mirror of
https://github.com/python/cpython.git
synced 2024-11-27 15:27:06 +01:00
dce642f244
Add `string.Template.get_identifiers()` method that returns the identifiers within the template. By default, raises an error if it encounters an invalid identifier (like `substitute()`). The keyword-only argument `raise_on_invalid` can be set to `False` to ignore invalid identifiers (like `safe_substitute()`). Automerge-Triggered-By: GH:warsaw
310 lines
12 KiB
Python
310 lines
12 KiB
Python
"""A collection of string constants.
|
|
|
|
Public module variables:
|
|
|
|
whitespace -- a string containing all ASCII whitespace
|
|
ascii_lowercase -- a string containing all ASCII lowercase letters
|
|
ascii_uppercase -- a string containing all ASCII uppercase letters
|
|
ascii_letters -- a string containing all ASCII letters
|
|
digits -- a string containing all ASCII decimal digits
|
|
hexdigits -- a string containing all ASCII hexadecimal digits
|
|
octdigits -- a string containing all ASCII octal digits
|
|
punctuation -- a string containing all ASCII punctuation characters
|
|
printable -- a string containing all ASCII characters considered printable
|
|
|
|
"""
|
|
|
|
__all__ = ["ascii_letters", "ascii_lowercase", "ascii_uppercase", "capwords",
|
|
"digits", "hexdigits", "octdigits", "printable", "punctuation",
|
|
"whitespace", "Formatter", "Template"]
|
|
|
|
import _string
|
|
|
|
# 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 = r"""!"#$%&'()*+,-./:;<=>?@[\]^_`{|}~"""
|
|
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. If the optional second argument sep is absent or None,
|
|
runs of whitespace characters are replaced by a single space
|
|
and leading and trailing whitespace are removed, otherwise
|
|
sep is used to split and join the words.
|
|
|
|
"""
|
|
return (sep or ' ').join(map(str.capitalize, s.split(sep)))
|
|
|
|
|
|
####################################################################
|
|
import re as _re
|
|
from collections import ChainMap as _ChainMap
|
|
|
|
_sentinel_dict = {}
|
|
|
|
class Template:
|
|
"""A string class for supporting $-substitutions."""
|
|
|
|
delimiter = '$'
|
|
# r'[a-z]' matches to non-ASCII letters when used with IGNORECASE, but
|
|
# without the ASCII flag. We can't add re.ASCII to flags because of
|
|
# backward compatibility. So we use the ?a local flag and [a-z] pattern.
|
|
# See https://bugs.python.org/issue31672
|
|
idpattern = r'(?a:[_a-z][_a-z0-9]*)'
|
|
braceidpattern = None
|
|
flags = _re.IGNORECASE
|
|
|
|
def __init_subclass__(cls):
|
|
super().__init_subclass__()
|
|
if 'pattern' in cls.__dict__:
|
|
pattern = cls.pattern
|
|
else:
|
|
delim = _re.escape(cls.delimiter)
|
|
id = cls.idpattern
|
|
bid = cls.braceidpattern or cls.idpattern
|
|
pattern = fr"""
|
|
{delim}(?:
|
|
(?P<escaped>{delim}) | # Escape sequence of two delimiters
|
|
(?P<named>{id}) | # delimiter and a Python identifier
|
|
{{(?P<braced>{bid})}} | # delimiter and a braced identifier
|
|
(?P<invalid>) # Other ill-formed delimiter exprs
|
|
)
|
|
"""
|
|
cls.pattern = _re.compile(pattern, cls.flags | _re.VERBOSE)
|
|
|
|
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(keepends=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, mapping=_sentinel_dict, /, **kws):
|
|
if mapping is _sentinel_dict:
|
|
mapping = kws
|
|
elif kws:
|
|
mapping = _ChainMap(kws, mapping)
|
|
# 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:
|
|
return str(mapping[named])
|
|
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, mapping=_sentinel_dict, /, **kws):
|
|
if mapping is _sentinel_dict:
|
|
mapping = kws
|
|
elif kws:
|
|
mapping = _ChainMap(kws, mapping)
|
|
# Helper function for .sub()
|
|
def convert(mo):
|
|
named = mo.group('named') or mo.group('braced')
|
|
if named is not None:
|
|
try:
|
|
return str(mapping[named])
