(delim)s) | # Escape sequence of two delimiters
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(?P<named>%(id)s) | # delimiter and a Python identifier
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{(?P<braced>%(id)s)} | # delimiter and a braced identifier
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(?P<invalid>) # Other ill-formed delimiter exprs
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)
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"""
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def __init__(cls, name, bases, dct):
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super(_TemplateMetaclass, cls).__init__(name, bases, dct)
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if 'pattern' in dct:
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pattern = cls.pattern
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else:
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pattern = _TemplateMetaclass.pattern % {
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'delim' : _re.escape(cls.delimiter),
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'id' : cls.idpattern,
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}
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cls.pattern = _re.compile(pattern, _re.IGNORECASE | _re.VERBOSE)
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class Template(metaclass=_TemplateMetaclass):
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"""A string class for supporting $-substitutions."""
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delimiter = '$'
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idpattern = r'[_a-z][_a-z0-9]*'
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def __init__(self, template):
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self.template = template
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# Search for $$, $identifier, ${identifier}, and any bare $'s
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def _invalid(self, mo):
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i = mo.start('invalid')
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lines = self.template[:i].splitlines(True)
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if not lines:
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colno = 1
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lineno = 1
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else:
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colno = i - len(''.join(lines[:-1]))
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lineno = len(lines)
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raise ValueError('Invalid placeholder in string: line %d, col %d' %
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(lineno, colno))
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def substitute(self, *args, **kws):
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if len(args) > 1:
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raise TypeError('Too many positional arguments')
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if not args:
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mapping = kws
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elif kws:
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mapping = _multimap(kws, args[0])
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else:
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mapping = args[0]
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# Helper function for .sub()
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def convert(mo):
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# Check the most common path first.
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named = mo.group('named') or mo.group('braced')
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if named is not None:
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val = mapping[named]
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# We use this idiom instead of str() because the latter will
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# fail if val is a Unicode containing non-ASCII characters.
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return '%s' % (val,)
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if mo.group('escaped') is not None:
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return self.delimiter
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if mo.group('invalid') is not None:
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self._invalid(mo)
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raise ValueError('Unrecognized named group in pattern',
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self.pattern)
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return self.pattern.sub(convert, self.template)
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def safe_substitute(self, *args, **kws):
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if len(args) > 1:
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raise TypeError('Too many positional arguments')
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if not args:
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mapping = kws
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elif kws:
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mapping = _multimap(kws, args[0])
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else:
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mapping = args[0]
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# Helper function for .sub()
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def convert(mo):
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named = mo.group('named')
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if named is not None:
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try:
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# We use this idiom instead of str() because the latter
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# will fail if val is a Unicode containing non-ASCII
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return '%s' % (mapping[named],)
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except KeyError:
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return self.delimiter + named
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braced = mo.group('braced')
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if braced is not None:
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try:
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return '%s' % (mapping[braced],)
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except KeyError:
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return self.delimiter + '{' + braced + '}'
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if mo.group('escaped') is not None:
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return self.delimiter
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if mo.group('invalid') is not None:
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return self.delimiter
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raise ValueError('Unrecognized named group in pattern',
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self.pattern)
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return self.pattern.sub(convert, self.template)
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# Try importing optional built-in module "strop" -- if it exists,
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# it redefines some string operations that are 100-1000 times faster.
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# It also defines values for whitespace, lowercase and uppercase
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# that match <ctype.h>'s definitions.
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try:
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from strop import maketrans
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except ImportError:
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pass # Use the original versions
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