"""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 # 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 map for bytes.translate def maketrans(frm, to): """maketrans(frm, to) -> bytes Return a translation table (a bytes object of length 256) suitable for use in bytes.translate where each byte in frm is mapped to the byte at the same position in to. The strings frm and to must be of the same length. """ if len(frm) != len(to): raise ValueError("maketrans arguments must have same length") if not (isinstance(frm, bytes) and isinstance(to, bytes)): raise TypeError("maketrans arguments must be bytes objects") L = bytes(range(256)) for i, c in enumerate(frm): L[c] = to[i] return 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 = set() result = [] for literal_text, field_name, format_spec, conversion in \ self.parse(format_string): # output the literal text if literal_text: result.append(literal_text) # if there's a field, output it if field_name is not None: # this is some markup, find the object and do # the formatting # given the field_name, find the object it references # and the argument it came from obj, arg_used = self.get_field(field_name, args, kwargs) used_args.add(arg_used) # 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)) self.check_unused_args(used_args, args, kwargs) return ''.join(result) 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) # literal_text can be zero length # field_name can be None, in which case there's no # object to format and output # if field_name is not None, it is looked up, formatted # with format_spec and conversion and then used 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 def get_field(self, field_name, args, kwargs): first, rest = field_name._formatter_field_name_split() 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, first