"""A collection of string constants. Public module variables: whitespace -- a string containing all characters considered whitespace lowercase -- a string containing all characters considered lowercase letters uppercase -- a string containing all characters considered uppercase letters letters -- a string containing all characters considered letters digits -- a string containing all characters considered decimal digits hexdigits -- a string containing all characters considered hexadecimal digits octdigits -- a string containing all characters considered octal digits punctuation -- a string containing all characters considered punctuation printable -- a string containing all characters considered printable """ # Some strings for ctype-style character classification whitespace = ' \t\n\r\v\f' ascii_lowercase = 'abcdefghijklmnopqrstuvwxyz' ascii_uppercase = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' ascii_letters = ascii_lowercase + ascii_uppercase digits = '0123456789' hexdigits = digits + 'abcdef' + 'ABCDEF' octdigits = '01234567' punctuation = """!"#$%&'()*+,-./:;<=>?@[\]^_`{|}~""" printable = digits + ascii_letters + punctuation + whitespace # Case conversion helpers # Use str to convert Unicode literal in case of -U _idmap = str('').join(chr(c) for c in range(256)) # Functions which aren't available as string methods. # Capitalize the words in a string, e.g. " aBc dEf " -> "Abc Def". def capwords(s, sep=None): """capwords(s, [sep]) -> string Split the argument into words using split, capitalize each word using capitalize, and join the capitalized words using join. Note that this replaces runs of whitespace characters by a single space. """ return (sep or ' ').join([x.capitalize() for x in s.split(sep)]) # Construct a translation string _idmapL = None def maketrans(fromstr, tostr): """maketrans(frm, to) -> string Return a translation table (a string of 256 bytes long) suitable for use in string.translate. The strings frm and to must be of the same length. """ if len(fromstr) != len(tostr): raise ValueError, "maketrans arguments must have same length" global _idmapL if not _idmapL: _idmapL = list(_idmap) L = _idmapL[:] for i, c in enumerate(fromstr): L[ord(c)] = tostr[i] return ''.join(L) #################################################################### import re as _re class _multimap: """Helper class for combining multiple mappings. Used by .{safe_,}substitute() to combine the mapping and keyword arguments. """ def __init__(self, primary, secondary): self._primary = primary self._secondary = secondary def __getitem__(self, key): try: return self._primary[key] except KeyError: return self._secondary[key] class _TemplateMetaclass(type): pattern = r""" %(delim)s(?: (?P%(delim)s) | # Escape sequence of two delimiters (?P%(id)s) | # delimiter and a Python identifier {(?P%(id)s)} | # delimiter and a braced identifier (?P) # Other ill-formed delimiter exprs ) """ def __init__(cls, name, bases, dct): super(_TemplateMetaclass, cls).__init__(name, bases, dct) if 'pattern' in dct: pattern = cls.pattern else: pattern = _TemplateMetaclass.pattern % { 'delim' : _re.escape(cls.delimiter), 'id' : cls.idpattern, } cls.pattern = _re.compile(pattern, _re.IGNORECASE | _re.VERBOSE) class Template(metaclass=_TemplateMetaclass): """A string class for supporting $-substitutions.""" delimiter = '$' idpattern = r'[_a-z][_a-z0-9]*' def __init__(self, template): self.template = template # Search for $$, $identifier, ${identifier}, and any bare $'s def _invalid(self, mo): i = mo.start('invalid') lines = self.template[:i].splitlines(True) if not lines: colno = 1 lineno = 1 else: colno = i - len(''.join(lines[:-1])) lineno = len(lines) raise ValueError('Invalid placeholder in string: line %d, col %d' % (lineno, colno)) def substitute(self, *args, **kws): if len(args) > 1: raise TypeError('Too many positional arguments') if not args: mapping = kws elif kws: mapping = _multimap(kws, args[0]) else: mapping = args[0] # Helper function for .sub() def convert(mo): # Check the most common path first. named = mo.group('named') or mo.group('braced') if named is not None: val = mapping[named] # We use this idiom instead of str() because the latter will # fail if val is a Unicode containing non-ASCII characters. return '%s' % (val,) if mo.group('escaped') is not None: return self.delimiter if mo.group('invalid') is not None: self._invalid(mo) raise ValueError('Unrecognized named group in pattern', self.pattern) return self.pattern.sub(convert, self.template) def safe_substitute(self, *args, **kws): if len(args) > 1: raise TypeError('Too many positional arguments') if not args: mapping = kws elif kws: mapping = _multimap(kws, args[0]) else: mapping = args[0] # Helper function for .sub() def convert(mo): named = mo.group('named') if named is not None: try: # We use this idiom instead of str() because the latter # will fail if val is a Unicode containing non-ASCII return '%s' % (mapping[named],) except KeyError: return self.delimiter + named braced = mo.group('braced') if braced is not None: try: return '%s' % (mapping[braced],) except KeyError: return self.delimiter + '{' + braced + '}' if mo.group('escaped') is not None: return self.delimiter if mo.group('invalid') is not None: return self.delimiter raise ValueError('Unrecognized named group in pattern', self.pattern) return self.pattern.sub(convert, self.template) ######################################################################## # the Formatter class # see PEP 3101 for details and purpose of this class # The hard parts are reused from the C implementation. They're # exposed here via the sys module. sys was chosen because it's always # available and doesn't have to be dynamically loaded. # The overall parser is implemented in str._formatter_parser. # The field name parser is implemented in str._formatter_field_name_split class Formatter: def format(self, format_string, *args, **kwargs): return self.vformat(format_string, args, kwargs) def vformat(self, format_string, args, kwargs): used_args = self.get_empty_used_args() result = [] for literal_text, field_name, format_spec, conversion in \ self.parse(format_string): if literal_text is None: # this is some markup, find the object and do # the formatting # given the field_name, find the object it references obj = self.get_field(field_name, args, kwargs, used_args) # do any conversion on the resulting object obj = self.convert_field(obj, conversion) # format the object and append to the result result.append(self.format_field(obj, format_spec)) else: # this is literal text, use it directly result.append(literal_text) self.check_unused_args(used_args, args, kwargs) return ''.join(result) def get_empty_used_args(self): return set() def get_value(self, key, args, kwargs): if isinstance(key, int): return args[key] else: return kwargs[key] def check_unused_args(self, used_args, args, kwargs): pass def format_field(self, value, format_spec): return format(value, format_spec) def convert_field(self, value, conversion): # do any conversion on the resulting object if conversion == 'r': return repr(value) elif conversion == 's': return str(value) else: assert conversion is None return value # returns an iterable that contains tuples of the form: # (literal_text, field_name, format_spec, conversion) def parse(self, format_string): return format_string._formatter_parser() # given a field_name, find the object it references. # field_name: the field being looked up, e.g. "0.name" # or "lookup[3]" # used_args: a set of which args have been used # args, kwargs: as passed in to vformat # also, mark it as used in 'used_args' def get_field(self, field_name, args, kwargs, used_args): first, rest = field_name._formatter_field_name_split() used_args.add(first) obj = self.get_value(first, args, kwargs) # loop through the rest of the field_name, doing # getattr or getitem as needed for is_attr, i in rest: if is_attr: obj = getattr(obj, i) else: obj = obj[i] return obj