|
|
except KeyError:
|
|
return mo.group()
|
|
if mo.group('escaped') is not None:
|
|
return self.delimiter
|
|
if mo.group('invalid') is not None:
|
|
return mo.group()
|
|
raise ValueError('Unrecognized named group in pattern',
|
|
self.pattern)
|
|
return self.pattern.sub(convert, self.template)
|
|
|
|
def is_valid(self):
|
|
for mo in self.pattern.finditer(self.template):
|
|
if mo.group('invalid') is not None:
|
|
return False
|
|
if (mo.group('named') is None
|
|
and mo.group('braced') is None
|
|
and mo.group('escaped') is None):
|
|
# If all the groups are None, there must be
|
|
# another group we're not expecting
|
|
raise ValueError('Unrecognized named group in pattern',
|
|
self.pattern)
|
|
return True
|
|
|
|
def get_identifiers(self):
|
|
ids = []
|
|
for mo in self.pattern.finditer(self.template):
|
|
named = mo.group('named') or mo.group('braced')
|
|
if named is not None and named not in ids:
|
|
# add a named group only the first time it appears
|
|
ids.append(named)
|
|
elif (named is None
|
|
and mo.group('invalid') is None
|
|
and mo.group('escaped') is None):
|
|
# If all the groups are None, there must be
|
|
# another group we're not expecting
|
|
raise ValueError('Unrecognized named group in pattern',
|
|
self.pattern)
|
|
return ids
|
|
|
|
# Initialize Template.pattern. __init_subclass__() is automatically called
|
|
# only for subclasses, not for the Template class itself.
|
|
Template.__init_subclass__()
|
|
|
|
|
|
########################################################################
|
|
# 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 as "_"
|
|
# prefixed methods of str.
|
|
|
|
# The overall parser is implemented in _string.formatter_parser.
|
|
# The field name parser is implemented in _string.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, _ = self._vformat(format_string, args, kwargs, used_args, 2)
|
|
self.check_unused_args(used_args, args, kwargs)
|
|
return result
|
|
|
|
def _vformat(self, format_string, args, kwargs, used_args, recursion_depth,
|
|
auto_arg_index=0):
|
|
if recursion_depth < 0:
|
|
raise ValueError('Max string recursion exceeded')
|
|
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
|
|
|
|
# handle arg indexing when empty field_names are given.
|
|
if field_name == '':
|
|
if auto_arg_index is False:
|
|
raise ValueError('cannot switch from manual field '
|
|
'specification to automatic field '
|
|
'numbering')
|
|
field_name = str(auto_arg_index)
|
|
auto_arg_index += 1
|
|
elif field_name.isdigit():
|
|
if auto_arg_index:
|
|
raise ValueError('cannot switch from manual field '
|
|
'specification to automatic field '
|
|
'numbering')
|
|
# disable auto arg incrementing, if it gets
|
|
# used later on, then an exception will be raised
|
|
auto_arg_index = False
|
|
|
|
# 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)
|
|
|
|
# expand the format spec, if needed
|
|
format_spec, auto_arg_index = self._vformat(
|
|
format_spec, args, kwargs,
|
|
used_args, recursion_depth-1,
|
|
auto_arg_index=auto_arg_index)
|
|
|
|
# format the object and append to the result
|
|
result.append(self.format_field(obj, format_spec))
|
|
|
|
return ''.join(result), auto_arg_index
|
|
|
|
|
|
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 is None:
|
|
return value
|
|
elif conversion == 's':
|
|
return str(value)
|
|
elif conversion == 'r':
|
|
return repr(value)
|
|
elif conversion == 'a':
|
|
return ascii(value)
|
|
raise ValueError("Unknown conversion specifier {0!s}".format(conversion))
|
|
|
|
|
|
# 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 _string.formatter_parser(format_string)
|
|
|
|
|
|
# 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 = _string.formatter_field_name_split(field_name)
|
|
|
|
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
|